[PATCH v5 01/24] pwm: introduce the pwm_args concept
From: Boris Brezillon <hidden>
Date: 2016-04-14 19:18:12
Also in:
intel-gfx, linux-arm-kernel, linux-clk, linux-input, linux-leds, linux-pwm, linux-rockchip, linux-samsung-soc, lkml
Subsystem:
pwm subsystem, the rest · Maintainers:
Uwe Kleine-König, Linus Torvalds
Currently the PWM core mixes the current PWM state with the per-platform reference config (specified through the PWM lookup table, DT definition or directly hardcoded in PWM drivers). Create a pwm_args struct to store this reference config, so that PWM users can differentiate the current config from the reference one. Patch all places where pwm->args should be initialized. We keep the pwm_set_polarity/period() calls until all PWM users are patched to use pwm_args instead of pwm_get_period/polarity(). Signed-off-by: Boris Brezillon <redacted> --- drivers/pwm/core.c | 22 +++++++++++++++------- drivers/pwm/pwm-clps711x.c | 2 +- drivers/pwm/pwm-pxa.c | 2 +- include/linux/pwm.h | 32 ++++++++++++++++++++++++++++++++ 4 files changed, 49 insertions(+), 9 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 7c330ff..ac89529 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c@@ -128,6 +128,14 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) set_bit(PWMF_REQUESTED, &pwm->flags); pwm->label = label; + /* + * FIXME: this should be removed as soon as all PWM users are + * properly making use of pwm_args to initialize the PWM device. + * If we don't get rid of it, then PWM state and hardware can be + * desynchronized. + */ + pwm_apply_args(pwm); + return 0; }
@@ -146,12 +154,12 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) if (IS_ERR(pwm)) return pwm; - pwm_set_period(pwm, args->args[1]); + pwm->args.period = args->args[1]; if (args->args[2] & PWM_POLARITY_INVERTED) - pwm_set_polarity(pwm, PWM_POLARITY_INVERSED); + pwm->args.polarity = PWM_POLARITY_INVERSED; else - pwm_set_polarity(pwm, PWM_POLARITY_NORMAL); + pwm->args.polarity = PWM_POLARITY_NORMAL; return pwm; }
@@ -172,7 +180,7 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) if (IS_ERR(pwm)) return pwm; - pwm_set_period(pwm, args->args[1]); + pwm->args.period = args->args[1]; return pwm; }
@@ -736,13 +744,13 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) if (!chip) goto out; + pwm->args.period = chosen->period; + pwm->args.polarity = chosen->polarity; + pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id); if (IS_ERR(pwm)) goto out; - pwm_set_period(pwm, chosen->period); - pwm_set_polarity(pwm, chosen->polarity); - out: mutex_unlock(&pwm_lookup_lock); return pwm;
diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index a80c108..7d33542 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c@@ -60,7 +60,7 @@ static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) return -EINVAL; /* Store constant period value */ - pwm_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq)); + pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq); return 0; }
diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
index cb2f702..58b709f 100644
--- a/drivers/pwm/pwm-pxa.c
+++ b/drivers/pwm/pwm-pxa.c@@ -160,7 +160,7 @@ pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) if (IS_ERR(pwm)) return pwm; - pwm_set_period(pwm, args->args[0]); + pwm->args.period = args->args[0]; return pwm; }
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 6555f01..c8859b7 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h@@ -74,6 +74,23 @@ enum pwm_polarity { PWM_POLARITY_INVERSED, }; +/** + * struct pwm_args - PWM arguments + * @period: reference period + * @polarity: reference polarity + * + * This structure describes board-dependent arguments attached to a PWM + * device. Those arguments are usually retrieved from the PWM lookup table or + * DT definition. + * This should not be confused with the PWM state: PWM args don't represent + * the current PWM state, but the configuration the PWM user plans to use + * on this PWM device. + */ +struct pwm_args { + unsigned int period; + enum pwm_polarity polarity; +}; + enum { PWMF_REQUESTED = 1 << 0, PWMF_ENABLED = 1 << 1,
@@ -91,6 +108,7 @@ enum { * @period: period of the PWM signal (in nanoseconds) * @duty_cycle: duty cycle of the PWM signal (in nanoseconds) * @polarity: polarity of the PWM signal + * @args: PWM arguments */ struct pwm_device { const char *label;
@@ -103,6 +121,8 @@ struct pwm_device { unsigned int period; unsigned int duty_cycle; enum pwm_polarity polarity; + + struct pwm_args args; }; static inline bool pwm_is_enabled(const struct pwm_device *pwm)
@@ -142,6 +162,18 @@ static inline enum pwm_polarity pwm_get_polarity(const struct pwm_device *pwm) return pwm ? pwm->polarity : PWM_POLARITY_NORMAL; } +static inline void pwm_get_args(const struct pwm_device *pwm, + struct pwm_args *args) +{ + *args = pwm->args; +} + +static inline void pwm_apply_args(struct pwm_device *pwm) +{ + pwm_set_period(pwm, pwm->args.period); + pwm_set_polarity(pwm, pwm->args.polarity); +} + /** * struct pwm_ops - PWM controller operations * @request: optional hook for requesting a PWM
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2.5.0