For backward compatibility board device tree may define amount of only
mandatory pwm properties, which is compared to a pwm driver specific
value, by default it is 2 and may be overwritten by a driver.
Any additional arguments shall be considered as optional and they are
taken into account, only if #pwm-cells is increased accordingly.
As a positive side effect specific pwm-specifier array may have
variable size of #pwm-cells (but not less than amount of mandatory
arguments), which allows to omit optional arguments. The parameters
array of a specific PWM is updated according to the actual data taken
from device tree file.
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@xxxxxxxxxx>
Cc: Lothar Waßmann <LW@xxxxxxxxxxxxxxxxxxx>
Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
---
drivers/pwm/core.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index f6231c6..4d9fc7f 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -543,12 +543,13 @@ 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) {
+ if (args.args_count < pc->of_pwm_n_cells) {
pr_err("%s: wrong #pwm-cells for %s\n", np->full_name,
args.np->full_name);
pwm = ERR_PTR(-EINVAL);
goto put;
}
+ pc->of_pwm_n_cells = args.args_count;
pwm = pc->of_xlate(pc, &args);
if (IS_ERR(pwm))
--
1.7.10.4
--
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