| Message ID | 1353347472-26863-1-git-send-email-avinashphilip@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Nov 19, 2012 at 11:21:12PM +0530, Philip, Avinash wrote: [...] > diff --git a/include/linux/pwm.h b/include/linux/pwm.h > index 112b314..70756f2 100644 > --- a/include/linux/pwm.h > +++ b/include/linux/pwm.h > @@ -78,6 +78,10 @@ enum { > PWMF_ENABLED = 1 << 1, > }; > > +/* flags in the third cell of the DT PWM specifier */ > +#define PWM_SPEC_POLARITY (1 << 0) > + > + This doesn't belong in this header. It should go into core.c in drivers/pwm. > struct pwm_device { > const char *label; > unsigned long flags; > @@ -176,6 +180,8 @@ void pwm_put(struct pwm_device *pwm); > > struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer); > void devm_pwm_put(struct device *dev, struct pwm_device *pwm); > +struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, > + const struct of_phandle_args *args); The placement of this prototype is odd. I think a better place would be between pwm_request_from_chip() and pwm_get(), separated by blank lines to make it stand out as an OF specific function. > #else > static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) > { > @@ -223,6 +229,12 @@ static inline struct pwm_device *devm_pwm_get(struct device *dev, > static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm) > { > } > + > +static inline struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, > + const struct of_phandle_args *args) > +{ > + return ERR_PTR(-ENODEV); > +} This function should only be used by PWM drivers and therefore doesn't need to have a dummy implementation such as this. Thierry
On Tue, Nov 20, 2012 at 20:37:55, Thierry Reding wrote: > On Mon, Nov 19, 2012 at 11:21:12PM +0530, Philip, Avinash wrote: > [...] > > diff --git a/include/linux/pwm.h b/include/linux/pwm.h > > index 112b314..70756f2 100644 > > --- a/include/linux/pwm.h > > +++ b/include/linux/pwm.h > > @@ -78,6 +78,10 @@ enum { > > PWMF_ENABLED = 1 << 1, > > }; > > > > +/* flags in the third cell of the DT PWM specifier */ > > +#define PWM_SPEC_POLARITY (1 << 0) > > + > > + > > This doesn't belong in this header. It should go into core.c in > drivers/pwm. I will move. > > > struct pwm_device { > > const char *label; > > unsigned long flags; > > @@ -176,6 +180,8 @@ void pwm_put(struct pwm_device *pwm); > > > > struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer); > > void devm_pwm_put(struct device *dev, struct pwm_device *pwm); > > +struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, > > + const struct of_phandle_args *args); > > The placement of this prototype is odd. I think a better place would be > between pwm_request_from_chip() and pwm_get(), separated by blank lines > to make it stand out as an OF specific function. Ok I will move to between pwm_request_from_chip() and pwm_get(). > > > #else > > static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) > > { > > @@ -223,6 +229,12 @@ static inline struct pwm_device *devm_pwm_get(struct device *dev, > > static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm) > > { > > } > > + > > +static inline struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, > > + const struct of_phandle_args *args) > > +{ > > + return ERR_PTR(-ENODEV); > > +} > > This function should only be used by PWM drivers and therefore doesn't > need to have a dummy implementation such as this. Ok I will remove. Thanks Avinash > > Thierry >
diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt index 73ec962..04b0dc4 100644 --- a/Documentation/devicetree/bindings/pwm/pwm.txt +++ b/Documentation/devicetree/bindings/pwm/pwm.txt @@ -37,10 +37,22 @@ device: pwm-names = "backlight"; }; +Note that in the example above, specifying the "pwm-names" is redundant +because the name "backlight" would be used as fallback anyway. + pwm-specifier typically encodes the chip-relative PWM number and the PWM -period in nanoseconds. Note that in the example above, specifying the -"pwm-names" is redundant because the name "backlight" would be used as -fallback anyway. +period in nanoseconds. + +Optionally, the pwm-specifier can encode a number of flags in a third cell: +- bit 0: PWM signal polarity (0: normal polarity, 1: inverse polarity) + +Example with optional PWM specifier for inverse polarity + + bl: backlight { + pwms = <&pwm 0 5000000 1>; + pwm-names = "backlight"; + }; + 2) PWM controller nodes ----------------------- diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index f5acdaa..9b49e78 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -129,6 +129,31 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) return 0; } +struct pwm_device * +of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) +{ + struct pwm_device *pwm; + + if (pc->of_pwm_n_cells < 3) + return ERR_PTR(-EINVAL); + + if (args->args[0] >= pc->npwm) + return ERR_PTR(-EINVAL); + + pwm = pwm_request_from_chip(pc, args->args[0], NULL); + if (IS_ERR(pwm)) + return pwm; + + pwm_set_period(pwm, args->args[1]); + + if (args->args[2] & PWM_SPEC_POLARITY) + pwm_set_polarity(pwm, PWM_POLARITY_INVERSED); + else + pwm_set_polarity(pwm, PWM_POLARITY_NORMAL); + + return pwm; +} + static struct pwm_device * of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) { diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 112b314..70756f2 100644 --- a/include/linux/pwm.h +++ b/include/linux/pwm.h @@ -78,6 +78,10 @@ enum { PWMF_ENABLED = 1 << 1, }; +/* flags in the third cell of the DT PWM specifier */ +#define PWM_SPEC_POLARITY (1 << 0) + + struct pwm_device { const char *label; unsigned long flags; @@ -176,6 +180,8 @@ void pwm_put(struct pwm_device *pwm); struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer); void devm_pwm_put(struct device *dev, struct pwm_device *pwm); +struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, + const struct of_phandle_args *args); #else static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data) { @@ -223,6 +229,12 @@ static inline struct pwm_device *devm_pwm_get(struct device *dev, static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm) { } + +static inline struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc, + const struct of_phandle_args *args) +{ + return ERR_PTR(-ENODEV); +} #endif struct pwm_lookup {
Add support for encoding PWM properties in bit encoded form with of_pwm_xlate_with_flags() function support. Platforms require platform specific PWM properties has to populate in 3rd cell of the pwm-specifier and PWM driver should also set .of_xlate support with this function. Currently PWM property polarity encoded in bit position 0 of the third cell in pwm-specifier. Signed-off-by: Philip, Avinash <avinashphilip@ti.com> --- Changes since v1: - of_pwm_xlate_with_flags function support added. - Documentation update :100644 100644 73ec962... 04b0dc4... M Documentation/devicetree/bindings/pwm/pwm.txt :100644 100644 f5acdaa... 9b49e78... M drivers/pwm/core.c :100644 100644 112b314... 70756f2... M include/linux/pwm.h Documentation/devicetree/bindings/pwm/pwm.txt | 18 +++++++++++++++--- drivers/pwm/core.c | 25 +++++++++++++++++++++++++ include/linux/pwm.h | 12 ++++++++++++ 3 files changed, 52 insertions(+), 3 deletions(-)