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SubjectRe: [PATCH v7 3/4] hwmon: (max6639) Change from pdata to dt configuration
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Hi Guenter,

On 25-11-2022 09:48 pm, Guenter Roeck wrote:
> On Mon, Nov 21, 2022 at 01:29:31PM +0100, Naresh Solanki wrote:
>> max6639_platform_data is not used by any in-kernel driver and does not
>> address the MAX6639 fans separately.
>> Move to device tree configuration with explicit properties to configure
>> each fan.
>>
>
> This patch does way more than that.
>
>> Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>> ---
>> drivers/hwmon/max6639.c | 246 +++++++++++++++++++-------
>> include/linux/platform_data/max6639.h | 15 --
>> 2 files changed, 178 insertions(+), 83 deletions(-)
>> delete mode 100644 include/linux/platform_data/max6639.h
>>
>> diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c
>> index 9b895402c80d..feafa3511297 100644
>> --- a/drivers/hwmon/max6639.c
>> +++ b/drivers/hwmon/max6639.c
>> @@ -19,7 +19,6 @@
>> #include <linux/hwmon-sysfs.h>
>> #include <linux/err.h>
>> #include <linux/mutex.h>
>> -#include <linux/platform_data/max6639.h>
>>
>> /* Addresses to scan */
>> static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
>> @@ -54,9 +53,12 @@ static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
>> #define MAX6639_GCONFIG_PWM_FREQ_HI 0x08
>>
>> #define MAX6639_FAN_CONFIG1_PWM 0x80
>> -
>> +#define MAX6639_REG_FAN_CONFIG2a_PWM_POL 0x02
>> #define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED 0x40
>> +#define MAX6639_FAN_CONFIG3_FREQ_MASK 0x03
>> +#define MAX6639_REG_TARGTDUTY_SLOT 120
>>
>> +/* Tach supported range. This internally controls tach frequency */
>> static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
>>
>> #define FAN_FROM_REG(val, rpm_range) ((val) == 0 || (val) == 255 ? \
>> @@ -76,18 +78,21 @@ struct max6639_data {
>> u16 temp[2]; /* Temperature, in 1/8 C, 0..255 C */
>> bool temp_fault[2]; /* Detected temperature diode failure */
>> u8 fan[2]; /* Register value: TACH count for fans >=30 */
>> + u32 target_rpm[2];
>> + u32 max_rpm[2];
>> + u8 pwm[2];
>> +
>> u8 status; /* Detected channel alarms and fan failures */
>>
>> /* Register values only written to */
>> - u8 pwm[2]; /* Register value: Duty cycle 0..120 */
>> u8 temp_therm[2]; /* THERM Temperature, 0..255 C (->_max) */
>> u8 temp_alert[2]; /* ALERT Temperature, 0..255 C (->_crit) */
>> u8 temp_ot[2]; /* OT Temperature, 0..255 C (->_emergency) */
>>
>> /* Register values initialized only once */
>> - u8 ppr; /* Pulses per rotation 0..3 for 1..4 ppr */
>> - u8 rpm_range; /* Index in above rpm_ranges table */
>> -
>> + u8 ppr[2]; /* Pulses per rotation 0..3 for 1..4 ppr */
>> + u8 rpm_range[2]; /* Index in above rpm_ranges table */
>> + u8 pwm_polarity[2];
>> /* Optional regulator for FAN supply */
>> struct regulator *reg;
>> };
>> @@ -282,6 +287,7 @@ static ssize_t pwm_show(struct device *dev, struct device_attribute *dev_attr,
>> struct max6639_data *data = dev_get_drvdata(dev);
>>
>> return sprintf(buf, "%d\n", data->pwm[attr->index] * 255 / 120);
>> +
>
> Unnecessary and wrong whitespace change.
>
>> }
>>
>> static ssize_t pwm_store(struct device *dev,
>> @@ -302,10 +308,10 @@ static ssize_t pwm_store(struct device *dev,
>>
>> mutex_lock(&data->update_lock);
>> data->pwm[attr->index] = (u8)(val * 120 / 255);
>> - i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_TARGTDUTY(attr->index),
>> - data->pwm[attr->index]);
>> + i2c_smbus_write_byte_data(client, MAX6639_REG_TARGTDUTY(attr->index),
>> + data->pwm[attr->index]);
>> mutex_unlock(&data->update_lock);
>> +
>> return count;
>
> Unnecessary formatting change. You may not like the original formatting,
> but that is no reason to change it.
>
>> }
>>
>> @@ -319,7 +325,7 @@ static ssize_t fan_input_show(struct device *dev,
>> return PTR_ERR(data);
>>
>> return sprintf(buf, "%d\n", FAN_FROM_REG(data->fan[attr->index],
>> - data->rpm_range));
>> + data->rpm_range[attr->index]));
>> }
>>
>> static ssize_t alarm_show(struct device *dev,
>> @@ -386,29 +392,40 @@ static struct attribute *max6639_attrs[] = {
>> ATTRIBUTE_GROUPS(max6639);
>>
>> /*
>> - * returns respective index in rpm_ranges table
>> - * 1 by default on invalid range
>> + * Get respective index in rpm_ranges table
>> */
>> -static int rpm_range_to_reg(int range)
>> +static int rpm_range_to_index(struct device *dev, u8 *index, int rpm)
>> {
>> - int i;
>> -
>> - for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
>> - if (rpm_ranges[i] == range)
>> - return i;
>> + if (rpm < 0)
>> + return -EINVAL;
>> +
>> + /* Set index based on chip support */
>> + switch (rpm) {
>> + case 0 ... 2000:
>> + *index = 0;
>> + break;
>> + case 2001 ... 4000:
>> + *index = 1;
>> + break;
>> + case 4001 ... 8000:
>> + *index = 2;
>> + break;
>> + case 8001 ... 16000:
>> + *index = 3;
>> + break;
>> + default:
>> + /* Use max range for higher RPM */
>> + dev_warn(dev,
>> + "RPM higher than supported range. Default to 16000 RPM");
>> + *index = 3;
>> }
>> -
>> - return 1; /* default: 4000 RPM */
>> + return 0;
>
> The above changes are unrelated to $subject. Also, the same could be
> accomplished by varying the range check in the for loop, making the
> change POV. The warning is both unacceptable and unnecessary.
>
>> }
>>
>> static int max6639_init_client(struct i2c_client *client,
>> struct max6639_data *data)
>> {
>> - struct max6639_platform_data *max6639_info =
>> - dev_get_platdata(&client->dev);
>> - int i;
>> - int rpm_range = 1; /* default: 4000 RPM */
>> - int err;
>> + int i, err;
>>
>> /* Reset chip to default values, see below for GCONFIG setup */
>> err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
>> @@ -416,51 +433,29 @@ static int max6639_init_client(struct i2c_client *client,
>> if (err)
>> goto exit;
>>
>> - /* Fans pulse per revolution is 2 by default */
>> - if (max6639_info && max6639_info->ppr > 0 &&
>> - max6639_info->ppr < 5)
>> - data->ppr = max6639_info->ppr;
>> - else
>> - data->ppr = 2;
>> - data->ppr -= 1;
>> -
>> - if (max6639_info)
>> - rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
>> - data->rpm_range = rpm_range;
>> -
>> for (i = 0; i < 2; i++) {
>>
>> /* Set Fan pulse per revolution */
>> - err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_FAN_PPR(i),
>> - data->ppr << 6);
>> + err = i2c_smbus_write_byte_data(client, MAX6639_REG_FAN_PPR(i),
>> + data->ppr[i] << 6);
>> if (err)
>> goto exit;
>>
>> /* Fans config PWM, RPM */
>> err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_FAN_CONFIG1(i),
>> - MAX6639_FAN_CONFIG1_PWM | rpm_range);
>> - if (err)
>> - goto exit;
>> -
>> - /* Fans PWM polarity high by default */
>> - if (max6639_info && max6639_info->pwm_polarity == 0)
>> - err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_FAN_CONFIG2a(i), 0x00);
>> - else
>> - err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_FAN_CONFIG2a(i), 0x02);
>> + MAX6639_REG_FAN_CONFIG1(i),
>> + MAX6639_FAN_CONFIG1_PWM |
>> + data->rpm_range[i]);
>
> The above change silently drops the configuration of
> MAX6639_REG_FAN_CONFIG2a, which is puzzling since the patch
> also introduces MAX6639_REG_FAN_CONFIG2a_PWM_POL which isn't
> used. I don't see what this has to do with $subject, and the
> lack of explanation is not really reassuring.
>
>> if (err)
>> goto exit;
>>
>> /*
>> - * /THERM full speed enable,
>> + * /THERM full speed disable,
>
> Change unrelated to $subject and possibly unexpected results
> for users of this driver.
>
>> * PWM frequency 25kHz, see also GCONFIG below
>> */
>> err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_FAN_CONFIG3(i),
>> - MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
>> + MAX6639_REG_FAN_CONFIG3(i),
>> + 0x03);
>> if (err)
>> goto exit;
>>
>> @@ -469,31 +464,34 @@ static int max6639_init_client(struct i2c_client *client,
>> data->temp_alert[i] = 90;
>> data->temp_ot[i] = 100;
>> err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_THERM_LIMIT(i),
>> - data->temp_therm[i]);
>> + MAX6639_REG_THERM_LIMIT(i),
>> + data->temp_therm[i]);
>> if (err)
>> goto exit;
>> err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_ALERT_LIMIT(i),
>> - data->temp_alert[i]);
>> + MAX6639_REG_ALERT_LIMIT(i),
>> + data->temp_alert[i]);
>
> Unrelated formatting changes above. Such changes just obfuscate functional
> changes made in the patch and are unacceptable. If you want to fix
> checkpatch issues, do it in a separate patch.
>
> I am stopping the review here. In the future, please refrain from making
> unrelated changes. One logical change per patch, please.
Sure. Thanks.
>
> Guenter
>
>> if (err)
>> goto exit;
>> err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_OT_LIMIT(i), data->temp_ot[i]);
>> + MAX6639_REG_OT_LIMIT(i),
>> + data->temp_ot[i]);
>> if (err)
>> goto exit;
>>
>> /* PWM 120/120 (i.e. 100%) */
>> - data->pwm[i] = 120;
>> - err = i2c_smbus_write_byte_data(client,
>> - MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
>> + data->pwm[i] = data->target_rpm[i];
>> + err = i2c_smbus_write_byte_data(client, MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
>> +
>> if (err)
>> goto exit;
>> +
>> }
>> /* Start monitoring */
>> err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
>> MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
>> MAX6639_GCONFIG_PWM_FREQ_HI);
>> +
>> exit:
>> return err;
>> }
>> @@ -524,12 +522,95 @@ static void max6639_regulator_disable(void *data)
>> regulator_disable(data);
>> }
>>
>> +static int max6639_probe_child_from_dt(struct i2c_client *client,
>> + struct device_node *child,
>> + struct max6639_data *data)
>> +
>> +{
>> + struct device *dev = &client->dev;
>> + u32 i, maxrpm;
>> + int val, err;
>> +
>> + err = of_property_read_u32(child, "reg", &i);
>> + if (err) {
>> + dev_err(dev, "missing reg property of %pOFn\n", child);
>> + return err;
>> + }
>> +
>> + if (i >= 2) {
>> + dev_err(dev, "invalid reg %d of %pOFn\n", i, child);
>> + return -EINVAL;
>> + }
>> +
>> + err = of_property_read_u32(child, "pulses-per-revolution", &val);
>> + if (err) {
>> + dev_err(dev, "missing pulses-per-revolution property of %pOFn",
>> + child);
>> + return err;
>> + }
>> +
>> + if (val < 0 || val > 5) {
>> + dev_err(dev, "invalid pulses-per-revolution %d of %pOFn\n", val,
>> + child);
>> + return -EINVAL;
>> + }
>> + data->ppr[i] = val;
>> +
>> + err = of_property_read_u32(child, "max-rpm", &maxrpm);
>> + if (err) {
>> + dev_err(dev, "missing max-rpm property of %pOFn\n", child);
>> + return err;
>> + }
>> +
>> + err = rpm_range_to_index(dev, &data->rpm_range[i], maxrpm);
>> + if (err) {
>> + dev_err(dev, "invalid max-rpm %d of %pOFn\n", maxrpm, child);
>> + return err;
>> + }
>> + data->max_rpm[i] = maxrpm;
>> +
>> + err = of_property_read_u32(child, "target-rpm", &val);
>> + /* Use provided target RPM else default to maxrpm */
>> + if (!err)
>> + data->target_rpm[i] = val;
>> + else
>> + data->target_rpm[i] = maxrpm;
>> +
>> + return 0;
>> +}
>> +
>> +static int max6639_probe_from_dt(struct i2c_client *client,
>> + struct max6639_data *data)
>> +{
>> + struct device *dev = &client->dev;
>> + const struct device_node *np = dev->of_node;
>> + struct device_node *child;
>> + int err;
>> +
>> + /* Compatible with non-DT platforms */
>> + if (!np)
>> + return 0;
>> +
>> + for_each_child_of_node(np, child) {
>> + if (strcmp(child->name, "fan"))
>> + continue;
>> +
>> + err = max6639_probe_child_from_dt(client, child, data);
>> + if (err) {
>> + of_node_put(child);
>> + return err;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static int max6639_probe(struct i2c_client *client)
>> {
>> struct device *dev = &client->dev;
>> struct max6639_data *data;
>> struct device *hwmon_dev;
>> - int err;
>> + int err, i;
>>
>> data = devm_kzalloc(dev, sizeof(struct max6639_data), GFP_KERNEL);
>> if (!data)
>> @@ -539,9 +620,11 @@ static int max6639_probe(struct i2c_client *client)
>>
>> data->reg = devm_regulator_get_optional(dev, "fan");
>> if (IS_ERR(data->reg)) {
>> - if (PTR_ERR(data->reg) != -ENODEV)
>> - return PTR_ERR(data->reg);
>> -
>> + if (PTR_ERR(data->reg) != -ENODEV) {
>> + err = (int)PTR_ERR(data->reg);
>> + return dev_err_probe(dev, err,
>> + "Failed looking up fan supply\n");
>> + }
>> data->reg = NULL;
>> } else {
>> /* Spin up fans */
>> @@ -560,6 +643,22 @@ static int max6639_probe(struct i2c_client *client)
>>
>> mutex_init(&data->update_lock);
>>
>> + /* Below are defaults later overridden by DT properties */
>> + for (i = 0; i < 2; i++) {
>> + /* 4000 RPM */
>> + data->rpm_range[i] = 1;
>> + data->ppr[i] = 2;
>> + /* Max. temp. 80C/90C/100C */
>> + data->temp_therm[i] = 80;
>> + data->temp_alert[i] = 90;
>> + data->temp_ot[i] = 100;
>> + }
>> +
>> + /* Probe from DT to get configuration */
>> + err = max6639_probe_from_dt(client, data);
>> + if (err)
>> + return err;
>> +
>> /* Initialize the max6639 chip */
>> err = max6639_init_client(client, data);
>> if (err < 0)
>> @@ -571,6 +670,7 @@ static int max6639_probe(struct i2c_client *client)
>> return PTR_ERR_OR_ZERO(hwmon_dev);
>> }
>>
>> +#if IS_ENABLED(CONFIG_PM_SLEEP)
>> static int max6639_suspend(struct device *dev)
>> {
>> struct i2c_client *client = to_i2c_client(dev);
>> @@ -608,6 +708,7 @@ static int max6639_resume(struct device *dev)
>> return i2c_smbus_write_byte_data(client,
>> MAX6639_REG_GCONFIG, ret & ~MAX6639_GCONFIG_STANDBY);
>> }
>> +#endif
>>
>> static const struct i2c_device_id max6639_id[] = {
>> {"max6639", 0},
>> @@ -616,13 +717,22 @@ static const struct i2c_device_id max6639_id[] = {
>>
>> MODULE_DEVICE_TABLE(i2c, max6639_id);
>>
>> -static DEFINE_SIMPLE_DEV_PM_OPS(max6639_pm_ops, max6639_suspend, max6639_resume);
>> +#ifdef CONFIG_OF
>> +static const struct of_device_id maxim_of_platform_match[] = {
>> + {.compatible = "maxim,max6639"},
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(of, maxim_of_platform_match);
>> +#endif
>> +
>> +static SIMPLE_DEV_PM_OPS(max6639_pm_ops, max6639_suspend, max6639_resume);
>>
>> static struct i2c_driver max6639_driver = {
>> .class = I2C_CLASS_HWMON,
>> .driver = {
>> .name = "max6639",
>> .pm = pm_sleep_ptr(&max6639_pm_ops),
>> + .of_match_table = of_match_ptr(maxim_of_platform_match),
>> },
>> .probe_new = max6639_probe,
>> .id_table = max6639_id,
>> diff --git a/include/linux/platform_data/max6639.h b/include/linux/platform_data/max6639.h
>> deleted file mode 100644
>> index 65bfdb4fdc15..000000000000
>> --- a/include/linux/platform_data/max6639.h
>> +++ /dev/null
>> @@ -1,15 +0,0 @@
>> -/* SPDX-License-Identifier: GPL-2.0 */
>> -#ifndef _LINUX_MAX6639_H
>> -#define _LINUX_MAX6639_H
>> -
>> -#include <linux/types.h>
>> -
>> -/* platform data for the MAX6639 temperature sensor and fan control */
>> -
>> -struct max6639_platform_data {
>> - bool pwm_polarity; /* Polarity low (0) or high (1, default) */
>> - int ppr; /* Pulses per rotation 1..4 (default == 2) */
>> - int rpm_range; /* 2000, 4000 (default), 8000 or 16000 */
>> -};
>> -
>> -#endif /* _LINUX_MAX6639_H */
Regrads,
Naresh

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