Re: [PATCH] hwmon: corsair-cpro: add reading pwm values

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

On Tue, Jul 21, 2020 at 10:54:47AM +0200, Marius Zachmann wrote:
> This adds the possibility for reading pwm values.
> These can not be read if the device is controlled via
> fan_target or a fan curve and will return an error in
> this case. Since an error is expected, this adds some
> rudimentary error handling.
> 
> Changes:
> - add CTL_GET_FAN_PWM and use it via get_data
> - pwm returns -ENODATA if the device returns error 0x12
> - fan_target now returns -ENODATA when the driver is
>   started or a pwm value is set.
> - add ccp_get_errno to determine errno from device error.
> - get_data now has a parameter to determine whether
>   to read one or two bytes of data.
> - update documentation
> - fix missing surname in MAINTAINERS
> 
> Signed-off-by: Marius Zachmann <mail@mariuszachmann.de>

Applied.

Thanks,
Guenter

> ---
>  Documentation/hwmon/corsair-cpro.rst |  7 ++-
>  MAINTAINERS                          |  2 +-
>  drivers/hwmon/corsair-cpro.c         | 64 +++++++++++++++++++---------
>  3 files changed, 48 insertions(+), 25 deletions(-)
> 
> diff --git a/Documentation/hwmon/corsair-cpro.rst b/Documentation/hwmon/corsair-cpro.rst
> index 78820156f07d..751f95476b57 100644
> --- a/Documentation/hwmon/corsair-cpro.rst
> +++ b/Documentation/hwmon/corsair-cpro.rst
> @@ -35,8 +35,7 @@ fan[1-6]_input		Connected fan rpm.
>  fan[1-6]_label		Shows fan type as detected by the device.
>  fan[1-6]_target		Sets fan speed target rpm.
>  			When reading, it reports the last value if it was set by the driver.
> -			Otherwise returns 0.
> -pwm[1-6]		Sets the fan speed. Values from 0-255.
> -			When reading, it reports the last value if it was set by the driver.
> -			Otherwise returns 0.
> +			Otherwise returns an error.
> +pwm[1-6]		Sets the fan speed. Values from 0-255. Can only be read if pwm
> +			was set directly.
>  ======================= =====================================================================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 06607125b793..a93aefab91f1 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4402,7 +4402,7 @@ F:	Documentation/hwmon/coretemp.rst
>  F:	drivers/hwmon/coretemp.c
> 
>  CORSAIR-CPRO HARDWARE MONITOR DRIVER
> -M:	Marius  <mail@mariuszachmann.de>
> +M:	Marius Zachmann <mail@mariuszachmann.de>
>  L:	linux-hwmon@vger.kernel.org
>  S:	Maintained
>  F:	drivers/hwmon/corsair-cpro.c
> diff --git a/drivers/hwmon/corsair-cpro.c b/drivers/hwmon/corsair-cpro.c
> index e8504267d0e8..591929ec217a 100644
> --- a/drivers/hwmon/corsair-cpro.c
> +++ b/drivers/hwmon/corsair-cpro.c
> @@ -36,11 +36,12 @@
>  					 * send: byte 1 is channel, rest zero
>  					 * rcv:  returns temp for channel in centi-degree celsius
>  					 * in bytes 1 and 2
> -					 * returns 17 in byte 0 if no sensor is connected
> +					 * returns 0x11 in byte 0 if no sensor is connected
>  					 */
>  #define CTL_GET_VOLT		0x12	/*
>  					 * send: byte 1 is rail number: 0 = 12v, 1 = 5v, 2 = 3.3v
>  					 * rcv:  returns millivolt in bytes 1,2
> +					 * returns error 0x10 if request is invalid
>  					 */
>  #define CTL_GET_FAN_CNCT	0x20	/*
>  					 * returns in bytes 1-6 for each fan:
> @@ -52,6 +53,12 @@
>  					 * send: byte 1 is channel, rest zero
>  					 * rcv:  returns rpm in bytes 1,2
>  					 */
> +#define CTL_GET_FAN_PWM		0x22	/*
> +					 * send: byte 1 is channel, rest zero
> +					 * rcv:  returns pwm in byte 1 if it was set
> +					 *	 returns error 0x12 if fan is controlled via
> +					 *	 fan_target or fan curve
> +					 */
>  #define CTL_SET_FAN_FPWM	0x23	/*
>  					 * set fixed pwm
>  					 * send: byte 1 is fan number
> @@ -73,13 +80,31 @@ struct ccp_device {
>  	struct completion wait_input_report;
>  	struct mutex mutex; /* whenever buffer is used, lock before send_usb_cmd */
>  	u8 *buffer;
> -	int pwm[6];
>  	int target[6];
>  	DECLARE_BITMAP(temp_cnct, NUM_TEMP_SENSORS);
>  	DECLARE_BITMAP(fan_cnct, NUM_FANS);
>  	char fan_label[6][LABEL_LENGTH];
>  };
> 
> +/* converts response error in buffer to errno */
> +static int ccp_get_errno(struct ccp_device *ccp)
> +{
> +	switch (ccp->buffer[0]) {
> +	case 0x00: /* success */
> +		return 0;
> +	case 0x01: /* called invalid command */
> +		return -EOPNOTSUPP;
> +	case 0x10: /* called GET_VOLT / GET_TMP with invalid arguments */
> +		return -EINVAL;
> +	case 0x11: /* requested temps of disconnected sensors */
> +	case 0x12: /* requested pwm of not pwm controlled channels */
> +		return -ENODATA;
> +	default:
> +		hid_dbg(ccp->hdev, "unknown device response error: %d", ccp->buffer[0]);
> +		return -EIO;
> +	}
> +}
> +
>  /* send command, check for error in response, response in ccp->buffer */
>  static int send_usb_cmd(struct ccp_device *ccp, u8 command, u8 byte1, u8 byte2, u8 byte3)
>  {
> @@ -102,13 +127,7 @@ static int send_usb_cmd(struct ccp_device *ccp, u8 command, u8 byte1, u8 byte2,
>  	if (!t)
>  		return -ETIMEDOUT;
> 
> -	/* first byte of response is error code */
> -	if (ccp->buffer[0] != 0x00) {
> -		hid_dbg(ccp->hdev, "device response error: %d", ccp->buffer[0]);
> -		return -EIO;
> -	}
> -
> -	return 0;
> +	return ccp_get_errno(ccp);
>  }
> 
>  static int ccp_raw_event(struct hid_device *hdev, struct hid_report *report, u8 *data, int size)
> @@ -126,7 +145,7 @@ static int ccp_raw_event(struct hid_device *hdev, struct hid_report *report, u8
>  }
> 
>  /* requests and returns single data values depending on channel */
> -static int get_data(struct ccp_device *ccp, int command, int channel)
> +static int get_data(struct ccp_device *ccp, int command, int channel, bool two_byte_data)
>  {
>  	int ret;
> 
> @@ -136,7 +155,9 @@ static int get_data(struct ccp_device *ccp, int command, int channel)
>  	if (ret)
>  		goto out_unlock;
> 
> -	ret = (ccp->buffer[1] << 8) + ccp->buffer[2];
> +	ret = ccp->buffer[1];
> +	if (two_byte_data)
> +		ret = (ret << 8) + ccp->buffer[2];
> 
>  out_unlock:
>  	mutex_unlock(&ccp->mutex);
> @@ -150,14 +171,14 @@ static int set_pwm(struct ccp_device *ccp, int channel, long val)
>  	if (val < 0 || val > 255)
>  		return -EINVAL;
> 
> -	ccp->pwm[channel] = val;
> -
>  	/* The Corsair Commander Pro uses values from 0-100 */
>  	val = DIV_ROUND_CLOSEST(val * 100, 255);
> 
>  	mutex_lock(&ccp->mutex);
> 
>  	ret = send_usb_cmd(ccp, CTL_SET_FAN_FPWM, channel, val, 0);
> +	if (!ret)
> +		ccp->target[channel] = -ENODATA;
> 
>  	mutex_unlock(&ccp->mutex);
>  	return ret;
> @@ -171,7 +192,6 @@ static int set_target(struct ccp_device *ccp, int channel, long val)
>  	ccp->target[channel] = val;
> 
>  	mutex_lock(&ccp->mutex);
> -
>  	ret = send_usb_cmd(ccp, CTL_SET_FAN_TARGET, channel, val >> 8, val);
> 
>  	mutex_unlock(&ccp->mutex);
> @@ -210,7 +230,7 @@ static int ccp_read(struct device *dev, enum hwmon_sensor_types type,
>  	case hwmon_temp:
>  		switch (attr) {
>  		case hwmon_temp_input:
> -			ret = get_data(ccp, CTL_GET_TMP, channel);
> +			ret = get_data(ccp, CTL_GET_TMP, channel, true);
>  			if (ret < 0)
>  				return ret;
>  			*val = ret * 10;
> @@ -222,7 +242,7 @@ static int ccp_read(struct device *dev, enum hwmon_sensor_types type,
>  	case hwmon_fan:
>  		switch (attr) {
>  		case hwmon_fan_input:
> -			ret = get_data(ccp, CTL_GET_FAN_RPM, channel);
> +			ret = get_data(ccp, CTL_GET_FAN_RPM, channel, true);
>  			if (ret < 0)
>  				return ret;
>  			*val = ret;
> @@ -230,6 +250,8 @@ static int ccp_read(struct device *dev, enum hwmon_sensor_types type,
>  		case hwmon_fan_target:
>  			/* how to read target values from the device is unknown */
>  			/* driver returns last set value or 0			*/
> +			if (ccp->target[channel] < 0)
> +				return -ENODATA;
>  			*val = ccp->target[channel];
>  			return 0;
>  		default:
> @@ -239,9 +261,10 @@ static int ccp_read(struct device *dev, enum hwmon_sensor_types type,
>  	case hwmon_pwm:
>  		switch (attr) {
>  		case hwmon_pwm_input:
> -			/* how to read pwm values from the device is currently unknown */
> -			/* driver returns last set value or 0		               */
> -			*val = ccp->pwm[channel];
> +			ret = get_data(ccp, CTL_GET_FAN_PWM, channel, false);
> +			if (ret < 0)
> +				return ret;
> +			*val = DIV_ROUND_CLOSEST(ret * 255, 100);
>  			return 0;
>  		default:
>  			break;
> @@ -250,7 +273,7 @@ static int ccp_read(struct device *dev, enum hwmon_sensor_types type,
>  	case hwmon_in:
>  		switch (attr) {
>  		case hwmon_in_input:
> -			ret = get_data(ccp, CTL_GET_VOLT, channel);
> +			ret = get_data(ccp, CTL_GET_VOLT, channel, true);
>  			if (ret < 0)
>  				return ret;
>  			*val = ret;
> @@ -416,6 +439,7 @@ static int get_fan_cnct(struct ccp_device *ccp)
>  			continue;
> 
>  		set_bit(channel, ccp->fan_cnct);
> +		ccp->target[channel] = -ENODATA;
> 
>  		switch (mode) {
>  		case 1:
> --
> 2.27.0