Messages in this thread | | | Date | Wed, 2 Apr 2014 07:53:50 +0200 | From | Sascha Hauer <> | Subject | Re: [PATCHv3 1/3] pwm: make the PWM_POLARITY flag in DTB optional |
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On Fri, Mar 28, 2014 at 09:48:58AM +0100, Lothar Waßmann wrote: > Change the pwm chip driver registration, so that a chip driver that > supports polarity inversion can still be used with DTBs that don't > provide the 'PWM_POLARITY' flag. > > This is done to provide polarity inversion support for the pwm-imx > driver without having to modify all existing DTS files. > > Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de> > --- > drivers/pwm/core.c | 46 ++++++++++++++++------------------------------ > 1 file changed, 16 insertions(+), 30 deletions(-) > diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c > index a804713..dc15543 100644 > --- a/drivers/pwm/core.c > +++ b/drivers/pwm/core.c > @@ -131,12 +131,12 @@ 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 *of_pwm_xlate(struct pwm_chip *pc, > + const struct of_phandle_args *args) > { > struct pwm_device *pwm; > > - if (pc->of_pwm_n_cells < 3) > + if (pc->of_pwm_n_cells < 2) > return ERR_PTR(-EINVAL); > > if (args->args[0] >= pc->npwm) > @@ -148,6 +148,9 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) > > pwm_set_period(pwm, args->args[1]); > > + if (pc->of_pwm_n_cells < 3) > + return pwm; > + > if (args->args[2] & PWM_POLARITY_INVERTED) > pwm_set_polarity(pwm, PWM_POLARITY_INVERSED); > else > @@ -155,27 +158,14 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args) > > return pwm; > } > -EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); > > -static struct pwm_device * > -of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) > +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 < 2) > - 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]); > - > - return pwm; > + return of_pwm_xlate(pc, args); > } > +EXPORT_SYMBOL_GPL(of_pwm_xlate_with_flags); > > static void of_pwmchip_add(struct pwm_chip *chip) > { > @@ -183,8 +173,11 @@ static void of_pwmchip_add(struct pwm_chip *chip) > return; > > if (!chip->of_xlate) { > - chip->of_xlate = of_pwm_simple_xlate; > - chip->of_pwm_n_cells = 2; > + chip->of_xlate = of_pwm_xlate; > + if (chip->ops->set_polarity) > + chip->of_pwm_n_cells = 3; > + else > + chip->of_pwm_n_cells = 2;
I think the presence of the set_polarity callback shouldn't influence the number of cells the parser expects. As commented on 2/2 this doesn't actually mean the device actually support polarity inversion. Also, polarity inversion could still be done in software for hardware that doesn't support it.
Sascha
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