Re: [PATCH v7 3/4] hwmon: (max6639) Change from pdata to dt configuration

From: Naresh Solanki
Date: Tue Nov 29 2022 - 11:11:51 EST


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@xxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
---
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