[RESEND PATCH v2 00/13] backlight: qcom-wled: fix and solidify handling of enabled-strings
This patchset fixes WLED's handling of enabled-strings: besides some cleanup it is now actually possible to specify a non-contiguous array of enabled strings (not necessarily starting at zero) and the values from DT are now validated to prevent possible unexpected out-of-bounds register and array element accesses. Off-by-one mistakes in the maximum number of strings, also causing out-of-bounds access, have been addressed as well.
Changes in v2: - Reordered patch 4/10 (Validate enabled string indices in DT) to sit before patch 1/10 (Pass number of elements to read to read_u32_array); - Pulled qcom,num-strings out of the DT enumeration parser, and moved it after qcom,enabled-strings parser to always have final sign-off over the number of strings; - Extra validation for this number of strings against qcom,enabled-strings; - Recombined patch 9 (Consistently use enabled-strings in set_brightness) and patch 10 (Consider enabled_strings in autodetection), which both solve the same problem in two different functions. In addition the autodetection code uses set_brightness as helper already; - Improved DT configurations for pmi8994 and pm660l, currently in 5.15 rc's.
v1: https://lore.kernel.org/dri-devel/20211004192741.621870-1-marijn.suijten@som...
Marijn Suijten (13): backlight: qcom-wled: Validate enabled string indices in DT backlight: qcom-wled: Pass number of elements to read to read_u32_array backlight: qcom-wled: Use cpu_to_le16 macro to perform conversion backlight: qcom-wled: Fix off-by-one maximum with default num_strings backlight: qcom-wled: Override default length with qcom,enabled-strings backlight: qcom-wled: Remove unnecessary 4th default string in WLED3 backlight: qcom-wled: Provide enabled_strings default for WLED 4 and 5 backlight: qcom-wled: Remove unnecessary double whitespace backlight: qcom-wled: Respect enabled-strings in set_brightness arm64: dts: qcom: pmi8994: Fix "eternal"->"external" typo in WLED node arm64: dts: qcom: pmi8994: Remove hardcoded linear WLED enabled-strings arm64: dts: qcom: Move WLED num-strings from pmi8994 to sony-xperia-tone arm64: dt: qcom: pm660l: Remove board-specific WLED configuration
.../dts/qcom/msm8996-sony-xperia-tone.dtsi | 1 + arch/arm64/boot/dts/qcom/pm660l.dtsi | 7 - arch/arm64/boot/dts/qcom/pmi8994.dtsi | 5 +- drivers/video/backlight/qcom-wled.c | 131 ++++++++++-------- 4 files changed, 73 insertions(+), 71 deletions(-)
-- 2.33.0
The strings passed in DT may possibly cause out-of-bounds register accesses and should be validated before use.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- drivers/video/backlight/qcom-wled.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index d094299c2a48..8a42ed89c59c 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1528,12 +1528,28 @@ static int wled_configure(struct wled *wled) string_len = of_property_count_elems_of_size(dev->of_node, "qcom,enabled-strings", sizeof(u32)); - if (string_len > 0) + if (string_len > 0) { + if (string_len > wled->max_string_count) { + dev_err(dev, "Cannot have more than %d strings\n", + wled->max_string_count); + return -EINVAL; + } + of_property_read_u32_array(dev->of_node, "qcom,enabled-strings", wled->cfg.enabled_strings, sizeof(u32));
+ for (i = 0; i < string_len; ++i) { + if (wled->cfg.enabled_strings[i] >= wled->max_string_count) { + dev_err(dev, + "qcom,enabled-strings index %d at %d is out of bounds\n", + wled->cfg.enabled_strings[i], i); + return -EINVAL; + } + } + } + return 0; }
-- 2.33.0
On Fri, Nov 12, 2021 at 01:26:54AM +0100, Marijn Suijten wrote:
The strings passed in DT may possibly cause out-of-bounds register accesses and should be validated before use.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
Reviewed-by: Daniel Thompson daniel.thompson@linaro.org
Daniel.
of_property_read_u32_array takes the number of elements to read as last argument. This does not always need to be 4 (sizeof(u32)) but should instead be the size of the array in DT as read just above with of_property_count_elems_of_size.
To not make such an error go unnoticed again the driver now bails accordingly when of_property_read_u32_array returns an error. Surprisingly the indentation of newlined arguments is lining up again after prepending `rc = `.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Reviewed-by: Daniel Thompson daniel.thompson@linaro.org --- drivers/video/backlight/qcom-wled.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 8a42ed89c59c..d413b913fef3 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1535,10 +1535,15 @@ static int wled_configure(struct wled *wled) return -EINVAL; }
- of_property_read_u32_array(dev->of_node, + rc = of_property_read_u32_array(dev->of_node, "qcom,enabled-strings", wled->cfg.enabled_strings, - sizeof(u32)); + string_len); + if (rc) { + dev_err(dev, "Failed to read %d elements from qcom,enabled-strings: %d\n", + string_len, rc); + return rc; + }
for (i = 0; i < string_len; ++i) { if (wled->cfg.enabled_strings[i] >= wled->max_string_count) { -- 2.33.0
The kernel already provides appropriate primitives to perform endianness conversion which should be used in favour of manual bit-wrangling.
Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Reviewed-by: Daniel Thompson daniel.thompson@linaro.org --- drivers/video/backlight/qcom-wled.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index d413b913fef3..977cd75827d7 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -231,14 +231,14 @@ struct wled { static int wled3_set_brightness(struct wled *wled, u16 brightness) { int rc, i; - u8 v[2]; + u16 v;
- v[0] = brightness & 0xff; - v[1] = (brightness >> 8) & 0xf; + v = cpu_to_le16(brightness & WLED3_SINK_REG_BRIGHT_MAX);
for (i = 0; i < wled->cfg.num_strings; ++i) { rc = regmap_bulk_write(wled->regmap, wled->ctrl_addr + - WLED3_SINK_REG_BRIGHT(i), v, 2); + WLED3_SINK_REG_BRIGHT(i), + &v, sizeof(v)); if (rc < 0) return rc; } @@ -249,19 +249,18 @@ static int wled3_set_brightness(struct wled *wled, u16 brightness) static int wled4_set_brightness(struct wled *wled, u16 brightness) { int rc, i; - u16 low_limit = wled->max_brightness * 4 / 1000; - u8 v[2]; + u16 v, low_limit = wled->max_brightness * 4 / 1000;
/* WLED4's lower limit of operation is 0.4% */ if (brightness > 0 && brightness < low_limit) brightness = low_limit;
- v[0] = brightness & 0xff; - v[1] = (brightness >> 8) & 0xf; + v = cpu_to_le16(brightness & WLED3_SINK_REG_BRIGHT_MAX);
for (i = 0; i < wled->cfg.num_strings; ++i) { rc = regmap_bulk_write(wled->regmap, wled->sink_addr + - WLED4_SINK_REG_BRIGHT(i), v, 2); + WLED4_SINK_REG_BRIGHT(i), + &v, sizeof(v)); if (rc < 0) return rc; } @@ -272,22 +271,20 @@ static int wled4_set_brightness(struct wled *wled, u16 brightness) static int wled5_set_brightness(struct wled *wled, u16 brightness) { int rc, offset; - u16 low_limit = wled->max_brightness * 1 / 1000; - u8 v[2]; + u16 v, low_limit = wled->max_brightness * 1 / 1000;
/* WLED5's lower limit is 0.1% */ if (brightness < low_limit) brightness = low_limit;
- v[0] = brightness & 0xff; - v[1] = (brightness >> 8) & 0x7f; + v = cpu_to_le16(brightness & WLED5_SINK_REG_BRIGHT_MAX_15B);
offset = (wled->cfg.mod_sel == MOD_A) ? WLED5_SINK_REG_MOD_A_BRIGHTNESS_LSB : WLED5_SINK_REG_MOD_B_BRIGHTNESS_LSB;
rc = regmap_bulk_write(wled->regmap, wled->sink_addr + offset, - v, 2); + &v, sizeof(v)); return rc; }
-- 2.33.0
When not specifying num-strings in the DT the default is used, but +1 is added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead of 3 and 4 respectively, causing out-of-bounds reads and register read/writes. This +1 exists for a deficiency in the DT parsing code, and is simply omitted entirely - solving this oob issue - by parsing the property separately much like qcom,enabled-strings.
This also allows more stringent checks on the maximum value when qcom,enabled-strings is provided in the DT. Note that num-strings is parsed after enabled-strings to give it final sign-off over the length, which DT currently utilizes to get around an incorrect fixed read of four elements from that array (has been addressed in a prior patch).
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- drivers/video/backlight/qcom-wled.c | 51 +++++++++++------------------ 1 file changed, 19 insertions(+), 32 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 977cd75827d7..c5232478a343 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1253,21 +1253,6 @@ static const struct wled_var_cfg wled5_ovp_cfg = { .size = 16, };
-static u32 wled3_num_strings_values_fn(u32 idx) -{ - return idx + 1; -} - -static const struct wled_var_cfg wled3_num_strings_cfg = { - .fn = wled3_num_strings_values_fn, - .size = 3, -}; - -static const struct wled_var_cfg wled4_num_strings_cfg = { - .fn = wled3_num_strings_values_fn, - .size = 4, -}; - static u32 wled3_switch_freq_values_fn(u32 idx) { return 19200 / (2 * (1 + idx)); @@ -1341,11 +1326,6 @@ static int wled_configure(struct wled *wled) .val_ptr = &cfg->switch_freq, .cfg = &wled3_switch_freq_cfg, }, - { - .name = "qcom,num-strings", - .val_ptr = &cfg->num_strings, - .cfg = &wled3_num_strings_cfg, - }, };
const struct wled_u32_opts wled4_opts[] = { @@ -1369,11 +1349,6 @@ static int wled_configure(struct wled *wled) .val_ptr = &cfg->switch_freq, .cfg = &wled3_switch_freq_cfg, }, - { - .name = "qcom,num-strings", - .val_ptr = &cfg->num_strings, - .cfg = &wled4_num_strings_cfg, - }, };
const struct wled_u32_opts wled5_opts[] = { @@ -1397,11 +1372,6 @@ static int wled_configure(struct wled *wled) .val_ptr = &cfg->switch_freq, .cfg = &wled3_switch_freq_cfg, }, - { - .name = "qcom,num-strings", - .val_ptr = &cfg->num_strings, - .cfg = &wled4_num_strings_cfg, - }, { .name = "qcom,modulator-sel", .val_ptr = &cfg->mod_sel, @@ -1520,8 +1490,6 @@ static int wled_configure(struct wled *wled) *bool_opts[i].val_ptr = true; }
- cfg->num_strings = cfg->num_strings + 1; - string_len = of_property_count_elems_of_size(dev->of_node, "qcom,enabled-strings", sizeof(u32)); @@ -1552,6 +1520,25 @@ static int wled_configure(struct wled *wled) } }
+ rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val); + if (!rc) { + if (val < 1 || val > wled->max_string_count) { + dev_err(dev, "qcom,num-strings must be between 1 and %d\n", + wled->max_string_count); + return -EINVAL; + } + + if (string_len > 0) { + dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n"); + if (val > string_len) { + dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n"); + return -EINVAL; + } + } + + cfg->num_strings = val; + } + return 0; }
-- 2.33.0
On Fri, Nov 12, 2021 at 01:26:57AM +0100, Marijn Suijten wrote:
When not specifying num-strings in the DT the default is used, but +1 is added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead of 3 and 4 respectively, causing out-of-bounds reads and register read/writes. This +1 exists for a deficiency in the DT parsing code, and is simply omitted entirely - solving this oob issue - by parsing the property separately much like qcom,enabled-strings.
This also allows more stringent checks on the maximum value when qcom,enabled-strings is provided in the DT. Note that num-strings is parsed after enabled-strings to give it final sign-off over the length, which DT currently utilizes to get around an incorrect fixed read of four elements from that array (has been addressed in a prior patch).
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 51 +++++++++++------------------ 1 file changed, 19 insertions(+), 32 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 977cd75827d7..c5232478a343 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1552,6 +1520,25 @@ static int wled_configure(struct wled *wled) } }
- rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
- if (!rc) {
if (val < 1 || val > wled->max_string_count) {dev_err(dev, "qcom,num-strings must be between 1 and %d\n",wled->max_string_count);return -EINVAL;}if (string_len > 0) {dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n");
This warning occurs even when there is no ambiguity.
This could be:
if (string_len > 0 && val != string_len)
The warning should also be below the error message on the next if statement. Combined these changes allows us to give a much more helpful and assertive warning message:
qcom,num-strings mis-matches and will partially override qcom,enabled-strings (remove qcom,num-strings?)
if (val > string_len) {dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n");return -EINVAL;}}
Daniel.
On 2021-11-12 12:08:39, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:57AM +0100, Marijn Suijten wrote:
When not specifying num-strings in the DT the default is used, but +1 is added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead of 3 and 4 respectively, causing out-of-bounds reads and register read/writes. This +1 exists for a deficiency in the DT parsing code, and is simply omitted entirely - solving this oob issue - by parsing the property separately much like qcom,enabled-strings.
This also allows more stringent checks on the maximum value when qcom,enabled-strings is provided in the DT. Note that num-strings is parsed after enabled-strings to give it final sign-off over the length, which DT currently utilizes to get around an incorrect fixed read of four elements from that array (has been addressed in a prior patch).
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 51 +++++++++++------------------ 1 file changed, 19 insertions(+), 32 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 977cd75827d7..c5232478a343 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1552,6 +1520,25 @@ static int wled_configure(struct wled *wled) } }
- rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
- if (!rc) {
if (val < 1 || val > wled->max_string_count) {dev_err(dev, "qcom,num-strings must be between 1 and %d\n",wled->max_string_count);return -EINVAL;}if (string_len > 0) {dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n");The warning should also be below the error message on the next if statement.
Agreed.
This warning occurs even when there is no ambiguity.
This could be:
if (string_len > 0 && val != string_len)
Combined these changes allows us to give a much more helpful and assertive warning message:
qcom,num-strings mis-matches and will partially override qcom,enabled-strings (remove qcom,num-strings?)
I want to let the user know it's set regardless of whether they're equivalent; no need to set both.
How about:
Only one of qcom,num-strings or qcom,enabled-strings should be set
That should be more descriptive? Otherwise, let me know if you really want to allow users to (unnecessarily) set both - or if it can / should be caught in DT validation instead.
- Marijn
if (val > string_len) {dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n");return -EINVAL;}}Daniel.
On Fri, Nov 12, 2021 at 01:35:01PM +0100, Marijn Suijten wrote:
On 2021-11-12 12:08:39, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:57AM +0100, Marijn Suijten wrote:
if (string_len > 0) {dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n");The warning should also be below the error message on the next if statement.
Agreed.
This warning occurs even when there is no ambiguity.
This could be:
if (string_len > 0 && val != string_len)
Combined these changes allows us to give a much more helpful and assertive warning message:
qcom,num-strings mis-matches and will partially override qcom,enabled-strings (remove qcom,num-strings?)
I want to let the user know it's set regardless of whether they're equivalent; no need to set both.
How about:
Only one of qcom,num-strings or qcom,enabled-strings should be setThat should be more descriptive? Otherwise, let me know if you really want to allow users to (unnecessarily) set both - or if it can / should be caught in DT validation instead.
Yes. I can live with that text. Let's use that.
Maybe I wouldn't if there gazilions of existing DTs with both properties but IIRC the number is likely to be small or zero (although we couldn't be 100% sure which).
Daniel.
On 2021-11-12 13:35:03, Marijn Suijten wrote:
On 2021-11-12 12:08:39, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:57AM +0100, Marijn Suijten wrote:
When not specifying num-strings in the DT the default is used, but +1 is added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead of 3 and 4 respectively, causing out-of-bounds reads and register read/writes. This +1 exists for a deficiency in the DT parsing code, and is simply omitted entirely - solving this oob issue - by parsing the property separately much like qcom,enabled-strings.
This also allows more stringent checks on the maximum value when qcom,enabled-strings is provided in the DT. Note that num-strings is parsed after enabled-strings to give it final sign-off over the length, which DT currently utilizes to get around an incorrect fixed read of four elements from that array (has been addressed in a prior patch).
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 51 +++++++++++------------------ 1 file changed, 19 insertions(+), 32 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 977cd75827d7..c5232478a343 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1552,6 +1520,25 @@ static int wled_configure(struct wled *wled) } }
- rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
- if (!rc) {
if (val < 1 || val > wled->max_string_count) {dev_err(dev, "qcom,num-strings must be between 1 and %d\n",wled->max_string_count);return -EINVAL;}if (string_len > 0) {dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n");The warning should also be below the error message on the next if statement.
Agreed.
Thinking about this again while reworking the patches, I initially put this above the error to make DT writers aware. There's no point telling them that their values are out of sync (num-strings > len(enabled-strings)), when they "shouldn't even" (don't need to) set both in the first place. They might needlessly fix the discrepancy, see the driver finally probe (working backlight) and carry on without noticing this warning that now appears.
Sorry for bringing this back up, but I'm curious about your opinion.
- Marijn
On Fri, Nov 12, 2021 at 10:43:37PM +0100, Marijn Suijten wrote:
On 2021-11-12 13:35:03, Marijn Suijten wrote:
On 2021-11-12 12:08:39, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:57AM +0100, Marijn Suijten wrote:
When not specifying num-strings in the DT the default is used, but +1 is added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead of 3 and 4 respectively, causing out-of-bounds reads and register read/writes. This +1 exists for a deficiency in the DT parsing code, and is simply omitted entirely - solving this oob issue - by parsing the property separately much like qcom,enabled-strings.
This also allows more stringent checks on the maximum value when qcom,enabled-strings is provided in the DT. Note that num-strings is parsed after enabled-strings to give it final sign-off over the length, which DT currently utilizes to get around an incorrect fixed read of four elements from that array (has been addressed in a prior patch).
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 51 +++++++++++------------------ 1 file changed, 19 insertions(+), 32 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 977cd75827d7..c5232478a343 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1552,6 +1520,25 @@ static int wled_configure(struct wled *wled) } }
- rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
- if (!rc) {
if (val < 1 || val > wled->max_string_count) {dev_err(dev, "qcom,num-strings must be between 1 and %d\n",wled->max_string_count);return -EINVAL;}if (string_len > 0) {dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n");The warning should also be below the error message on the next if statement.
Agreed.
Thinking about this again while reworking the patches, I initially put this above the error to make DT writers aware. There's no point telling them that their values are out of sync (num-strings > len(enabled-strings)), when they "shouldn't even" (don't need to) set both in the first place. They might needlessly fix the discrepancy, see the driver finally probe (working backlight) and carry on without noticing this warning that now appears.
Sorry for bringing this back up, but I'm curious about your opinion.
With a more helpful warning about how to fix then I think it is OK to have both the warning and the error.
Daniel.
On 2021-11-15 11:23:27, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 10:43:37PM +0100, Marijn Suijten wrote:
On 2021-11-12 13:35:03, Marijn Suijten wrote:
On 2021-11-12 12:08:39, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:57AM +0100, Marijn Suijten wrote:
When not specifying num-strings in the DT the default is used, but +1 is added to it which turns WLED3 into 4 and WLED4/5 into 5 strings instead of 3 and 4 respectively, causing out-of-bounds reads and register read/writes. This +1 exists for a deficiency in the DT parsing code, and is simply omitted entirely - solving this oob issue - by parsing the property separately much like qcom,enabled-strings.
This also allows more stringent checks on the maximum value when qcom,enabled-strings is provided in the DT. Note that num-strings is parsed after enabled-strings to give it final sign-off over the length, which DT currently utilizes to get around an incorrect fixed read of four elements from that array (has been addressed in a prior patch).
Fixes: 93c64f1ea1e8 ("leds: add Qualcomm PM8941 WLED driver") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 51 +++++++++++------------------ 1 file changed, 19 insertions(+), 32 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 977cd75827d7..c5232478a343 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1552,6 +1520,25 @@ static int wled_configure(struct wled *wled) } }
- rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
- if (!rc) {
if (val < 1 || val > wled->max_string_count) {dev_err(dev, "qcom,num-strings must be between 1 and %d\n",wled->max_string_count);return -EINVAL;}if (string_len > 0) {dev_warn(dev, "qcom,num-strings and qcom,enabled-strings are ambiguous\n");The warning should also be below the error message on the next if statement.
Agreed.
Thinking about this again while reworking the patches, I initially put this above the error to make DT writers aware. There's no point telling them that their values are out of sync (num-strings > len(enabled-strings)), when they "shouldn't even" (don't need to) set both in the first place. They might needlessly fix the discrepancy, see the driver finally probe (working backlight) and carry on without noticing this warning that now appears.
Sorry for bringing this back up, but I'm curious about your opinion.
With a more helpful warning about how to fix then I think it is OK to have both the warning and the error.
Thanks - I presume the message we settled upon last time is helpful enough:
Only one of qcom,num-strings or qcom,enabled-strings should be set
I'll respin this, together with this warning reordered into the next commit, and using __le16 for the cpu_to_le16 output.
- Marijn
The length of qcom,enabled-strings as property array is enough to determine the number of strings to be enabled, without needing to set qcom,num-strings to override the default number of strings when less than the default (which is also the maxium) is provided in DT.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- drivers/video/backlight/qcom-wled.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index c5232478a343..9bfbf601762a 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1518,6 +1518,8 @@ static int wled_configure(struct wled *wled) return -EINVAL; } } + + cfg->num_strings = string_len; }
rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val); -- 2.33.0
On Fri, Nov 12, 2021 at 01:26:58AM +0100, Marijn Suijten wrote:
The length of qcom,enabled-strings as property array is enough to determine the number of strings to be enabled, without needing to set qcom,num-strings to override the default number of strings when less than the default (which is also the maxium) is provided in DT.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index c5232478a343..9bfbf601762a 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1518,6 +1518,8 @@ static int wled_configure(struct wled *wled) return -EINVAL; } }
cfg->num_strings = string_len;
I still don't really understand why this wants to be a separate patch.
The warning text emitted by the previous patch (whatever text we agree on) will be nonsense until this patch is applied.
If this patch cannot appear before the warning is introduces then there is no correct order for patches 4 and 5 (which implies they should be the same patch).
Daniel.
On 2021-11-12 12:12:38, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:58AM +0100, Marijn Suijten wrote:
The length of qcom,enabled-strings as property array is enough to determine the number of strings to be enabled, without needing to set qcom,num-strings to override the default number of strings when less than the default (which is also the maxium) is provided in DT.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index c5232478a343..9bfbf601762a 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1518,6 +1518,8 @@ static int wled_configure(struct wled *wled) return -EINVAL; } }
cfg->num_strings = string_len;I still don't really understand why this wants to be a separate patch.
I'm viewing this as a separate issue, and this makes it easier to document the change in a loose commit.
The warning text emitted by the previous patch (whatever text we agree on) will be nonsense until this patch is applied.
If this patch cannot appear before the warning is introduces then there is no correct order for patches 4 and 5 (which implies they should be the same patch).
Agreed, this is a weird way of doing things in v2 - the error message is printed yet the length of qcom,enabled-strings is always ignored before this patch.
If we were to reorder patch 5 before patch 4 that should also temporarily move `cfg->num_strings = cfg->num_strings + 1;` right below this `if` so that `qcom,num-strings` remains the definitive way to set/override length. That's doable, and makes it easier to read patch 4 as that bit of code will be replaced by of_property_read_u32 on that exact line. Let me know which method you prefer.
- Marijn
On Fri, Nov 12, 2021 at 01:45:22PM +0100, Marijn Suijten wrote:
On 2021-11-12 12:12:38, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:58AM +0100, Marijn Suijten wrote:
The length of qcom,enabled-strings as property array is enough to determine the number of strings to be enabled, without needing to set qcom,num-strings to override the default number of strings when less than the default (which is also the maxium) is provided in DT.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index c5232478a343..9bfbf601762a 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1518,6 +1518,8 @@ static int wled_configure(struct wled *wled) return -EINVAL; } }
cfg->num_strings = string_len;I still don't really understand why this wants to be a separate patch.
I'm viewing this as a separate issue, and this makes it easier to document the change in a loose commit.
The warning text emitted by the previous patch (whatever text we agree on) will be nonsense until this patch is applied.
If this patch cannot appear before the warning is introduces then there is no correct order for patches 4 and 5 (which implies they should be the same patch).
Agreed, this is a weird way of doing things in v2 - the error message is printed yet the length of qcom,enabled-strings is always ignored before this patch.
If we were to reorder patch 5 before patch 4 that should also temporarily move `cfg->num_strings = cfg->num_strings + 1;` right below this `if` so that `qcom,num-strings` remains the definitive way to set/override length. That's doable, and makes it easier to read patch 4 as that bit of code will be replaced by of_property_read_u32 on that exact line. Let me know which method you prefer.
Personally I would just squash them together. There are no redundant values in the DT that could be fixed until we can use the string_len to set num_strings.
However I won't object to the other approach providing the result is bisectable.
Daniel.
On 2021-11-12 13:23:36, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:45:22PM +0100, Marijn Suijten wrote:
On 2021-11-12 12:12:38, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:58AM +0100, Marijn Suijten wrote:
The length of qcom,enabled-strings as property array is enough to determine the number of strings to be enabled, without needing to set qcom,num-strings to override the default number of strings when less than the default (which is also the maxium) is provided in DT.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index c5232478a343..9bfbf601762a 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1518,6 +1518,8 @@ static int wled_configure(struct wled *wled) return -EINVAL; } }
cfg->num_strings = string_len;I still don't really understand why this wants to be a separate patch.
I'm viewing this as a separate issue, and this makes it easier to document the change in a loose commit.
The warning text emitted by the previous patch (whatever text we agree on) will be nonsense until this patch is applied.
If this patch cannot appear before the warning is introduces then there is no correct order for patches 4 and 5 (which implies they should be the same patch).
Agreed, this is a weird way of doing things in v2 - the error message is printed yet the length of qcom,enabled-strings is always ignored before this patch.
If we were to reorder patch 5 before patch 4 that should also temporarily move `cfg->num_strings = cfg->num_strings + 1;` right below this `if` so that `qcom,num-strings` remains the definitive way to set/override length. That's doable, and makes it easier to read patch 4 as that bit of code will be replaced by of_property_read_u32 on that exact line. Let me know which method you prefer.
Personally I would just squash them together. There are no redundant values in the DT that could be fixed until we can use the string_len to set num_strings.
Reordering this patch before patch 4 in the way described above should allow just that, except that no warnings will be given for ambiguity until patch 4 is applied after that - which is weird given that that patch only intends the off-by-one error. Perhaps we should keep the order as it is, but add the ambiguity warning in this patch instead.
That means we have one patch to fix the off-by-one first, and another that allows qcom,num-strings to provide a default for num_strings. I guess that's better to keep separated?
- Marijn
On Fri, Nov 12, 2021 at 03:19:17PM +0100, Marijn Suijten wrote:
On 2021-11-12 13:23:36, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:45:22PM +0100, Marijn Suijten wrote:
On 2021-11-12 12:12:38, Daniel Thompson wrote:
On Fri, Nov 12, 2021 at 01:26:58AM +0100, Marijn Suijten wrote:
The length of qcom,enabled-strings as property array is enough to determine the number of strings to be enabled, without needing to set qcom,num-strings to override the default number of strings when less than the default (which is also the maxium) is provided in DT.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
drivers/video/backlight/qcom-wled.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index c5232478a343..9bfbf601762a 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1518,6 +1518,8 @@ static int wled_configure(struct wled *wled) return -EINVAL; } }
cfg->num_strings = string_len;I still don't really understand why this wants to be a separate patch.
I'm viewing this as a separate issue, and this makes it easier to document the change in a loose commit.
The warning text emitted by the previous patch (whatever text we agree on) will be nonsense until this patch is applied.
If this patch cannot appear before the warning is introduces then there is no correct order for patches 4 and 5 (which implies they should be the same patch).
Agreed, this is a weird way of doing things in v2 - the error message is printed yet the length of qcom,enabled-strings is always ignored before this patch.
If we were to reorder patch 5 before patch 4 that should also temporarily move `cfg->num_strings = cfg->num_strings + 1;` right below this `if` so that `qcom,num-strings` remains the definitive way to set/override length. That's doable, and makes it easier to read patch 4 as that bit of code will be replaced by of_property_read_u32 on that exact line. Let me know which method you prefer.
Personally I would just squash them together. There are no redundant values in the DT that could be fixed until we can use the string_len to set num_strings.
Reordering this patch before patch 4 in the way described above should allow just that, except that no warnings will be given for ambiguity until patch 4 is applied after that - which is weird given that that patch only intends the off-by-one error. Perhaps we should keep the order as it is, but add the ambiguity warning in this patch instead.
That works for me. Sounds good.
Daniel.
The previous commit improves num_strings parsing to not go over the maximum of 3 strings for WLED3 anymore. Likewise this default index for a hypothetical 4th string is invalid and could access registers that are not mapped to the desired purpose. Removing this value gets rid of undesired confusion and avoids the possibility of accessing registers at this offset even if the 4th array element is used by accident.
Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Reviewed-by: Daniel Thompson daniel.thompson@linaro.org --- drivers/video/backlight/qcom-wled.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 9bfbf601762a..c342cd8440e1 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -946,7 +946,7 @@ static const struct wled_config wled3_config_defaults = { .cs_out_en = false, .ext_gen = false, .cabc = false, - .enabled_strings = {0, 1, 2, 3}, + .enabled_strings = {0, 1, 2}, };
static int wled4_setup(struct wled *wled) -- 2.33.0
Only WLED 3 sets a sensible default that allows operating this driver with just qcom,num-strings in the DT; WLED 4 and 5 require qcom,enabled-strings to be provided otherwise enabled_strings remains zero-initialized, resuling in every string-specific register write (currently only the setup and config functions, brightness follows in a future patch) to only configure the zero'th string multiple times.
Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Reviewed-by: Daniel Thompson daniel.thompson@linaro.org --- drivers/video/backlight/qcom-wled.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index c342cd8440e1..a8fb8f19922d 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -1077,6 +1077,7 @@ static const struct wled_config wled4_config_defaults = { .cabc = false, .external_pfet = false, .auto_detection_enabled = false, + .enabled_strings = {0, 1, 2, 3}, };
static int wled5_setup(struct wled *wled) @@ -1190,6 +1191,7 @@ static const struct wled_config wled5_config_defaults = { .cabc = false, .external_pfet = false, .auto_detection_enabled = false, + .enabled_strings = {0, 1, 2, 3}, };
static const u32 wled3_boost_i_limit_values[] = { -- 2.33.0
Remove redundant spaces inside for loop conditions. No other double spaces were found that are not part of indentation with `[^\s] `.
Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org Reviewed-by: Daniel Thompson daniel.thompson@linaro.org --- drivers/video/backlight/qcom-wled.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index a8fb8f19922d..4524e80591cd 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -235,7 +235,7 @@ static int wled3_set_brightness(struct wled *wled, u16 brightness)
v = cpu_to_le16(brightness & WLED3_SINK_REG_BRIGHT_MAX);
- for (i = 0; i < wled->cfg.num_strings; ++i) { + for (i = 0; i < wled->cfg.num_strings; ++i) { rc = regmap_bulk_write(wled->regmap, wled->ctrl_addr + WLED3_SINK_REG_BRIGHT(i), &v, sizeof(v)); @@ -257,7 +257,7 @@ static int wled4_set_brightness(struct wled *wled, u16 brightness)
v = cpu_to_le16(brightness & WLED3_SINK_REG_BRIGHT_MAX);
- for (i = 0; i < wled->cfg.num_strings; ++i) { + for (i = 0; i < wled->cfg.num_strings; ++i) { rc = regmap_bulk_write(wled->regmap, wled->sink_addr + WLED4_SINK_REG_BRIGHT(i), &v, sizeof(v)); -- 2.33.0
The hardware is capable of controlling any non-contiguous sequence of LEDs specified in the DT using qcom,enabled-strings as u32 array, and this also follows from the DT-bindings documentation. The numbers specified in this array represent indices of the LED strings that are to be enabled and disabled.
Its value is appropriately used to setup and enable string modules, but completely disregarded in the set_brightness paths which only iterate over the number of strings linearly. Take an example where only string 2 is enabled with qcom,enabled_strings=<2>: this string is appropriately enabled but subsequent brightness changes would have only touched the zero'th brightness register because num_strings is 1 here. This is simply addressed by looking up the string for this index in the enabled_strings array just like the other codepaths that iterate over num_strings.
Likewise enabled_strings is now also used in the autodetection path for consistent behaviour: when a list of strings is specified in DT only those strings will be probed for autodetection, analogous to how the number of strings that need to be probed is already bound by qcom,num-strings. After all autodetection uses the set_brightness helpers to set an initial value, which could otherwise end up changing brightness on a different set of strings.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Fixes: 03b2b5e86986 ("backlight: qcom-wled: Add support for WLED4 peripheral") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- drivers/video/backlight/qcom-wled.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 4524e80591cd..bdda6b424113 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -237,7 +237,7 @@ static int wled3_set_brightness(struct wled *wled, u16 brightness)
for (i = 0; i < wled->cfg.num_strings; ++i) { rc = regmap_bulk_write(wled->regmap, wled->ctrl_addr + - WLED3_SINK_REG_BRIGHT(i), + WLED3_SINK_REG_BRIGHT(wled->cfg.enabled_strings[i]), &v, sizeof(v)); if (rc < 0) return rc; @@ -259,7 +259,7 @@ static int wled4_set_brightness(struct wled *wled, u16 brightness)
for (i = 0; i < wled->cfg.num_strings; ++i) { rc = regmap_bulk_write(wled->regmap, wled->sink_addr + - WLED4_SINK_REG_BRIGHT(i), + WLED4_SINK_REG_BRIGHT(wled->cfg.enabled_strings[i]), &v, sizeof(v)); if (rc < 0) return rc; @@ -569,7 +569,7 @@ static irqreturn_t wled_short_irq_handler(int irq, void *_wled)
static void wled_auto_string_detection(struct wled *wled) { - int rc = 0, i, delay_time_us; + int rc = 0, i, j, delay_time_us; u32 sink_config = 0; u8 sink_test = 0, sink_valid = 0, val; bool fault_set; @@ -616,14 +616,15 @@ static void wled_auto_string_detection(struct wled *wled)
/* Iterate through the strings one by one */ for (i = 0; i < wled->cfg.num_strings; i++) { - sink_test = BIT((WLED4_SINK_REG_CURR_SINK_SHFT + i)); + j = wled->cfg.enabled_strings[i]; + sink_test = BIT((WLED4_SINK_REG_CURR_SINK_SHFT + j));
/* Enable feedback control */ rc = regmap_write(wled->regmap, wled->ctrl_addr + - WLED3_CTRL_REG_FEEDBACK_CONTROL, i + 1); + WLED3_CTRL_REG_FEEDBACK_CONTROL, j + 1); if (rc < 0) { dev_err(wled->dev, "Failed to enable feedback for SINK %d rc = %d\n", - i + 1, rc); + j + 1, rc); goto failed_detect; }
@@ -632,7 +633,7 @@ static void wled_auto_string_detection(struct wled *wled) WLED4_SINK_REG_CURR_SINK, sink_test); if (rc < 0) { dev_err(wled->dev, "Failed to configure SINK %d rc=%d\n", - i + 1, rc); + j + 1, rc); goto failed_detect; }
@@ -659,7 +660,7 @@ static void wled_auto_string_detection(struct wled *wled)
if (fault_set) dev_dbg(wled->dev, "WLED OVP fault detected with SINK %d\n", - i + 1); + j + 1); else sink_valid |= sink_test;
@@ -699,15 +700,16 @@ static void wled_auto_string_detection(struct wled *wled) /* Enable valid sinks */ if (wled->version == 4) { for (i = 0; i < wled->cfg.num_strings; i++) { + j = wled->cfg.enabled_strings[i]; if (sink_config & - BIT(WLED4_SINK_REG_CURR_SINK_SHFT + i)) + BIT(WLED4_SINK_REG_CURR_SINK_SHFT + j)) val = WLED4_SINK_REG_STR_MOD_MASK; else /* Disable modulator_en for unused sink */ val = 0;
rc = regmap_write(wled->regmap, wled->sink_addr + - WLED4_SINK_REG_STR_MOD_EN(i), val); + WLED4_SINK_REG_STR_MOD_EN(j), val); if (rc < 0) { dev_err(wled->dev, "Failed to configure MODULATOR_EN rc=%d\n", rc); -- 2.33.0
On Fri, Nov 12, 2021 at 01:27:02AM +0100, Marijn Suijten wrote:
The hardware is capable of controlling any non-contiguous sequence of LEDs specified in the DT using qcom,enabled-strings as u32 array, and this also follows from the DT-bindings documentation. The numbers specified in this array represent indices of the LED strings that are to be enabled and disabled.
Its value is appropriately used to setup and enable string modules, but completely disregarded in the set_brightness paths which only iterate over the number of strings linearly. Take an example where only string 2 is enabled with qcom,enabled_strings=<2>: this string is appropriately enabled but subsequent brightness changes would have only touched the zero'th brightness register because num_strings is 1 here. This is simply addressed by looking up the string for this index in the enabled_strings array just like the other codepaths that iterate over num_strings.
Likewise enabled_strings is now also used in the autodetection path for consistent behaviour: when a list of strings is specified in DT only those strings will be probed for autodetection, analogous to how the number of strings that need to be probed is already bound by qcom,num-strings. After all autodetection uses the set_brightness helpers to set an initial value, which could otherwise end up changing brightness on a different set of strings.
Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3") Fixes: 03b2b5e86986 ("backlight: qcom-wled: Add support for WLED4 peripheral") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org
Reviewed-by: Daniel Thompson daniel.thompson@linaro.org
Daniel.
The property is named "qcom,external-pfet", as found by dt_binding_check:
'qcom,eternal-pfet' does not match any of the regexes
Fixes: 37aa540cbd30 ("arm64: dts: qcom: pmi8994: Add WLED node") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- arch/arm64/boot/dts/qcom/pmi8994.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/qcom/pmi8994.dtsi b/arch/arm64/boot/dts/qcom/pmi8994.dtsi index b4ac900ab115..a06ea9adae81 100644 --- a/arch/arm64/boot/dts/qcom/pmi8994.dtsi +++ b/arch/arm64/boot/dts/qcom/pmi8994.dtsi @@ -42,7 +42,7 @@ pmi8994_wled: wled@d800 { /* Yes, all four strings *have to* be defined or things won't work. */ qcom,enabled-strings = <0 1 2 3>; qcom,cabc; - qcom,eternal-pfet; + qcom,external-pfet; status = "disabled"; }; }; -- 2.33.0
The driver now sets an appropriate default for WLED4 (and WLED5) just like WLED3 making this linear array from 0-3 redundant. In addition the driver is now able to parse arrays of variable length solving the "all four strings *have to* be defined" comment.
Besides the driver will now warn when both properties are specified to prevent ambiguity: the length of the array is enough to imply a set number of strings.
Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- arch/arm64/boot/dts/qcom/pmi8994.dtsi | 2 -- 1 file changed, 2 deletions(-)
diff --git a/arch/arm64/boot/dts/qcom/pmi8994.dtsi b/arch/arm64/boot/dts/qcom/pmi8994.dtsi index a06ea9adae81..89ba4146e747 100644 --- a/arch/arm64/boot/dts/qcom/pmi8994.dtsi +++ b/arch/arm64/boot/dts/qcom/pmi8994.dtsi @@ -39,8 +39,6 @@ pmi8994_wled: wled@d800 { interrupts = <3 0xd8 0x02 IRQ_TYPE_EDGE_RISING>; interrupt-names = "short"; qcom,num-strings = <3>; - /* Yes, all four strings *have to* be defined or things won't work. */ - qcom,enabled-strings = <0 1 2 3>; qcom,cabc; qcom,external-pfet; status = "disabled"; -- 2.33.0
The number of WLED strings used by a certain platform depend on the panel connected to that board and may not be the same for every user of pmi8994.
Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- arch/arm64/boot/dts/qcom/msm8996-sony-xperia-tone.dtsi | 1 + arch/arm64/boot/dts/qcom/pmi8994.dtsi | 1 - 2 files changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/qcom/msm8996-sony-xperia-tone.dtsi b/arch/arm64/boot/dts/qcom/msm8996-sony-xperia-tone.dtsi index 507396c4d23b..ff7f39d29dd5 100644 --- a/arch/arm64/boot/dts/qcom/msm8996-sony-xperia-tone.dtsi +++ b/arch/arm64/boot/dts/qcom/msm8996-sony-xperia-tone.dtsi @@ -620,6 +620,7 @@ pmi8994_s11: s11 { &pmi8994_wled { status = "okay"; default-brightness = <512>; + qcom,num-strings = <3>; };
&rpm_requests { diff --git a/arch/arm64/boot/dts/qcom/pmi8994.dtsi b/arch/arm64/boot/dts/qcom/pmi8994.dtsi index 89ba4146e747..6e7c252568e6 100644 --- a/arch/arm64/boot/dts/qcom/pmi8994.dtsi +++ b/arch/arm64/boot/dts/qcom/pmi8994.dtsi @@ -38,7 +38,6 @@ pmi8994_wled: wled@d800 { reg = <0xd800 0xd900>; interrupts = <3 0xd8 0x02 IRQ_TYPE_EDGE_RISING>; interrupt-names = "short"; - qcom,num-strings = <3>; qcom,cabc; qcom,external-pfet; status = "disabled"; -- 2.33.0
This string- and electrical configuration depend on the board and panel, and should hence not be defined generically for every user of pm660l. SoMainline will pick this configuration again when enabling WLED on the Sony Nile platform.
Fixes: 7b56a804e58b ("arm64: dts: qcom: pm660l: Add WLED support") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-By: AngeloGioacchino Del Regno angelogioacchino.delregno@somainline.org --- arch/arm64/boot/dts/qcom/pm660l.dtsi | 7 ------- 1 file changed, 7 deletions(-)
diff --git a/arch/arm64/boot/dts/qcom/pm660l.dtsi b/arch/arm64/boot/dts/qcom/pm660l.dtsi index 05086cbe573b..cfef42353611 100644 --- a/arch/arm64/boot/dts/qcom/pm660l.dtsi +++ b/arch/arm64/boot/dts/qcom/pm660l.dtsi @@ -72,13 +72,6 @@ pm660l_wled: leds@d800 { interrupt-names = "ovp"; label = "backlight";
- qcom,switching-freq = <800>; - qcom,ovp-millivolt = <29600>; - qcom,current-boost-limit = <970>; - qcom,current-limit-microamp = <20000>; - qcom,num-strings = <2>; - qcom,enabled-strings = <0 1>; - status = "disabled"; };
-- 2.33.0
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