Re: [PATCH 2/2] hwmon: (pmbus/ibm-cffps) Fix LED blink behavior

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Nov 06, 2019 at 02:01:06PM -0600, Eddie James wrote:
> The LED blink_set function incorrectly did not tell the PSU LED to blink
> if brightness was LED_OFF. Fix this, and also correct the LED_OFF
> command data, which should give control of the LED back to the PSU
> firmware. Also prevent I2C failures from getting the driver LED state
> out of sync and add some dev_dbg statements.
> 
> Signed-off-by: Eddie James <eajames@linux.ibm.com>

Applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/pmbus/ibm-cffps.c | 27 +++++++++++++++++++--------
>  1 file changed, 19 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
> index c6a00e83aac6..d359b76bcb36 100644
> --- a/drivers/hwmon/pmbus/ibm-cffps.c
> +++ b/drivers/hwmon/pmbus/ibm-cffps.c
> @@ -44,9 +44,13 @@
>  #define CFFPS_MFR_VAUX_FAULT			BIT(6)
>  #define CFFPS_MFR_CURRENT_SHARE_WARNING		BIT(7)
>  
> +/*
> + * LED off state actually relinquishes LED control to PSU firmware, so it can
> + * turn on the LED for faults.
> + */
> +#define CFFPS_LED_OFF				0
>  #define CFFPS_LED_BLINK				BIT(0)
>  #define CFFPS_LED_ON				BIT(1)
> -#define CFFPS_LED_OFF				BIT(2)
>  #define CFFPS_BLINK_RATE_MS			250
>  
>  enum {
> @@ -301,23 +305,31 @@ static int ibm_cffps_led_brightness_set(struct led_classdev *led_cdev,
>  					enum led_brightness brightness)
>  {
>  	int rc;
> +	u8 next_led_state;
>  	struct ibm_cffps *psu = container_of(led_cdev, struct ibm_cffps, led);
>  
>  	if (brightness == LED_OFF) {
> -		psu->led_state = CFFPS_LED_OFF;
> +		next_led_state = CFFPS_LED_OFF;
>  	} else {
>  		brightness = LED_FULL;
> +
>  		if (psu->led_state != CFFPS_LED_BLINK)
> -			psu->led_state = CFFPS_LED_ON;
> +			next_led_state = CFFPS_LED_ON;
> +		else
> +			next_led_state = CFFPS_LED_BLINK;
>  	}
>  
> +	dev_dbg(&psu->client->dev, "LED brightness set: %d. Command: %d.\n",
> +		brightness, next_led_state);
> +
>  	pmbus_set_page(psu->client, 0);
>  
>  	rc = i2c_smbus_write_byte_data(psu->client, CFFPS_SYS_CONFIG_CMD,
> -				       psu->led_state);
> +				       next_led_state);
>  	if (rc < 0)
>  		return rc;
>  
> +	psu->led_state = next_led_state;
>  	led_cdev->brightness = brightness;
>  
>  	return 0;
> @@ -330,10 +342,7 @@ static int ibm_cffps_led_blink_set(struct led_classdev *led_cdev,
>  	int rc;
>  	struct ibm_cffps *psu = container_of(led_cdev, struct ibm_cffps, led);
>  
> -	psu->led_state = CFFPS_LED_BLINK;
> -
> -	if (led_cdev->brightness == LED_OFF)
> -		return 0;
> +	dev_dbg(&psu->client->dev, "LED blink set.\n");
>  
>  	pmbus_set_page(psu->client, 0);
>  
> @@ -342,6 +351,8 @@ static int ibm_cffps_led_blink_set(struct led_classdev *led_cdev,
>  	if (rc < 0)
>  		return rc;
>  
> +	psu->led_state = CFFPS_LED_BLINK;
> +	led_cdev->brightness = LED_FULL;
>  	*delay_on = CFFPS_BLINK_RATE_MS;
>  	*delay_off = CFFPS_BLINK_RATE_MS;
>