[PATCH v2 3/3] pwm: jz4740: Allow selection of PWM channels 0 and 1

Paul Cercueil
2019-11-16T17:42:57Z

The TCU channels 0 and 1 were previously reserved for system tasks, and
thus unavailable for PWM.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
---

Notes:
v2: No change

drivers/pwm/pwm-jz4740.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
index a5368b98652d..801dfabfa6f4 100644
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -33,6 +33,19 @@ static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
return container_of(chip, struct jz4740_pwm_chip, chip);
}

+static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz,
+ unsigned int channel)
+{
+ /* Enable all TCU channels for PWM use by default except channels 0/1 */
+ u32 pwm_channels_mask = GENMASK(NUM_PWM - 1, 2);
+
+ device_property_read_u32(jz->chip.dev->parent,
+ "ingenic,pwm-channels-mask",
+ &pwm_channels_mask);
+
+ return !!(pwm_channels_mask & BIT(channel));
+}
+
static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct jz4740_pwm_chip *jz = to_jz4740(chip);
@@ -40,11 +53,7 @@ static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
char clk_name[16];
int ret;

- /*
- * Timers 0 and 1 are used for system tasks, so they are unavailable
- * for use as PWMs.
- */
- if (pwm->hwpwm < 2)
+ if (!jz4740_pwm_can_use_chn(jz, pwm->hwpwm))
return -EBUSY;

snprintf(clk_name, sizeof(clk_name), "timer%u", pwm->hwpwm);
--
2.24.0