From: Claudiu Beznea <claudiu.bez...@microchip.com> 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 PWM capabilities (in this case the PWM capabilities will contain only PWM normal mode). To retrieve capabilities the pwm_get_caps() function could be used. Every PWM channel have associated a mode in the PWM state. Proper support was added to get/set PWM mode. Only modes supported by PWM channel could be set. Signed-off-by: Claudiu Beznea <claudiu.bez...@microchip.com> --- drivers/pwm/core.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++- drivers/pwm/sysfs.c | 61 +++++++++++++++++++++++++++++++++++ include/linux/pwm.h | 35 +++++++++++++++++++++ 3 files changed, 186 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 1581f6ab1b1f..eb444ee8d486 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -249,6 +249,88 @@ static bool pwm_ops_check(const struct pwm_ops *ops) return false; } +static int pwm_get_default_caps(struct pwm_caps *caps) +{ + static const struct pwm_caps default_caps = { + .modes_msk = PWM_MODE_BIT(NORMAL), + }; + + if (!caps) + return -EINVAL; + + *caps = default_caps; + + return 0; +} + +/** + * pwm_get_caps() - get PWM capabilities of a PWM device + * @pwm: PWM device to get the capabilities for + * @caps: returned capabilities + * + * Returns: 0 on success or a negative error code on failure + */ +int pwm_get_caps(const struct pwm_device *pwm, struct pwm_caps *caps) +{ + if (!pwm || !caps) + return -EINVAL; + + if (pwm->chip->ops->get_caps) + return pwm->chip->ops->get_caps(pwm->chip, pwm, caps); + + return pwm_get_default_caps(caps); +} +EXPORT_SYMBOL_GPL(pwm_get_caps); + +/** + * pwm_get_default_modebit() - get the default mode for PWM (as a bit mask) + * @pwm: PWM device to get the default mode for + * + * Returns: the default PWM mode (as a bit mask) for PWM device + */ +unsigned long pwm_get_default_modebit(const struct pwm_device *pwm) +{ + struct pwm_caps caps; + + if (pwm_get_caps(pwm, &caps)) + return PWM_MODE_BIT(NORMAL); + + return BIT(ffs(caps.modes_msk) - 1); +} +EXPORT_SYMBOL_GPL(pwm_get_default_modebit); + +/** + * pwm_supports_mode() - check if PWM mode is supported by PWM device + * @pwm: PWM device + * @modebit: PWM mode bit mask to be checked (see PWM_MODE_BIT()) + * + * Returns: true if PWM mode is supported, false otherwise + */ +bool pwm_supports_mode(const struct pwm_device *pwm, unsigned long modebit) +{ + struct pwm_caps caps; + + if (!pwm || !modebit) + return false; + + if (hweight_long(modebit) != 1 || ffs(modebit) - 1 >= PWM_MODE_CNT) + return false; + + if (pwm_get_caps(pwm, &caps)) + return false; + + return !!(caps.modes_msk & modebit); +} +EXPORT_SYMBOL_GPL(pwm_supports_mode); + +const char *pwm_get_mode_name(unsigned long modebit) +{ + if (modebit == PWM_MODE_BIT(COMPLEMENTARY)) + return "complementary"; + + return "normal"; +} + /** * pwmchip_add_with_polarity() - register a new PWM chip * @chip: the PWM chip to add @@ -294,6 +376,7 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip, pwm->pwm = chip->base + i; pwm->hwpwm = i; pwm->state.polarity = polarity; + pwm->state.modebit = pwm_get_default_modebit(pwm); if (chip->ops->get_state) chip->ops->get_state(chip, pwm, &pwm->state); @@ -469,7 +552,8 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) int err; if (!pwm || !state || !state->period || - state->duty_cycle > state->period) + state->duty_cycle > state->period || + !pwm_supports_mode(pwm, state->modebit)) return -EINVAL; if (!memcmp(state, &pwm->state, sizeof(*state))) @@ -530,6 +614,8 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) pwm->state.enabled = state->enabled; } + + pwm->state.modebit = state->modebit; } return 0; @@ -579,6 +665,8 @@ int pwm_adjust_config(struct pwm_device *pwm) pwm_get_args(pwm, &pargs); pwm_get_state(pwm, &state); + state.modebit = pwm_get_default_modebit(pwm); + /* * 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 @@ -999,6 +1087,7 @@ 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_get_mode_name(state.modebit)); seq_puts(s, "\n"); } diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c index ceb233dd6048..7865fbafbeb4 100644 --- a/drivers/pwm/sysfs.c +++ b/drivers/pwm/sysfs.c @@ -223,11 +223,71 @@ 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; + unsigned long modebit; + enum pwm_mode mode; + int len = 0; + + pwm_get_state(pwm, &state); + + for (mode = PWM_MODE_NORMAL; mode < PWM_MODE_CNT; mode++) { + modebit = BIT(mode); + if (pwm_supports_mode(pwm, modebit)) { + if (state.modebit == modebit) + len += scnprintf(buf + len, + PAGE_SIZE - len, "[%s] ", + pwm_get_mode_name(modebit)); + else + len += scnprintf(buf + len, + PAGE_SIZE - len, "%s ", + pwm_get_mode_name(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; + unsigned long modebit; + enum pwm_mode mode; + int ret; + + for (mode = PWM_MODE_NORMAL; mode < PWM_MODE_CNT; mode++) { + modebit = BIT(mode); + if (sysfs_streq(buf, pwm_get_mode_name(modebit))) + break; + } + + if (mode == PWM_MODE_CNT) + return -EINVAL; + + mutex_lock(&export->lock); + pwm_get_state(pwm, &state); + state.modebit = 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 +295,7 @@ 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..abe189d891af 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -10,6 +10,9 @@ struct pwm_capture; struct seq_file; struct pwm_chip; +struct pwm_device; + +unsigned long pwm_get_default_modebit(const struct pwm_device *pwm); /** * enum pwm_polarity - polarity of a PWM signal @@ -26,6 +29,28 @@ enum pwm_polarity { }; /** + * PWM modes capabilities + * @PWM_MODE_NORMAL: PWM has one output + * @PWM_MODE_COMPLEMENTARY: PWM has 2 outputs with opposite polarities + * @PWM_MODE_CNT: PWM modes count + */ +enum pwm_mode { + PWM_MODE_NORMAL, + PWM_MODE_COMPLEMENTARY, + PWM_MODE_CNT, +}; + +#define PWM_MODE_BIT(name) BIT(PWM_MODE_##name) + +/** + * struct pwm_caps - PWM capabilities + * @modes_msk: bitmask of supported modes (see PWM_MODE_*) + */ +struct pwm_caps { + unsigned long modes_msk; +}; + +/** * struct pwm_args - board-dependent PWM arguments * @period: reference period * @polarity: reference polarity @@ -53,12 +78,14 @@ enum { * @period: PWM period (in nanoseconds) * @duty_cycle: PWM duty cycle (in nanoseconds) * @polarity: PWM polarity + * @modebit: PWM mode bit * @enabled: PWM enabled status */ struct pwm_state { unsigned int period; unsigned int duty_cycle; enum pwm_polarity polarity; + unsigned long modebit; bool enabled; }; @@ -181,6 +208,7 @@ static inline void pwm_init_state(const struct pwm_device *pwm, state->period = args.period; state->polarity = args.polarity; state->duty_cycle = 0; + state->modebit = pwm_get_default_modebit(pwm); } /** @@ -254,6 +282,7 @@ 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 +301,8 @@ struct pwm_ops { struct pwm_state *state); void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state); + int (*get_caps)(const struct pwm_chip *chip, + const struct pwm_device *pwm, struct pwm_caps *caps); #ifdef CONFIG_DEBUG_FS void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s); #endif @@ -438,6 +469,9 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, unsigned int index, const char *label); +int pwm_get_caps(const struct pwm_device *pwm, struct pwm_caps *caps); +bool pwm_supports_mode(const struct pwm_device *pwm, unsigned long modebit); +const char *pwm_get_mode_name(unsigned long modebit); struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args); @@ -592,6 +626,7 @@ static inline void pwm_apply_args(struct pwm_device *pwm) state.enabled = false; state.polarity = pwm->args.polarity; state.period = pwm->args.period; + state.modebit = pwm_get_default_modebit(pwm); pwm_apply_state(pwm, &state); } -- 2.7.4