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@xxxxxxxxxxxx>
---
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@xxxxxxxxxxxx>
*/
+#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, ®val);
+ 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,
+ ®val);
+ 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
