[PATCH v3 2/6] pwm: core: make the PWM_POLARITY flag in DTB optional

Bhuvanchandra DV
2016-10-07T18:47:09Z

From: Lothar Wassmann <LW@KARO-electronics.de>

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>
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Suggested-by: Sascha Hauer <s.hauer at pengutronix.de>
---
drivers/pwm/core.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 195373e..85cdda6 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -137,9 +137,14 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;

+ /* check, whether the driver supports a third cell for flags */
if (pc->of_pwm_n_cells < 3)
return ERR_PTR(-EINVAL);

+ /* flags in the third cell are optional */
+ if (args->args_count < 2)
+ return ERR_PTR(-EINVAL);
+
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);

@@ -148,11 +153,10 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
return pwm;

pwm->args.period = args->args[1];
+ pwm->args.polarity = PWM_POLARITY_NORMAL;

- if (args->args[2] & PWM_POLARITY_INVERTED)
+ if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
pwm->args.polarity = PWM_POLARITY_INVERSED;
- else
- pwm->args.polarity = PWM_POLARITY_NORMAL;

return pwm;
}
@@ -163,9 +167,14 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
{
struct pwm_device *pwm;

+ /* sanity check driver support */
if (pc->of_pwm_n_cells < 2)
return ERR_PTR(-EINVAL);

+ /* all cells are required */
+ if (args->args_count != pc->of_pwm_n_cells)
+ return ERR_PTR(-EINVAL);
+
if (args->args[0] >= pc->npwm)
return ERR_PTR(-EINVAL);

@@ -672,13 +681,6 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
goto put;
}

- if (args.args_count != pc->of_pwm_n_cells) {
- pr_debug("%s: wrong #pwm-cells for %s\n", np->full_name,
- args.np->full_name);
- pwm = ERR_PTR(-EINVAL);
- goto put;
- }
-
pwm = pc->of_xlate(pc, &args);
if (IS_ERR(pwm))
goto put;
--
2.10.0