[PATCH v7 4/4] hwmon: (max6639) Add pwm support
From: Naresh Solanki
Date: Mon Nov 21 2022 - 07:30:25 EST
Add pwm support for max6639. Also configure pwm fan speed based on pwm
provided in DT.
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
---
drivers/hwmon/Kconfig | 1 +
drivers/hwmon/max6639.c | 229 +++++++++++++++++++++++++++++++++++++---
2 files changed, 216 insertions(+), 14 deletions(-)
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 3176c33af6c6..56d9004b7a38 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1115,6 +1115,7 @@ config SENSORS_MAX6621
config SENSORS_MAX6639
tristate "Maxim MAX6639 sensor chip"
depends on I2C
+ depends on PWM
help
If you say yes here you get support for the MAX6639
sensor chips.
diff --git a/drivers/hwmon/max6639.c b/drivers/hwmon/max6639.c
index feafa3511297..5bfeee35abf0 100644
--- a/drivers/hwmon/max6639.c
+++ b/drivers/hwmon/max6639.c
@@ -19,6 +19,7 @@
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
+#include <linux/pwm.h>
/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
@@ -61,6 +62,10 @@ static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };
/* Tach supported range. This internally controls tach frequency */
static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };
+/* Supported PWM frequency */
+static const unsigned int freq_table[] = { 20, 33, 50, 100, 5000, 8333, 12500,
+ 25000 };
+
#define FAN_FROM_REG(val, rpm_range) ((val) == 0 || (val) == 255 ? \
0 : (rpm_ranges[rpm_range] * 30) / (val))
#define TEMP_LIMIT_TO_REG(val) clamp_val((val) / 1000, 0, 255)
@@ -78,9 +83,9 @@ 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 */
+ struct pwm_device *pwmd[2]; /* max6639 has two pwm device */
u32 target_rpm[2];
u32 max_rpm[2];
- u8 pwm[2];
u8 status; /* Detected channel alarms and fan failures */
@@ -92,9 +97,10 @@ struct max6639_data {
/* Register values initialized only once */
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;
+ /* max6639 pwm chip */
+ struct pwm_chip chip;
};
static struct max6639_data *max6639_update_device(struct device *dev)
@@ -285,8 +291,11 @@ static ssize_t pwm_show(struct device *dev, struct device_attribute *dev_attr,
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
struct max6639_data *data = dev_get_drvdata(dev);
+ struct pwm_state state;
+
+ pwm_get_state(data->pwmd[attr->index], &state);
- return sprintf(buf, "%d\n", data->pwm[attr->index] * 255 / 120);
+ return sprintf(buf, "%d\n", pwm_get_relative_duty_cycle(&state, 255));
}
@@ -296,9 +305,9 @@ static ssize_t pwm_store(struct device *dev,
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
struct max6639_data *data = dev_get_drvdata(dev);
- struct i2c_client *client = data->client;
unsigned long val;
int res;
+ struct pwm_state state;
res = kstrtoul(buf, 10, &val);
if (res)
@@ -306,11 +315,11 @@ static ssize_t pwm_store(struct device *dev,
val = clamp_val(val, 0, 255);
- 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]);
- mutex_unlock(&data->update_lock);
+ pwm_get_state(data->pwmd[attr->index], &state);
+ pwm_set_relative_duty_cycle(&state, val, 255);
+ res = pwm_apply_state(data->pwmd[attr->index], &state);
+ if (res)
+ return res;
return count;
}
@@ -426,6 +435,7 @@ static int max6639_init_client(struct i2c_client *client,
struct max6639_data *data)
{
int i, err;
+ struct pwm_state state;
/* Reset chip to default values, see below for GCONFIG setup */
err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
@@ -479,10 +489,11 @@ static int max6639_init_client(struct i2c_client *client,
if (err)
goto exit;
- /* PWM 120/120 (i.e. 100%) */
- data->pwm[i] = data->target_rpm[i];
- err = i2c_smbus_write_byte_data(client, MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
-
+ /* Configure PWM controller */
+ pwm_get_state(data->pwmd[i], &state);
+ pwm_set_relative_duty_cycle(&state, data->target_rpm[i],
+ data->max_rpm[i]);
+ err = pwm_apply_state(data->pwmd[i], &state);
if (err)
goto exit;
@@ -576,7 +587,22 @@ static int max6639_probe_child_from_dt(struct i2c_client *client,
else
data->target_rpm[i] = maxrpm;
- return 0;
+ /* Get pwms property for PWM control */
+ data->pwmd[i] = devm_fwnode_pwm_get(dev, &child->fwnode, NULL);
+
+ if (!IS_ERR(data->pwmd[i]))
+ return 0;
+
+ if (PTR_ERR(data->pwmd[i]) == -EPROBE_DEFER)
+ return PTR_ERR(data->pwmd[i]);
+
+ dev_dbg(dev, "Using chip default PWM");
+ data->pwmd[i] = pwm_request_from_chip(&data->chip, i, NULL);
+ if (!IS_ERR(data->pwmd[i]))
+ return 0;
+
+ dev_dbg(dev, "Failed to configure pwm for fan %d", i);
+ return PTR_ERR_OR_ZERO(data->pwmd[i]);
}
static int max6639_probe_from_dt(struct i2c_client *client,
@@ -605,6 +631,172 @@ static int max6639_probe_from_dt(struct i2c_client *client,
return 0;
}
+static struct max6639_data *to_max6639_pwm(struct pwm_chip *chip)
+{
+ return container_of(chip, struct max6639_data, chip);
+}
+
+static void max6639_pwm_get_state(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+
+ struct max6639_data *data = to_max6639_pwm(chip);
+ struct i2c_client *client = data->client;
+ int value, i = pwm->hwpwm, x;
+ unsigned int freq;
+
+ mutex_lock(&data->update_lock);
+
+ value = i2c_smbus_read_byte_data(client, MAX6639_REG_FAN_CONFIG1(i));
+ if (value < 0)
+ goto abort;
+
+ if (value & MAX6639_FAN_CONFIG1_PWM) {
+ state->enabled = true;
+
+ /* Determine frequency from respective registers */
+ value = i2c_smbus_read_byte_data(client,
+ MAX6639_REG_FAN_CONFIG3(i));
+ if (value < 0)
+ goto abort;
+ x = value & MAX6639_FAN_CONFIG3_FREQ_MASK;
+
+ value = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
+ if (value < 0)
+ goto abort;
+ if (value & MAX6639_GCONFIG_PWM_FREQ_HI)
+ x |= 0x4;
+ x &= 0x7;
+ freq = freq_table[x];
+
+ state->period = DIV_ROUND_UP(NSEC_PER_SEC, freq);
+
+ value = i2c_smbus_read_byte_data(client,
+ MAX6639_REG_TARGTDUTY(i));
+ if (value < 0)
+ goto abort;
+ /* max6639 supports 120 slots only */
+ state->duty_cycle = mul_u64_u32_div(state->period, value, 120);
+
+ value = i2c_smbus_read_byte_data(client,
+ MAX6639_REG_FAN_CONFIG2a(i));
+ if (value < 0)
+ goto abort;
+ value &= MAX6639_REG_FAN_CONFIG2a_PWM_POL;
+ state->polarity = (value != 0);
+ } else
+ state->enabled = false;
+
+abort:
+ mutex_unlock(&data->update_lock);
+
+}
+
+static int max6639_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct max6639_data *data = to_max6639_pwm(chip);
+ struct i2c_client *client = data->client;
+ int value = 0, i = pwm->hwpwm, x;
+ unsigned int freq;
+ struct pwm_state cstate;
+
+ cstate = pwm->state;
+
+ mutex_lock(&data->update_lock);
+
+ if (state->period != cstate.period) {
+ /* Configure frequency */
+ freq = DIV_ROUND_UP_ULL(NSEC_PER_SEC, state->period);
+ /* Chip supports limited number of frequency */
+ for (x = 0; x < sizeof(freq_table); x++)
+ if (freq <= freq_table[x])
+ break;
+
+ value = i2c_smbus_read_byte_data(client,
+ MAX6639_REG_FAN_CONFIG3(i));
+ if (value < 0)
+ goto abort;
+ value &= ~MAX6639_FAN_CONFIG3_FREQ_MASK;
+ value |= (x & MAX6639_FAN_CONFIG3_FREQ_MASK);
+ value = i2c_smbus_write_byte_data(client,
+ MAX6639_REG_FAN_CONFIG3(i),
+ value);
+
+ value = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
+ if (value < 0)
+ goto abort;
+
+ if (x >> 2)
+ value &= ~MAX6639_GCONFIG_PWM_FREQ_HI;
+ else
+ value |= MAX6639_GCONFIG_PWM_FREQ_HI;
+ value = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
+ value);
+ if (value < 0)
+ goto abort;
+ }
+
+ /* Configure dutycycle */
+ if (state->duty_cycle != cstate.duty_cycle ||
+ state->period != cstate.period) {
+ value = DIV_ROUND_DOWN_ULL(
+ state->duty_cycle * MAX6639_REG_TARGTDUTY_SLOT,
+ state->period);
+ value = i2c_smbus_write_byte_data(client,
+ MAX6639_REG_TARGTDUTY(i),
+ value);
+ if (value < 0)
+ goto abort;
+ }
+
+ /* Configure polarity */
+ if (state->polarity != cstate.polarity) {
+ value = i2c_smbus_read_byte_data(client,
+ MAX6639_REG_FAN_CONFIG2a(i));
+ if (value < 0)
+ goto abort;
+ if (state->polarity == PWM_POLARITY_NORMAL)
+ value |= MAX6639_REG_FAN_CONFIG2a_PWM_POL;
+ else
+ value &= ~MAX6639_REG_FAN_CONFIG2a_PWM_POL;
+ value = i2c_smbus_write_byte_data(client,
+ MAX6639_REG_FAN_CONFIG2a(i),
+ value);
+ if (value < 0)
+ goto abort;
+ }
+
+ if (state->enabled == cstate.enabled)
+ goto abort;
+
+ value = i2c_smbus_read_byte_data(client, MAX6639_REG_FAN_CONFIG1(i));
+ if (value < 0)
+ goto abort;
+ if (state->enabled)
+ value |= MAX6639_FAN_CONFIG1_PWM;
+ else
+ value &= ~MAX6639_FAN_CONFIG1_PWM;
+
+ value = i2c_smbus_write_byte_data(client, MAX6639_REG_FAN_CONFIG1(i),
+ value);
+ if (value < 0)
+ goto abort;
+ value = 0;
+
+abort:
+ mutex_unlock(&data->update_lock);
+
+ return value;
+}
+
+static const struct pwm_ops max6639_pwm_ops = {
+ .apply = max6639_pwm_apply,
+ .get_state = max6639_pwm_get_state,
+ .owner = THIS_MODULE,
+};
+
static int max6639_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
@@ -618,6 +810,15 @@ static int max6639_probe(struct i2c_client *client)
data->client = client;
+ /* Add PWM controller of max6639 */
+ data->chip.dev = dev;
+ data->chip.ops = &max6639_pwm_ops;
+ data->chip.npwm = 2;
+
+ err = devm_pwmchip_add(dev, &data->chip);
+ if (err < 0)
+ return dev_err_probe(dev, err, "failed to add PWM chip\n");
+
data->reg = devm_regulator_get_optional(dev, "fan");
if (IS_ERR(data->reg)) {
if (PTR_ERR(data->reg) != -ENODEV) {
--
2.37.3