hwmon: (pmbus/mp2975) Add OCP limit

Add support for PMBUS_IOUT_OC_FAULT_LIMIT.
Add a helper function to convert the limit to LINEAR11 format
and read data->info.phases[0] on MP2971 and MP2973 as well.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Link: https://lore.kernel.org/r/20230714135124.2645339-8-Naresh.Solanki@9elements.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/pmbus/mp2975.c b/drivers/hwmon/pmbus/mp2975.c
index 5fb21b9f4ab3db702a36154642ce786cdf8e25e2..28f33f4618fae1c3fafb77c08a5dcabd34e61510 100644 (file)
--- a/drivers/hwmon/pmbus/mp2975.c
+++ b/drivers/hwmon/pmbus/mp2975.c
@@ -65,6 +65,10 @@
 #define MP2973_VID_STEP_SEL_R2         BIT(3)
 #define MP2973_IMVP9_EN_R2             BIT(13)
 
+#define MP2973_MFR_OCP_TOTAL_SET       0x5f
+#define MP2973_OCP_TOTAL_CUR_MASK      GENMASK(6, 0)
+#define MP2973_MFR_OCP_LEVEL_RES       BIT(15)
+
 #define MP2973_MFR_READ_IOUT_PK                0x90
 #define MP2973_MFR_READ_POUT_PK                0x91
 
@@ -153,6 +157,41 @@ mp2975_vid2direct(int vrf, int val)
        return 0;
 }
 
+#define MAX_LIN_MANTISSA       (1023 * 1000)
+#define MIN_LIN_MANTISSA       (511 * 1000)
+
+/* Converts a milli-unit DIRECT value to LINEAR11 format */
+static u16 mp2975_data2reg_linear11(s64 val)
+{
+       s16 exponent = 0, mantissa;
+       bool negative = false;
+
+       /* simple case */
+       if (val == 0)
+               return 0;
+
+       /* Reduce large mantissa until it fits into 10 bit */
+       while (val >= MAX_LIN_MANTISSA && exponent < 15) {
+               exponent++;
+               val >>= 1;
+       }
+       /* Increase small mantissa to improve precision */
+       while (val < MIN_LIN_MANTISSA && exponent > -15) {
+               exponent--;
+               val <<= 1;
+       }
+
+       /* Convert mantissa from milli-units to units */
+       mantissa = clamp_val(DIV_ROUND_CLOSEST_ULL(val, 1000), 0, 0x3ff);
+
+       /* restore sign */
+       if (negative)
+               mantissa = -mantissa;
+
+       /* Convert to 5 bit exponent, 11 bit mantissa */
+       return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
+}
+
 static int
 mp2975_read_phase(struct i2c_client *client, struct mp2975_data *data,
                  int page, int phase, u8 reg)
@@ -297,6 +336,20 @@ static int mp2973_read_word_data(struct i2c_client *client, int page,
                ret = pmbus_read_word_data(client, page, phase,
                                           MP2973_MFR_READ_IOUT_PK);
                break;
+       case PMBUS_IOUT_OC_FAULT_LIMIT:
+               ret = mp2975_read_word_helper(client, page, phase,
+                                             MP2973_MFR_OCP_TOTAL_SET,
+                                             GENMASK(15, 0));
+               if (ret < 0)
+                       return ret;
+
+               if (ret & MP2973_MFR_OCP_LEVEL_RES)
+                       ret = 2 * (ret & MP2973_OCP_TOTAL_CUR_MASK);
+               else
+                       ret = ret & MP2973_OCP_TOTAL_CUR_MASK;
+
+               ret = mp2975_data2reg_linear11(ret * info->phases[page] * 1000);
+               break;
        case PMBUS_UT_WARN_LIMIT:
        case PMBUS_UT_FAULT_LIMIT:
        case PMBUS_VIN_UV_WARN_LIMIT:
@@ -307,7 +360,6 @@ static int mp2973_read_word_data(struct i2c_client *client, int page,
        case PMBUS_IIN_OC_FAULT_LIMIT:
        case PMBUS_IOUT_OC_LV_FAULT_LIMIT:
        case PMBUS_IOUT_OC_WARN_LIMIT:
-       case PMBUS_IOUT_OC_FAULT_LIMIT:
        case PMBUS_IOUT_UC_FAULT_LIMIT:
        case PMBUS_POUT_OP_FAULT_LIMIT:
        case PMBUS_POUT_OP_WARN_LIMIT:
@@ -481,11 +533,13 @@ mp2975_identify_multiphase(struct i2c_client *client, struct mp2975_data *data,
        if (info->phases[0] > data->max_phases[0])
                return -EINVAL;
 
-       mp2975_set_phase_rail1(info);
-       num_phases2 = min(data->max_phases[0] - info->phases[0],
-                         data->max_phases[1]);
-       if (info->phases[1] && info->phases[1] <= num_phases2)
-               mp2975_set_phase_rail2(info, num_phases2);
+       if (data->chip_id == mp2975) {
+               mp2975_set_phase_rail1(info);
+               num_phases2 = min(data->max_phases[0] - info->phases[0],
+                                 data->max_phases[1]);
+               if (info->phases[1] && info->phases[1] <= num_phases2)
+                       mp2975_set_phase_rail2(info, num_phases2);
+       }
 
        return 0;
 }
@@ -878,12 +932,12 @@ static int mp2975_probe(struct i2c_client *client)
                        data->info.num_regulators = MP2975_PAGE_NUM;
        }
 
-       if (data->chip_id == mp2975) {
-               /* Identify multiphase configuration. */
-               ret = mp2975_identify_multiphase(client, data, info);
-               if (ret)
-                       return ret;
+       /* Identify multiphase configuration. */
+       ret = mp2975_identify_multiphase(client, data, info);
+       if (ret)
+               return ret;
 
+       if (data->chip_id == mp2975) {
                /* Identify VID setting per rail. */
                ret = mp2975_identify_rails_vid(client, data, info);
                if (ret < 0)