Handle the short circuit interrupt and check if the short circuit interrupt is valid. Re-enable the module to check if it goes away. Disable the module altogether if the short circuit event persists.
Signed-off-by: Kiran Gunda kgunda@codeaurora.org Reviewed-by: Bjorn Andersson bjorn.andersson@linaro.org --- Changes from V3: - Added Reviewed by tag. - Addressed minor comments from Vinod
Changes from V4: - Changed the return value from -EINVAL to -ENXIO - Re-initializing the short_count from 0 to 1.
drivers/video/backlight/qcom-wled.c | 132 ++++++++++++++++++++++++++++++++++-- 1 file changed, 128 insertions(+), 4 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c index 49fdd23..d891067 100644 --- a/drivers/video/backlight/qcom-wled.c +++ b/drivers/video/backlight/qcom-wled.c @@ -10,6 +10,9 @@ * GNU General Public License for more details. */
+#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/ktime.h> #include <linux/kernel.h> #include <linux/backlight.h> #include <linux/module.h> @@ -64,6 +67,16 @@ #define WLED3_SINK_REG_STR_CABC(n) (0x66 + (n * 0x10)) #define WLED3_SINK_REG_STR_CABC_MASK BIT(7)
+/* WLED4 specific control registers */ +#define WLED4_CTRL_REG_SHORT_PROTECT 0x5e +#define WLED4_CTRL_REG_SHORT_EN_MASK BIT(7) + +#define WLED4_CTRL_REG_SEC_ACCESS 0xd0 +#define WLED4_CTRL_REG_SEC_UNLOCK 0xa5 + +#define WLED4_CTRL_REG_TEST1 0xe2 +#define WLED4_CTRL_REG_TEST1_EXT_FET_DTEST2 0x09 + /* WLED4 specific sink registers */ #define WLED4_SINK_REG_CURR_SINK 0x46 #define WLED4_SINK_REG_CURR_SINK_MASK GENMASK(7, 4) @@ -113,17 +126,23 @@ struct wled_config { bool cs_out_en; bool ext_gen; bool cabc; + bool external_pfet; };
struct wled { const char *name; struct device *dev; struct regmap *regmap; + struct mutex lock; /* Lock to avoid race from thread irq handler */ + ktime_t last_short_event; u16 ctrl_addr; u16 sink_addr; u16 max_string_count; u32 brightness; u32 max_brightness; + u32 short_count; + bool disabled_by_short; + bool has_short_detect;
struct wled_config cfg; int (*wled_set_brightness)(struct wled *wled, u16 brightness); @@ -174,6 +193,9 @@ static int wled_module_enable(struct wled *wled, int val) { int rc;
+ if (wled->disabled_by_short) + return -ENXIO; + rc = regmap_update_bits(wled->regmap, wled->ctrl_addr + WLED_CTRL_REG_MOD_EN, WLED_CTRL_REG_MOD_EN_MASK, @@ -210,18 +232,19 @@ static int wled_update_status(struct backlight_device *bl) bl->props.state & BL_CORE_FBBLANK) brightness = 0;
+ mutex_lock(&wled->lock); if (brightness) { rc = wled->wled_set_brightness(wled, brightness); if (rc < 0) { dev_err(wled->dev, "wled failed to set brightness rc:%d\n", rc); - return rc; + goto unlock_mutex; }
rc = wled_sync_toggle(wled); if (rc < 0) { dev_err(wled->dev, "wled sync failed rc:%d\n", rc); - return rc; + goto unlock_mutex; } }
@@ -229,15 +252,61 @@ static int wled_update_status(struct backlight_device *bl) rc = wled_module_enable(wled, !!brightness); if (rc < 0) { dev_err(wled->dev, "wled enable failed rc:%d\n", rc); - return rc; + goto unlock_mutex; } }
wled->brightness = brightness;
+unlock_mutex: + mutex_unlock(&wled->lock); + return rc; }
+#define WLED_SHORT_DLY_MS 20 +#define WLED_SHORT_CNT_MAX 5 +#define WLED_SHORT_RESET_CNT_DLY_US USEC_PER_SEC + +static irqreturn_t wled_short_irq_handler(int irq, void *_wled) +{ + struct wled *wled = _wled; + int rc; + s64 elapsed_time; + + wled->short_count++; + mutex_lock(&wled->lock); + rc = wled_module_enable(wled, false); + if (rc < 0) { + dev_err(wled->dev, "wled disable failed rc:%d\n", rc); + goto unlock_mutex; + } + + elapsed_time = ktime_us_delta(ktime_get(), + wled->last_short_event); + if (elapsed_time > WLED_SHORT_RESET_CNT_DLY_US) + wled->short_count = 1; + + if (wled->short_count > WLED_SHORT_CNT_MAX) { + dev_err(wled->dev, "Short trigged %d times, disabling WLED forever!\n", + wled->short_count); + wled->disabled_by_short = true; + goto unlock_mutex; + } + + wled->last_short_event = ktime_get(); + + msleep(WLED_SHORT_DLY_MS); + rc = wled_module_enable(wled, true); + if (rc < 0) + dev_err(wled->dev, "wled enable failed rc:%d\n", rc); + +unlock_mutex: + mutex_unlock(&wled->lock); + + return IRQ_HANDLED; +} + static int wled3_setup(struct wled *wled) { u16 addr; @@ -326,7 +395,7 @@ static int wled4_setup(struct wled *wled) int rc, temp, i, j; u16 addr; u8 sink_en = 0; - u32 sink_cfg = 0; + u32 sink_cfg;
rc = regmap_update_bits(wled->regmap, wled->ctrl_addr + WLED_CTRL_REG_OVP, @@ -348,6 +417,21 @@ static int wled4_setup(struct wled *wled) if (rc < 0) return rc;
+ if (wled->cfg.external_pfet) { + /* Unlock the secure register access */ + rc = regmap_write(wled->regmap, wled->ctrl_addr + + WLED4_CTRL_REG_SEC_ACCESS, + WLED4_CTRL_REG_SEC_UNLOCK); + if (rc < 0) + return rc; + + rc = regmap_write(wled->regmap, + wled->ctrl_addr + WLED4_CTRL_REG_TEST1, + WLED4_CTRL_REG_TEST1_EXT_FET_DTEST2); + if (rc < 0) + return rc; + } + rc = regmap_read(wled->regmap, wled->sink_addr + WLED4_SINK_REG_CURR_SINK, &sink_cfg); if (rc < 0) @@ -433,6 +517,7 @@ static int wled4_setup(struct wled *wled) .num_strings = 4, .switch_freq = 11, .cabc = false, + .external_pfet = false, };
static const u32 wled3_boost_i_limit_values[] = { @@ -598,6 +683,7 @@ static int wled_configure(struct wled *wled, int version) { "qcom,cs-out", &cfg->cs_out_en, }, { "qcom,ext-gen", &cfg->ext_gen, }, { "qcom,cabc", &cfg->cabc, }, + { "qcom,external-pfet", &cfg->external_pfet, }, };
prop_addr = of_get_address(dev->of_node, 0, NULL, NULL); @@ -686,6 +772,38 @@ static int wled_configure(struct wled *wled, int version) return 0; }
+static int wled_configure_short_irq(struct wled *wled, + struct platform_device *pdev) +{ + int rc, short_irq; + + if (!wled->has_short_detect) + return 0; + + rc = regmap_update_bits(wled->regmap, wled->ctrl_addr + + WLED4_CTRL_REG_SHORT_PROTECT, + WLED4_CTRL_REG_SHORT_EN_MASK, + WLED4_CTRL_REG_SHORT_EN_MASK); + if (rc < 0) + return rc; + + short_irq = platform_get_irq_byname(pdev, "short"); + if (short_irq < 0) { + dev_dbg(&pdev->dev, "short irq is not used\n"); + return 0; + } + + rc = devm_request_threaded_irq(wled->dev, short_irq, + NULL, wled_short_irq_handler, + IRQF_ONESHOT, + "wled_short_irq", wled); + if (rc < 0) + dev_err(wled->dev, "Unable to request short_irq (err:%d)\n", + rc); + + return rc; +} + static const struct backlight_ops wled_ops = { .update_status = wled_update_status, }; @@ -719,6 +837,7 @@ static int wled_probe(struct platform_device *pdev) return -ENODEV; }
+ mutex_init(&wled->lock); rc = wled_configure(wled, version); if (rc) return rc; @@ -733,6 +852,7 @@ static int wled_probe(struct platform_device *pdev) break;
case 4: + wled->has_short_detect = true; rc = wled4_setup(wled); if (rc) { dev_err(&pdev->dev, "wled4_setup failed\n"); @@ -745,6 +865,10 @@ static int wled_probe(struct platform_device *pdev) break; }
+ rc = wled_configure_short_irq(wled, pdev); + if (rc < 0) + return rc; + val = WLED_DEFAULT_BRIGHTNESS; of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);