Re: [PATCH v2 2/3] lm25066: support SAMPLES_FOR_AVG register

[Guenter Roeck]

On 4/13/19 9:03 AM, Adamski, Krzysztof (Nokia - PL/Wroclaw) wrote:

Manufacturer specific SAMPLES_FOR_AVG register allows setting the number
of samples used in computing the average values (PMBUS_VIRT_READ_*_AVG).
The number we write is an exponent of base 2 of the number of samples so
for example writing 3 will result in 8 samples average.

Signed-off-by: Krzysztof Adamski <krzysztof.adam...@nokia.com>
---
  drivers/hwmon/pmbus/lm25066.c | 15 ++++++++++++++-
  1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/lm25066.c b/drivers/hwmon/pmbus/lm25066.c
index 53db78753a0d..b560d33db459 100644
--- a/drivers/hwmon/pmbus/lm25066.c
+++ b/drivers/hwmon/pmbus/lm25066.c
@@ -26,6 +26,7 @@
  #include <linux/err.h>
  #include <linux/slab.h>
  #include <linux/i2c.h>
+#include <linux/log2.h>
  #include "pmbus.h"

enum chips { lm25056, lm25066, lm5064, lm5066, lm5066i };

@@ -39,12 +40,15 @@ enum chips { lm25056, lm25066, lm5064, lm5066, lm5066i };
  #define LM25066_CLEAR_PIN_PEAK                0xd6
  #define LM25066_DEVICE_SETUP          0xd9
  #define LM25066_READ_AVG_VIN          0xdc
+#define LM25066_SAMPLES_FOR_AVG                0xdb
  #define LM25066_READ_AVG_VOUT         0xdd
  #define LM25066_READ_AVG_IIN          0xde
  #define LM25066_READ_AVG_PIN          0xdf

#define LM25066_DEV_SETUP_CL BIT(4) /* Current limit */ +#define LM25066_SAMPLES_FOR_AVG_MAX 4096

+
  /* LM25056 only */

#define LM25056_VAUX_OV_WARN_LIMIT 0xe3

@@ -284,6 +288,10 @@ static int lm25066_read_word_data(struct i2c_client 
*client, int page, int reg)
        case PMBUS_VIRT_RESET_PIN_HISTORY:
                ret = 0;
                break;
+       case PMBUS_VIRT_SAMPLES:
+               ret = pmbus_read_byte_data(client, 0, LM25066_SAMPLES_FOR_AVG);

                if (ret < 0)
                        return ret;

+               ret = 1 << ret;
+               break;
        default:
                ret = -ENODATA;
                break;
@@ -398,6 +406,11 @@ static int lm25066_write_word_data(struct i2c_client 
*client, int page, int reg,
        case PMBUS_VIRT_RESET_PIN_HISTORY:
                ret = pmbus_write_byte(client, 0, LM25066_CLEAR_PIN_PEAK);
                break;
+       case PMBUS_VIRT_SAMPLES:
+               word = clamp_val(word, 0, LM25066_SAMPLES_FOR_AVG_MAX);

0 is not valid, and ilog2(0) returns -1 (or is undefined).

+               ret = pmbus_write_byte_data(client, 0, LM25066_SAMPLES_FOR_AVG,
+                                           ilog2(word));
+               break;
        default:
                ret = -ENODATA;
                break;
@@ -438,7 +451,7 @@ static int lm25066_probe(struct i2c_client *client,

info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VMON

          | PMBUS_HAVE_PIN | PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT
-         | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
+         | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP | PMBUS_HAVE_SAMPLES;

if (data->id == lm25056) {

                info->func[0] |= PMBUS_HAVE_STATUS_VMON;