Hi Clemens, minor nit below.
On Wed, Dec 16, 2020 at 7:53 AM Clemens Gruber
<[email protected]> wrote:
>
> Reset the prescale and ON/OFF registers to their POR default state in
> the probe function. Otherwise, the PWMs could still be active after a
> watchdog reset and reboot, etc.
>
> Signed-off-by: Clemens Gruber <[email protected]>
> ---
> drivers/pwm/pwm-pca9685.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c
> index 7b14447f3c05..38aadaf50996 100644
> --- a/drivers/pwm/pwm-pca9685.c
> +++ b/drivers/pwm/pwm-pca9685.c
> @@ -47,6 +47,7 @@
> #define PCA9685_ALL_LED_OFF_H 0xFD
> #define PCA9685_PRESCALE 0xFE
>
> +#define PCA9685_PRESCALE_DEF 0x1E /* => default frequency of ~200 Hz */
> #define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
> #define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */
>
> @@ -446,9 +447,11 @@ static int pca9685_pwm_probe(struct i2c_client *client,
> reg &= ~(MODE1_ALLCALL | MODE1_SUB1 | MODE1_SUB2 | MODE1_SUB3);
> regmap_write(pca->regmap, PCA9685_MODE1, reg);
>
> - /* Clear all "full off" bits */
> + /* Reset ON/OFF registers to HW defaults (only full OFF bit is set) */
> + regmap_write(pca->regmap, PCA9685_ALL_LED_ON_L, 0);
> + regmap_write(pca->regmap, PCA9685_ALL_LED_ON_H, 0);
> regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
> - regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
> + regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, LED_FULL);
>
> pca->chip.ops = &pca9685_pwm_ops;
> /* Add an extra channel for ALL_LED */
> @@ -470,8 +473,10 @@ static int pca9685_pwm_probe(struct i2c_client *client,
> /*
> * The chip comes out of power-up in the sleep state,
> * but force it to sleep in case it was woken up before
> + * and set the default prescale value
> */
> pca9685_set_sleep_mode(pca, true);
> + regmap_write(pca->regmap, PCA9685_PRESCALE, PCA9685_PRESCALE_DEF);
> pm_runtime_set_suspended(&client->dev);
> pm_runtime_enable(&client->dev);
Consider making it clearer that prescale can only be touched when the chip is
in sleep mode. Suggestion:
/* set the default prescale value - chip _must_ be in sleep mode */
regmap_write(pca->regmap, PCA9685_PRESCALE, PCA9685_PRESCALE_DEF);
>
> --
> 2.29.2
>
