hwmon: (mr75203) add support for series 6 temperature equation

The current equation used in code is aligned to series 5:
T = G + H * (n / cal5 - 0.5) + J * F
Where:
G = 60, H = 200, cal5 = 4094, J = -0.1, F = frequency clock in MHz

Series 6 has a slightly different equation:
T = G + H * (n / cal5 - 0.5)
and a different set of coefficients:
G = 57.4, H = 249.4, cal5 = 4096

This change supports equation and coefficients for both series.
(for series 6, J is set to 0).

The series is determined according to “moortec,ts-series” property in
the device tree.
If absent, series 5 is assumed to be the default.

Signed-off-by: Eliav Farber <farbere@amazon.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220908152449.35457-18-farbere@amazon.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 5ee1666..ce00349 100644 (file)
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -115,6 +115,15 @@
 #define PVT_SERIES5_J_CONST    -100
 #define PVT_SERIES5_CAL5_CONST 4094
 
+/* Temperature coefficients for series 6 */
+#define PVT_SERIES6_H_CONST    249400
+#define PVT_SERIES6_G_CONST    57400
+#define PVT_SERIES6_J_CONST    0
+#define PVT_SERIES6_CAL5_CONST 4096
+
+#define TEMPERATURE_SENSOR_SERIES_5    5
+#define TEMPERATURE_SENSOR_SERIES_6    6
+
 #define PRE_SCALER_X1  1
 #define PRE_SCALER_X2  2
 
@@ -147,6 +156,13 @@ struct voltage_channels {
        u8 max;
 };
 
+struct temp_coeff {
+       u32 h;
+       u32 g;
+       u32 cal5;
+       s32 j;
+};
+
 struct pvt_device {
        struct regmap           *c_map;
        struct regmap           *t_map;
@@ -156,6 +172,7 @@ struct pvt_device {
        struct reset_control    *rst;
        struct voltage_device   *vd;
        struct voltage_channels vm_channels;
+       struct temp_coeff       ts_coeff;
        u32                     t_num;
        u32                     p_num;
        u32                     v_num;
@@ -186,10 +203,12 @@ static long pvt_calc_temp(struct pvt_device *pvt, u32 nbs)
         * Convert the register value to degrees centigrade temperature:
         * T = G + H * (n / cal5 - 0.5) + J * F
         */
-       s64 tmp = PVT_SERIES5_G_CONST +
-               PVT_SERIES5_H_CONST * (s64)nbs / PVT_SERIES5_CAL5_CONST -
-               PVT_SERIES5_H_CONST / 2 +
-               PVT_SERIES5_J_CONST * (s64)pvt->ip_freq / HZ_PER_MHZ;
+       struct temp_coeff *ts_coeff = &pvt->ts_coeff;
+
+       s64 tmp = ts_coeff->g +
+               ts_coeff->h * (s64)nbs / ts_coeff->cal5 -
+               ts_coeff->h / 2 +
+               ts_coeff->j * (s64)pvt->ip_freq / HZ_PER_MHZ;
 
        return clamp_val(tmp, PVT_TEMP_MIN_mC, PVT_TEMP_MAX_mC);
 }
@@ -658,6 +677,41 @@ out:
        return ret;
 }
 
+static int pvt_set_temp_coeff(struct device *dev, struct pvt_device *pvt)
+{
+       struct temp_coeff *ts_coeff = &pvt->ts_coeff;
+       u32 series;
+       int ret;
+
+       /* Incase ts-series property is not defined, use default 5. */
+       ret = device_property_read_u32(dev, "moortec,ts-series", &series);
+       if (ret)
+               series = TEMPERATURE_SENSOR_SERIES_5;
+
+       switch (series) {
+       case TEMPERATURE_SENSOR_SERIES_5:
+               ts_coeff->h = PVT_SERIES5_H_CONST;
+               ts_coeff->g = PVT_SERIES5_G_CONST;
+               ts_coeff->j = PVT_SERIES5_J_CONST;
+               ts_coeff->cal5 = PVT_SERIES5_CAL5_CONST;
+               break;
+       case TEMPERATURE_SENSOR_SERIES_6:
+               ts_coeff->h = PVT_SERIES6_H_CONST;
+               ts_coeff->g = PVT_SERIES6_G_CONST;
+               ts_coeff->j = PVT_SERIES6_J_CONST;
+               ts_coeff->cal5 = PVT_SERIES6_CAL5_CONST;
+               break;
+       default:
+               dev_err(dev, "invalid temperature sensor series (%u)\n",
+                       series);
+               return -EINVAL;
+       }
+
+       dev_dbg(dev, "temperature sensor series = %u\n", series);
+
+       return 0;
+}
+
 static int mr75203_probe(struct platform_device *pdev)
 {
        u32 ts_num, vm_num, pd_num, ch_num, val, index, i;
@@ -728,6 +782,10 @@ static int mr75203_probe(struct platform_device *pdev)
                if (ret)
                        return ret;
 
+               ret = pvt_set_temp_coeff(dev, pvt);
+               if (ret)
+                       return ret;
+
                temp_config = devm_kcalloc(dev, ts_num + 1,
                                           sizeof(*temp_config), GFP_KERNEL);
                if (!temp_config)