Add basic PWM modes: normal and complementary. These modes should differentiate the single output PWM channels from two outputs PWM channels. These modes could be set as follow: 1. PWM channels with one output per channel: - normal mode 2. PWM channels with two outputs per channel: - normal mode - complementary mode Since users could use a PWM channel with two output as one output PWM channel, the PWM normal mode is allowed to be set for PWM channels with two outputs; in fact PWM normal mode should be supported by all PWMs.
The PWM capabilities were implemented per PWM channel. Every PWM controller will register a function to get PWM capabilities. If this is not explicitly set by the driver a default function will be used to retrieve the the PWM capabilities (in this case the PWM capabilities will contain only PWM normal mode). This function is set in pwmchip_add_with_polarity() as a member of "struct pwm_chip". To retrieve capabilities the pwm_get_caps() function could be used.
Every PWM channel will have associated a mode in the PWM state. Proper helper functions were added to get/set PWM mode. The mode could also be set from DT via flag cells. The valid DT modes could be located in include/dt-bindings/pwm/pwm.h. Only modes supported by PWM channel could be set. If nothing is specified for a PWM channel, via DT, the first available mode will be used (normally, this will be PWM normal mode).
Signed-off-by: Claudiu Beznea claudiu.beznea@microchip.com --- drivers/pwm/core.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++--- drivers/pwm/sysfs.c | 56 ++++++++++++++++++++++++++++++ include/linux/pwm.h | 87 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 237 insertions(+), 4 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 1581f6ab1b1f..16a409d452c0 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -136,6 +136,8 @@ struct pwm_device * of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) { struct pwm_device *pwm; + struct pwm_caps caps; + int modebit;
/* check, whether the driver supports a third cell for flags */ if (pc->of_pwm_n_cells < 3) @@ -152,11 +154,23 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) if (IS_ERR(pwm)) return pwm;
+ pwm_get_caps(pc, pwm, &caps); + pwm->args.period = args->args[1]; pwm->args.polarity = PWM_POLARITY_NORMAL; + pwm->args.mode = BIT(ffs(caps.modes) - 1); + + if (args->args_count > 2) { + if (args->args[2] & PWM_POLARITY_INVERTED) + pwm->args.polarity = PWM_POLARITY_INVERSED;
- if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED) - pwm->args.polarity = PWM_POLARITY_INVERSED; + for (modebit = PWM_MODE_COMPLEMENTARY_BIT; + modebit < PWM_MODE_CNT; modebit++) + if (args->args[2] & BIT(modebit)) { + pwm->args.mode = BIT(modebit); + break; + } + }
return pwm; } @@ -166,6 +180,7 @@ static struct pwm_device * of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) { struct pwm_device *pwm; + struct pwm_caps caps;
/* sanity check driver support */ if (pc->of_pwm_n_cells < 2) @@ -182,7 +197,9 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) if (IS_ERR(pwm)) return pwm;
+ pwm_get_caps(pc, pwm, &caps); pwm->args.period = args->args[1]; + pwm->args.mode = BIT(ffs(caps.modes) - 1);
return pwm; } @@ -250,6 +267,39 @@ static bool pwm_ops_check(const struct pwm_ops *ops) }
/** + * pwm_get_caps() - get PWM capabilities + * @chip: PWM chip + * @pwm: PWM device to get the capabilities for + * @caps: returned capabilities + * + * Retrievers capabilities for PWM device. + */ +void pwm_get_caps(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_caps *caps) +{ + if (!chip || !pwm || !caps) + return; + + if (chip->ops && chip->ops->get_caps) + pwm->chip->ops->get_caps(chip, pwm, caps); + else if (chip->get_default_caps) + chip->get_default_caps(caps); +} +EXPORT_SYMBOL_GPL(pwm_get_caps); + +static void pwmchip_get_default_caps(struct pwm_caps *caps) +{ + static const struct pwm_caps default_caps = { + .modes = PWM_MODE(NORMAL), + }; + + if (!caps) + return; + + *caps = default_caps; +} + +/** * pwmchip_add_with_polarity() - register a new PWM chip * @chip: the PWM chip to add * @polarity: initial polarity of PWM channels @@ -264,7 +314,8 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, enum pwm_polarity polarity) { struct pwm_device *pwm; - unsigned int i; + struct pwm_caps caps; + unsigned int i, j; int ret;
if (!chip || !chip->dev || !chip->ops || !chip->npwm) @@ -275,6 +326,8 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
mutex_lock(&pwm_lock);
+ chip->get_default_caps = pwmchip_get_default_caps; + ret = alloc_pwms(chip->base, chip->npwm); if (ret < 0) goto out; @@ -295,6 +348,16 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, pwm->hwpwm = i; pwm->state.polarity = polarity;
+ pwm_get_caps(chip, pwm, &caps); + + /* Check if modes are supported. */ + if (!pwm_caps_valid(caps)) { + ret = -EINVAL; + goto free; + } + + pwm->state.mode = BIT(ffs(caps.modes) - 1); + if (chip->ops->get_state) chip->ops->get_state(chip, pwm, &pwm->state);
@@ -316,6 +379,17 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, out: mutex_unlock(&pwm_lock); return ret; + +free: + for (j = 0; j < i; j++) { + pwm = &chip->pwms[j]; + radix_tree_delete(&pwm_tree, pwm->pwm); + } + kfree(chip->pwms); + chip->pwms = NULL; + + mutex_unlock(&pwm_lock); + return ret; } EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
@@ -466,10 +540,17 @@ EXPORT_SYMBOL_GPL(pwm_free); */ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) { + struct pwm_caps caps; int err;
if (!pwm || !state || !state->period || - state->duty_cycle > state->period) + state->duty_cycle > state->period || + !pwm_mode_valid(state->mode)) + return -EINVAL; + + /* Check if mode is supported by PWM. */ + pwm_get_caps(pwm->chip, pwm, &caps); + if (!(caps.modes & state->mode)) return -EINVAL;
if (!memcmp(state, &pwm->state, sizeof(*state))) @@ -530,6 +611,9 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
pwm->state.enabled = state->enabled; } + + /* No mode support for non-atomic PWM. */ + pwm->state.mode = state->mode; }
return 0; @@ -579,6 +663,8 @@ int pwm_adjust_config(struct pwm_device *pwm) pwm_get_args(pwm, &pargs); pwm_get_state(pwm, &state);
+ state.mode = pargs.mode; + /* * If the current period is zero it means that either the PWM driver * does not support initial state retrieval or the PWM has not yet @@ -767,6 +853,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) unsigned int best = 0; struct pwm_lookup *p, *chosen = NULL; unsigned int match; + struct pwm_caps caps; int err;
/* look up via DT first */ @@ -848,8 +935,10 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) if (IS_ERR(pwm)) return pwm;
+ pwm_get_caps(chip, pwm, &caps); pwm->args.period = chosen->period; pwm->args.polarity = chosen->polarity; + pwm->args.mode = BIT(ffs(caps.modes) - 1);
return pwm; } @@ -999,6 +1088,7 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s) seq_printf(s, " duty: %u ns", state.duty_cycle); seq_printf(s, " polarity: %s", state.polarity ? "inverse" : "normal"); + seq_printf(s, " mode: %s", pwm_mode_desc(state.mode));
seq_puts(s, "\n"); } diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c index 83f2b0b15712..d9eb0eb63d23 100644 --- a/drivers/pwm/sysfs.c +++ b/drivers/pwm/sysfs.c @@ -223,11 +223,66 @@ static ssize_t capture_show(struct device *child, return sprintf(buf, "%u %u\n", result.period, result.duty_cycle); }
+static ssize_t mode_show(struct device *child, + struct device_attribute *attr, + char *buf) +{ + struct pwm_device *pwm = child_to_pwm_device(child); + struct pwm_state state; + struct pwm_caps caps; + int modebit, len = 0; + + pwm_get_state(pwm, &state); + pwm_get_caps(pwm->chip, pwm, &caps); + + for (modebit = PWM_MODE_NORMAL_BIT; modebit < PWM_MODE_CNT; modebit++) + if (caps.modes & BIT(modebit)) { + if (state.mode == BIT(modebit)) + len += scnprintf(buf + len, + PAGE_SIZE - len, "[%s] ", + pwm_mode_desc(BIT(modebit))); + else + len += scnprintf(buf + len, + PAGE_SIZE - len, "%s ", + pwm_mode_desc(BIT(modebit))); + } + + len += scnprintf(buf + len, PAGE_SIZE - len, "\n"); + + return len; +} + +static ssize_t mode_store(struct device *child, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct pwm_export *export = child_to_pwm_export(child); + struct pwm_device *pwm = export->pwm; + struct pwm_state state; + int modebit, ret; + + for (modebit = PWM_MODE_NORMAL_BIT; modebit < PWM_MODE_CNT; modebit++) + if (sysfs_streq(buf, pwm_mode_desc(BIT(modebit)))) + break; + + if (modebit == PWM_MODE_CNT) + return -EINVAL; + + mutex_lock(&export->lock); + pwm_get_state(pwm, &state); + state.mode = BIT(modebit); + ret = pwm_apply_state(pwm, &state); + mutex_unlock(&export->lock); + + return ret ? : size; +} + static DEVICE_ATTR_RW(period); static DEVICE_ATTR_RW(duty_cycle); static DEVICE_ATTR_RW(enable); static DEVICE_ATTR_RW(polarity); static DEVICE_ATTR_RO(capture); +static DEVICE_ATTR_RW(mode);
static struct attribute *pwm_attrs[] = { &dev_attr_period.attr, @@ -235,6 +290,7 @@ static struct attribute *pwm_attrs[] = { &dev_attr_enable.attr, &dev_attr_polarity.attr, &dev_attr_capture.attr, + &dev_attr_mode.attr, NULL }; ATTRIBUTE_GROUPS(pwm); diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 56518adc31dd..e62349f48129 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -26,9 +26,32 @@ enum pwm_polarity { };
/** + * PWM modes + * @PWM_MODE_NORMAL_BIT: PWM has one output + * @PWM_MODE_COMPLEMENTARY_BIT: PWM has 2 outputs with opposite polarities + * @PWM_MODE_CNT: PWM modes count + */ +enum { + PWM_MODE_NORMAL_BIT, + PWM_MODE_COMPLEMENTARY_BIT, + PWM_MODE_CNT, +}; + +#define PWM_MODE(name) BIT(PWM_MODE_##name##_BIT) + +/** + * struct pwm_caps - PWM capabilities + * @modes: PWM modes + */ +struct pwm_caps { + unsigned long modes; +}; + +/** * struct pwm_args - board-dependent PWM arguments * @period: reference period * @polarity: reference polarity + * @mode: reference mode * * This structure describes board-dependent arguments attached to a PWM * device. These arguments are usually retrieved from the PWM lookup table or @@ -41,6 +64,7 @@ enum pwm_polarity { struct pwm_args { unsigned int period; enum pwm_polarity polarity; + unsigned long mode; };
enum { @@ -53,12 +77,14 @@ enum { * @period: PWM period (in nanoseconds) * @duty_cycle: PWM duty cycle (in nanoseconds) * @polarity: PWM polarity + * @mode: PWM mode * @enabled: PWM enabled status */ struct pwm_state { unsigned int period; unsigned int duty_cycle; enum pwm_polarity polarity; + unsigned long mode; bool enabled; };
@@ -181,6 +207,7 @@ static inline void pwm_init_state(const struct pwm_device *pwm, state->period = args.period; state->polarity = args.polarity; state->duty_cycle = 0; + state->mode = args.mode; }
/** @@ -254,6 +281,7 @@ pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle, * @get_state: get the current PWM state. This function is only * called once per PWM device when the PWM chip is * registered. + * @get_caps: get PWM capabilities. * @dbg_show: optional routine to show contents in debugfs * @owner: helps prevent removal of modules exporting active PWMs */ @@ -272,6 +300,8 @@ struct pwm_ops { struct pwm_state *state); void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state); + void (*get_caps)(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_caps *caps); #ifdef CONFIG_DEBUG_FS void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s); #endif @@ -287,6 +317,7 @@ struct pwm_ops { * @npwm: number of PWMs controlled by this chip * @pwms: array of PWM devices allocated by the framework * @of_xlate: request a PWM device given a device tree PWM specifier + * @get_default_caps: get default PWM capabilities * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier */ struct pwm_chip { @@ -300,6 +331,7 @@ struct pwm_chip {
struct pwm_device * (*of_xlate)(struct pwm_chip *pc, const struct of_phandle_args *args); + void (*get_default_caps)(struct pwm_caps *caps); unsigned int of_pwm_n_cells; };
@@ -424,6 +456,37 @@ static inline void pwm_disable(struct pwm_device *pwm) pwm_apply_state(pwm, &state); }
+static inline bool pwm_mode_valid(unsigned long mode) +{ + return (mode && + hweight_long(mode) == 1 && + ffs(mode) - 1 < PWM_MODE_CNT); +} + +static inline bool pwm_caps_valid(struct pwm_caps caps) +{ + unsigned int last; + + if (!caps.modes) + return false; + + last = fls(caps.modes) - 1; + if (last >= PWM_MODE_CNT) + return false; + + return true; +} + +static inline const char * const pwm_mode_desc(unsigned long mode) +{ + static const char * const modes[] = { "normal", "complementary" }; + + if (!pwm_mode_valid(mode)) + return "invalid"; + + return modes[ffs(mode) - 1]; +} + /* PWM provider APIs */ int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result, unsigned long timeout); @@ -438,6 +501,9 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, unsigned int index, const char *label);
+void pwm_get_caps(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_caps *caps); + struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args);
@@ -498,6 +564,26 @@ static inline void pwm_disable(struct pwm_device *pwm) { }
+static inline bool pwm_mode_valid(unsigned long mode) +{ + return false; +} + +static inline bool pwm_caps_valid(struct pwm_caps caps) +{ + return false; +} + +static inline const char * const pwm_mode_desc(unsigned long mode) +{ + return NULL; +} + +static inline void pwm_get_caps(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_caps *caps) +{ +} + static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) { return -EINVAL; @@ -592,6 +678,7 @@ static inline void pwm_apply_args(struct pwm_device *pwm) state.enabled = false; state.polarity = pwm->args.polarity; state.period = pwm->args.period; + state.mode = pwm->args.mode;
pwm_apply_state(pwm, &state); }