[PATCH v3 15/19] hwmon: (mr75203) add support for series 6 temperature equation

Eliav Farber
2022-08-30T19:24:14Z

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

Signed-off-by: Eliav Farber <farbere@amazon.com>
---
V3 -> V2:
- New patch to support temperature sensor series 6 instead of having to
set all 4 coefficients.

drivers/hwmon/mr75203.c | 69 +++++++++++++++++++++++++++++++++++++----
1 file changed, 63 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 5b8ca1ee4a54..6a035fd115ca 100644
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -103,10 +103,6 @@

#define PVT_POLL_DELAY_US 20
#define PVT_POLL_TIMEOUT_US 20000
-#define PVT_H_CONST 200000
-#define PVT_G_CONST 60000
-#define PVT_J_CONST -100
-#define PVT_CAL5_CONST 4094
#define PVT_CONV_BITS 10
#define PVT_N_CONST 90
#define PVT_R_CONST 245805
@@ -114,9 +110,31 @@
#define PVT_TEMP_MIN -40000
#define PVT_TEMP_MAX 125000

+/* Temperature coefficients for series 5 */
+#define PVT_SERIES5_H_CONST 200000
+#define PVT_SERIES5_G_CONST 60000
+#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

+struct temp_coeff {
+ u32 h;
+ u32 g;
+ u32 cal5;
+ s32 j;
+};
+
struct voltage_device {
u32 vm_map; /* Map channel number to VM index */
u32 ch_map; /* Map channel number to channel index */
@@ -137,6 +155,7 @@ 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;
@@ -167,8 +186,9 @@ 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_G_CONST + PVT_H_CONST * (s64)nbs / PVT_CAL5_CONST -
- PVT_H_CONST / 2 + PVT_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, PVT_TEMP_MAX);
}
@@ -652,6 +672,39 @@ static int pvt_get_pre_scaler(struct device *dev, struct pvt_device *pvt)
return ret;
}

+static int pvt_set_temp_coeff(struct device *dev, struct pvt_device *pvt)
+{
+ struct temp_coeff *ts_coeff = &pvt->ts_coeff;
+ const struct device_node *np = dev->of_node;
+ u32 series;
+ int ret;
+
+ /* Incase ts-series property is not defined, use default 5. */
+ ret = of_property_read_u32(np, "moortec,ts-series", &series);
+ if (ret)
+ series = TEMPERATURE_SENSOR_SERIES_5;
+
+ if (series == 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;
+ } else if (series == 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;
+ } else {
+ 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)
{
const struct hwmon_channel_info **pvt_info;
@@ -722,6 +775,10 @@ 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)
--
2.37.1