Hi Lukasz,
On 10/06/16 12:06, Lukasz Majewski wrote:
Hi Bhuvanchandra,
From: Lothar Wassmann <[email protected]>
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 <[email protected]>
Signed-off-by: Bhuvanchandra DV <[email protected]>
Suggested-by: Thierry Reding <[email protected]>
---
drivers/pwm/core.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 195373e..aae8db3 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);
@@ -149,10 +154,12 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc,
const struct of_phandle_args *args)
pwm->args.period = args->args[1];
- if (args->args[2] & PWM_POLARITY_INVERTED)
- pwm->args.polarity = PWM_POLARITY_INVERSED;
- else
- pwm->args.polarity = PWM_POLARITY_NORMAL;
+ if (args->args_count > 2) {
+ if (args->args[2] & PWM_POLARITY_INVERTED)
+ pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
^^^^^^^^^^^^^^^^
here we should set pwm->args.polarity, since
the pwm_set_polarity() calls pwm_apply_state()
which requires duty_cycle and period to be set.
In this particular moment it is not yet set and
polarity is not properly configured.
Agreed. Will do a clean v3 patchset along with the patch you sent
(pwm: core: Use pwm->args.polarity to setup PWM_POLARITY_INVERSED).
--
Bhuvan
Patch fixing this will be sent as a reply to this e-mail. Please just
squash it and test on your platform.
Best regards,
Łukasz Majewski
+ else
+ pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
+ }
return pwm;
}
@@ -163,9 +170,14 @@ 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 +684,6 @@ 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;
