From 42883cbc086b3f7aca9f1754f2d570af922825fc Mon Sep 17 00:00:00 2001 From: Lothar Wassmann Date: Sun, 29 Jan 2017 22:54:13 +0100 Subject: [PATCH] pwm: Make the PWM_POLARITY flag in DTB optional 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 polarity flag as part of the specifier. 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 Signed-off-by: Bhuvanchandra DV Suggested-by: Sascha Hauer Signed-off-by: Lukasz Majewski Reviewed-by: Boris Brezillon Signed-off-by: Thierry Reding --- 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 012e27c..e3d6c54 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); @@ -674,13 +683,6 @@ 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; -- 2.7.4