Merge branch 'for-4.7/pwm-regulator' of git://git.kernel.org/pub/scm/linux/kernel...

[cascardo/linux.git] / drivers / regulator / pwm-regulator.c

diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index ffdb895..fafa348 100644 (file)
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -70,7 +70,7 @@ static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
 
        ret = pwm_config(drvdata->pwm, dutycycle, pargs.period);
        if (ret) {
-               dev_err(&rdev->dev, "Failed to configure PWM\n");
+               dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
                return ret;
        }
 
@@ -113,18 +113,6 @@ static int pwm_regulator_is_enabled(struct regulator_dev *dev)
        return pwm_is_enabled(drvdata->pwm);
 }
 
-/**
- * Continuous voltage call-backs
- */
-static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV)
-{
-       int min_uV = rdev->constraints->min_uV;
-       int max_uV = rdev->constraints->max_uV;
-       int diff = max_uV - min_uV;
-
-       return ((req_uV * 100) - (min_uV * 100)) / diff;
-}
-
 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 {
        struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
@@ -139,22 +127,41 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
        struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
        unsigned int ramp_delay = rdev->constraints->ramp_delay;
        struct pwm_args pargs;
-       int duty_cycle;
+       unsigned int req_diff = min_uV - rdev->constraints->min_uV;
+       unsigned int diff;
+       unsigned int duty_pulse;
+       u64 req_period;
+       u32 rem;
        int ret;
 
        pwm_get_args(drvdata->pwm, &pargs);
-       duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV);
+       diff = rdev->constraints->max_uV - rdev->constraints->min_uV;
+
+       /* First try to find out if we get the iduty cycle time which is
+        * factor of PWM period time. If (request_diff_to_min * pwm_period)
+        * is perfect divided by voltage_range_diff then it is possible to
+        * get duty cycle time which is factor of PWM period. This will help
+        * to get output voltage nearer to requested value as there is no
+        * calculation loss.
+        */
+       req_period = req_diff * pargs.period;
+       div_u64_rem(req_period, diff, &rem);
+       if (!rem) {
+               do_div(req_period, diff);
+               duty_pulse = (unsigned int)req_period;
+       } else {
+               duty_pulse = (pargs.period / 100) * ((req_diff * 100) / diff);
+       }
 
-       ret = pwm_config(drvdata->pwm, (pargs.period / 100) * duty_cycle,
-                        pargs.period);
+       ret = pwm_config(drvdata->pwm, duty_pulse, pargs.period);
        if (ret) {
-               dev_err(&rdev->dev, "Failed to configure PWM\n");
+               dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
                return ret;
        }
 
        ret = pwm_enable(drvdata->pwm);
        if (ret) {
-               dev_err(&rdev->dev, "Failed to enable PWM\n");
+               dev_err(&rdev->dev, "Failed to enable PWM: %d\n", ret);
                return ret;
        }
        drvdata->volt_uV = min_uV;
@@ -202,8 +209,7 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
 
        if ((length < sizeof(*duty_cycle_table)) ||
            (length % sizeof(*duty_cycle_table))) {
-               dev_err(&pdev->dev,
-                       "voltage-table length(%d) is invalid\n",
+               dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
                        length);
                return -EINVAL;
        }
@@ -216,7 +222,7 @@ static int pwm_regulator_init_table(struct platform_device *pdev,
                                         (u32 *)duty_cycle_table,
                                         length / sizeof(u32));
        if (ret) {
-               dev_err(&pdev->dev, "Failed to read voltage-table\n");
+               dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
                return ret;
        }
 
@@ -279,8 +285,9 @@ static int pwm_regulator_probe(struct platform_device *pdev)
 
        drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
        if (IS_ERR(drvdata->pwm)) {
-               dev_err(&pdev->dev, "Failed to get PWM\n");
-               return PTR_ERR(drvdata->pwm);
+               ret = PTR_ERR(drvdata->pwm);
+               dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
+               return ret;
        }
 
        /*
@@ -292,9 +299,10 @@ static int pwm_regulator_probe(struct platform_device *pdev)
        regulator = devm_regulator_register(&pdev->dev,
                                            &drvdata->desc, &config);
        if (IS_ERR(regulator)) {
-               dev_err(&pdev->dev, "Failed to register regulator %s\n",
-                       drvdata->desc.name);
-               return PTR_ERR(regulator);
+               ret = PTR_ERR(regulator);
+               dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
+                       drvdata->desc.name, ret);
+               return ret;
        }
 
        return 0;