diff options
author | Thierry Reding <thierry.reding@avionic-design.de> | 2011-12-14 11:12:23 +0100 |
---|---|---|
committer | Thierry Reding <thierry.reding@avionic-design.de> | 2012-06-15 12:56:52 +0200 |
commit | f051c466cf690ac661d713d3ceb56b4efcecc853 (patch) | |
tree | 15291a08d3ec44e8ab81c44370e1ac2bbb366ec5 /include | |
parent | 0c2498f1660878339350bea8d18550b1b87ca055 (diff) |
pwm: Allow chips to support multiple PWMs
Many PWM controllers provide access to more than a single PWM output and
may even share some resource among them. Allowing a PWM chip to provide
multiple PWM devices enables better sharing of those resources. As a
side-effect this change allows easy integration with the device tree
where a given PWM can be looked up based on the PWM chip's phandle and a
corresponding index.
This commit modifies the PWM core to support multiple PWMs per struct
pwm_chip. It achieves this in a similar way to how gpiolib works, by
allowing PWM ranges to be requested dynamically (pwm_chip.base == -1) or
starting at a given offset (pwm_chip.base >= 0). A chip specifies how
many PWMs it controls using the npwm member. Each of the functions in
the pwm_ops structure gets an additional argument that specified the PWM
number (it can be converted to a per-chip index by subtracting the
chip's base).
The total maximum number of PWM devices is currently fixed to 1024 while
the data is actually stored in a radix tree, thus saving resources if
not all of them are used.
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
[eric@eukrea.com: fix error handling in pwmchip_add]
Signed-off-by: Eric BĂ©nard <eric@eukrea.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/pwm.h | 71 |
1 files changed, 58 insertions, 13 deletions
diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 1f308a13105f..57103911f4c7 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -31,6 +31,33 @@ void pwm_disable(struct pwm_device *pwm); #ifdef CONFIG_PWM struct pwm_chip; +enum { + PWMF_REQUESTED = 1 << 0, + PWMF_ENABLED = 1 << 1, +}; + +struct pwm_device { + const char *label; + unsigned long flags; + unsigned int hwpwm; + unsigned int pwm; + struct pwm_chip *chip; + void *chip_data; + + unsigned int period; /* in nanoseconds */ +}; + +static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period) +{ + if (pwm) + pwm->period = period; +} + +static inline unsigned int pwm_get_period(struct pwm_device *pwm) +{ + return pwm ? pwm->period : 0; +} + /** * struct pwm_ops - PWM controller operations * @request: optional hook for requesting a PWM @@ -41,29 +68,47 @@ struct pwm_chip; * @owner: helps prevent removal of modules exporting active PWMs */ struct pwm_ops { - int (*request)(struct pwm_chip *chip); - void (*free)(struct pwm_chip *chip); - int (*config)(struct pwm_chip *chip, int duty_ns, - int period_ns); - int (*enable)(struct pwm_chip *chip); - void (*disable)(struct pwm_chip *chip); + int (*request)(struct pwm_chip *chip, + struct pwm_device *pwm); + void (*free)(struct pwm_chip *chip, + struct pwm_device *pwm); + int (*config)(struct pwm_chip *chip, + struct pwm_device *pwm, + int duty_ns, int period_ns); + int (*enable)(struct pwm_chip *chip, + struct pwm_device *pwm); + void (*disable)(struct pwm_chip *chip, + struct pwm_device *pwm); struct module *owner; }; /** - * struct pwm_chip - abstract a PWM - * @pwm_id: global PWM device index - * @label: PWM device label - * @ops: controller operations + * struct pwm_chip - abstract a PWM controller + * @dev: device providing the PWMs + * @list: list node for internal use + * @ops: callbacks for this PWM controller + * @base: number of first PWM controlled by this chip + * @npwm: number of PWMs controlled by this chip + * @pwms: array of PWM devices allocated by the framework */ struct pwm_chip { - int pwm_id; - const char *label; - struct pwm_ops *ops; + struct device *dev; + struct list_head list; + const struct pwm_ops *ops; + int base; + unsigned int npwm; + + struct pwm_device *pwms; }; +int pwm_set_chip_data(struct pwm_device *pwm, void *data); +void *pwm_get_chip_data(struct pwm_device *pwm); + int pwmchip_add(struct pwm_chip *chip); int pwmchip_remove(struct pwm_chip *chip); +struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip, + unsigned int index, + const char *label); #endif #endif /* __LINUX_PWM_H */ |