Re: [PATCH v3 2/3] hwmon: (adt7475) Add support for pin configuration

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

On Wed, Mar 23, 2022 at 04:40:55PM +1300, Chris Packham wrote:
> The adt7473, adt7475, adt7476 and adt7490 have pins that can be used for
> different functions. On the adt7473 and  adt7475 this is pins 5 and 9.
> On the adt7476 and adt7490 this is pins 10 and 14.
> 
> The first pin can either be PWM2(default) or SMBALERT#. The second pin
> can be TACH4(default), THERM#, SMBALERT# or GPIO.
> 
> The adt7475 driver has always been able to detect the configuration if
> it had been done by an earlier boot stage. Add support for configuring
> the pins based on the hardware description in the device tree.
> 
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>

For my reference:

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> 
> Notes:
>     Changes in v3:
>     - None
>     Changes in v2:
>     - Use load_config{3,4} instead of load_pin{10,14}_config
>     - Handle errors from adt7475_read()
>     - Remove obsolete check on chip type
>     - Use enum chips instead of int
>     - Update error messages
> 
>  drivers/hwmon/adt7475.c | 96 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 96 insertions(+)
> 
> diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
> index 9d5b019651f2..6de501de41b2 100644
> --- a/drivers/hwmon/adt7475.c
> +++ b/drivers/hwmon/adt7475.c
> @@ -112,6 +112,8 @@
>  #define CONFIG3_THERM		0x02
>  
>  #define CONFIG4_PINFUNC		0x03
> +#define CONFIG4_THERM		0x01
> +#define CONFIG4_SMBALERT	0x02
>  #define CONFIG4_MAXDUTY		0x08
>  #define CONFIG4_ATTN_IN10	0x30
>  #define CONFIG4_ATTN_IN43	0xC0
> @@ -1460,6 +1462,96 @@ static int adt7475_update_limits(struct i2c_client *client)
>  	return 0;
>  }
>  
> +static int load_config3(const struct i2c_client *client, const char *propname)
> +{
> +	const char *function;
> +	u8 config3;
> +	int ret;
> +
> +	ret = of_property_read_string(client->dev.of_node, propname, &function);
> +	if (!ret) {
> +		ret = adt7475_read(REG_CONFIG3);
> +		if (ret < 0)
> +			return ret;
> +
> +		config3 = ret & ~CONFIG3_SMBALERT;
> +		if (!strcmp("pwm2", function))
> +			;
> +		else if (!strcmp("smbalert#", function))
> +			config3 |= CONFIG3_SMBALERT;
> +		else
> +			return -EINVAL;
> +
> +		return i2c_smbus_write_byte_data(client, REG_CONFIG3, config3);
> +	}
> +
> +	return 0;
> +}
> +
> +static int load_config4(const struct i2c_client *client, const char *propname)
> +{
> +	const char *function;
> +	u8 config4;
> +	int ret;
> +
> +	ret = of_property_read_string(client->dev.of_node, propname, &function);
> +	if (!ret) {
> +		ret = adt7475_read(REG_CONFIG4);
> +		if (ret < 0)
> +			return ret;
> +
> +		config4 = ret & ~CONFIG4_PINFUNC;
> +
> +		if (!strcmp("tach4", function))
> +			;
> +		else if (!strcmp("therm#", function))
> +			config4 |= CONFIG4_THERM;
> +		else if (!strcmp("smbalert#", function))
> +			config4 |= CONFIG4_SMBALERT;
> +		else if (!strcmp("gpio", function))
> +			config4 |= CONFIG4_PINFUNC;
> +		else
> +			return -EINVAL;
> +
> +		return i2c_smbus_write_byte_data(client, REG_CONFIG4, config4);
> +	}
> +
> +	return 0;
> +}
> +
> +static int load_config(const struct i2c_client *client, enum chips chip)
> +{
> +	int err;
> +	const char *prop1, *prop2;
> +
> +	switch (chip) {
> +	case adt7473:
> +	case adt7475:
> +		prop1 = "adi,pin5-function";
> +		prop2 = "adi,pin9-function";
> +		break;
> +	case adt7476:
> +	case adt7490:
> +		prop1 = "adi,pin10-function";
> +		prop2 = "adi,pin14-function";
> +		break;
> +	}
> +
> +	err = load_config3(client, prop1);
> +	if (err) {
> +		dev_err(&client->dev, "failed to configure %s\n", prop1);
> +		return err;
> +	}
> +
> +	err = load_config4(client, prop2);
> +	if (err) {
> +		dev_err(&client->dev, "failed to configure %s\n", prop2);
> +		return err;
> +	}
> +
> +	return 0;
> +}
> +
>  static int set_property_bit(const struct i2c_client *client, char *property,
>  			    u8 *config, u8 bit_index)
>  {
> @@ -1585,6 +1677,10 @@ static int adt7475_probe(struct i2c_client *client)
>  		revision = adt7475_read(REG_DEVID2) & 0x07;
>  	}
>  
> +	ret = load_config(client, chip);
> +	if (ret)
> +		return ret;
> +
>  	config3 = adt7475_read(REG_CONFIG3);
>  	/* Pin PWM2 may alternatively be used for ALERT output */
>  	if (!(config3 & CONFIG3_SMBALERT))