Re: [PATCH] adm1275: support PMBUS_VIRT_*_SAMPLES

[Guenter Roeck]

On Fri, May 24, 2019 at 12:49:13PM +0000, Adamski, Krzysztof (Nokia - PL/Wroclaw) wrote:
> The device supports setting the number of samples for averaging the
> measurements. There are two separate settings - PWR_AVG for averaging
> PIN and VI_AVG for averaging VIN/VAUX/IOUT, both being part of
> PMON_CONFIG register. The values are stored as exponent of base 2 of the
> actual number of samples that will be taken.
> 
> Signed-off-by: Krzysztof Adamski <krzysztof.adamski@xxxxxxxxx>
> ---
>  drivers/hwmon/pmbus/adm1275.c | 68 ++++++++++++++++++++++++++++++++++-
>  1 file changed, 67 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/pmbus/adm1275.c b/drivers/hwmon/pmbus/adm1275.c
> index f569372c9204..4efe1a9df563 100644
> --- a/drivers/hwmon/pmbus/adm1275.c
> +++ b/drivers/hwmon/pmbus/adm1275.c
> @@ -23,6 +23,8 @@
>  #include <linux/slab.h>
>  #include <linux/i2c.h>
>  #include <linux/bitops.h>
> +#include <linux/bitfield.h>
> +#include <linux/log2.h>
>  #include "pmbus.h"
>  
>  enum chips { adm1075, adm1272, adm1275, adm1276, adm1278, adm1293, adm1294 };
> @@ -78,6 +80,10 @@ enum chips { adm1075, adm1272, adm1275, adm1276, adm1278, adm1293, adm1294 };
>  #define ADM1075_VAUX_OV_WARN		BIT(7)
>  #define ADM1075_VAUX_UV_WARN		BIT(6)
>  
> +#define ADM1275_PWR_AVG_MASK		GENMASK(13, 11)
> +#define ADM1275_VI_AVG_MASK		GENMASK(10, 8)
> +#define ADM1275_SAMPLES_AVG_MAX	128
> +
>  struct adm1275_data {
>  	int id;
>  	bool have_oc_fault;
> @@ -90,6 +96,7 @@ struct adm1275_data {
>  	bool have_pin_max;
>  	bool have_temp_max;
>  	struct pmbus_driver_info info;
> +	struct mutex lock;
>  };
>  
>  #define to_adm1275_data(x)  container_of(x, struct adm1275_data, info)
> @@ -164,6 +171,38 @@ static const struct coefficients adm1293_coefficients[] = {
>  	[18] = { 7658, 0, -3 },		/* power, 21V, irange200 */
>  };
>  
> +static inline int adm1275_read_pmon_config(struct i2c_client *client, u64 mask)

Why is the mask passed through as u64 ?

> +{
> +	int ret;
> +
> +	ret = i2c_smbus_read_word_data(client, ADM1275_PMON_CONFIG);
> +	if (ret < 0)
> +		return ret;
> +
> +	return FIELD_GET(mask, ret);
> +}
> +
> +static inline int adm1275_write_pmon_config(struct i2c_client *client, u64 mask,
> +					    u16 word)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct adm1275_data *data = to_adm1275_data(info);
> +	int ret;
> +
> +	mutex_lock(&data->lock);

Why is another lock on top of the lock provided by the pmbus core required ?

> +	ret = i2c_smbus_read_word_data(client, ADM1275_PMON_CONFIG);
> +	if (ret < 0) {
> +		mutex_unlock(&data->lock);
> +		return ret;
> +	}
> +
> +	word = FIELD_PREP(mask, word) | (ret & ~mask);
> +	ret = i2c_smbus_write_word_data(client, ADM1275_PMON_CONFIG, word);
> +	mutex_unlock(&data->lock);
> +
> +	return ret;
> +}
> +
>  static int adm1275_read_word_data(struct i2c_client *client, int page, int reg)
>  {
>  	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> @@ -242,6 +281,19 @@ static int adm1275_read_word_data(struct i2c_client *client, int page, int reg)
>  		if (!data->have_temp_max)
>  			return -ENXIO;
>  		break;
> +	case PMBUS_VIRT_POWER_SAMPLES:
> +		ret = adm1275_read_pmon_config(client, ADM1275_PWR_AVG_MASK);
> +		if (ret < 0)
> +			break;
> +		ret = 1 << ret;

		ret = BIT(ret);

> +		break;
> +	case PMBUS_VIRT_IN_SAMPLES:
> +	case PMBUS_VIRT_CURR_SAMPLES:
> +		ret = adm1275_read_pmon_config(client, ADM1275_VI_AVG_MASK);
> +		if (ret < 0)
> +			break;
> +		ret = 1 << ret;

		ret = BIT(ret);

> +		break;
>  	default:
>  		ret = -ENODATA;
>  		break;
> @@ -286,6 +338,17 @@ static int adm1275_write_word_data(struct i2c_client *client, int page, int reg,
>  	case PMBUS_VIRT_RESET_TEMP_HISTORY:
>  		ret = pmbus_write_word_data(client, 0, ADM1278_PEAK_TEMP, 0);
>  		break;
> +	case PMBUS_VIRT_POWER_SAMPLES:
> +		word = clamp_val(word, 1, ADM1275_SAMPLES_AVG_MAX);
> +		ret = adm1275_write_pmon_config(client, ADM1275_PWR_AVG_MASK,
> +						ilog2(word));
> +		break;
> +	case PMBUS_VIRT_IN_SAMPLES:
> +	case PMBUS_VIRT_CURR_SAMPLES:
> +		word = clamp_val(word, 1, ADM1275_SAMPLES_AVG_MAX);
> +		ret = adm1275_write_pmon_config(client, ADM1275_VI_AVG_MASK,
> +						ilog2(word));
> +		break;
>  	default:
>  		ret = -ENODATA;
>  		break;
> @@ -422,6 +485,8 @@ static int adm1275_probe(struct i2c_client *client,
>  	if (!data)
>  		return -ENOMEM;
>  
> +	mutex_init(&data->lock);
> +
>  	if (of_property_read_u32(client->dev.of_node,
>  				 "shunt-resistor-micro-ohms", &shunt))
>  		shunt = 1000; /* 1 mOhm if not set via DT */
> @@ -439,7 +504,8 @@ static int adm1275_probe(struct i2c_client *client,
>  	info->format[PSC_CURRENT_OUT] = direct;
>  	info->format[PSC_POWER] = direct;
>  	info->format[PSC_TEMPERATURE] = direct;
> -	info->func[0] = PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
> +	info->func[0] = PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
> +			PMBUS_HAVE_SAMPLES;
>  
>  	info->read_word_data = adm1275_read_word_data;
>  	info->read_byte_data = adm1275_read_byte_data;
> -- 
> 2.20.1
>