[PATCH v6 0/2] Variety of fixes and new features for mr75203 driver

[PATCH v6 0/2] Variety of fixes and new features for mr75203 driver

[Eliav Farber]

List of fixes:
 - Fix "intel,vm-map" property to be optional.
 - Fix VM sensor allocation when "intel,vm-map" not defined.
 - Fix multi-channel voltage reading.
 - Fix voltage equation for negative source input.
 - Modify the temperature equation according to series 5 datasheet.
 - Fix coding style issue.

List of new features:
 - Modify "reset" property to be optional.
 - Add optional "moortec,vm-active-channels" property to define the number
   of active channels per VM.
 - Add support for mr76006 pre-scaler to multiply the voltage result by 2.
 - Add support for series 6 temperature equation.
 - Add coefficient properties to fine tune the temperature equation.
 - Add debugfs to read and write temperature coefficients

---------

Changes between v5 and v6:
- fix undefined reference to `__divdi3' for 32-bit machines.

!!! Note: The patches of this series were pushed to hwmon-next and then
I got an automatic reply saying that these patches failed on some builds.
I sent separately an incremental patch which fixes the problem, and in
addition these two "replacement" patches for you do choose the option
you prefer. !!!

Changes between v4 and v5:
- 0004: Add detailed comment in code explaining the cast and the div instead of
  right shift or use of BIT().
- 0011: Fix typo in description (nou --> not).
- 0020: Return j coefficient to use debugfs_create_file() instead of
  debugfs_create_u32() because j is signed.
- 0021: Move the coding style patch to be last in the series (it does not fix
  the code), and remove the "Fixes:" tag.

Changes between v3 and v4:
*) Provide a Fixes tag for all fixes in the series.
*) Start series with fixes.
*) New patch to add description in moortec,mr75203.yaml.
*) New patch to add moortec to vendor-prefixes.
*) Fix moortec,mr75203.yaml checker errors.
*) Remove validation of device-tree parameters.
*) Fix per patch specific comments (detailed in each patch).

Changes between v2 and v3:
*) Add "moortec" prefix to all new device-tree properties.
*) Change order of patches.
*) Add explanations to better understand the changes.
*) Change "reset" property to be optional and remove the
  "reset-control-skip" property.
*) Split the patch for "fix multi-channel voltage reading" to two
   patches.
*) Change pre-scaler property format and fix typo (scalar --> scaler).
*) Fix voltage equation to support negative values instead of limiting
   value to zero.
*) Temperature equation - protect from overflow and add clamping.
*) Add new "moortec,ts-series" property to select between temperature
   equation of series 5 or series 6.

Changes between v1 and v2:
 *) Fix compilation error for patch 08/16:
    "warning: ISO C90 forbids variable length array"

---------

Eliav Farber (2):
  hwmon: (mr75203) modify the temperature equation according to series 5
    datasheet
  hwmon: (mr75203) add support for series 6 temperature equation

 drivers/hwmon/mr75203.c | 91 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 83 insertions(+), 8 deletions(-)

-- 
2.37.1

[PATCH v6 1/2] hwmon: (mr75203) modify the temperature equation according to series 5 datasheet

[Eliav Farber]

Modify the equation and coefficients used to convert the digital output
to temperature according to series 5 of the Moortec Embedded Temperature
Sensor (METS) datasheet:
T = G + H * (n / cal5 - 0.5) + J * F

Where:
*) G = 60, H = 200, cal5 = 4094, J = -0.1.
*) F = frequency clock in MHz.
*) n is the digital output.

In code, the G, H and J coefficients are multiplied by a factor of 1000
to get the temperature in milli-Celsius.
Final result is clamped in case it exceeds min/max thresholds.

Change is done since it is unclear where the current equation and
coefficients came from.

Signed-off-by: Eliav Farber <farbere@amazon.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: kernel test robot <lkp@intel.com>
---
V5 -> V4:
- fix undefined reference to `__divdi3'

V4 -> V3:
- Change 'not clear' to 'unclear' in commit message.
- Add _mC prefix to temperature mix/max defines.
- Add SERIES5 to coefficient defines.

V3 -> V2:
- Protect from overflow.
- Add temperature clamping.
- Add better documentation.

 drivers/hwmon/mr75203.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index 8a6ae72fed20..fb262fd2b511 100644
--- a/drivers/hwmon/mr75203.c
+++ b/drivers/hwmon/mr75203.c
@@ -102,13 +102,19 @@
 
 #define PVT_POLL_DELAY_US	20
 #define PVT_POLL_TIMEOUT_US	20000
-#define PVT_H_CONST		100000
-#define PVT_CAL5_CONST		2047
-#define PVT_G_CONST		40000
 #define PVT_CONV_BITS		10
 #define PVT_N_CONST		90
 #define PVT_R_CONST		245805
 
+#define PVT_TEMP_MIN_mC		-40000
+#define PVT_TEMP_MAX_mC		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
+
 #define PRE_SCALER_X1	1
 #define PRE_SCALER_X2	2
 
@@ -174,13 +180,26 @@ static umode_t pvt_is_visible(const void *data, enum hwmon_sensor_types type,
 	return 0;
 }
 
+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 +
+		div_s64(PVT_SERIES5_H_CONST * (s64)nbs, PVT_SERIES5_CAL5_CONST) -
+		PVT_SERIES5_H_CONST / 2 +
+		div_s64(PVT_SERIES5_J_CONST * (s64)pvt->ip_freq, HZ_PER_MHZ);
+
+	return clamp_val(tmp, PVT_TEMP_MIN_mC, PVT_TEMP_MAX_mC);
+}
+
 static int pvt_read_temp(struct device *dev, u32 attr, int channel, long *val)
 {
 	struct pvt_device *pvt = dev_get_drvdata(dev);
 	struct regmap *t_map = pvt->t_map;
 	u32 stat, nbs;
 	int ret;
-	u64 tmp;
 
 	switch (attr) {
 	case hwmon_temp_input:
@@ -201,9 +220,7 @@ static int pvt_read_temp(struct device *dev, u32 attr, int channel, long *val)
 		 * Convert the register value to
 		 * degrees centigrade temperature
 		 */
-		tmp = nbs * PVT_H_CONST;
-		do_div(tmp, PVT_CAL5_CONST);
-		*val = tmp - PVT_G_CONST - pvt->ip_freq;
+		*val = pvt_calc_temp(pvt, nbs);
 
 		return 0;
 	default:
@@ -337,7 +354,7 @@ static int pvt_init(struct pvt_device *pvt)
 		    (key >> 1) << CLK_SYNTH_HI_SFT |
 		    (key >> 1) << CLK_SYNTH_HOLD_SFT | CLK_SYNTH_EN;
 
-	pvt->ip_freq = sys_freq * 100 / (key + 2);
+	pvt->ip_freq = clk_get_rate(pvt->clk) / (key + 2);
 
 	if (t_num) {
 		ret = regmap_write(t_map, SDIF_SMPL_CTRL, 0x0);
-- 
2.37.1

[PATCH v6 2/2] hwmon: (mr75203) add support for series 6 temperature equation

[Eliav Farber]

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>
Reported-by: kernel test robot <lkp@intel.com>
---
V5 -> V4:
- fix undefined reference to `__divdi3'

V4 -> V3:
- Replace of_property_read_u32() with device_property_read_u32().
- Use switch-case instead of if-else.

V3 -> V2:
- New patch to support temperature sensor series 6 instead of having to
  set all 4 coefficients.

 drivers/hwmon/mr75203.c | 66 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 62 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c
index fb262fd2b511..f17050e11328 100644
--- 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 +
-		div_s64(PVT_SERIES5_H_CONST * (s64)nbs, PVT_SERIES5_CAL5_CONST) -
-		PVT_SERIES5_H_CONST / 2 +
-		div_s64(PVT_SERIES5_J_CONST * (s64)pvt->ip_freq, HZ_PER_MHZ);
+	struct temp_coeff *ts_coeff = &pvt->ts_coeff;
+
+	s64 tmp = ts_coeff->g +
+		div_s64(ts_coeff->h * (s64)nbs, ts_coeff->cal5) -
+		ts_coeff->h / 2 +
+		div_s64(ts_coeff->j * (s64)pvt->ip_freq, HZ_PER_MHZ);
 
 	return clamp_val(tmp, PVT_TEMP_MIN_mC, PVT_TEMP_MAX_mC);
 }
@@ -668,6 +687,41 @@ 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;
+	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;
@@ -738,6 +792,10 @@ 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

Re: [PATCH v6 1/2] hwmon: (mr75203) modify the temperature equation according to series 5 datasheet

[Sudip Mukherjee]

On Wed, Sep 21, 2022 at 1:18 PM Eliav Farber <farbere@amazon.com> wrote:
>
> Modify the equation and coefficients used to convert the digital output
> to temperature according to series 5 of the Moortec Embedded Temperature
> Sensor (METS) datasheet:
> T = G + H * (n / cal5 - 0.5) + J * F
>
> Where:
> *) G = 60, H = 200, cal5 = 4094, J = -0.1.
> *) F = frequency clock in MHz.
> *) n is the digital output.
>
> In code, the G, H and J coefficients are multiplied by a factor of 1000
> to get the temperature in milli-Celsius.
> Final result is clamped in case it exceeds min/max thresholds.
>
> Change is done since it is unclear where the current equation and
> coefficients came from.
>
> Signed-off-by: Eliav Farber <farbere@amazon.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reported-by: kernel test robot <lkp@intel.com>

Only build tested on top of next-20220921 after reverting v5 patches.

Tested-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>


-- 
Regards
Sudip

Re: [PATCH v6 2/2] hwmon: (mr75203) add support for series 6 temperature equation

[Sudip Mukherjee]

On Wed, Sep 21, 2022 at 1:19 PM Eliav Farber <farbere@amazon.com> wrote:
>
> 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>
> Reported-by: kernel test robot <lkp@intel.com>

Only build tested on top of next-20220921 after reverting v5 patches.

Tested-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>

-- 
Regards
Sudip