[PATCH v3 00/11] hwmon: (amc6821) Various improvements

[PATCH v3 00/11] hwmon: (amc6821) Various improvements

[Guenter Roeck]

Cleanup and modernize the amc2821 driver.

Summary of changes:

- Stop accepting invalid pwm values.
- Improve consistency of reading vs. writing fan speed limits
- Rename fan1_div to fan1_pulses
- Add support for fan1_target and pwm1_enable mode 4
- Reorder include files, drop unnecessary ones
- Use tabs for column alignment in defines
- Use BIT() and GENMASK()
- Drop unnecessary enum chips
- Convert to use regmap
- Convert to with_info API
- Add support for pwm1_mode attribute

v3:
- Added Quentin's Reviewed-by: tag to several patches
- Change valid range of pwm1_auto_point2_pwm from [0..254] to
  [0, 255]
- Various improvements of regmap conversion
- Fix register when writing pwm1_mode

v2:
- Use kstrtou8() instead of kstrtol() where possible
- Limit range of pwm1_auto_point_pwm to 0..254 in patch 1
  instead of limiting it later, and do not accept invalid
  values for the attribute
- Do not accept negative fan speed values
- Display fan speed and speed limit as 0 if register value is 0
  (instead of 6000000), as in original code
- Only permit writing 0 (unlimited) for the maximum fan speed
- Add Reviewed-by: tags where given
- Fix definition of AMC6821_CONF1_FDRC1 in patch 7/10
- Use sign_extend32() instead of odd type cast
- Drop remaining spurious debug message in patch 9 instead of patch 10
- Add missing "select REGMAP_I2C" to Kconfig
- Change misleading variable name from 'mask' to 'mode'
- Use sysfs_emit instead of sprintf everywhere
- Add support for pwm1_mode attribute

----------------------------------------------------------------
Guenter Roeck (11):
      hwmon: (amc6821) Stop accepting invalid pwm values
      hwmon: (amc6821) Make reading and writing fan speed limits consistent
      hwmon: (amc6821) Rename fan1_div to fan1_pulses
      hwmon: (amc6821) Add support for fan1_target and pwm1_enable mode 4
      hwmon: (amc2821) Reorder include files, drop unnecessary ones
      hwmon: (amc6821) Use tabs for column alignment in defines
      hwmon: (amc2821) Use BIT() and GENMASK()
      hwmon: (amc6821) Drop unnecessary enum chips
      hwmon: (amc6821) Convert to use regmap
      hwmon: (amc6821) Convert to with_info API
      hwmon: (amc6821) Add support for pwm1_mode attribute

 Documentation/hwmon/amc6821.rst |    7 +-
 drivers/hwmon/Kconfig           |    1 +
 drivers/hwmon/amc6821.c         | 1393 +++++++++++++++++++--------------------
 3 files changed, 701 insertions(+), 700 deletions(-)

[PATCH v3 01/11] hwmon: (amc6821) Stop accepting invalid pwm values

[Guenter Roeck]

The pwm value range is well defined from 0..255. Don't accept any values
outside this range.

This changes the valid range of pwm1_auto_point2_pwm from 0..254 to 0..255,
meaning it can now be equivalent to not only pwm1_auto_point1_pwm (which is
always 0) but also to pwm1_auto_point3_pwm (which is always 255). While
that may not be practical, there seems to be no technical reason for
preventing a user from doing it.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Change valid range of  pwm1_auto_point2_pwm from [0..254] to
    [0, 255]
    Add Quentin's Reviewed-by: tag

v2: Use kstrtou8() instead of kstrtol() where possible.
    Limit range of pwm1_auto_point_pwm to 0..254 in patch 1
    instead of limiting it later, and do not accept invalid
    values for the attribute.


 drivers/hwmon/amc6821.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 9b02b304c2f5..dc35e9b21f91 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -355,13 +355,13 @@ static ssize_t pwm1_store(struct device *dev,
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
-	long val;
-	int ret = kstrtol(buf, 10, &val);
+	u8 val;
+	int ret = kstrtou8(buf, 10, &val);
 	if (ret)
 		return ret;
 
 	mutex_lock(&data->update_lock);
-	data->pwm1 = clamp_val(val , 0, 255);
+	data->pwm1 = val;
 	i2c_smbus_write_byte_data(client, AMC6821_REG_DCY, data->pwm1);
 	mutex_unlock(&data->update_lock);
 	return count;
@@ -558,13 +558,15 @@ static ssize_t pwm1_auto_point_pwm_store(struct device *dev,
 	struct amc6821_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
 	int dpwm;
-	long val;
-	int ret = kstrtol(buf, 10, &val);
+	u8 val;
+	int ret;
+
+	ret = kstrtou8(buf, 10, &val);
 	if (ret)
 		return ret;
 
 	mutex_lock(&data->update_lock);
-	data->pwm1_auto_point_pwm[1] = clamp_val(val, 0, 254);
+	data->pwm1_auto_point_pwm[1] = val;
 	if (i2c_smbus_write_byte_data(client, AMC6821_REG_DCY_LOW_TEMP,
 			data->pwm1_auto_point_pwm[1])) {
 		dev_err(&client->dev, "Register write error, aborting.\n");
-- 
2.39.2

[PATCH v3 02/11] hwmon: (amc6821) Make reading and writing fan speed limits consistent

[Guenter Roeck]

The default value of the maximum fan speed limit register is 0,
essentially translating to an unlimited fan speed. When reading
the limit, a value of 0 is reported in this case. However, writing
a value of 0 results in writing a value of 0xffff into the register,
which is inconsistent.

To solve the problem, permit writing a limit of 0 for the maximim fan
speed, effectively translating to "no limit". Write 0 into the register
if a limit value of 0 is written. Otherwise limit the range to
<1..6000000> and write 1..0xffff into the register. This ensures that
reading and writing from and to a limit register return the same value
while at the same time not changing reported values when reading the
speed or limits.

While at it, restrict fan limit writes to non-negative numbers; writing
a negative limit does not make sense and should be reported instead of
being corrected.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Add Quentin's Reviewed-by: tag

v2: Do not accept negative fan speed values
    Display fan speed and speed limit as 0 if register value is 0
    (instead of 6000000), as in original code.
    Only permit writing 0 (unlimited) for the maximum fan speed.

 drivers/hwmon/amc6821.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index dc35e9b21f91..8e3cc33d8073 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -616,15 +616,20 @@ static ssize_t fan_store(struct device *dev, struct device_attribute *attr,
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
-	long val;
+	unsigned long val;
 	int ix = to_sensor_dev_attr(attr)->index;
-	int ret = kstrtol(buf, 10, &val);
+	int ret = kstrtoul(buf, 10, &val);
 	if (ret)
 		return ret;
-	val = 1 > val ? 0xFFFF : 6000000/val;
+
+	/* The minimum fan speed must not be unlimited (0) */
+	if (ix == IDX_FAN1_MIN && !val)
+		return -EINVAL;
+
+	val = val > 0 ? 6000000 / clamp_val(val, 1, 6000000) : 0;
 
 	mutex_lock(&data->update_lock);
-	data->fan[ix] = (u16) clamp_val(val, 1, 0xFFFF);
+	data->fan[ix] = clamp_val(val, 0, 0xFFFF);
 	if (i2c_smbus_write_byte_data(client, fan_reg_low[ix],
 			data->fan[ix] & 0xFF)) {
 		dev_err(&client->dev, "Register write error, aborting.\n");
-- 
2.39.2

[PATCH v3 03/11] hwmon: (amc6821) Rename fan1_div to fan1_pulses

[Guenter Roeck]

The chip does not have a fan divisor. What it does have is a configuration
to set either 2 or 4 pulses per fan rotation. Rename the attribute to
reflect its use. Update documentation accordingly.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: No change

v2: Add Quentin's Reviewed-by: tag

 Documentation/hwmon/amc6821.rst |  2 +-
 drivers/hwmon/amc6821.c         | 26 +++++++++++++-------------
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/Documentation/hwmon/amc6821.rst b/Documentation/hwmon/amc6821.rst
index 5ddb2849da90..4ce67c268e52 100644
--- a/Documentation/hwmon/amc6821.rst
+++ b/Documentation/hwmon/amc6821.rst
@@ -47,7 +47,7 @@ fan1_input		ro	tachometer speed
 fan1_min		rw	"
 fan1_max		rw	"
 fan1_fault		ro	"
-fan1_div		rw	Fan divisor can be either 2 or 4.
+fan1_pulses		rw	Pulses per revolution can be either 2 or 4.
 
 pwm1			rw	pwm1
 pwm1_enable		rw	regulator mode, 1=open loop, 2=fan controlled
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 8e3cc33d8073..39bf52a5c432 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -148,7 +148,7 @@ struct amc6821_data {
 	int temp[TEMP_IDX_LEN];
 
 	u16 fan[FAN1_IDX_LEN];
-	u8 fan1_div;
+	u8 fan1_pulses;
 
 	u8 pwm1;
 	u8 temp1_auto_point_temp[3];
@@ -193,9 +193,9 @@ static struct amc6821_data *amc6821_update_device(struct device *dev)
 					client,
 					fan_reg_hi[i]) << 8;
 		}
-		data->fan1_div = i2c_smbus_read_byte_data(client,
+		data->fan1_pulses = i2c_smbus_read_byte_data(client,
 			AMC6821_REG_CONF4);
-		data->fan1_div = data->fan1_div & AMC6821_CONF4_PSPR ? 4 : 2;
+		data->fan1_pulses = data->fan1_pulses & AMC6821_CONF4_PSPR ? 4 : 2;
 
 		data->pwm1_auto_point_pwm[0] = 0;
 		data->pwm1_auto_point_pwm[2] = 255;
@@ -646,16 +646,16 @@ static ssize_t fan_store(struct device *dev, struct device_attribute *attr,
 	return count;
 }
 
-static ssize_t fan1_div_show(struct device *dev,
-			     struct device_attribute *devattr, char *buf)
+static ssize_t fan1_pulses_show(struct device *dev,
+				struct device_attribute *devattr, char *buf)
 {
 	struct amc6821_data *data = amc6821_update_device(dev);
-	return sprintf(buf, "%d\n", data->fan1_div);
+	return sprintf(buf, "%d\n", data->fan1_pulses);
 }
 
-static ssize_t fan1_div_store(struct device *dev,
-			      struct device_attribute *attr, const char *buf,
-			      size_t count)
+static ssize_t fan1_pulses_store(struct device *dev,
+				 struct device_attribute *attr, const char *buf,
+				 size_t count)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
@@ -675,11 +675,11 @@ static ssize_t fan1_div_store(struct device *dev,
 	switch (val) {
 	case 2:
 		config &= ~AMC6821_CONF4_PSPR;
-		data->fan1_div = 2;
+		data->fan1_pulses = 2;
 		break;
 	case 4:
 		config |= AMC6821_CONF4_PSPR;
-		data->fan1_div = 4;
+		data->fan1_pulses = 4;
 		break;
 	default:
 		count = -EINVAL;
@@ -714,7 +714,7 @@ static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, IDX_FAN1_INPUT);
 static SENSOR_DEVICE_ATTR_RW(fan1_min, fan, IDX_FAN1_MIN);
 static SENSOR_DEVICE_ATTR_RW(fan1_max, fan, IDX_FAN1_MAX);
 static SENSOR_DEVICE_ATTR_RO(fan1_fault, fan1_fault, 0);
-static SENSOR_DEVICE_ATTR_RW(fan1_div, fan1_div, 0);
+static SENSOR_DEVICE_ATTR_RW(fan1_pulses, fan1_pulses, 0);
 
 static SENSOR_DEVICE_ATTR_RW(pwm1, pwm1, 0);
 static SENSOR_DEVICE_ATTR_RW(pwm1_enable, pwm1_enable, 0);
@@ -757,7 +757,7 @@ static struct attribute *amc6821_attrs[] = {
 	&sensor_dev_attr_fan1_min.dev_attr.attr,
 	&sensor_dev_attr_fan1_max.dev_attr.attr,
 	&sensor_dev_attr_fan1_fault.dev_attr.attr,
-	&sensor_dev_attr_fan1_div.dev_attr.attr,
+	&sensor_dev_attr_fan1_pulses.dev_attr.attr,
 	&sensor_dev_attr_pwm1.dev_attr.attr,
 	&sensor_dev_attr_pwm1_enable.dev_attr.attr,
 	&sensor_dev_attr_pwm1_auto_channels_temp.dev_attr.attr,
-- 
2.39.2

[PATCH v3 04/11] hwmon: (amc6821) Add support for fan1_target and pwm1_enable mode 4

[Guenter Roeck]

After setting fan1_target and setting pwm1_enable to 4,
the fan controller tries to achieve the requested fan speed.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Add Quentin's Reviewed-by: tag

v2: Do not permit writing negative or unlimited target fan speed

 Documentation/hwmon/amc6821.rst |  4 ++++
 drivers/hwmon/amc6821.c         | 25 +++++++++++++++++--------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/Documentation/hwmon/amc6821.rst b/Documentation/hwmon/amc6821.rst
index 4ce67c268e52..96e604c5ea8e 100644
--- a/Documentation/hwmon/amc6821.rst
+++ b/Documentation/hwmon/amc6821.rst
@@ -48,12 +48,16 @@ fan1_min		rw	"
 fan1_max		rw	"
 fan1_fault		ro	"
 fan1_pulses		rw	Pulses per revolution can be either 2 or 4.
+fan1_target		rw	Target fan speed, to be used with pwm1_enable
+				mode 4.
 
 pwm1			rw	pwm1
 pwm1_enable		rw	regulator mode, 1=open loop, 2=fan controlled
 				by remote temperature, 3=fan controlled by
 				combination of the on-chip temperature and
 				remote-sensor temperature,
+				4=fan controlled by target rpm set with
+				fan1_target attribute.
 pwm1_auto_channels_temp ro	1 if pwm_enable==2, 3 if pwm_enable==3
 pwm1_auto_point1_pwm	ro	Hardwired to 0, shared for both
 				temperature channels.
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 39bf52a5c432..9e9a70afbfd4 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -66,6 +66,8 @@ enum chips { amc6821 };
 #define AMC6821_REG_TACH_LLIMITH 0x11
 #define AMC6821_REG_TACH_HLIMITL 0x12
 #define AMC6821_REG_TACH_HLIMITH 0x13
+#define AMC6821_REG_TACH_SETTINGL 0x1e
+#define AMC6821_REG_TACH_SETTINGH 0x1f
 
 #define AMC6821_CONF1_START 0x01
 #define AMC6821_CONF1_FAN_INT_EN 0x02
@@ -122,17 +124,18 @@ static const u8 temp_reg[] = {AMC6821_REG_LTEMP_HI,
 			AMC6821_REG_RTEMP_LIMIT_MAX,
 			AMC6821_REG_RTEMP_CRIT, };
 
-enum {IDX_FAN1_INPUT = 0, IDX_FAN1_MIN, IDX_FAN1_MAX,
+enum {IDX_FAN1_INPUT = 0, IDX_FAN1_MIN, IDX_FAN1_MAX, IDX_FAN1_TARGET,
 	FAN1_IDX_LEN, };
 
 static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
 			AMC6821_REG_TACH_LLIMITL,
-			AMC6821_REG_TACH_HLIMITL, };
-
+			AMC6821_REG_TACH_HLIMITL,
+			AMC6821_REG_TACH_SETTINGL, };
 
 static const u8 fan_reg_hi[] = {AMC6821_REG_TDATA_HI,
 			AMC6821_REG_TACH_LLIMITH,
-			AMC6821_REG_TACH_HLIMITH, };
+			AMC6821_REG_TACH_HLIMITH,
+			AMC6821_REG_TACH_SETTINGH, };
 
 /*
  * Client data (each client gets its own)
@@ -250,10 +253,10 @@ static struct amc6821_data *amc6821_update_device(struct device *dev)
 			break;
 		case 1: /*
 			 * semi-open loop: software sets rpm, chip controls
-			 * pwm1, currently not implemented
+			 * pwm1
 			 */
 			data->pwm1_auto_channels_temp = 0;
-			data->pwm1_enable = 0;
+			data->pwm1_enable = 4;
 			break;
 		}
 
@@ -407,6 +410,10 @@ static ssize_t pwm1_enable_store(struct device *dev,
 		config |= AMC6821_CONF1_FDRC0;
 		config |= AMC6821_CONF1_FDRC1;
 		break;
+	case 4:
+		config |= AMC6821_CONF1_FDRC0;
+		config &= ~AMC6821_CONF1_FDRC1;
+		break;
 	default:
 		count = -EINVAL;
 		goto unlock;
@@ -622,8 +629,8 @@ static ssize_t fan_store(struct device *dev, struct device_attribute *attr,
 	if (ret)
 		return ret;
 
-	/* The minimum fan speed must not be unlimited (0) */
-	if (ix == IDX_FAN1_MIN && !val)
+	/* Minimum and target fan speed must not be unlimited (0) */
+	if ((ix == IDX_FAN1_MIN || ix == IDX_FAN1_TARGET) && !val)
 		return -EINVAL;
 
 	val = val > 0 ? 6000000 / clamp_val(val, 1, 6000000) : 0;
@@ -713,6 +720,7 @@ static SENSOR_DEVICE_ATTR_RO(temp2_crit_alarm, temp_alarm, IDX_TEMP2_CRIT);
 static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, IDX_FAN1_INPUT);
 static SENSOR_DEVICE_ATTR_RW(fan1_min, fan, IDX_FAN1_MIN);
 static SENSOR_DEVICE_ATTR_RW(fan1_max, fan, IDX_FAN1_MAX);
+static SENSOR_DEVICE_ATTR_RW(fan1_target, fan, IDX_FAN1_TARGET);
 static SENSOR_DEVICE_ATTR_RO(fan1_fault, fan1_fault, 0);
 static SENSOR_DEVICE_ATTR_RW(fan1_pulses, fan1_pulses, 0);
 
@@ -756,6 +764,7 @@ static struct attribute *amc6821_attrs[] = {
 	&sensor_dev_attr_fan1_input.dev_attr.attr,
 	&sensor_dev_attr_fan1_min.dev_attr.attr,
 	&sensor_dev_attr_fan1_max.dev_attr.attr,
+	&sensor_dev_attr_fan1_target.dev_attr.attr,
 	&sensor_dev_attr_fan1_fault.dev_attr.attr,
 	&sensor_dev_attr_fan1_pulses.dev_attr.attr,
 	&sensor_dev_attr_pwm1.dev_attr.attr,
-- 
2.39.2

[PATCH v3 05/11] hwmon: (amc2821) Reorder include files, drop unnecessary ones

[Guenter Roeck]

Reorder include files to alphabetic order to simplify maintenance,
and drop the unnecessary kernel.h include.

No functional change intended.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: No change

v2: Add Quentin's Reviewed-by: tag

 drivers/hwmon/amc6821.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 9e9a70afbfd4..8869dbe5a733 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -8,16 +8,15 @@
  * Copyright (C) 2007 Hans J. Koch <hjk@hansjkoch.de>
  */
 
-#include <linux/kernel.h>	/* Needed for KERN_INFO */
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/slab.h>
-#include <linux/jiffies.h>
-#include <linux/i2c.h>
+#include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
-#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/slab.h>
 
 /*
  * Addresses to scan.
-- 
2.39.2

[PATCH v3 06/11] hwmon: (amc6821) Use tabs for column alignment in defines

[Guenter Roeck]

Using tabs for column alignment makes the code easier to read.

No functional change intended.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: No change

v2: Add Quentin's Reviewed-by: tag

 drivers/hwmon/amc6821.c | 128 ++++++++++++++++++++--------------------
 1 file changed, 64 insertions(+), 64 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 8869dbe5a733..bb20ccde5fea 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -37,77 +37,77 @@ module_param(init, int, 0444);
 
 enum chips { amc6821 };
 
-#define AMC6821_REG_DEV_ID 0x3D
-#define AMC6821_REG_COMP_ID 0x3E
-#define AMC6821_REG_CONF1 0x00
-#define AMC6821_REG_CONF2 0x01
-#define AMC6821_REG_CONF3 0x3F
-#define AMC6821_REG_CONF4 0x04
-#define AMC6821_REG_STAT1 0x02
-#define AMC6821_REG_STAT2 0x03
-#define AMC6821_REG_TDATA_LOW 0x08
-#define AMC6821_REG_TDATA_HI 0x09
-#define AMC6821_REG_LTEMP_HI 0x0A
-#define AMC6821_REG_RTEMP_HI 0x0B
-#define AMC6821_REG_LTEMP_LIMIT_MIN 0x15
-#define AMC6821_REG_LTEMP_LIMIT_MAX 0x14
-#define AMC6821_REG_RTEMP_LIMIT_MIN 0x19
-#define AMC6821_REG_RTEMP_LIMIT_MAX 0x18
-#define AMC6821_REG_LTEMP_CRIT 0x1B
-#define AMC6821_REG_RTEMP_CRIT 0x1D
-#define AMC6821_REG_PSV_TEMP 0x1C
-#define AMC6821_REG_DCY 0x22
-#define AMC6821_REG_LTEMP_FAN_CTRL 0x24
-#define AMC6821_REG_RTEMP_FAN_CTRL 0x25
-#define AMC6821_REG_DCY_LOW_TEMP 0x21
+#define AMC6821_REG_DEV_ID		0x3D
+#define AMC6821_REG_COMP_ID		0x3E
+#define AMC6821_REG_CONF1		0x00
+#define AMC6821_REG_CONF2		0x01
+#define AMC6821_REG_CONF3		0x3F
+#define AMC6821_REG_CONF4		0x04
+#define AMC6821_REG_STAT1		0x02
+#define AMC6821_REG_STAT2		0x03
+#define AMC6821_REG_TDATA_LOW		0x08
+#define AMC6821_REG_TDATA_HI		0x09
+#define AMC6821_REG_LTEMP_HI		0x0A
+#define AMC6821_REG_RTEMP_HI		0x0B
+#define AMC6821_REG_LTEMP_LIMIT_MIN	0x15
+#define AMC6821_REG_LTEMP_LIMIT_MAX	0x14
+#define AMC6821_REG_RTEMP_LIMIT_MIN	0x19
+#define AMC6821_REG_RTEMP_LIMIT_MAX	0x18
+#define AMC6821_REG_LTEMP_CRIT		0x1B
+#define AMC6821_REG_RTEMP_CRIT		0x1D
+#define AMC6821_REG_PSV_TEMP		0x1C
+#define AMC6821_REG_DCY			0x22
+#define AMC6821_REG_LTEMP_FAN_CTRL	0x24
+#define AMC6821_REG_RTEMP_FAN_CTRL	0x25
+#define AMC6821_REG_DCY_LOW_TEMP	0x21
 
-#define AMC6821_REG_TACH_LLIMITL 0x10
-#define AMC6821_REG_TACH_LLIMITH 0x11
-#define AMC6821_REG_TACH_HLIMITL 0x12
-#define AMC6821_REG_TACH_HLIMITH 0x13
-#define AMC6821_REG_TACH_SETTINGL 0x1e
-#define AMC6821_REG_TACH_SETTINGH 0x1f
+#define AMC6821_REG_TACH_LLIMITL	0x10
+#define AMC6821_REG_TACH_LLIMITH	0x11
+#define AMC6821_REG_TACH_HLIMITL	0x12
+#define AMC6821_REG_TACH_HLIMITH	0x13
+#define AMC6821_REG_TACH_SETTINGL	0x1e
+#define AMC6821_REG_TACH_SETTINGH	0x1f
 
-#define AMC6821_CONF1_START 0x01
-#define AMC6821_CONF1_FAN_INT_EN 0x02
-#define AMC6821_CONF1_FANIE 0x04
-#define AMC6821_CONF1_PWMINV 0x08
-#define AMC6821_CONF1_FAN_FAULT_EN 0x10
-#define AMC6821_CONF1_FDRC0 0x20
-#define AMC6821_CONF1_FDRC1 0x40
-#define AMC6821_CONF1_THERMOVIE 0x80
+#define AMC6821_CONF1_START		0x01
+#define AMC6821_CONF1_FAN_INT_EN	0x02
+#define AMC6821_CONF1_FANIE		0x04
+#define AMC6821_CONF1_PWMINV		0x08
+#define AMC6821_CONF1_FAN_FAULT_EN	0x10
+#define AMC6821_CONF1_FDRC0		0x20
+#define AMC6821_CONF1_FDRC1		0x40
+#define AMC6821_CONF1_THERMOVIE		0x80
 
-#define AMC6821_CONF2_PWM_EN 0x01
-#define AMC6821_CONF2_TACH_MODE 0x02
-#define AMC6821_CONF2_TACH_EN 0x04
-#define AMC6821_CONF2_RTFIE 0x08
-#define AMC6821_CONF2_LTOIE 0x10
-#define AMC6821_CONF2_RTOIE 0x20
-#define AMC6821_CONF2_PSVIE 0x40
-#define AMC6821_CONF2_RST 0x80
+#define AMC6821_CONF2_PWM_EN		0x01
+#define AMC6821_CONF2_TACH_MODE		0x02
+#define AMC6821_CONF2_TACH_EN		0x04
+#define AMC6821_CONF2_RTFIE		0x08
+#define AMC6821_CONF2_LTOIE		0x10
+#define AMC6821_CONF2_RTOIE		0x20
+#define AMC6821_CONF2_PSVIE		0x40
+#define AMC6821_CONF2_RST		0x80
 
-#define AMC6821_CONF3_THERM_FAN_EN 0x80
-#define AMC6821_CONF3_REV_MASK 0x0F
+#define AMC6821_CONF3_THERM_FAN_EN	0x80
+#define AMC6821_CONF3_REV_MASK		0x0F
 
-#define AMC6821_CONF4_OVREN 0x10
-#define AMC6821_CONF4_TACH_FAST 0x20
-#define AMC6821_CONF4_PSPR 0x40
-#define AMC6821_CONF4_MODE 0x80
+#define AMC6821_CONF4_OVREN		0x10
+#define AMC6821_CONF4_TACH_FAST		0x20
+#define AMC6821_CONF4_PSPR		0x40
+#define AMC6821_CONF4_MODE		0x80
 
-#define AMC6821_STAT1_RPM_ALARM 0x01
-#define AMC6821_STAT1_FANS 0x02
-#define AMC6821_STAT1_RTH 0x04
-#define AMC6821_STAT1_RTL 0x08
-#define AMC6821_STAT1_R_THERM 0x10
-#define AMC6821_STAT1_RTF 0x20
-#define AMC6821_STAT1_LTH 0x40
-#define AMC6821_STAT1_LTL 0x80
+#define AMC6821_STAT1_RPM_ALARM		0x01
+#define AMC6821_STAT1_FANS		0x02
+#define AMC6821_STAT1_RTH		0x04
+#define AMC6821_STAT1_RTL		0x08
+#define AMC6821_STAT1_R_THERM		0x10
+#define AMC6821_STAT1_RTF		0x20
+#define AMC6821_STAT1_LTH		0x40
+#define AMC6821_STAT1_LTL		0x80
 
-#define AMC6821_STAT2_RTC 0x08
-#define AMC6821_STAT2_LTC 0x10
-#define AMC6821_STAT2_LPSV 0x20
-#define AMC6821_STAT2_L_THERM 0x40
-#define AMC6821_STAT2_THERM_IN 0x80
+#define AMC6821_STAT2_RTC		0x08
+#define AMC6821_STAT2_LTC		0x10
+#define AMC6821_STAT2_LPSV		0x20
+#define AMC6821_STAT2_L_THERM		0x40
+#define AMC6821_STAT2_THERM_IN		0x80
 
 enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
 	IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
-- 
2.39.2

[PATCH v3 07/11] hwmon: (amc2821) Use BIT() and GENMASK()

[Guenter Roeck]

Use BIT() and GENMASK() for bit and mask definitions
to help distinguish bit and mask definitions from other
defines and to make the code easier to read.

No functional change intended.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Add Quentin's Reviewed-by: tag

v2: Fix definition of AMC6821_CONF1_FDRC1 in this patch

 drivers/hwmon/amc6821.c | 71 +++++++++++++++++++++--------------------
 1 file changed, 36 insertions(+), 35 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index bb20ccde5fea..546e79ce93b9 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -8,6 +8,7 @@
  * Copyright (C) 2007 Hans J. Koch <hjk@hansjkoch.de>
  */
 
+#include <linux/bits.h>
 #include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
@@ -68,46 +69,46 @@ enum chips { amc6821 };
 #define AMC6821_REG_TACH_SETTINGL	0x1e
 #define AMC6821_REG_TACH_SETTINGH	0x1f
 
-#define AMC6821_CONF1_START		0x01
-#define AMC6821_CONF1_FAN_INT_EN	0x02
-#define AMC6821_CONF1_FANIE		0x04
-#define AMC6821_CONF1_PWMINV		0x08
-#define AMC6821_CONF1_FAN_FAULT_EN	0x10
-#define AMC6821_CONF1_FDRC0		0x20
-#define AMC6821_CONF1_FDRC1		0x40
-#define AMC6821_CONF1_THERMOVIE		0x80
+#define AMC6821_CONF1_START		BIT(0)
+#define AMC6821_CONF1_FAN_INT_EN	BIT(1)
+#define AMC6821_CONF1_FANIE		BIT(2)
+#define AMC6821_CONF1_PWMINV		BIT(3)
+#define AMC6821_CONF1_FAN_FAULT_EN	BIT(4)
+#define AMC6821_CONF1_FDRC0		BIT(5)
+#define AMC6821_CONF1_FDRC1		BIT(6)
+#define AMC6821_CONF1_THERMOVIE		BIT(7)
 
-#define AMC6821_CONF2_PWM_EN		0x01
-#define AMC6821_CONF2_TACH_MODE		0x02
-#define AMC6821_CONF2_TACH_EN		0x04
-#define AMC6821_CONF2_RTFIE		0x08
-#define AMC6821_CONF2_LTOIE		0x10
-#define AMC6821_CONF2_RTOIE		0x20
-#define AMC6821_CONF2_PSVIE		0x40
-#define AMC6821_CONF2_RST		0x80
+#define AMC6821_CONF2_PWM_EN		BIT(0)
+#define AMC6821_CONF2_TACH_MODE		BIT(1)
+#define AMC6821_CONF2_TACH_EN		BIT(2)
+#define AMC6821_CONF2_RTFIE		BIT(3)
+#define AMC6821_CONF2_LTOIE		BIT(4)
+#define AMC6821_CONF2_RTOIE		BIT(5)
+#define AMC6821_CONF2_PSVIE		BIT(6)
+#define AMC6821_CONF2_RST		BIT(7)
 
-#define AMC6821_CONF3_THERM_FAN_EN	0x80
-#define AMC6821_CONF3_REV_MASK		0x0F
+#define AMC6821_CONF3_THERM_FAN_EN	BIT(7)
+#define AMC6821_CONF3_REV_MASK		GENMASK(3, 0)
 
-#define AMC6821_CONF4_OVREN		0x10
-#define AMC6821_CONF4_TACH_FAST		0x20
-#define AMC6821_CONF4_PSPR		0x40
-#define AMC6821_CONF4_MODE		0x80
+#define AMC6821_CONF4_OVREN		BIT(4)
+#define AMC6821_CONF4_TACH_FAST		BIT(5)
+#define AMC6821_CONF4_PSPR		BIT(6)
+#define AMC6821_CONF4_MODE		BIT(7)
 
-#define AMC6821_STAT1_RPM_ALARM		0x01
-#define AMC6821_STAT1_FANS		0x02
-#define AMC6821_STAT1_RTH		0x04
-#define AMC6821_STAT1_RTL		0x08
-#define AMC6821_STAT1_R_THERM		0x10
-#define AMC6821_STAT1_RTF		0x20
-#define AMC6821_STAT1_LTH		0x40
-#define AMC6821_STAT1_LTL		0x80
+#define AMC6821_STAT1_RPM_ALARM		BIT(0)
+#define AMC6821_STAT1_FANS		BIT(1)
+#define AMC6821_STAT1_RTH		BIT(2)
+#define AMC6821_STAT1_RTL		BIT(3)
+#define AMC6821_STAT1_R_THERM		BIT(4)
+#define AMC6821_STAT1_RTF		BIT(5)
+#define AMC6821_STAT1_LTH		BIT(6)
+#define AMC6821_STAT1_LTL		BIT(7)
 
-#define AMC6821_STAT2_RTC		0x08
-#define AMC6821_STAT2_LTC		0x10
-#define AMC6821_STAT2_LPSV		0x20
-#define AMC6821_STAT2_L_THERM		0x40
-#define AMC6821_STAT2_THERM_IN		0x80
+#define AMC6821_STAT2_RTC		BIT(3)
+#define AMC6821_STAT2_LTC		BIT(4)
+#define AMC6821_STAT2_LPSV		BIT(5)
+#define AMC6821_STAT2_L_THERM		BIT(6)
+#define AMC6821_STAT2_THERM_IN		BIT(7)
 
 enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
 	IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
-- 
2.39.2

[PATCH v3 08/11] hwmon: (amc6821) Drop unnecessary enum chips

[Guenter Roeck]

The driver only supports a single chip, so an enum
to determine the chip type is unnecessary. Drop it.

No functional change intended.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: No change

v2: Add Quentin's Reviewed-by: tag

 drivers/hwmon/amc6821.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 546e79ce93b9..295a9148779d 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -36,8 +36,6 @@ module_param(pwminv, int, 0444);
 static int init = 1; /*Power-on initialization.*/
 module_param(init, int, 0444);
 
-enum chips { amc6821 };
-
 #define AMC6821_REG_DEV_ID		0x3D
 #define AMC6821_REG_COMP_ID		0x3E
 #define AMC6821_REG_CONF1		0x00
@@ -944,7 +942,7 @@ static int amc6821_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id amc6821_id[] = {
-	{ "amc6821", amc6821 },
+	{ "amc6821", 0 },
 	{ }
 };
 
@@ -953,7 +951,6 @@ MODULE_DEVICE_TABLE(i2c, amc6821_id);
 static const struct of_device_id __maybe_unused amc6821_of_match[] = {
 	{
 		.compatible = "ti,amc6821",
-		.data = (void *)amc6821,
 	},
 	{ }
 };
-- 
2.39.2

[PATCH v3 09/11] hwmon: (amc6821) Convert to use regmap

[Guenter Roeck]

Use regmap for register accesses and caching.

While at it, use sysfs_emit() instead of sprintf() to write sysfs
attribute data, and remove spurious debug messages which would only
be seen as result of a bug in the code. Also make sure that error
codes are propagated and not replaced with -EIO.

While at it, introduce rounding of written temperature values and for
internal calculations to reduce deviation from written values and as
much as possible.

No functional change intended except for differences introduced by
rounding.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Add more details to patch description
    Cache all attributes
    Introduce rounding when writing attributes and for some calculations
    Always return error codes from regmap operations; never replace with
    -EIO

v2: Drop another spurious debug message in this patch instead of patch 10
    Add missing "select REGMAP_I2C" to Kconfig
    Change misleading variable name from 'mask' to 'mode'.
    Use sysfs_emit instead of sprintf everywhere


 drivers/hwmon/Kconfig   |   1 +
 drivers/hwmon/amc6821.c | 812 ++++++++++++++++++----------------------
 2 files changed, 373 insertions(+), 440 deletions(-)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e14ae18a973b..a8fa87a96e8f 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2127,6 +2127,7 @@ config SENSORS_ADS7871
 config SENSORS_AMC6821
 	tristate "Texas Instruments AMC6821"
 	depends on I2C
+	select REGMAP_I2C
 	help
 	  If you say yes here you get support for the Texas Instruments
 	  AMC6821 hardware monitoring chips.
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 295a9148779d..a5abd36a1430 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -8,15 +8,18 @@
  * Copyright (C) 2007 Hans J. Koch <hjk@hansjkoch.de>
  */
 
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
 #include <linux/bits.h>
 #include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
-#include <linux/jiffies.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/regmap.h>
 #include <linux/slab.h>
 
 /*
@@ -44,6 +47,7 @@ module_param(init, int, 0444);
 #define AMC6821_REG_CONF4		0x04
 #define AMC6821_REG_STAT1		0x02
 #define AMC6821_REG_STAT2		0x03
+#define AMC6821_REG_TEMP_LO		0x06
 #define AMC6821_REG_TDATA_LOW		0x08
 #define AMC6821_REG_TDATA_HI		0x09
 #define AMC6821_REG_LTEMP_HI		0x0A
@@ -61,11 +65,8 @@ module_param(init, int, 0444);
 #define AMC6821_REG_DCY_LOW_TEMP	0x21
 
 #define AMC6821_REG_TACH_LLIMITL	0x10
-#define AMC6821_REG_TACH_LLIMITH	0x11
 #define AMC6821_REG_TACH_HLIMITL	0x12
-#define AMC6821_REG_TACH_HLIMITH	0x13
 #define AMC6821_REG_TACH_SETTINGL	0x1e
-#define AMC6821_REG_TACH_SETTINGH	0x1f
 
 #define AMC6821_CONF1_START		BIT(0)
 #define AMC6821_CONF1_FAN_INT_EN	BIT(1)
@@ -108,6 +109,9 @@ module_param(init, int, 0444);
 #define AMC6821_STAT2_L_THERM		BIT(6)
 #define AMC6821_STAT2_THERM_IN		BIT(7)
 
+#define AMC6821_TEMP_SLOPE_MASK		GENMASK(2, 0)
+#define AMC6821_TEMP_LIMIT_MASK		GENMASK(7, 3)
+
 enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
 	IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
 	IDX_TEMP2_MAX, IDX_TEMP2_CRIT,
@@ -130,224 +134,155 @@ static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
 			AMC6821_REG_TACH_HLIMITL,
 			AMC6821_REG_TACH_SETTINGL, };
 
-static const u8 fan_reg_hi[] = {AMC6821_REG_TDATA_HI,
-			AMC6821_REG_TACH_LLIMITH,
-			AMC6821_REG_TACH_HLIMITH,
-			AMC6821_REG_TACH_SETTINGH, };
-
 /*
  * Client data (each client gets its own)
  */
 
 struct amc6821_data {
-	struct i2c_client *client;
+	struct regmap *regmap;
 	struct mutex update_lock;
-	bool valid; /* false until following fields are valid */
-	unsigned long last_updated; /* in jiffies */
-
-	/* register values */
-	int temp[TEMP_IDX_LEN];
-
-	u16 fan[FAN1_IDX_LEN];
-	u8 fan1_pulses;
-
-	u8 pwm1;
-	u8 temp1_auto_point_temp[3];
-	u8 temp2_auto_point_temp[3];
-	u8 pwm1_auto_point_pwm[3];
-	u8 pwm1_enable;
-	u8 pwm1_auto_channels_temp;
-
-	u8 stat1;
-	u8 stat2;
 };
 
-static struct amc6821_data *amc6821_update_device(struct device *dev)
+/*
+ * Return set of three temperatures:
+ * temps[0]: Passive cooling temperature, applies to both channels
+ * temps[1]: Low temperature, start slope calculations
+ * temps[2]: High temperature
+ */
+static int amc6821_get_auto_point_temps(struct regmap *regmap, int channel, u8 *temps)
 {
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
-	int timeout = HZ;
-	u8 reg;
-	int i;
+	u32 pwm, regval;
+	int err;
 
-	mutex_lock(&data->update_lock);
+	err = regmap_read(regmap, AMC6821_REG_DCY_LOW_TEMP, &pwm);
+	if (err)
+		return err;
 
-	if (time_after(jiffies, data->last_updated + timeout) ||
-			!data->valid) {
+	err = regmap_read(regmap, AMC6821_REG_PSV_TEMP, &regval);
+	if (err)
+		return err;
+	temps[0] = regval;
 
-		for (i = 0; i < TEMP_IDX_LEN; i++)
-			data->temp[i] = (int8_t)i2c_smbus_read_byte_data(
-				client, temp_reg[i]);
+	err = regmap_read(regmap,
+			  channel ? AMC6821_REG_RTEMP_FAN_CTRL : AMC6821_REG_LTEMP_FAN_CTRL,
+			  &regval);
+	if (err)
+		return err;
+	temps[1] = (regval & 0xF8) >> 1;
 
-		data->stat1 = i2c_smbus_read_byte_data(client,
-			AMC6821_REG_STAT1);
-		data->stat2 = i2c_smbus_read_byte_data(client,
-			AMC6821_REG_STAT2);
+	regval &= 0x07;
+	regval = 0x20 >> regval;
+	if (regval)
+		temps[2] = temps[1] + DIV_ROUND_CLOSEST(255 - pwm, regval);
+	else
+		temps[2] = 255;
 
-		data->pwm1 = i2c_smbus_read_byte_data(client,
-			AMC6821_REG_DCY);
-		for (i = 0; i < FAN1_IDX_LEN; i++) {
-			data->fan[i] = i2c_smbus_read_byte_data(
-					client,
-					fan_reg_low[i]);
-			data->fan[i] += i2c_smbus_read_byte_data(
-					client,
-					fan_reg_hi[i]) << 8;
-		}
-		data->fan1_pulses = i2c_smbus_read_byte_data(client,
-			AMC6821_REG_CONF4);
-		data->fan1_pulses = data->fan1_pulses & AMC6821_CONF4_PSPR ? 4 : 2;
-
-		data->pwm1_auto_point_pwm[0] = 0;
-		data->pwm1_auto_point_pwm[2] = 255;
-		data->pwm1_auto_point_pwm[1] = i2c_smbus_read_byte_data(client,
-			AMC6821_REG_DCY_LOW_TEMP);
-
-		data->temp1_auto_point_temp[0] =
-			i2c_smbus_read_byte_data(client,
-					AMC6821_REG_PSV_TEMP);
-		data->temp2_auto_point_temp[0] =
-				data->temp1_auto_point_temp[0];
-		reg = i2c_smbus_read_byte_data(client,
-			AMC6821_REG_LTEMP_FAN_CTRL);
-		data->temp1_auto_point_temp[1] = (reg & 0xF8) >> 1;
-		reg &= 0x07;
-		reg = 0x20 >> reg;
-		if (reg > 0)
-			data->temp1_auto_point_temp[2] =
-				data->temp1_auto_point_temp[1] +
-				(data->pwm1_auto_point_pwm[2] -
-				data->pwm1_auto_point_pwm[1]) / reg;
-		else
-			data->temp1_auto_point_temp[2] = 255;
-
-		reg = i2c_smbus_read_byte_data(client,
-			AMC6821_REG_RTEMP_FAN_CTRL);
-		data->temp2_auto_point_temp[1] = (reg & 0xF8) >> 1;
-		reg &= 0x07;
-		reg = 0x20 >> reg;
-		if (reg > 0)
-			data->temp2_auto_point_temp[2] =
-				data->temp2_auto_point_temp[1] +
-				(data->pwm1_auto_point_pwm[2] -
-				data->pwm1_auto_point_pwm[1]) / reg;
-		else
-			data->temp2_auto_point_temp[2] = 255;
-
-		reg = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
-		reg = (reg >> 5) & 0x3;
-		switch (reg) {
-		case 0: /*open loop: software sets pwm1*/
-			data->pwm1_auto_channels_temp = 0;
-			data->pwm1_enable = 1;
-			break;
-		case 2: /*closed loop: remote T (temp2)*/
-			data->pwm1_auto_channels_temp = 2;
-			data->pwm1_enable = 2;
-			break;
-		case 3: /*closed loop: local and remote T (temp2)*/
-			data->pwm1_auto_channels_temp = 3;
-			data->pwm1_enable = 3;
-			break;
-		case 1: /*
-			 * semi-open loop: software sets rpm, chip controls
-			 * pwm1
-			 */
-			data->pwm1_auto_channels_temp = 0;
-			data->pwm1_enable = 4;
-			break;
-		}
-
-		data->last_updated = jiffies;
-		data->valid = true;
-	}
-	mutex_unlock(&data->update_lock);
-	return data;
+	return 0;
 }
 
 static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
 			 char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
+	struct amc6821_data *data = dev_get_drvdata(dev);
 	int ix = to_sensor_dev_attr(devattr)->index;
+	u32 regval;
+	int err;
 
-	return sprintf(buf, "%d\n", data->temp[ix] * 1000);
+	err = regmap_read(data->regmap, temp_reg[ix], &regval);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", sign_extend32(regval, 7) * 1000);
 }
 
 static ssize_t temp_store(struct device *dev, struct device_attribute *attr,
 			  const char *buf, size_t count)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
 	int ix = to_sensor_dev_attr(attr)->index;
 	long val;
+	int err;
 
 	int ret = kstrtol(buf, 10, &val);
 	if (ret)
 		return ret;
 	val = clamp_val(val / 1000, -128, 127);
 
-	mutex_lock(&data->update_lock);
-	data->temp[ix] = val;
-	if (i2c_smbus_write_byte_data(client, temp_reg[ix], data->temp[ix])) {
-		dev_err(&client->dev, "Register write error, aborting.\n");
-		count = -EIO;
-	}
-	mutex_unlock(&data->update_lock);
+	err = regmap_write(data->regmap, temp_reg[ix], val);
+	if (err)
+		return err;
+
 	return count;
 }
 
 static ssize_t temp_alarm_show(struct device *dev,
 			       struct device_attribute *devattr, char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
+	struct amc6821_data *data = dev_get_drvdata(dev);
 	int ix = to_sensor_dev_attr(devattr)->index;
-	u8 flag;
+	u32 regval, mask, reg;
+	int err;
 
 	switch (ix) {
 	case IDX_TEMP1_MIN:
-		flag = data->stat1 & AMC6821_STAT1_LTL;
+		reg = AMC6821_REG_STAT1;
+		mask = AMC6821_STAT1_LTL;
 		break;
 	case IDX_TEMP1_MAX:
-		flag = data->stat1 & AMC6821_STAT1_LTH;
+		reg = AMC6821_REG_STAT1;
+		mask = AMC6821_STAT1_LTH;
 		break;
 	case IDX_TEMP1_CRIT:
-		flag = data->stat2 & AMC6821_STAT2_LTC;
+		reg = AMC6821_REG_STAT2;
+		mask = AMC6821_STAT2_LTC;
 		break;
 	case IDX_TEMP2_MIN:
-		flag = data->stat1 & AMC6821_STAT1_RTL;
+		reg = AMC6821_REG_STAT1;
+		mask = AMC6821_STAT1_RTL;
 		break;
 	case IDX_TEMP2_MAX:
-		flag = data->stat1 & AMC6821_STAT1_RTH;
+		reg = AMC6821_REG_STAT1;
+		mask = AMC6821_STAT1_RTH;
 		break;
 	case IDX_TEMP2_CRIT:
-		flag = data->stat2 & AMC6821_STAT2_RTC;
+		reg = AMC6821_REG_STAT2;
+		mask = AMC6821_STAT2_RTC;
 		break;
 	default:
-		dev_dbg(dev, "Unknown attr->index (%d).\n", ix);
 		return -EINVAL;
 	}
-	if (flag)
-		return sprintf(buf, "1");
-	else
-		return sprintf(buf, "0");
+	err = regmap_read(data->regmap, reg, &regval);
+	if (err)
+		return err;
+	return sysfs_emit(buf, "%d\n", !!(regval & mask));
 }
 
 static ssize_t temp2_fault_show(struct device *dev,
 				struct device_attribute *devattr, char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
-	if (data->stat1 & AMC6821_STAT1_RTF)
-		return sprintf(buf, "1");
-	else
-		return sprintf(buf, "0");
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	u32 regval;
+	int err;
+
+	err = regmap_read(data->regmap, AMC6821_REG_STAT1, &regval);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", !!(regval & AMC6821_STAT1_RTF));
 }
 
 static ssize_t pwm1_show(struct device *dev, struct device_attribute *devattr,
 			 char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
-	return sprintf(buf, "%d\n", data->pwm1);
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	u32 regval;
+	int err;
+
+	err = regmap_read(data->regmap, AMC6821_REG_DCY, &regval);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", regval);
 }
 
 static ssize_t pwm1_store(struct device *dev,
@@ -355,24 +290,43 @@ static ssize_t pwm1_store(struct device *dev,
 			  size_t count)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
 	u8 val;
 	int ret = kstrtou8(buf, 10, &val);
 	if (ret)
 		return ret;
 
-	mutex_lock(&data->update_lock);
-	data->pwm1 = val;
-	i2c_smbus_write_byte_data(client, AMC6821_REG_DCY, data->pwm1);
-	mutex_unlock(&data->update_lock);
+	ret = regmap_write(data->regmap, AMC6821_REG_DCY, val);
+	if (ret)
+		return ret;
+
 	return count;
 }
 
 static ssize_t pwm1_enable_show(struct device *dev,
 				struct device_attribute *devattr, char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
-	return sprintf(buf, "%d\n", data->pwm1_enable);
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	int err;
+	u32 val;
+
+	err = regmap_read(data->regmap, AMC6821_REG_CONF1, &val);
+	if (err)
+		return err;
+	switch (val & (AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1)) {
+	case 0:
+		val = 1;	/* manual */
+		break;
+	case AMC6821_CONF1_FDRC0:
+		val = 4;	/* target rpm (fan1_target) controlled */
+		break;
+	case AMC6821_CONF1_FDRC1:
+		val = 2;	/* remote temp controlled */
+		break;
+	default:
+		val = 3;	/* max(local, remote) temp controlled */
+		break;
+	}
+	return sysfs_emit(buf, "%d\n", val);
 }
 
 static ssize_t pwm1_enable_store(struct device *dev,
@@ -380,49 +334,37 @@ static ssize_t pwm1_enable_store(struct device *dev,
 				 const char *buf, size_t count)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
 	long val;
-	int config = kstrtol(buf, 10, &val);
-	if (config)
-		return config;
+	u32 mode;
+	int err;
 
-	mutex_lock(&data->update_lock);
-	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
-	if (config < 0) {
-			dev_err(&client->dev,
-			"Error reading configuration register, aborting.\n");
-			count = config;
-			goto unlock;
-	}
+	err = kstrtol(buf, 10, &val);
+	if (err)
+		return err;
 
 	switch (val) {
 	case 1:
-		config &= ~AMC6821_CONF1_FDRC0;
-		config &= ~AMC6821_CONF1_FDRC1;
+		mode = 0;
 		break;
 	case 2:
-		config &= ~AMC6821_CONF1_FDRC0;
-		config |= AMC6821_CONF1_FDRC1;
+		mode = AMC6821_CONF1_FDRC1;
 		break;
 	case 3:
-		config |= AMC6821_CONF1_FDRC0;
-		config |= AMC6821_CONF1_FDRC1;
+		mode = AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1;
 		break;
 	case 4:
-		config |= AMC6821_CONF1_FDRC0;
-		config &= ~AMC6821_CONF1_FDRC1;
+		mode = AMC6821_CONF1_FDRC0;
 		break;
 	default:
-		count = -EINVAL;
-		goto unlock;
+		return -EINVAL;
 	}
-	if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF1, config)) {
-			dev_err(&client->dev,
-			"Configuration register write error, aborting.\n");
-			count = -EIO;
-	}
-unlock:
-	mutex_unlock(&data->update_lock);
+
+	err = regmap_update_bits(data->regmap, AMC6821_REG_CONF1,
+				 AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1,
+				 mode);
+	if (err)
+		return err;
+
 	return count;
 }
 
@@ -430,130 +372,163 @@ static ssize_t pwm1_auto_channels_temp_show(struct device *dev,
 					    struct device_attribute *devattr,
 					    char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
-	return sprintf(buf, "%d\n", data->pwm1_auto_channels_temp);
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	u32 val;
+	int err;
+
+	err = regmap_read(data->regmap, AMC6821_REG_CONF1, &val);
+	if (err)
+		return err;
+	switch (val & (AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1)) {
+	case 0:
+	case AMC6821_CONF1_FDRC0:
+		val = 0;	/* manual or target rpm controlled */
+		break;
+	case AMC6821_CONF1_FDRC1:
+		val = 2;	/* remote temp controlled */
+		break;
+	default:
+		val = 3;	/* max(local, remote) temp controlled */
+		break;
+	}
+
+	return sysfs_emit(buf, "%d\n", val);
 }
 
 static ssize_t temp_auto_point_temp_show(struct device *dev,
 					 struct device_attribute *devattr,
 					 char *buf)
 {
+	struct amc6821_data *data = dev_get_drvdata(dev);
 	int ix = to_sensor_dev_attr_2(devattr)->index;
 	int nr = to_sensor_dev_attr_2(devattr)->nr;
-	struct amc6821_data *data = amc6821_update_device(dev);
-	switch (nr) {
-	case 1:
-		return sprintf(buf, "%d\n",
-			data->temp1_auto_point_temp[ix] * 1000);
-	case 2:
-		return sprintf(buf, "%d\n",
-			data->temp2_auto_point_temp[ix] * 1000);
-	default:
-		dev_dbg(dev, "Unknown attr->nr (%d).\n", nr);
-		return -EINVAL;
-	}
+	u8 temps[3];
+	int err;
+
+	mutex_lock(&data->update_lock);
+	err = amc6821_get_auto_point_temps(data->regmap, nr, temps);
+	mutex_unlock(&data->update_lock);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", temps[ix] * 1000);
 }
 
 static ssize_t pwm1_auto_point_pwm_show(struct device *dev,
 					struct device_attribute *devattr,
 					char *buf)
 {
+	struct amc6821_data *data = dev_get_drvdata(dev);
 	int ix = to_sensor_dev_attr(devattr)->index;
-	struct amc6821_data *data = amc6821_update_device(dev);
-	return sprintf(buf, "%d\n", data->pwm1_auto_point_pwm[ix]);
+	u32 val;
+	int err;
+
+	switch (ix) {
+	case 0:
+		val = 0;
+		break;
+	case 1:
+		err = regmap_read(data->regmap, AMC6821_REG_DCY_LOW_TEMP, &val);
+		if (err)
+			return err;
+		break;
+	default:
+		val = 255;
+		break;
+	}
+	return sysfs_emit(buf, "%d\n", val);
 }
 
-static inline ssize_t set_slope_register(struct i2c_client *client,
-		u8 reg,
-		u8 dpwm,
-		u8 *ptemp)
+static inline int set_slope_register(struct regmap *regmap, int channel, u8 *temps)
 {
-	int dt;
-	u8 tmp;
+	u8 tmp, dpwm;
+	int err, dt;
+	u32 pwm;
 
-	dt = ptemp[2]-ptemp[1];
+	err = regmap_read(regmap, AMC6821_REG_DCY_LOW_TEMP, &pwm);
+	if (err)
+		return err;
+
+	dpwm = 255 - pwm;
+
+	dt = temps[2] - temps[1];
 	for (tmp = 4; tmp > 0; tmp--) {
 		if (dt * (0x20 >> tmp) >= dpwm)
 			break;
 	}
-	tmp |= (ptemp[1] & 0x7C) << 1;
-	if (i2c_smbus_write_byte_data(client,
-			reg, tmp)) {
-		dev_err(&client->dev, "Register write error, aborting.\n");
-		return -EIO;
-	}
-	return 0;
+	return regmap_update_bits(regmap,
+				  channel ? AMC6821_REG_RTEMP_FAN_CTRL : AMC6821_REG_LTEMP_FAN_CTRL,
+				  AMC6821_TEMP_SLOPE_MASK,
+				  tmp);
 }
 
 static ssize_t temp_auto_point_temp_store(struct device *dev,
 					  struct device_attribute *attr,
 					  const char *buf, size_t count)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
-	struct i2c_client *client = data->client;
+	struct amc6821_data *data = dev_get_drvdata(dev);
 	int ix = to_sensor_dev_attr_2(attr)->index;
 	int nr = to_sensor_dev_attr_2(attr)->nr;
-	u8 *ptemp;
-	u8 reg;
-	int dpwm;
+	struct regmap *regmap = data->regmap;
+	u8 temps[3], otemps[3];
 	long val;
-	int ret = kstrtol(buf, 10, &val);
+	int ret;
+
+	ret = kstrtol(buf, 10, &val);
 	if (ret)
 		return ret;
 
-	switch (nr) {
-	case 1:
-		ptemp = data->temp1_auto_point_temp;
-		reg = AMC6821_REG_LTEMP_FAN_CTRL;
-		break;
-	case 2:
-		ptemp = data->temp2_auto_point_temp;
-		reg = AMC6821_REG_RTEMP_FAN_CTRL;
-		break;
-	default:
-		dev_dbg(dev, "Unknown attr->nr (%d).\n", nr);
-		return -EINVAL;
-	}
-
 	mutex_lock(&data->update_lock);
-	data->valid = false;
+
+	ret = amc6821_get_auto_point_temps(data->regmap, nr, temps);
+	if (ret)
+		goto unlock;
+	ret = amc6821_get_auto_point_temps(data->regmap, 1 - nr, otemps);
+	if (ret)
+		goto unlock;
 
 	switch (ix) {
 	case 0:
-		ptemp[0] = clamp_val(val / 1000, 0,
-				     data->temp1_auto_point_temp[1]);
-		ptemp[0] = clamp_val(ptemp[0], 0,
-				     data->temp2_auto_point_temp[1]);
-		ptemp[0] = clamp_val(ptemp[0], 0, 63);
-		if (i2c_smbus_write_byte_data(
-					client,
-					AMC6821_REG_PSV_TEMP,
-					ptemp[0])) {
-				dev_err(&client->dev,
-					"Register write error, aborting.\n");
-				count = -EIO;
-		}
-		goto EXIT;
+		/*
+		 * Passive cooling temperature. Range limit against low limit
+		 * of both channels.
+		 */
+		val = DIV_ROUND_CLOSEST(clamp_val(val, 0, 63000), 1000);
+		val = clamp_val(val, 0, min(temps[1], otemps[1]));
+		ret = regmap_write(regmap, AMC6821_REG_PSV_TEMP, val);
+		break;
 	case 1:
-		ptemp[1] = clamp_val(val / 1000, (ptemp[0] & 0x7C) + 4, 124);
-		ptemp[1] &= 0x7C;
-		ptemp[2] = clamp_val(ptemp[2], ptemp[1] + 1, 255);
+		/*
+		 * Low limit; must be between passive and high limit,
+		 * and not exceed 124. Step size is 4 degrees C.
+		 */
+		val = clamp_val(val, DIV_ROUND_UP(temps[0], 4) * 4000, 124000);
+		temps[1] = DIV_ROUND_CLOSEST(val, 4000) * 4;
+		val = temps[1] / 4;
+		/* Auto-adjust high limit if necessary */
+		temps[2] = clamp_val(temps[2], temps[1] + 1, 255);
+		ret = regmap_update_bits(regmap,
+					 nr ? AMC6821_REG_RTEMP_FAN_CTRL
+					    : AMC6821_REG_LTEMP_FAN_CTRL,
+					 AMC6821_TEMP_LIMIT_MASK,
+					 FIELD_PREP(AMC6821_TEMP_LIMIT_MASK, val));
+		if (ret)
+			break;
+		ret = set_slope_register(regmap, nr, temps);
 		break;
 	case 2:
-		ptemp[2] = clamp_val(val / 1000, ptemp[1]+1, 255);
+		/* high limit, must be higher than low limit */
+		val = clamp_val(val, (temps[1] + 1) * 1000, 255000);
+		temps[2] = DIV_ROUND_CLOSEST(val, 1000);
+		ret = set_slope_register(regmap, nr, temps);
 		break;
 	default:
-		dev_dbg(dev, "Unknown attr->index (%d).\n", ix);
-		count = -EINVAL;
-		goto EXIT;
+		ret = -EINVAL;
+		break;
 	}
-	dpwm = data->pwm1_auto_point_pwm[2] - data->pwm1_auto_point_pwm[1];
-	if (set_slope_register(client, reg, dpwm, ptemp))
-		count = -EIO;
-
-EXIT:
+unlock:
 	mutex_unlock(&data->update_lock);
-	return count;
+	return ret ? : count;
 }
 
 static ssize_t pwm1_auto_point_pwm_store(struct device *dev,
@@ -561,101 +536,107 @@ static ssize_t pwm1_auto_point_pwm_store(struct device *dev,
 					 const char *buf, size_t count)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
-	int dpwm;
+	struct regmap *regmap = data->regmap;
+	int i, ret;
 	u8 val;
-	int ret;
 
 	ret = kstrtou8(buf, 10, &val);
 	if (ret)
 		return ret;
 
 	mutex_lock(&data->update_lock);
-	data->pwm1_auto_point_pwm[1] = val;
-	if (i2c_smbus_write_byte_data(client, AMC6821_REG_DCY_LOW_TEMP,
-			data->pwm1_auto_point_pwm[1])) {
-		dev_err(&client->dev, "Register write error, aborting.\n");
-		count = -EIO;
-		goto EXIT;
-	}
-	dpwm = data->pwm1_auto_point_pwm[2] - data->pwm1_auto_point_pwm[1];
-	if (set_slope_register(client, AMC6821_REG_LTEMP_FAN_CTRL, dpwm,
-			data->temp1_auto_point_temp)) {
-		count = -EIO;
-		goto EXIT;
-	}
-	if (set_slope_register(client, AMC6821_REG_RTEMP_FAN_CTRL, dpwm,
-			data->temp2_auto_point_temp)) {
-		count = -EIO;
-		goto EXIT;
-	}
+	ret = regmap_write(regmap, AMC6821_REG_DCY_LOW_TEMP, val);
+	if (ret)
+		goto unlock;
 
-EXIT:
-	data->valid = false;
+	for (i = 0; i < 2; i++) {
+		u8 temps[3];
+
+		ret = amc6821_get_auto_point_temps(regmap, i, temps);
+		if (ret)
+			break;
+		ret = set_slope_register(regmap, i, temps);
+		if (ret)
+			break;
+	}
+unlock:
 	mutex_unlock(&data->update_lock);
-	return count;
+	return ret ? : count;
 }
 
 static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
 			char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
+	struct amc6821_data *data = dev_get_drvdata(dev);
 	int ix = to_sensor_dev_attr(devattr)->index;
-	if (0 == data->fan[ix])
-		return sprintf(buf, "0");
-	return sprintf(buf, "%d\n", (int)(6000000 / data->fan[ix]));
+	u32 regval;
+	u8 regs[2];
+	int err;
+
+	err = regmap_bulk_read(data->regmap, fan_reg_low[ix], regs, 2);
+	if (err)
+		return err;
+	regval = (regs[1] << 8) | regs[0];
+
+	return sysfs_emit(buf, "%d\n", 6000000 / (regval ? : 1));
 }
 
 static ssize_t fan1_fault_show(struct device *dev,
 			       struct device_attribute *devattr, char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
-	if (data->stat1 & AMC6821_STAT1_FANS)
-		return sprintf(buf, "1");
-	else
-		return sprintf(buf, "0");
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	u32 regval;
+	int err;
+
+	err = regmap_read(data->regmap, AMC6821_REG_STAT1, &regval);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", !!(regval & AMC6821_STAT1_FANS));
 }
 
 static ssize_t fan_store(struct device *dev, struct device_attribute *attr,
 			 const char *buf, size_t count)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
-	unsigned long val;
 	int ix = to_sensor_dev_attr(attr)->index;
-	int ret = kstrtoul(buf, 10, &val);
-	if (ret)
-		return ret;
+	unsigned long val;
+	u8 regs[2];
+	int err;
+
+	err = kstrtoul(buf, 10, &val);
+	if (err)
+		return err;
 
 	/* Minimum and target fan speed must not be unlimited (0) */
 	if ((ix == IDX_FAN1_MIN || ix == IDX_FAN1_TARGET) && !val)
 		return -EINVAL;
 
 	val = val > 0 ? 6000000 / clamp_val(val, 1, 6000000) : 0;
+	val = clamp_val(val, 0, 0xFFFF);
+
+	regs[0] = val & 0xff;
+	regs[1] = val >> 8;
+
+	err = regmap_bulk_write(data->regmap, fan_reg_low[ix], regs, 2);
+	if (err)
+		return err;
 
-	mutex_lock(&data->update_lock);
-	data->fan[ix] = clamp_val(val, 0, 0xFFFF);
-	if (i2c_smbus_write_byte_data(client, fan_reg_low[ix],
-			data->fan[ix] & 0xFF)) {
-		dev_err(&client->dev, "Register write error, aborting.\n");
-		count = -EIO;
-		goto EXIT;
-	}
-	if (i2c_smbus_write_byte_data(client,
-			fan_reg_hi[ix], data->fan[ix] >> 8)) {
-		dev_err(&client->dev, "Register write error, aborting.\n");
-		count = -EIO;
-	}
-EXIT:
-	mutex_unlock(&data->update_lock);
 	return count;
 }
 
 static ssize_t fan1_pulses_show(struct device *dev,
 				struct device_attribute *devattr, char *buf)
 {
-	struct amc6821_data *data = amc6821_update_device(dev);
-	return sprintf(buf, "%d\n", data->fan1_pulses);
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	u32 regval;
+	int err;
+
+	err = regmap_read(data->regmap, AMC6821_REG_CONF4, &regval);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", (regval & AMC6821_CONF4_PSPR) ? 4 : 2);
 }
 
 static ssize_t fan1_pulses_store(struct device *dev,
@@ -663,40 +644,22 @@ static ssize_t fan1_pulses_store(struct device *dev,
 				 size_t count)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
-	struct i2c_client *client = data->client;
 	long val;
-	int config = kstrtol(buf, 10, &val);
-	if (config)
-		return config;
+	int err;
+
+	err = kstrtol(buf, 10, &val);
+	if (err)
+		return err;
+
+	if (val != 2 && val != 4)
+		return -EINVAL;
+
+	err = regmap_update_bits(data->regmap, AMC6821_REG_CONF4,
+				 AMC6821_CONF4_PSPR,
+				 val == 4 ? AMC6821_CONF4_PSPR : 0);
+	if (err)
+		return err;
 
-	mutex_lock(&data->update_lock);
-	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF4);
-	if (config < 0) {
-		dev_err(&client->dev,
-			"Error reading configuration register, aborting.\n");
-		count = config;
-		goto EXIT;
-	}
-	switch (val) {
-	case 2:
-		config &= ~AMC6821_CONF4_PSPR;
-		data->fan1_pulses = 2;
-		break;
-	case 4:
-		config |= AMC6821_CONF4_PSPR;
-		data->fan1_pulses = 4;
-		break;
-	default:
-		count = -EINVAL;
-		goto EXIT;
-	}
-	if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF4, config)) {
-		dev_err(&client->dev,
-			"Configuration register write error, aborting.\n");
-		count = -EIO;
-	}
-EXIT:
-	mutex_unlock(&data->update_lock);
 	return count;
 }
 
@@ -730,18 +693,18 @@ static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point3_pwm, pwm1_auto_point_pwm, 2);
 static SENSOR_DEVICE_ATTR_RO(pwm1_auto_channels_temp, pwm1_auto_channels_temp,
 			     0);
 static SENSOR_DEVICE_ATTR_2_RO(temp1_auto_point1_temp, temp_auto_point_temp,
-			       1, 0);
+			       0, 0);
 static SENSOR_DEVICE_ATTR_2_RW(temp1_auto_point2_temp, temp_auto_point_temp,
-			       1, 1);
+			       0, 1);
 static SENSOR_DEVICE_ATTR_2_RW(temp1_auto_point3_temp, temp_auto_point_temp,
-			       1, 2);
+			       0, 2);
 
 static SENSOR_DEVICE_ATTR_2_RW(temp2_auto_point1_temp, temp_auto_point_temp,
-			       2, 0);
+			       1, 0);
 static SENSOR_DEVICE_ATTR_2_RW(temp2_auto_point2_temp, temp_auto_point_temp,
-			       2, 1);
+			       1, 1);
 static SENSOR_DEVICE_ATTR_2_RW(temp2_auto_point3_temp, temp_auto_point_temp,
-			       2, 2);
+			       1, 2);
 
 static struct attribute *amc6821_attrs[] = {
 	&sensor_dev_attr_temp1_input.dev_attr.attr,
@@ -828,110 +791,79 @@ static int amc6821_detect(
 	return 0;
 }
 
-static int amc6821_init_client(struct i2c_client *client)
+static int amc6821_init_client(struct amc6821_data *data)
 {
-	int config;
-	int err = -EIO;
+	struct regmap *regmap = data->regmap;
+	int err;
 
 	if (init) {
-		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF4);
-
-		if (config < 0) {
-				dev_err(&client->dev,
-			"Error reading configuration register, aborting.\n");
-				return err;
-		}
-
-		config |= AMC6821_CONF4_MODE;
-
-		if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF4,
-				config)) {
-			dev_err(&client->dev,
-			"Configuration register write error, aborting.\n");
+		err = regmap_set_bits(regmap, AMC6821_REG_CONF4, AMC6821_CONF4_MODE);
+		if (err)
 			return err;
-		}
-
-		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF3);
-
-		if (config < 0) {
-			dev_err(&client->dev,
-			"Error reading configuration register, aborting.\n");
+		err = regmap_clear_bits(regmap, AMC6821_REG_CONF3, AMC6821_CONF3_THERM_FAN_EN);
+		if (err)
 			return err;
-		}
-
-		dev_info(&client->dev, "Revision %d\n", config & 0x0f);
-
-		config &= ~AMC6821_CONF3_THERM_FAN_EN;
-
-		if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF3,
-				config)) {
-			dev_err(&client->dev,
-			"Configuration register write error, aborting.\n");
+		err = regmap_clear_bits(regmap, AMC6821_REG_CONF2,
+					AMC6821_CONF2_RTFIE |
+					AMC6821_CONF2_LTOIE |
+					AMC6821_CONF2_RTOIE);
+		if (err)
 			return err;
-		}
 
-		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF2);
-
-		if (config < 0) {
-			dev_err(&client->dev,
-			"Error reading configuration register, aborting.\n");
+		err = regmap_update_bits(regmap, AMC6821_REG_CONF1,
+					 AMC6821_CONF1_THERMOVIE | AMC6821_CONF1_FANIE |
+					 AMC6821_CONF1_START | AMC6821_CONF1_PWMINV,
+					 AMC6821_CONF1_START |
+					 (pwminv ? AMC6821_CONF1_PWMINV : 0));
+		if (err)
 			return err;
-		}
-
-		config &= ~AMC6821_CONF2_RTFIE;
-		config &= ~AMC6821_CONF2_LTOIE;
-		config &= ~AMC6821_CONF2_RTOIE;
-		if (i2c_smbus_write_byte_data(client,
-				AMC6821_REG_CONF2, config)) {
-			dev_err(&client->dev,
-			"Configuration register write error, aborting.\n");
-			return err;
-		}
-
-		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
-
-		if (config < 0) {
-			dev_err(&client->dev,
-			"Error reading configuration register, aborting.\n");
-			return err;
-		}
-
-		config &= ~AMC6821_CONF1_THERMOVIE;
-		config &= ~AMC6821_CONF1_FANIE;
-		config |= AMC6821_CONF1_START;
-		if (pwminv)
-			config |= AMC6821_CONF1_PWMINV;
-		else
-			config &= ~AMC6821_CONF1_PWMINV;
-
-		if (i2c_smbus_write_byte_data(
-				client, AMC6821_REG_CONF1, config)) {
-			dev_err(&client->dev,
-			"Configuration register write error, aborting.\n");
-			return err;
-		}
 	}
 	return 0;
 }
 
+static bool amc6821_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case AMC6821_REG_STAT1:
+	case AMC6821_REG_STAT2:
+	case AMC6821_REG_TEMP_LO:
+	case AMC6821_REG_TDATA_LOW:
+	case AMC6821_REG_LTEMP_HI:
+	case AMC6821_REG_RTEMP_HI:
+	case AMC6821_REG_TDATA_HI:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config amc6821_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = AMC6821_REG_CONF3,
+	.volatile_reg = amc6821_volatile_reg,
+	.cache_type = REGCACHE_MAPLE,
+};
+
 static int amc6821_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct amc6821_data *data;
 	struct device *hwmon_dev;
+	struct regmap *regmap;
 	int err;
 
 	data = devm_kzalloc(dev, sizeof(struct amc6821_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
-	data->client = client;
-	mutex_init(&data->update_lock);
+	regmap = devm_regmap_init_i2c(client, &amc6821_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "Failed to initialize regmap\n");
+	data->regmap = regmap;
 
-	/*
-	 * Initialize the amc6821 chip
-	 */
-	err = amc6821_init_client(client);
+	err = amc6821_init_client(data);
 	if (err)
 		return err;
 
-- 
2.39.2

[PATCH v3 10/11] hwmon: (amc6821) Convert to with_info API

[Guenter Roeck]

Convert to use with_info API to simplify the code and make it easier
to maintain. This also reduces code size by approximately 20%.

No functional change intended.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Add Quentin's Reviewed-by: tag

v2: Adjust to changes made in preceding patches

 drivers/hwmon/amc6821.c | 744 +++++++++++++++++++++-------------------
 1 file changed, 390 insertions(+), 354 deletions(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index a5abd36a1430..be3e590aba3d 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -6,6 +6,9 @@
  *
  * Based on max6650.c:
  * Copyright (C) 2007 Hans J. Koch <hjk@hansjkoch.de>
+ *
+ * Conversion to regmap and with_info API:
+ * Copyright (C) 2024 Guenter Roeck <linux@roeck-us.net>
  */
 
 #include <linux/bitfield.h>
@@ -112,28 +115,6 @@ module_param(init, int, 0444);
 #define AMC6821_TEMP_SLOPE_MASK		GENMASK(2, 0)
 #define AMC6821_TEMP_LIMIT_MASK		GENMASK(7, 3)
 
-enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
-	IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
-	IDX_TEMP2_MAX, IDX_TEMP2_CRIT,
-	TEMP_IDX_LEN, };
-
-static const u8 temp_reg[] = {AMC6821_REG_LTEMP_HI,
-			AMC6821_REG_LTEMP_LIMIT_MIN,
-			AMC6821_REG_LTEMP_LIMIT_MAX,
-			AMC6821_REG_LTEMP_CRIT,
-			AMC6821_REG_RTEMP_HI,
-			AMC6821_REG_RTEMP_LIMIT_MIN,
-			AMC6821_REG_RTEMP_LIMIT_MAX,
-			AMC6821_REG_RTEMP_CRIT, };
-
-enum {IDX_FAN1_INPUT = 0, IDX_FAN1_MIN, IDX_FAN1_MAX, IDX_FAN1_TARGET,
-	FAN1_IDX_LEN, };
-
-static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
-			AMC6821_REG_TACH_LLIMITL,
-			AMC6821_REG_TACH_HLIMITL,
-			AMC6821_REG_TACH_SETTINGL, };
-
 /*
  * Client data (each client gets its own)
  */
@@ -180,219 +161,319 @@ static int amc6821_get_auto_point_temps(struct regmap *regmap, int channel, u8 *
 	return 0;
 }
 
-static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,
-			 char *buf)
+static int amc6821_temp_read_values(struct regmap *regmap, u32 attr, int channel, long *val)
 {
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	int ix = to_sensor_dev_attr(devattr)->index;
+	int reg, err;
 	u32 regval;
-	int err;
 
-	err = regmap_read(data->regmap, temp_reg[ix], &regval);
-	if (err)
-		return err;
-
-	return sysfs_emit(buf, "%d\n", sign_extend32(regval, 7) * 1000);
-}
-
-static ssize_t temp_store(struct device *dev, struct device_attribute *attr,
-			  const char *buf, size_t count)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	int ix = to_sensor_dev_attr(attr)->index;
-	long val;
-	int err;
-
-	int ret = kstrtol(buf, 10, &val);
-	if (ret)
-		return ret;
-	val = clamp_val(val / 1000, -128, 127);
-
-	err = regmap_write(data->regmap, temp_reg[ix], val);
-	if (err)
-		return err;
-
-	return count;
-}
-
-static ssize_t temp_alarm_show(struct device *dev,
-			       struct device_attribute *devattr, char *buf)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	int ix = to_sensor_dev_attr(devattr)->index;
-	u32 regval, mask, reg;
-	int err;
-
-	switch (ix) {
-	case IDX_TEMP1_MIN:
-		reg = AMC6821_REG_STAT1;
-		mask = AMC6821_STAT1_LTL;
+	switch (attr) {
+	case hwmon_temp_input:
+		reg = channel ? AMC6821_REG_RTEMP_HI : AMC6821_REG_LTEMP_HI;
 		break;
-	case IDX_TEMP1_MAX:
-		reg = AMC6821_REG_STAT1;
-		mask = AMC6821_STAT1_LTH;
+	case hwmon_temp_min:
+		reg = channel ? AMC6821_REG_RTEMP_LIMIT_MIN : AMC6821_REG_LTEMP_LIMIT_MIN;
 		break;
-	case IDX_TEMP1_CRIT:
-		reg = AMC6821_REG_STAT2;
-		mask = AMC6821_STAT2_LTC;
+	case hwmon_temp_max:
+		reg = channel ? AMC6821_REG_RTEMP_LIMIT_MAX : AMC6821_REG_LTEMP_LIMIT_MAX;
 		break;
-	case IDX_TEMP2_MIN:
-		reg = AMC6821_REG_STAT1;
-		mask = AMC6821_STAT1_RTL;
-		break;
-	case IDX_TEMP2_MAX:
-		reg = AMC6821_REG_STAT1;
-		mask = AMC6821_STAT1_RTH;
-		break;
-	case IDX_TEMP2_CRIT:
-		reg = AMC6821_REG_STAT2;
-		mask = AMC6821_STAT2_RTC;
+	case hwmon_temp_crit:
+		reg = channel ? AMC6821_REG_RTEMP_CRIT : AMC6821_REG_LTEMP_CRIT;
 		break;
 	default:
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
-	err = regmap_read(data->regmap, reg, &regval);
+	err = regmap_read(regmap, reg, &regval);
 	if (err)
 		return err;
-	return sysfs_emit(buf, "%d\n", !!(regval & mask));
+	*val = sign_extend32(regval, 7) * 1000;
+	return 0;
 }
 
-static ssize_t temp2_fault_show(struct device *dev,
-				struct device_attribute *devattr, char *buf)
+static int amc6821_read_alarms(struct regmap *regmap, enum hwmon_sensor_types type,
+			       u32 attr, int channel, long *val)
 {
-	struct amc6821_data *data = dev_get_drvdata(dev);
+	int reg, mask, err;
 	u32 regval;
-	int err;
 
-	err = regmap_read(data->regmap, AMC6821_REG_STAT1, &regval);
-	if (err)
-		return err;
-
-	return sysfs_emit(buf, "%d\n", !!(regval & AMC6821_STAT1_RTF));
-}
-
-static ssize_t pwm1_show(struct device *dev, struct device_attribute *devattr,
-			 char *buf)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	u32 regval;
-	int err;
-
-	err = regmap_read(data->regmap, AMC6821_REG_DCY, &regval);
-	if (err)
-		return err;
-
-	return sysfs_emit(buf, "%d\n", regval);
-}
-
-static ssize_t pwm1_store(struct device *dev,
-			  struct device_attribute *devattr, const char *buf,
-			  size_t count)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	u8 val;
-	int ret = kstrtou8(buf, 10, &val);
-	if (ret)
-		return ret;
-
-	ret = regmap_write(data->regmap, AMC6821_REG_DCY, val);
-	if (ret)
-		return ret;
-
-	return count;
-}
-
-static ssize_t pwm1_enable_show(struct device *dev,
-				struct device_attribute *devattr, char *buf)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	int err;
-	u32 val;
-
-	err = regmap_read(data->regmap, AMC6821_REG_CONF1, &val);
-	if (err)
-		return err;
-	switch (val & (AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1)) {
-	case 0:
-		val = 1;	/* manual */
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_min_alarm:
+			reg = AMC6821_REG_STAT1;
+			mask = channel ? AMC6821_STAT1_RTL : AMC6821_STAT1_LTL;
+			break;
+		case hwmon_temp_max_alarm:
+			reg = AMC6821_REG_STAT1;
+			mask = channel ? AMC6821_STAT1_RTH : AMC6821_STAT1_LTH;
+			break;
+		case hwmon_temp_crit_alarm:
+			reg = AMC6821_REG_STAT2;
+			mask = channel ? AMC6821_STAT2_RTC : AMC6821_STAT2_LTC;
+			break;
+		case hwmon_temp_fault:
+			reg = AMC6821_REG_STAT1;
+			mask = AMC6821_STAT1_RTF;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
 		break;
-	case AMC6821_CONF1_FDRC0:
-		val = 4;	/* target rpm (fan1_target) controlled */
-		break;
-	case AMC6821_CONF1_FDRC1:
-		val = 2;	/* remote temp controlled */
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_fault:
+			reg = AMC6821_REG_STAT1;
+			mask = AMC6821_STAT1_FANS;
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
 		break;
 	default:
-		val = 3;	/* max(local, remote) temp controlled */
-		break;
+		return -EOPNOTSUPP;
 	}
-	return sysfs_emit(buf, "%d\n", val);
+	err = regmap_read(regmap, reg, &regval);
+	if (err)
+		return err;
+	*val = !!(regval & mask);
+	return 0;
 }
 
-static ssize_t pwm1_enable_store(struct device *dev,
-				 struct device_attribute *attr,
-				 const char *buf, size_t count)
+static int amc6821_temp_read(struct device *dev, u32 attr, int channel, long *val)
 {
 	struct amc6821_data *data = dev_get_drvdata(dev);
-	long val;
+
+	switch (attr) {
+	case hwmon_temp_input:
+	case hwmon_temp_min:
+	case hwmon_temp_max:
+	case hwmon_temp_crit:
+		return amc6821_temp_read_values(data->regmap, attr, channel, val);
+	case hwmon_temp_min_alarm:
+	case hwmon_temp_max_alarm:
+	case hwmon_temp_crit_alarm:
+	case hwmon_temp_fault:
+		return amc6821_read_alarms(data->regmap, hwmon_temp, attr, channel, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int amc6821_temp_write(struct device *dev, u32 attr, int channel, long val)
+{
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	int reg;
+
+	val = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000);
+
+	switch (attr) {
+	case hwmon_temp_min:
+		reg = channel ? AMC6821_REG_RTEMP_LIMIT_MIN : AMC6821_REG_LTEMP_LIMIT_MIN;
+		break;
+	case hwmon_temp_max:
+		reg = channel ? AMC6821_REG_RTEMP_LIMIT_MAX : AMC6821_REG_LTEMP_LIMIT_MAX;
+		break;
+	case hwmon_temp_crit:
+		reg = channel ? AMC6821_REG_RTEMP_CRIT : AMC6821_REG_LTEMP_CRIT;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+	return regmap_write(data->regmap, reg, val);
+}
+
+static int amc6821_pwm_read(struct device *dev, u32 attr, long *val)
+{
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	u32 regval;
+	int err;
+
+	switch (attr) {
+	case hwmon_pwm_enable:
+		err = regmap_read(regmap, AMC6821_REG_CONF1, &regval);
+		if (err)
+			return err;
+		switch (regval & (AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1)) {
+		case 0:
+			*val = 1;	/* manual */
+			break;
+		case AMC6821_CONF1_FDRC0:
+			*val = 4;	/* target rpm (fan1_target) controlled */
+			break;
+		case AMC6821_CONF1_FDRC1:
+			*val = 2;	/* remote temp controlled */
+			break;
+		default:
+			*val = 3;	/* max(local, remote) temp controlled */
+			break;
+		}
+		return 0;
+	case hwmon_pwm_auto_channels_temp:
+		err = regmap_read(regmap, AMC6821_REG_CONF1, &regval);
+		if (err)
+			return err;
+		switch (regval & (AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1)) {
+		case 0:
+		case AMC6821_CONF1_FDRC0:
+			*val = 0;	/* manual or target rpm controlled */
+			break;
+		case AMC6821_CONF1_FDRC1:
+			*val = 2;	/* remote temp controlled */
+			break;
+		default:
+			*val = 3;	/* max(local, remote) temp controlled */
+			break;
+		}
+		return 0;
+	case hwmon_pwm_input:
+		err = regmap_read(regmap, AMC6821_REG_DCY, &regval);
+		if (err)
+			return err;
+		*val = regval;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int amc6821_pwm_write(struct device *dev, u32 attr, long val)
+{
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
 	u32 mode;
-	int err;
 
-	err = kstrtol(buf, 10, &val);
-	if (err)
-		return err;
-
-	switch (val) {
-	case 1:
-		mode = 0;
-		break;
-	case 2:
-		mode = AMC6821_CONF1_FDRC1;
-		break;
-	case 3:
-		mode = AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1;
-		break;
-	case 4:
-		mode = AMC6821_CONF1_FDRC0;
-		break;
+	switch (attr) {
+	case hwmon_pwm_enable:
+		switch (val) {
+		case 1:
+			mode = 0;
+			break;
+		case 2:
+			mode = AMC6821_CONF1_FDRC1;
+			break;
+		case 3:
+			mode = AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1;
+			break;
+		case 4:
+			mode = AMC6821_CONF1_FDRC0;
+			break;
+		default:
+			return -EINVAL;
+		}
+		return regmap_update_bits(regmap, AMC6821_REG_CONF1,
+					  AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1,
+					  mode);
+	case hwmon_pwm_input:
+		if (val < 0 || val > 255)
+			return -EINVAL;
+		return regmap_write(regmap, AMC6821_REG_DCY, val);
 	default:
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
-
-	err = regmap_update_bits(data->regmap, AMC6821_REG_CONF1,
-				 AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1,
-				 mode);
-	if (err)
-		return err;
-
-	return count;
 }
 
-static ssize_t pwm1_auto_channels_temp_show(struct device *dev,
-					    struct device_attribute *devattr,
-					    char *buf)
+static int amc6821_fan_read_rpm(struct regmap *regmap, u32 attr, long *val)
 {
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	u32 val;
-	int err;
+	int reg, err;
+	u8 regs[2];
+	u32 regval;
 
-	err = regmap_read(data->regmap, AMC6821_REG_CONF1, &val);
-	if (err)
-		return err;
-	switch (val & (AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1)) {
-	case 0:
-	case AMC6821_CONF1_FDRC0:
-		val = 0;	/* manual or target rpm controlled */
+	switch (attr) {
+	case hwmon_fan_input:
+		reg = AMC6821_REG_TDATA_LOW;
 		break;
-	case AMC6821_CONF1_FDRC1:
-		val = 2;	/* remote temp controlled */
+	case hwmon_fan_min:
+		reg = AMC6821_REG_TACH_LLIMITL;
+		break;
+	case hwmon_fan_max:
+		reg = AMC6821_REG_TACH_HLIMITL;
+		break;
+	case hwmon_fan_target:
+		reg = AMC6821_REG_TACH_SETTINGL;
 		break;
 	default:
-		val = 3;	/* max(local, remote) temp controlled */
-		break;
+		return -EOPNOTSUPP;
 	}
 
-	return sysfs_emit(buf, "%d\n", val);
+	err = regmap_bulk_read(regmap, reg, regs, 2);
+	if (err)
+		return err;
+
+	regval = (regs[1] << 8) | regs[0];
+	*val = regval ? 6000000 / regval : 0;
+
+	return 0;
+}
+
+static int amc6821_fan_read(struct device *dev, u32 attr, long *val)
+{
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	u32 regval;
+	int err;
+
+	switch (attr) {
+	case hwmon_fan_input:
+	case hwmon_fan_min:
+	case hwmon_fan_max:
+	case hwmon_fan_target:
+		return amc6821_fan_read_rpm(regmap, attr, val);
+	case hwmon_fan_fault:
+		return amc6821_read_alarms(regmap, hwmon_fan, attr, 0, val);
+	case hwmon_fan_pulses:
+		err = regmap_read(regmap, AMC6821_REG_CONF4, &regval);
+		if (err)
+			return err;
+		*val = (regval & AMC6821_CONF4_PSPR) ? 4 : 2;
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int amc6821_fan_write(struct device *dev, u32 attr, long val)
+{
+	struct amc6821_data *data = dev_get_drvdata(dev);
+	struct regmap *regmap = data->regmap;
+	u8 regs[2];
+	int reg;
+
+	if (attr == hwmon_fan_pulses) {
+		if (val != 2 && val != 4)
+			return -EINVAL;
+		return regmap_update_bits(regmap, AMC6821_REG_CONF4,
+					 AMC6821_CONF4_PSPR,
+					 val == 4 ? AMC6821_CONF4_PSPR : 0);
+	}
+
+	if (val < 0)
+		return -EINVAL;
+
+	switch (attr) {
+	case hwmon_fan_min:
+		if (!val)	/* no unlimited minimum speed */
+			return -EINVAL;
+		reg = AMC6821_REG_TACH_LLIMITL;
+		break;
+	case hwmon_fan_max:
+		reg = AMC6821_REG_TACH_HLIMITL;
+		break;
+	case hwmon_fan_target:
+		if (!val)	/* no unlimited target speed */
+			return -EINVAL;
+		reg = AMC6821_REG_TACH_SETTINGL;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	val = val ? 6000000 / clamp_val(val, 1, 6000000) : 0;
+	val = clamp_val(val, 0, 0xffff);
+
+	regs[0] = val & 0xff;
+	regs[1] = val >> 8;
+
+	return regmap_bulk_write(data->regmap, reg, regs, 2);
 }
 
 static ssize_t temp_auto_point_temp_show(struct device *dev,
@@ -564,134 +645,9 @@ static ssize_t pwm1_auto_point_pwm_store(struct device *dev,
 	return ret ? : count;
 }
 
-static ssize_t fan_show(struct device *dev, struct device_attribute *devattr,
-			char *buf)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	int ix = to_sensor_dev_attr(devattr)->index;
-	u32 regval;
-	u8 regs[2];
-	int err;
-
-	err = regmap_bulk_read(data->regmap, fan_reg_low[ix], regs, 2);
-	if (err)
-		return err;
-	regval = (regs[1] << 8) | regs[0];
-
-	return sysfs_emit(buf, "%d\n", 6000000 / (regval ? : 1));
-}
-
-static ssize_t fan1_fault_show(struct device *dev,
-			       struct device_attribute *devattr, char *buf)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	u32 regval;
-	int err;
-
-	err = regmap_read(data->regmap, AMC6821_REG_STAT1, &regval);
-	if (err)
-		return err;
-
-	return sysfs_emit(buf, "%d\n", !!(regval & AMC6821_STAT1_FANS));
-}
-
-static ssize_t fan_store(struct device *dev, struct device_attribute *attr,
-			 const char *buf, size_t count)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	int ix = to_sensor_dev_attr(attr)->index;
-	unsigned long val;
-	u8 regs[2];
-	int err;
-
-	err = kstrtoul(buf, 10, &val);
-	if (err)
-		return err;
-
-	/* Minimum and target fan speed must not be unlimited (0) */
-	if ((ix == IDX_FAN1_MIN || ix == IDX_FAN1_TARGET) && !val)
-		return -EINVAL;
-
-	val = val > 0 ? 6000000 / clamp_val(val, 1, 6000000) : 0;
-	val = clamp_val(val, 0, 0xFFFF);
-
-	regs[0] = val & 0xff;
-	regs[1] = val >> 8;
-
-	err = regmap_bulk_write(data->regmap, fan_reg_low[ix], regs, 2);
-	if (err)
-		return err;
-
-	return count;
-}
-
-static ssize_t fan1_pulses_show(struct device *dev,
-				struct device_attribute *devattr, char *buf)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	u32 regval;
-	int err;
-
-	err = regmap_read(data->regmap, AMC6821_REG_CONF4, &regval);
-	if (err)
-		return err;
-
-	return sysfs_emit(buf, "%d\n", (regval & AMC6821_CONF4_PSPR) ? 4 : 2);
-}
-
-static ssize_t fan1_pulses_store(struct device *dev,
-				 struct device_attribute *attr, const char *buf,
-				 size_t count)
-{
-	struct amc6821_data *data = dev_get_drvdata(dev);
-	long val;
-	int err;
-
-	err = kstrtol(buf, 10, &val);
-	if (err)
-		return err;
-
-	if (val != 2 && val != 4)
-		return -EINVAL;
-
-	err = regmap_update_bits(data->regmap, AMC6821_REG_CONF4,
-				 AMC6821_CONF4_PSPR,
-				 val == 4 ? AMC6821_CONF4_PSPR : 0);
-	if (err)
-		return err;
-
-	return count;
-}
-
-static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, IDX_TEMP1_INPUT);
-static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, IDX_TEMP1_MIN);
-static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, IDX_TEMP1_MAX);
-static SENSOR_DEVICE_ATTR_RW(temp1_crit, temp, IDX_TEMP1_CRIT);
-static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, temp_alarm, IDX_TEMP1_MIN);
-static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, temp_alarm, IDX_TEMP1_MAX);
-static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, temp_alarm, IDX_TEMP1_CRIT);
-static SENSOR_DEVICE_ATTR_RO(temp2_input, temp, IDX_TEMP2_INPUT);
-static SENSOR_DEVICE_ATTR_RW(temp2_min, temp, IDX_TEMP2_MIN);
-static SENSOR_DEVICE_ATTR_RW(temp2_max, temp, IDX_TEMP2_MAX);
-static SENSOR_DEVICE_ATTR_RW(temp2_crit, temp, IDX_TEMP2_CRIT);
-static SENSOR_DEVICE_ATTR_RO(temp2_fault, temp2_fault, 0);
-static SENSOR_DEVICE_ATTR_RO(temp2_min_alarm, temp_alarm, IDX_TEMP2_MIN);
-static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, temp_alarm, IDX_TEMP2_MAX);
-static SENSOR_DEVICE_ATTR_RO(temp2_crit_alarm, temp_alarm, IDX_TEMP2_CRIT);
-static SENSOR_DEVICE_ATTR_RO(fan1_input, fan, IDX_FAN1_INPUT);
-static SENSOR_DEVICE_ATTR_RW(fan1_min, fan, IDX_FAN1_MIN);
-static SENSOR_DEVICE_ATTR_RW(fan1_max, fan, IDX_FAN1_MAX);
-static SENSOR_DEVICE_ATTR_RW(fan1_target, fan, IDX_FAN1_TARGET);
-static SENSOR_DEVICE_ATTR_RO(fan1_fault, fan1_fault, 0);
-static SENSOR_DEVICE_ATTR_RW(fan1_pulses, fan1_pulses, 0);
-
-static SENSOR_DEVICE_ATTR_RW(pwm1, pwm1, 0);
-static SENSOR_DEVICE_ATTR_RW(pwm1_enable, pwm1_enable, 0);
 static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point1_pwm, pwm1_auto_point_pwm, 0);
 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_pwm, pwm1_auto_point_pwm, 1);
 static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point3_pwm, pwm1_auto_point_pwm, 2);
-static SENSOR_DEVICE_ATTR_RO(pwm1_auto_channels_temp, pwm1_auto_channels_temp,
-			     0);
 static SENSOR_DEVICE_ATTR_2_RO(temp1_auto_point1_temp, temp_auto_point_temp,
 			       0, 0);
 static SENSOR_DEVICE_ATTR_2_RW(temp1_auto_point2_temp, temp_auto_point_temp,
@@ -707,30 +663,6 @@ static SENSOR_DEVICE_ATTR_2_RW(temp2_auto_point3_temp, temp_auto_point_temp,
 			       1, 2);
 
 static struct attribute *amc6821_attrs[] = {
-	&sensor_dev_attr_temp1_input.dev_attr.attr,
-	&sensor_dev_attr_temp1_min.dev_attr.attr,
-	&sensor_dev_attr_temp1_max.dev_attr.attr,
-	&sensor_dev_attr_temp1_crit.dev_attr.attr,
-	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_input.dev_attr.attr,
-	&sensor_dev_attr_temp2_min.dev_attr.attr,
-	&sensor_dev_attr_temp2_max.dev_attr.attr,
-	&sensor_dev_attr_temp2_crit.dev_attr.attr,
-	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
-	&sensor_dev_attr_temp2_fault.dev_attr.attr,
-	&sensor_dev_attr_fan1_input.dev_attr.attr,
-	&sensor_dev_attr_fan1_min.dev_attr.attr,
-	&sensor_dev_attr_fan1_max.dev_attr.attr,
-	&sensor_dev_attr_fan1_target.dev_attr.attr,
-	&sensor_dev_attr_fan1_fault.dev_attr.attr,
-	&sensor_dev_attr_fan1_pulses.dev_attr.attr,
-	&sensor_dev_attr_pwm1.dev_attr.attr,
-	&sensor_dev_attr_pwm1_enable.dev_attr.attr,
-	&sensor_dev_attr_pwm1_auto_channels_temp.dev_attr.attr,
 	&sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,
 	&sensor_dev_attr_pwm1_auto_point2_pwm.dev_attr.attr,
 	&sensor_dev_attr_pwm1_auto_point3_pwm.dev_attr.attr,
@@ -742,13 +674,117 @@ static struct attribute *amc6821_attrs[] = {
 	&sensor_dev_attr_temp2_auto_point3_temp.dev_attr.attr,
 	NULL
 };
-
 ATTRIBUTE_GROUPS(amc6821);
 
+static int amc6821_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	switch (type) {
+	case hwmon_temp:
+		return amc6821_temp_read(dev, attr, channel, val);
+	case hwmon_fan:
+		return amc6821_fan_read(dev, attr, val);
+	case hwmon_pwm:
+		return amc6821_pwm_read(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int amc6821_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_temp:
+		return amc6821_temp_write(dev, attr, channel, val);
+	case hwmon_fan:
+		return amc6821_fan_write(dev, attr, val);
+	case hwmon_pwm:
+		return amc6821_pwm_write(dev, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t amc6821_is_visible(const void *data,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	switch (type) {
+	case hwmon_temp:
+		switch (attr) {
+		case hwmon_temp_input:
+		case hwmon_temp_min_alarm:
+		case hwmon_temp_max_alarm:
+		case hwmon_temp_crit_alarm:
+		case hwmon_temp_fault:
+			return 0444;
+		case hwmon_temp_min:
+		case hwmon_temp_max:
+		case hwmon_temp_crit:
+			return 0644;
+		default:
+			return 0;
+		}
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+		case hwmon_fan_fault:
+			return 0444;
+		case hwmon_fan_pulses:
+		case hwmon_fan_min:
+		case hwmon_fan_max:
+		case hwmon_fan_target:
+			return 0644;
+		default:
+			return 0;
+		}
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_enable:
+		case hwmon_pwm_input:
+			return 0644;
+		case hwmon_pwm_auto_channels_temp:
+			return 0444;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static const struct hwmon_channel_info * const amc6821_info[] = {
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+			   HWMON_T_CRIT | HWMON_T_MIN_ALARM |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM,
+			   HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
+			   HWMON_T_CRIT | HWMON_T_MIN_ALARM |
+			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
+			   HWMON_T_FAULT),
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+			   HWMON_F_TARGET | HWMON_F_PULSES | HWMON_F_FAULT),
+	HWMON_CHANNEL_INFO(pwm,
+			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE |
+			   HWMON_PWM_AUTO_CHANNELS_TEMP),
+	NULL
+};
+
+static const struct hwmon_ops amc6821_hwmon_ops = {
+	.is_visible = amc6821_is_visible,
+	.read = amc6821_read,
+	.write = amc6821_write,
+};
+
+static const struct hwmon_chip_info amc6821_chip_info = {
+	.ops = &amc6821_hwmon_ops,
+	.info = amc6821_info,
+};
+
 /* Return 0 if detection is successful, -ENODEV otherwise */
-static int amc6821_detect(
-		struct i2c_client *client,
-		struct i2c_board_info *info)
+static int amc6821_detect(struct i2c_client *client, struct i2c_board_info *info)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	int address = client->addr;
@@ -867,9 +903,9 @@ static int amc6821_probe(struct i2c_client *client)
 	if (err)
 		return err;
 
-	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
-							   data,
-							   amc6821_groups);
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 data, &amc6821_chip_info,
+							 amc6821_groups);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }
 
-- 
2.39.2

[PATCH v3 11/11] hwmon: (amc6821) Add support for pwm1_mode attribute

[Guenter Roeck]

AMC6821 supports configuring if a fan is DC or PWM controlled.
Add support for the pwm1_mode attribute to make it runtime configurable.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Fix wrong register used when writing the attribute

v2: New patch

 Documentation/hwmon/amc6821.rst |  1 +
 drivers/hwmon/amc6821.c         | 16 +++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Documentation/hwmon/amc6821.rst b/Documentation/hwmon/amc6821.rst
index 96e604c5ea8e..dbd544cd1160 100644
--- a/Documentation/hwmon/amc6821.rst
+++ b/Documentation/hwmon/amc6821.rst
@@ -58,6 +58,7 @@ pwm1_enable		rw	regulator mode, 1=open loop, 2=fan controlled
 				remote-sensor temperature,
 				4=fan controlled by target rpm set with
 				fan1_target attribute.
+pwm1_mode		rw	Fan duty control mode (0=DC, 1=PWM)
 pwm1_auto_channels_temp ro	1 if pwm_enable==2, 3 if pwm_enable==3
 pwm1_auto_point1_pwm	ro	Hardwired to 0, shared for both
 				temperature channels.
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index be3e590aba3d..4e3f8a6e8354 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -308,6 +308,12 @@ static int amc6821_pwm_read(struct device *dev, u32 attr, long *val)
 			break;
 		}
 		return 0;
+	case hwmon_pwm_mode:
+		err = regmap_read(regmap, AMC6821_REG_CONF2, &regval);
+		if (err)
+			return err;
+		*val = !!(regval & AMC6821_CONF2_TACH_MODE);
+		return 0;
 	case hwmon_pwm_auto_channels_temp:
 		err = regmap_read(regmap, AMC6821_REG_CONF1, &regval);
 		if (err)
@@ -363,6 +369,13 @@ static int amc6821_pwm_write(struct device *dev, u32 attr, long val)
 		return regmap_update_bits(regmap, AMC6821_REG_CONF1,
 					  AMC6821_CONF1_FDRC0 | AMC6821_CONF1_FDRC1,
 					  mode);
+	case hwmon_pwm_mode:
+		if (val < 0 || val > 1)
+			return -EINVAL;
+		return regmap_update_bits(regmap, AMC6821_REG_CONF2,
+					  AMC6821_CONF2_TACH_MODE,
+					  val ? AMC6821_CONF2_TACH_MODE : 0);
+		break;
 	case hwmon_pwm_input:
 		if (val < 0 || val > 255)
 			return -EINVAL;
@@ -741,6 +754,7 @@ static umode_t amc6821_is_visible(const void *data,
 		}
 	case hwmon_pwm:
 		switch (attr) {
+		case hwmon_pwm_mode:
 		case hwmon_pwm_enable:
 		case hwmon_pwm_input:
 			return 0644;
@@ -767,7 +781,7 @@ static const struct hwmon_channel_info * const amc6821_info[] = {
 			   HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
 			   HWMON_F_TARGET | HWMON_F_PULSES | HWMON_F_FAULT),
 	HWMON_CHANNEL_INFO(pwm,
-			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE |
+			   HWMON_PWM_INPUT | HWMON_PWM_ENABLE | HWMON_PWM_MODE |
 			   HWMON_PWM_AUTO_CHANNELS_TEMP),
 	NULL
 };
-- 
2.39.2

Re: [PATCH v3 09/11] hwmon: (amc6821) Convert to use regmap

[Quentin Schulz]

Hi Guenter,

On 7/4/24 7:52 PM, Guenter Roeck wrote:
> Use regmap for register accesses and caching.
> 
> While at it, use sysfs_emit() instead of sprintf() to write sysfs
> attribute data, and remove spurious debug messages which would only
> be seen as result of a bug in the code. Also make sure that error
> codes are propagated and not replaced with -EIO.
> 
> While at it, introduce rounding of written temperature values and for
> internal calculations to reduce deviation from written values and as
> much as possible.
> 
> No functional change intended except for differences introduced by
> rounding.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> v3: Add more details to patch description
>      Cache all attributes
>      Introduce rounding when writing attributes and for some calculations
>      Always return error codes from regmap operations; never replace with
>      -EIO
> 
> v2: Drop another spurious debug message in this patch instead of patch 10
>      Add missing "select REGMAP_I2C" to Kconfig
>      Change misleading variable name from 'mask' to 'mode'.
>      Use sysfs_emit instead of sprintf everywhere
> 
> 
>   drivers/hwmon/Kconfig   |   1 +
>   drivers/hwmon/amc6821.c | 812 ++++++++++++++++++----------------------
>   2 files changed, 373 insertions(+), 440 deletions(-)
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index e14ae18a973b..a8fa87a96e8f 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -2127,6 +2127,7 @@ config SENSORS_ADS7871
>   config SENSORS_AMC6821
>   	tristate "Texas Instruments AMC6821"
>   	depends on I2C
> +	select REGMAP_I2C
>   	help
>   	  If you say yes here you get support for the Texas Instruments
>   	  AMC6821 hardware monitoring chips.
> diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
> index 295a9148779d..a5abd36a1430 100644
> --- a/drivers/hwmon/amc6821.c
> +++ b/drivers/hwmon/amc6821.c
> @@ -8,15 +8,18 @@
>    * Copyright (C) 2007 Hans J. Koch <hjk@hansjkoch.de>
>    */
>   
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
>   #include <linux/bits.h>
>   #include <linux/err.h>
>   #include <linux/hwmon.h>
>   #include <linux/hwmon-sysfs.h>
>   #include <linux/i2c.h>
>   #include <linux/init.h>
> -#include <linux/jiffies.h>
> +#include <linux/minmax.h>
>   #include <linux/module.h>
>   #include <linux/mutex.h>
> +#include <linux/regmap.h>
>   #include <linux/slab.h>
>   
>   /*
> @@ -44,6 +47,7 @@ module_param(init, int, 0444);
>   #define AMC6821_REG_CONF4		0x04
>   #define AMC6821_REG_STAT1		0x02
>   #define AMC6821_REG_STAT2		0x03
> +#define AMC6821_REG_TEMP_LO		0x06
>   #define AMC6821_REG_TDATA_LOW		0x08
>   #define AMC6821_REG_TDATA_HI		0x09
>   #define AMC6821_REG_LTEMP_HI		0x0A
> @@ -61,11 +65,8 @@ module_param(init, int, 0444);
>   #define AMC6821_REG_DCY_LOW_TEMP	0x21
>   
>   #define AMC6821_REG_TACH_LLIMITL	0x10
> -#define AMC6821_REG_TACH_LLIMITH	0x11
>   #define AMC6821_REG_TACH_HLIMITL	0x12
> -#define AMC6821_REG_TACH_HLIMITH	0x13
>   #define AMC6821_REG_TACH_SETTINGL	0x1e
> -#define AMC6821_REG_TACH_SETTINGH	0x1f
>   
>   #define AMC6821_CONF1_START		BIT(0)
>   #define AMC6821_CONF1_FAN_INT_EN	BIT(1)
> @@ -108,6 +109,9 @@ module_param(init, int, 0444);
>   #define AMC6821_STAT2_L_THERM		BIT(6)
>   #define AMC6821_STAT2_THERM_IN		BIT(7)
>   
> +#define AMC6821_TEMP_SLOPE_MASK		GENMASK(2, 0)
> +#define AMC6821_TEMP_LIMIT_MASK		GENMASK(7, 3)
> +
>   enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
>   	IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
>   	IDX_TEMP2_MAX, IDX_TEMP2_CRIT,
> @@ -130,224 +134,155 @@ static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
>   			AMC6821_REG_TACH_HLIMITL,
>   			AMC6821_REG_TACH_SETTINGL, };
>   
> -static const u8 fan_reg_hi[] = {AMC6821_REG_TDATA_HI,
> -			AMC6821_REG_TACH_LLIMITH,
> -			AMC6821_REG_TACH_HLIMITH,
> -			AMC6821_REG_TACH_SETTINGH, };
> -
>   /*
>    * Client data (each client gets its own)
>    */
>   
>   struct amc6821_data {
> -	struct i2c_client *client;
> +	struct regmap *regmap;
>   	struct mutex update_lock;
> -	bool valid; /* false until following fields are valid */
> -	unsigned long last_updated; /* in jiffies */
> -
> -	/* register values */
> -	int temp[TEMP_IDX_LEN];
> -
> -	u16 fan[FAN1_IDX_LEN];
> -	u8 fan1_pulses;
> -
> -	u8 pwm1;
> -	u8 temp1_auto_point_temp[3];
> -	u8 temp2_auto_point_temp[3];
> -	u8 pwm1_auto_point_pwm[3];
> -	u8 pwm1_enable;
> -	u8 pwm1_auto_channels_temp;
> -
> -	u8 stat1;
> -	u8 stat2;
>   };
>   
> -static struct amc6821_data *amc6821_update_device(struct device *dev)
> +/*
> + * Return set of three temperatures:

It actually returns 0 if successful, negative errno otherwise (matches 
regmap_* return values).

But it does write to temps array with those values.

Would be nice to say what we're expecting in channel, i.e. 0 for Remote 
and 1 for Local.

> + * temps[0]: Passive cooling temperature, applies to both channels
> + * temps[1]: Low temperature, start slope calculations
> + * temps[2]: High temperature
> + */

IIUC, we have different units there, >> 3 (/4) °C for 0 and 2, but °C 
for temps[1] ? If I didn't misunderstand, I think it's worth making it 
explicit in the docs (or make them have the same unit).

> +static int amc6821_get_auto_point_temps(struct regmap *regmap, int channel, u8 *temps)
>   {
> -	struct amc6821_data *data = dev_get_drvdata(dev);
> -	struct i2c_client *client = data->client;
> -	int timeout = HZ;
> -	u8 reg;
> -	int i;
> +	u32 pwm, regval;
> +	int err;
>   
> -	mutex_lock(&data->update_lock);
> +	err = regmap_read(regmap, AMC6821_REG_DCY_LOW_TEMP, &pwm);
> +	if (err)
> +		return err;
>   
> -	if (time_after(jiffies, data->last_updated + timeout) ||
> -			!data->valid) {
> +	err = regmap_read(regmap, AMC6821_REG_PSV_TEMP, &regval);
> +	if (err)
> +		return err;
> +	temps[0] = regval;
>   
> -		for (i = 0; i < TEMP_IDX_LEN; i++)
> -			data->temp[i] = (int8_t)i2c_smbus_read_byte_data(
> -				client, temp_reg[i]);
> +	err = regmap_read(regmap,
> +			  channel ? AMC6821_REG_RTEMP_FAN_CTRL : AMC6821_REG_LTEMP_FAN_CTRL,
> +			  &regval);
> +	if (err)
> +		return err;
> +	temps[1] = (regval & 0xF8) >> 1;

I think we want to use AMC6821_TEMP_LIMIT_MASK here instead of 0xF8?

I guess we could also use FIELD_GET?

>   
> -		data->stat1 = i2c_smbus_read_byte_data(client,
> -			AMC6821_REG_STAT1);
> -		data->stat2 = i2c_smbus_read_byte_data(client,
> -			AMC6821_REG_STAT2);
> +	regval &= 0x07;

I think we want to use AMC6821_TEMP_SLOPE_MASK instead of 0x07 here?

I guess we could also use FIELD_GET?

[...]

>   static ssize_t temp_auto_point_temp_store(struct device *dev,
>   					  struct device_attribute *attr,
>   					  const char *buf, size_t count)
>   {
> -	struct amc6821_data *data = amc6821_update_device(dev);
> -	struct i2c_client *client = data->client;
> +	struct amc6821_data *data = dev_get_drvdata(dev);
>   	int ix = to_sensor_dev_attr_2(attr)->index;
>   	int nr = to_sensor_dev_attr_2(attr)->nr;
> -	u8 *ptemp;
> -	u8 reg;
> -	int dpwm;
> +	struct regmap *regmap = data->regmap;
> +	u8 temps[3], otemps[3];
>   	long val;
> -	int ret = kstrtol(buf, 10, &val);
> +	int ret;
> +
> +	ret = kstrtol(buf, 10, &val);
>   	if (ret)
>   		return ret;
>   
> -	switch (nr) {
> -	case 1:
> -		ptemp = data->temp1_auto_point_temp;
> -		reg = AMC6821_REG_LTEMP_FAN_CTRL;
> -		break;
> -	case 2:
> -		ptemp = data->temp2_auto_point_temp;
> -		reg = AMC6821_REG_RTEMP_FAN_CTRL;
> -		break;
> -	default:
> -		dev_dbg(dev, "Unknown attr->nr (%d).\n", nr);
> -		return -EINVAL;
> -	}
> -
>   	mutex_lock(&data->update_lock);
> -	data->valid = false;
> +
> +	ret = amc6821_get_auto_point_temps(data->regmap, nr, temps);
> +	if (ret)
> +		goto unlock;
> +	ret = amc6821_get_auto_point_temps(data->regmap, 1 - nr, otemps);
> +	if (ret)
> +		goto unlock;
>   

We could reduce the scope of otemps since it's only used in the ix==0 
case below.

>   	switch (ix) {
>   	case 0:
> -		ptemp[0] = clamp_val(val / 1000, 0,
> -				     data->temp1_auto_point_temp[1]);
> -		ptemp[0] = clamp_val(ptemp[0], 0,
> -				     data->temp2_auto_point_temp[1]);
> -		ptemp[0] = clamp_val(ptemp[0], 0, 63);
> -		if (i2c_smbus_write_byte_data(
> -					client,
> -					AMC6821_REG_PSV_TEMP,
> -					ptemp[0])) {
> -				dev_err(&client->dev,
> -					"Register write error, aborting.\n");
> -				count = -EIO;
> -		}
> -		goto EXIT;
> +		/*
> +		 * Passive cooling temperature. Range limit against low limit
> +		 * of both channels.
> +		 */
> +		val = DIV_ROUND_CLOSEST(clamp_val(val, 0, 63000), 1000);

This was already in the original code, but I think 64°C should be doable 
as well? The datasheet says:

"""
The PSV ranges from 0°C to +64°C.
"""

And there's a PSV8 bit we can write, meaning we can do (1 << 8) with a 
step of 4°C which gives us 64°C? In a separate commit though, to not mix 
too many fixes into one, making it easier for people to identify and 
possibly revert them if necessary.

> +		val = clamp_val(val, 0, min(temps[1], otemps[1]));
> +		ret = regmap_write(regmap, AMC6821_REG_PSV_TEMP, val);
> +		break;
>   	case 1:
> -		ptemp[1] = clamp_val(val / 1000, (ptemp[0] & 0x7C) + 4, 124);
> -		ptemp[1] &= 0x7C;
> -		ptemp[2] = clamp_val(ptemp[2], ptemp[1] + 1, 255);
> +		/*
> +		 * Low limit; must be between passive and high limit,
> +		 * and not exceed 124. Step size is 4 degrees C.
> +		 */
> +		val = clamp_val(val, DIV_ROUND_UP(temps[0], 4) * 4000, 124000);

Oof. I think the issue is that we have different units for temps[0], 
temps[1] and temps[2]?

temps[1] is in °C, while temps[0] is in °C >> 3 (so / 4) because we read 
from PSV-Temp register directly, which only exposes PSV[8:3] and 
PSV[2:0] are 0. I'm wondering if we shouldn't just have the same unit 
when filled by amc6821_get_auto_point_temps?

temps[2] is also °C >> 3 (4°C step in the register). I think we would 
benefit from having the same unit here to make it easier to do maths 
with temps[1] and temps[0/2]. What do you think?

If we didn't have this °C >> 3 formula, we could simply divide by 1000 
to get the value and then do the same maths for writing to the registers 
(except a different offset for temps[0] than temps[1/2]).


> +		temps[1] = DIV_ROUND_CLOSEST(val, 4000) * 4;
> +		val = temps[1] / 4;
> +		/* Auto-adjust high limit if necessary */
> +		temps[2] = clamp_val(temps[2], temps[1] + 1, 255);

Is this why we didn't want 255 for temps[1]? Because then we could have 
256 here?

> +		ret = regmap_update_bits(regmap,
> +					 nr ? AMC6821_REG_RTEMP_FAN_CTRL
> +					    : AMC6821_REG_LTEMP_FAN_CTRL,
> +					 AMC6821_TEMP_LIMIT_MASK,
> +					 FIELD_PREP(AMC6821_TEMP_LIMIT_MASK, val));
> +		if (ret)
> +			break;
> +		ret = set_slope_register(regmap, nr, temps);

I'm wondering if we shouldn't put the writes to the TEMP_LIMIT_MASK and 
AMC6821_TEMP_SLOPE_MASK into the same regmap write, otherwise there's a 
small timeframe during which the slope is not matching the TEMP_LIMIT. I 
guess it's probably not that big of a deal but still bringing this up.

Cheers,
Quentin

Re: [PATCH v3 11/11] hwmon: (amc6821) Add support for pwm1_mode attribute

[Quentin Schulz]

Hi Guenter,

On 7/4/24 7:52 PM, Guenter Roeck wrote:
> AMC6821 supports configuring if a fan is DC or PWM controlled.
> Add support for the pwm1_mode attribute to make it runtime configurable.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>

Thanks!
Quentin

Re: [PATCH v3 09/11] hwmon: (amc6821) Convert to use regmap

[Guenter Roeck]

On 7/5/24 03:59, Quentin Schulz wrote:
> Hi Guenter,
> 
> On 7/4/24 7:52 PM, Guenter Roeck wrote:
>> Use regmap for register accesses and caching.
>>
>> While at it, use sysfs_emit() instead of sprintf() to write sysfs
>> attribute data, and remove spurious debug messages which would only
>> be seen as result of a bug in the code. Also make sure that error
>> codes are propagated and not replaced with -EIO.
>>
>> While at it, introduce rounding of written temperature values and for
>> internal calculations to reduce deviation from written values and as
>> much as possible.
>>
>> No functional change intended except for differences introduced by
>> rounding.
>>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
>> v3: Add more details to patch description
>>      Cache all attributes
>>      Introduce rounding when writing attributes and for some calculations
>>      Always return error codes from regmap operations; never replace with
>>      -EIO
>>
>> v2: Drop another spurious debug message in this patch instead of patch 10
>>      Add missing "select REGMAP_I2C" to Kconfig
>>      Change misleading variable name from 'mask' to 'mode'.
>>      Use sysfs_emit instead of sprintf everywhere
>>
>>
>>   drivers/hwmon/Kconfig   |   1 +
>>   drivers/hwmon/amc6821.c | 812 ++++++++++++++++++----------------------
>>   2 files changed, 373 insertions(+), 440 deletions(-)
>>
>> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> index e14ae18a973b..a8fa87a96e8f 100644
>> --- a/drivers/hwmon/Kconfig
>> +++ b/drivers/hwmon/Kconfig
>> @@ -2127,6 +2127,7 @@ config SENSORS_ADS7871
>>   config SENSORS_AMC6821
>>       tristate "Texas Instruments AMC6821"
>>       depends on I2C
>> +    select REGMAP_I2C
>>       help
>>         If you say yes here you get support for the Texas Instruments
>>         AMC6821 hardware monitoring chips.
>> diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
>> index 295a9148779d..a5abd36a1430 100644
>> --- a/drivers/hwmon/amc6821.c
>> +++ b/drivers/hwmon/amc6821.c
>> @@ -8,15 +8,18 @@
>>    * Copyright (C) 2007 Hans J. Koch <hjk@hansjkoch.de>
>>    */
>> +#include <linux/bitfield.h>
>> +#include <linux/bitops.h>
>>   #include <linux/bits.h>
>>   #include <linux/err.h>
>>   #include <linux/hwmon.h>
>>   #include <linux/hwmon-sysfs.h>
>>   #include <linux/i2c.h>
>>   #include <linux/init.h>
>> -#include <linux/jiffies.h>
>> +#include <linux/minmax.h>
>>   #include <linux/module.h>
>>   #include <linux/mutex.h>
>> +#include <linux/regmap.h>
>>   #include <linux/slab.h>
>>   /*
>> @@ -44,6 +47,7 @@ module_param(init, int, 0444);
>>   #define AMC6821_REG_CONF4        0x04
>>   #define AMC6821_REG_STAT1        0x02
>>   #define AMC6821_REG_STAT2        0x03
>> +#define AMC6821_REG_TEMP_LO        0x06
>>   #define AMC6821_REG_TDATA_LOW        0x08
>>   #define AMC6821_REG_TDATA_HI        0x09
>>   #define AMC6821_REG_LTEMP_HI        0x0A
>> @@ -61,11 +65,8 @@ module_param(init, int, 0444);
>>   #define AMC6821_REG_DCY_LOW_TEMP    0x21
>>   #define AMC6821_REG_TACH_LLIMITL    0x10
>> -#define AMC6821_REG_TACH_LLIMITH    0x11
>>   #define AMC6821_REG_TACH_HLIMITL    0x12
>> -#define AMC6821_REG_TACH_HLIMITH    0x13
>>   #define AMC6821_REG_TACH_SETTINGL    0x1e
>> -#define AMC6821_REG_TACH_SETTINGH    0x1f
>>   #define AMC6821_CONF1_START        BIT(0)
>>   #define AMC6821_CONF1_FAN_INT_EN    BIT(1)
>> @@ -108,6 +109,9 @@ module_param(init, int, 0444);
>>   #define AMC6821_STAT2_L_THERM        BIT(6)
>>   #define AMC6821_STAT2_THERM_IN        BIT(7)
>> +#define AMC6821_TEMP_SLOPE_MASK        GENMASK(2, 0)
>> +#define AMC6821_TEMP_LIMIT_MASK        GENMASK(7, 3)
>> +
>>   enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
>>       IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
>>       IDX_TEMP2_MAX, IDX_TEMP2_CRIT,
>> @@ -130,224 +134,155 @@ static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
>>               AMC6821_REG_TACH_HLIMITL,
>>               AMC6821_REG_TACH_SETTINGL, };
>> -static const u8 fan_reg_hi[] = {AMC6821_REG_TDATA_HI,
>> -            AMC6821_REG_TACH_LLIMITH,
>> -            AMC6821_REG_TACH_HLIMITH,
>> -            AMC6821_REG_TACH_SETTINGH, };
>> -
>>   /*
>>    * Client data (each client gets its own)
>>    */
>>   struct amc6821_data {
>> -    struct i2c_client *client;
>> +    struct regmap *regmap;
>>       struct mutex update_lock;
>> -    bool valid; /* false until following fields are valid */
>> -    unsigned long last_updated; /* in jiffies */
>> -
>> -    /* register values */
>> -    int temp[TEMP_IDX_LEN];
>> -
>> -    u16 fan[FAN1_IDX_LEN];
>> -    u8 fan1_pulses;
>> -
>> -    u8 pwm1;
>> -    u8 temp1_auto_point_temp[3];
>> -    u8 temp2_auto_point_temp[3];
>> -    u8 pwm1_auto_point_pwm[3];
>> -    u8 pwm1_enable;
>> -    u8 pwm1_auto_channels_temp;
>> -
>> -    u8 stat1;
>> -    u8 stat2;
>>   };
>> -static struct amc6821_data *amc6821_update_device(struct device *dev)
>> +/*
>> + * Return set of three temperatures:
> 
> It actually returns 0 if successful, negative errno otherwise (matches regmap_* return values).
> 
I'll rephrase.

> But it does write to temps array with those values.
> 
> Would be nice to say what we're expecting in channel, i.e. 0 for Remote and 1 for Local.
> 

1 for remote

>> + * temps[0]: Passive cooling temperature, applies to both channels
>> + * temps[1]: Low temperature, start slope calculations
>> + * temps[2]: High temperature
>> + */
> 
> IIUC, we have different units there, >> 3 (/4) °C for 0 and 2, but °C for temps[1] ? If I didn't misunderstand, I think it's worth making it explicit in the docs (or make them have the same unit).
> 

It should be all in °C.

>> +static int amc6821_get_auto_point_temps(struct regmap *regmap, int channel, u8 *temps)
>>   {
>> -    struct amc6821_data *data = dev_get_drvdata(dev);
>> -    struct i2c_client *client = data->client;
>> -    int timeout = HZ;
>> -    u8 reg;
>> -    int i;
>> +    u32 pwm, regval;
>> +    int err;
>> -    mutex_lock(&data->update_lock);
>> +    err = regmap_read(regmap, AMC6821_REG_DCY_LOW_TEMP, &pwm);
>> +    if (err)
>> +        return err;
>> -    if (time_after(jiffies, data->last_updated + timeout) ||
>> -            !data->valid) {
>> +    err = regmap_read(regmap, AMC6821_REG_PSV_TEMP, &regval);
>> +    if (err)
>> +        return err;
>> +    temps[0] = regval;
>> -        for (i = 0; i < TEMP_IDX_LEN; i++)
>> -            data->temp[i] = (int8_t)i2c_smbus_read_byte_data(
>> -                client, temp_reg[i]);
>> +    err = regmap_read(regmap,
>> +              channel ? AMC6821_REG_RTEMP_FAN_CTRL : AMC6821_REG_LTEMP_FAN_CTRL,
>> +              &regval);
>> +    if (err)
>> +      return err;
>> +    temps[1] = (regval & 0xF8) >> 1;
> 
> I think we want to use AMC6821_TEMP_LIMIT_MASK here instead of 0xF8?
> 
> I guess we could also use FIELD_GET?
> 

Yes. The value in the register is in °C * 4, so that is going to be
	temps[1] = FIELD_GET(regval, AMC6821_TEMP_LIMIT_MASK) * 4;
which improves readability and should also clarify the units a bit
better.

Note hat
	(regval & 0xF8) >> 1;
resulted in the temperature in °C (shift right 1 instead of 3).

>> -        data->stat1 = i2c_smbus_read_byte_data(client,
>> -            AMC6821_REG_STAT1);
>> -        data->stat2 = i2c_smbus_read_byte_data(client,
>> -            AMC6821_REG_STAT2);
>> +    regval &= 0x07;
> 
> I think we want to use AMC6821_TEMP_SLOPE_MASK instead of 0x07 here?
> 
> I guess we could also use FIELD_GET?
> 
Done, making it
	regval = BIT(5) >> FIELD_GET(regval, AMC6821_TEMP_SLOPE_MASK);

> [...]
> 
>>   static ssize_t temp_auto_point_temp_store(struct device *dev,
>>                         struct device_attribute *attr,
>>                         const char *buf, size_t count)
>>   {
>> -    struct amc6821_data *data = amc6821_update_device(dev);
>> -    struct i2c_client *client = data->client;
>> +    struct amc6821_data *data = dev_get_drvdata(dev);
>>       int ix = to_sensor_dev_attr_2(attr)->index;
>>       int nr = to_sensor_dev_attr_2(attr)->nr;
>> -    u8 *ptemp;
>> -    u8 reg;
>> -    int dpwm;
>> +    struct regmap *regmap = data->regmap;
>> +    u8 temps[3], otemps[3];
>>       long val;
>> -    int ret = kstrtol(buf, 10, &val);
>> +    int ret;
>> +
>> +    ret = kstrtol(buf, 10, &val);
>>       if (ret)
>>           return ret;
>> -    switch (nr) {
>> -    case 1:
>> -        ptemp = data->temp1_auto_point_temp;
>> -        reg = AMC6821_REG_LTEMP_FAN_CTRL;
>> -        break;
>> -    case 2:
>> -        ptemp = data->temp2_auto_point_temp;
>> -        reg = AMC6821_REG_RTEMP_FAN_CTRL;
>> -        break;
>> -    default:
>> -        dev_dbg(dev, "Unknown attr->nr (%d).\n", nr);
>> -        return -EINVAL;
>> -    }
>> -
>>       mutex_lock(&data->update_lock);
>> -    data->valid = false;
>> +
>> +    ret = amc6821_get_auto_point_temps(data->regmap, nr, temps);
>> +    if (ret)
>> +        goto unlock;
>> +    ret = amc6821_get_auto_point_temps(data->regmap, 1 - nr, otemps);
>> +    if (ret)
>> +        goto unlock;
> 
> We could reduce the scope of otemps since it's only used in the ix==0 case below.
> 
Done.

>>       switch (ix) {
>>       case 0:
>> -        ptemp[0] = clamp_val(val / 1000, 0,
>> -                     data->temp1_auto_point_temp[1]);
>> -        ptemp[0] = clamp_val(ptemp[0], 0,
>> -                     data->temp2_auto_point_temp[1]);
>> -        ptemp[0] = clamp_val(ptemp[0], 0, 63);
>> -        if (i2c_smbus_write_byte_data(
>> -                    client,
>> -                    AMC6821_REG_PSV_TEMP,
>> -                    ptemp[0])) {
>> -                dev_err(&client->dev,
>> -                    "Register write error, aborting.\n");
>> -                count = -EIO;
>> -        }
>> -        goto EXIT;
>> +        /*
>> +         * Passive cooling temperature. Range limit against low limit
>> +         * of both channels.
>> +         */
>> +        val = DIV_ROUND_CLOSEST(clamp_val(val, 0, 63000), 1000);
> 
> This was already in the original code, but I think 64°C should be doable as well? The datasheet says:
> 
> """
> The PSV ranges from 0°C to +64°C.
> """
> 

Yes, but I am sure the datasheet is wrong here. The register has 6 active bits,
which means the highest possible value is 0x3f or 63.

> And there's a PSV8 bit we can write, meaning we can do (1 << 8) with a step of 4°C which gives us 64°C? In a separate commit though, to not mix too many fixes into one, making it easier for people to identify and possibly revert them if necessary.
> 
Not sure I understand. Can you clarify ?

Temperature bit assignments in the datasheet are confusing. PSV3
means full degrees C, PSV8 means 32 degrees C. That is all in one register.
On the other side, L-TEMP0 reflects _4_ degrees C.

Am I missing something ?

>> +        val = clamp_val(val, 0, min(temps[1], otemps[1]));
>> +        ret = regmap_write(regmap, AMC6821_REG_PSV_TEMP, val);
>> +        break;
>>       case 1:
>> -        ptemp[1] = clamp_val(val / 1000, (ptemp[0] & 0x7C) + 4, 124);
>> -        ptemp[1] &= 0x7C;
>> -        ptemp[2] = clamp_val(ptemp[2], ptemp[1] + 1, 255);
>> +        /*
>> +         * Low limit; must be between passive and high limit,
>> +         * and not exceed 124. Step size is 4 degrees C.
>> +         */
>> +        val = clamp_val(val, DIV_ROUND_UP(temps[0], 4) * 4000, 124000);
> 
> Oof. I think the issue is that we have different units for temps[0], temps[1] and temps[2]?
> 
> temps[1] is in °C, while temps[0] is in °C >> 3 (so / 4) because we read from PSV-Temp register directly, which only exposes PSV[8:3] and PSV[2:0] are 0. I'm wondering if we shouldn't just have the same unit when filled by amc6821_get_auto_point_temps?
> 
No, they are all in °C. I think the confusion arises from L-TEMP[0..4] which is in multiples
of 4 °C. Since L-TEMP needs to be in multiples of 4 degrees C, and temps[0] is in degrees C,
the above sets the lower limit to the next multiple of 4 °C at or above temps[0].
The upper limit is 124 degrees C per datasheet.

> temps[2] is also °C >> 3 (4°C step in the register). I think we would benefit from having the same unit here to make it easier to do maths with temps[1] and temps[0/2]. What do you think?
> 
> If we didn't have this °C >> 3 formula, we could simply divide by 1000 to get the value and then do the same maths for writing to the registers (except a different offset for temps[0] than temps[1/2]).
> 
> 
>> +        temps[1] = DIV_ROUND_CLOSEST(val, 4000) * 4;

The DIV_ROUND_CLOSEST() here is to improve rounding to 4 degrees C. The resulting value
in temp[1] is {0, 4, 8, ... 124}.

>> +        val = temps[1] / 4;

This is the register value to be written.

>> +        /* Auto-adjust high limit if necessary */
>> +        temps[2] = clamp_val(temps[2], temps[1] + 1, 255);
> 
> Is this why we didn't want 255 for temps[1]? Because then we could have 256 here?
> 

The highest possible value for temps[1] is 124, so the lower clamp value
would never be 256. The above only ensures that temps[2] is > temps[1].

>> +        ret = regmap_update_bits(regmap,
>> +                     nr ? AMC6821_REG_RTEMP_FAN_CTRL
>> +                        : AMC6821_REG_LTEMP_FAN_CTRL,
>> +                     AMC6821_TEMP_LIMIT_MASK,
>> +                     FIELD_PREP(AMC6821_TEMP_LIMIT_MASK, val));
>> +        if (ret)
>> +            break;
>> +        ret = set_slope_register(regmap, nr, temps);
> 
> I'm wondering if we shouldn't put the writes to the TEMP_LIMIT_MASK and AMC6821_TEMP_SLOPE_MASK into the same regmap write, otherwise there's a small timeframe during which the slope is not matching the TEMP_LIMIT. I guess it's probably not that big of a deal but still bringing this up.
> 

Hmm, you mean to let set_slope_register() also update the low temperature limit
based on temps[1] ? Excellent idea. I'll do that; it will save a register write
to the chip.

Thanks,
Guenter

Re: [PATCH v3 09/11] hwmon: (amc6821) Convert to use regmap

[Quentin Schulz]

Hi Guenter,

On 7/5/24 4:28 PM, Guenter Roeck wrote:
> On 7/5/24 03:59, Quentin Schulz wrote:
>> Hi Guenter,
>>
>> On 7/4/24 7:52 PM, Guenter Roeck wrote:
[...]
>>> +    err = regmap_read(regmap,
>>> +              channel ? AMC6821_REG_RTEMP_FAN_CTRL : 
>>> AMC6821_REG_LTEMP_FAN_CTRL,
>>> +              &regval);
>>> +    if (err)
>>> +      return err;
>>> +    temps[1] = (regval & 0xF8) >> 1;
>>
>> I think we want to use AMC6821_TEMP_LIMIT_MASK here instead of 0xF8?
>>
>> I guess we could also use FIELD_GET?
>>
> 
> Yes. The value in the register is in °C * 4, so that is going to be
>      temps[1] = FIELD_GET(regval, AMC6821_TEMP_LIMIT_MASK) * 4;
> which improves readability and should also clarify the units a bit
> better.
> 
> Note hat
>      (regval & 0xF8) >> 1;
> resulted in the temperature in °C (shift right 1 instead of 3).
> 

Yes, it actually took me a while to figure out why this 1b shift was 
necessary as it didn't match what I got from the datasheet, but the 
formula was actually (>>3) * 4. Former because the register starts at 
bit 3, so we need to right-shift by three bits to have the actual value. 
Then multiply by 4 because a bit in the register means 4°C.

So yes, much more readable with this instead :)

[...]

>>> +        /*
>>> +         * Passive cooling temperature. Range limit against low limit
>>> +         * of both channels.
>>> +         */
>>> +        val = DIV_ROUND_CLOSEST(clamp_val(val, 0, 63000), 1000);
>>
>> This was already in the original code, but I think 64°C should be 
>> doable as well? The datasheet says:
>>
>> """
>> The PSV ranges from 0°C to +64°C.
>> """
>>
> 
> Yes, but I am sure the datasheet is wrong here. The register has 6 
> active bits,
> which means the highest possible value is 0x3f or 63.
> 
>> And there's a PSV8 bit we can write, meaning we can do (1 << 8) with a 
>> step of 4°C which gives us 64°C? In a separate commit though, to not 
>> mix too many fixes into one, making it easier for people to identify 
>> and possibly revert them if necessary.
>>
> Not sure I understand. Can you clarify ?
> 
> Temperature bit assignments in the datasheet are confusing. PSV3
> means full degrees C, PSV8 means 32 degrees C. That is all in one register.
> On the other side, L-TEMP0 reflects _4_ degrees C.
> 
> Am I missing something ?
> 

No, my brain came up with its own math. Register value TEMPERATURE 
MONITORING section all seems to be 1°C increments (except 
Temp-DATA-LByte since it represents 0.125°C increments for a few select 
registers.

Thanks for taking the time to explain!
Quentin