PWMOUT pins on MAX31790 can be configured as a tachometer input pin by
setting bit[0] in the Configuration Register. When the bit[0] of a channel
is set, the PWMOUT pin becomes the tach input pin for the channel plus six.
This commit allows the kernel to set those pins when necessary if the
pwmout-pin-as-tach-input DT property exists.
Signed-off-by: Chanh Nguyen <chanh@xxxxxxxxxxxxxxxxxxxxxx>
---
drivers/hwmon/max31790.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
index 3dc95196b229..33ca8d1721c0 100644
--- a/drivers/hwmon/max31790.c
+++ b/drivers/hwmon/max31790.c
@@ -12,6 +12,7 @@
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/module.h>
+#include <linux/property.h>
#include <linux/slab.h>
/* MAX31790 registers */
@@ -506,9 +507,12 @@ static int max31790_probe(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
struct device *dev = &client->dev;
+ u8 pwmout_to_tach[NR_CHANNEL];
struct max31790_data *data;
struct device *hwmon_dev;
int err;
+ u8 tmp;
+ int i;
if (!i2c_check_functionality(adapter,
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
@@ -528,6 +532,33 @@ static int max31790_probe(struct i2c_client *client)
if (err)
return err;
+ if (device_property_present(dev, "pwmout-pin-as-tach-input")) {
+ err = device_property_read_u8_array(dev, "pwmout-pin-as-tach-input",
+ pwmout_to_tach, NR_CHANNEL);
+ if (err) {
+ /* The pwmout-pin-as-tach-input is an array of six values */
+ dev_warn(dev, "The pwmout-pin-as-tach-input property exist but malform");
+ } else {
+ for (i = 0; i < NR_CHANNEL; i++) {
+ tmp = data->fan_config[i];
+ if (pwmout_to_tach[i])
+ data->fan_config[i] |= MAX31790_FAN_CFG_TACH_INPUT;
+ else
+ data->fan_config[i] &= ~(MAX31790_FAN_CFG_TACH_INPUT);
+
+ if (tmp != data->fan_config[i]) {
+ err = i2c_smbus_write_byte_data(client,
+ MAX31790_REG_FAN_CONFIG(i),
+ data->fan_config[i]);
+ if (err < 0)
+ dev_warn(dev,
+ "Fail to apply fan configuration at channel %d",
+ i);
+ }
+ }
+ }
+ }
+
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
data,
&max31790_chip_info,
--
2.17.1
