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Message-ID: <e38ceaf9-c904-41f1-a32d-14a150c92f30@cherry.de>
Date: Mon, 8 Jul 2024 12:58:45 +0200
From: Quentin Schulz <quentin.schulz@...rry.de>
To: Guenter Roeck <linux@...ck-us.net>, linux-hwmon@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, Farouk Bouabid <farouk.bouabid@...rry.de>
Subject: Re: [PATCH v4 09/11] hwmon: (amc6821) Convert to use regmap
Hi Guenter,
On 7/5/24 11:35 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@...ck-us.net>
> ---
> v4: Improve function comments
> Better use of BIT(), FIELD_GET(), and FIELD_PREP()
> Use min() instead of clamp_val() in fan_store() since it is already
> known that the value is > 0
> In pwm1_auto_point_pwm_store(), use '0' for unlimited to match
> the original code
> In set_slope_register(), set both temperature limit and
> slope to avoid an extra register write operation when setting the
> limit
> In temp_auto_point_temp_store(), only read the other set of
> temperature registers when writing the PSV temperature
>
> 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 | 822 +++++++++++++++++++---------------------
> 2 files changed, 381 insertions(+), 442 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..90efd6a0dfd3 100644
> --- a/drivers/hwmon/amc6821.c
> +++ b/drivers/hwmon/amc6821.c
> @@ -8,15 +8,18 @@
> * Copyright (C) 2007 Hans J. Koch <hjk@...sjkoch.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 +134,158 @@ 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 0 on success or negative error code.
> + *
> + * temps returns set of three temperatures, in °C:
> + * temps[0]: Passive cooling temperature, applies to both channels
> + * temps[1]: Low temperature, start slope calculations
> + * temps[2]: High temperature
> + *
> + * Channel 0: local, channel 1: remote.
> + */
> +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] = FIELD_GET(AMC6821_TEMP_LIMIT_MASK, regval) * 4;
>
> - data->stat1 = i2c_smbus_read_byte_data(client,
> - AMC6821_REG_STAT1);
> - data->stat2 = i2c_smbus_read_byte_data(client,
> - AMC6821_REG_STAT2);
> + regval = BIT(5) >> FIELD_GET(AMC6821_TEMP_SLOPE_MASK, regval);
BIT(5) doesn't have real meaning in the datasheet, what is in the
datasheet though is that the slope is 32 / L-SLP[2:0] (well, you can
more easily guess it from the datasheet than 0x20 or BIT(5) IMO).
[...]
> +static inline int set_slope_register(struct regmap *regmap, int channel, u8 *temps)
> {
> - int dt;
> - u8 tmp;
> + u8 regval = FIELD_PREP(AMC6821_TEMP_LIMIT_MASK, temps[1] / 4);
> + 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)
> + if (dt * (BIT(5) >> tmp) >= dpwm)
Ditto I think?
> 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;
> + regval |= FIELD_PREP(AMC6821_TEMP_SLOPE_MASK, tmp);
> +
> + return regmap_write(regmap,
> + channel ? AMC6821_REG_RTEMP_FAN_CTRL : AMC6821_REG_LTEMP_FAN_CTRL,
> + regval);
> }
>
> 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;
>
> 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.
> + */
> + ret = amc6821_get_auto_point_temps(data->regmap, 1 - nr, otemps);
I would have been more comfortable with
nr ? 0 : 1
Only nitpicks, so:
Reviewed-by: Quentin Schulz <quentin.schulz@...rry.de>
Thanks for making it easier for us to add some patches on top of AMC6821
soon, really appreciate it.
Quentin
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