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authorPhilip, Avinash <avinashphilip@ti.com>2012-11-21 11:40:44 +0400
committerThierry Reding <thierry.reding@avionic-design.de>2012-11-23 01:47:12 +0400
commit83af24027b3df1af5c5a9aa9adcdcfeb3429d3be (patch)
tree3e104ed41554bb7e97378cc7cc3866c842306dff /drivers/pwm/core.c
parent422470a8265fbb1d182c00ab2421f4b416ab2dba (diff)
downloadlinux-83af24027b3df1af5c5a9aa9adcdcfeb3429d3be.tar.xz
pwm: Device tree support for PWM polarity
Add support for encoding PWM properties in bit encoded form with of_pwm_xlate_with_flags() function support. Platforms require platform specific PWM properties has to populate in 3rd cell of the pwm-specifier and PWM driver should also set .of_xlate support with this function. Currently PWM property polarity encoded in bit position 0 of the third cell in pwm-specifier. Signed-off-by: Philip, Avinash <avinashphilip@ti.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Diffstat (limited to 'drivers/pwm/core.c')
-rw-r--r--drivers/pwm/core.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index f5acdaa52707..780cb6b8a8f0 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -32,6 +32,9 @@
#define MAX_PWMS 1024
+/* flags in the third cell of the DT PWM specifier */
+#define PWM_SPEC_POLARITY (1 << 0)
+
static DEFINE_MUTEX(pwm_lookup_lock);
static LIST_HEAD(pwm_lookup_list);
static DEFINE_MUTEX(pwm_lock);
@@ -129,6 +132,31 @@ 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 *pwm;
+
+ if (pc->of_pwm_n_cells < 3)
+ 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]);
+
+ if (args->args[2] & PWM_SPEC_POLARITY)
+ pwm_set_polarity(pwm, PWM_POLARITY_INVERSED);
+ else
+ pwm_set_polarity(pwm, PWM_POLARITY_NORMAL);
+
+ return pwm;
+}
+
static struct pwm_device *
of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
{