diff mbox series

[02/11] hwmon: (max6650) Introduce pwm_to_dac and dac_to_pwm

Message ID 1556026391-15360-2-git-send-email-linux@roeck-us.net (mailing list archive)
State Changes Requested
Headers show
Series [01/11] hwmon: (max6650) Use devm_add_action to unregister thermal device | expand

Commit Message

Guenter Roeck April 23, 2019, 1:33 p.m. UTC 
Consolidate conversion from pwm value to dac value and from dac value
to pwm value into helper functions.

While doing this, only update the cached dac value if writing it to
the chip was successful after an update. Also, put macro argument of
DIV_FROM_REG() into ().

Cc: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/max6650.c | 53 ++++++++++++++++++++++++-------------------------
 1 file changed, 26 insertions(+), 27 deletions(-)

Comments

Jean-François Dagenais April 23, 2019, 3:23 p.m. UTC | #1 
> On Apr 23, 2019, at 09:33, Guenter Roeck <linux@roeck-us.net> wrote:
> 
> -
> +	dac = pwm_to_dac(pwm, data->config & MAX6650_CFG_V12);
> +	err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, dac);
> +	if (!err)
> +		data->dac = dac;
> 	mutex_unlock(&data->update_lock);
> 
> 	return err < 0 ? err : count;

When I created max6650_set_cur_state, I copied over the pwm1_store code. I ended
up with a "return err < 0 ? ..." which I adjusted. However, as my colleague
pointed out, the set_cur_state return style matches that of
i2c_smbus_write_byte_data so we should simply "return err;" in
max6650_set_cur_state. Since the driver is in great flux state right now, I
cannot make a patch only for that and you should probably just include that in
your series. Or I can submit it later when your series is applied?
Guenter Roeck April 23, 2019, 5:02 p.m. UTC | #2 
On Tue, Apr 23, 2019 at 11:23:00AM -0400, Jean-Francois Dagenais wrote:
> 
> 
> > On Apr 23, 2019, at 09:33, Guenter Roeck <linux@roeck-us.net> wrote:
> > 
> > -
> > +	dac = pwm_to_dac(pwm, data->config & MAX6650_CFG_V12);
> > +	err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, dac);
> > +	if (!err)
> > +		data->dac = dac;
> > 	mutex_unlock(&data->update_lock);
> > 
> > 	return err < 0 ? err : count;
> 
> When I created max6650_set_cur_state, I copied over the pwm1_store code. I ended
> up with a "return err < 0 ? ..." which I adjusted. However, as my colleague
> pointed out, the set_cur_state return style matches that of
> i2c_smbus_write_byte_data so we should simply "return err;" in
> max6650_set_cur_state. Since the driver is in great flux state right now, I
> cannot make a patch only for that and you should probably just include that in
> your series. Or I can submit it later when your series is applied?
> 
Just a patch for that should work; I don't think I changed the code
around it too much. Can you give it a try ?

Guenter
diff mbox series

Patch

diff --git a/drivers/hwmon/max6650.c b/drivers/hwmon/max6650.c
index 6cce199dab6a..b6b8f8edc1b0 100644
--- a/drivers/hwmon/max6650.c
+++ b/drivers/hwmon/max6650.c
@@ -105,7 +105,8 @@  module_param(clock, int, 0444);
 #define FAN_RPM_MIN 240
 #define FAN_RPM_MAX 30000
 
-#define DIV_FROM_REG(reg) (1 << (reg & 7))
+#define DIV_FROM_REG(reg)	(1 << ((reg) & 7))
+#define DAC_LIMIT(v12)		((v12) ? 180 : 76)
 
 /*
  * Client data (each client gets its own)
@@ -150,6 +151,22 @@  static const struct of_device_id __maybe_unused max6650_dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, max6650_dt_match);
 
+static int dac_to_pwm(int dac, bool v12)
+{
+	/*
+	 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
+	 * Lower DAC values mean higher speeds.
+	 */
+	return clamp_val(255 - (255 * dac) / DAC_LIMIT(v12), 0, 255);
+}
+
+static u8 pwm_to_dac(unsigned int pwm, bool v12)
+{
+	int limit = DAC_LIMIT(v12);
+
+	return limit - (limit * pwm) / 255;
+}
+
 static struct max6650_data *max6650_update_device(struct device *dev)
 {
 	struct max6650_data *data = dev_get_drvdata(dev);
@@ -357,22 +374,10 @@  static ssize_t fan1_target_store(struct device *dev,
 static ssize_t pwm1_show(struct device *dev, struct device_attribute *devattr,
 			 char *buf)
 {
-	int pwm;
 	struct max6650_data *data = max6650_update_device(dev);
 
-	/*
-	 * Useful range for dac is 0-180 for 12V fans and 0-76 for 5V fans.
-	 * Lower DAC values mean higher speeds.
-	 */
-	if (data->config & MAX6650_CFG_V12)
-		pwm = 255 - (255 * (int)data->dac)/180;
-	else
-		pwm = 255 - (255 * (int)data->dac)/76;
-
-	if (pwm < 0)
-		pwm = 0;
-
-	return sprintf(buf, "%d\n", pwm);
+	return sprintf(buf, "%d\n", dac_to_pwm(data->dac,
+					       data->config & MAX6650_CFG_V12));
 }
 
 static ssize_t pwm1_store(struct device *dev,
@@ -383,6 +388,7 @@  static ssize_t pwm1_store(struct device *dev,
 	struct i2c_client *client = data->client;
 	unsigned long pwm;
 	int err;
+	u8 dac;
 
 	err = kstrtoul(buf, 10, &pwm);
 	if (err)
@@ -391,13 +397,10 @@  static ssize_t pwm1_store(struct device *dev,
 	pwm = clamp_val(pwm, 0, 255);
 
 	mutex_lock(&data->update_lock);
-
-	if (data->config & MAX6650_CFG_V12)
-		data->dac = 180 - (180 * pwm)/255;
-	else
-		data->dac = 76 - (76 * pwm)/255;
-	err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
-
+	dac = pwm_to_dac(pwm, data->config & MAX6650_CFG_V12);
+	err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, dac);
+	if (!err)
+		data->dac = dac;
 	mutex_unlock(&data->update_lock);
 
 	return err < 0 ? err : count;
@@ -728,11 +731,7 @@  static int max6650_set_cur_state(struct thermal_cooling_device *cdev,
 
 	mutex_lock(&data->update_lock);
 
-	if (data->config & MAX6650_CFG_V12)
-		data->dac = 180 - (180 * state)/255;
-	else
-		data->dac = 76 - (76 * state)/255;
-
+	data->dac = pwm_to_dac(state, data->config & MAX6650_CFG_V12);
 	err = i2c_smbus_write_byte_data(client, MAX6650_REG_DAC, data->dac);
 
 	if (!err) {