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authorLee Jones <lee.jones@linaro.org>2015-07-07 16:06:52 +0100
committerMark Brown <broonie@kernel.org>2015-07-07 18:58:28 +0100
commitcae897dec26a9d81dcb5182b13b08450f38d6bde (patch)
tree2b60310636df499b0380f1aeb1004e3323d4670f /drivers
parent4773be185a0f7c1c09d8966e100c76f4fa9a3227 (diff)
downloadblackbird-op-linux-cae897dec26a9d81dcb5182b13b08450f38d6bde.tar.gz
blackbird-op-linux-cae897dec26a9d81dcb5182b13b08450f38d6bde.zip
regulator: pwm-regulator: Simplify voltage to duty-cycle call
If we reverse some of the logic and change the formula used, we can simplify the function greatly. It is intentional that this function is supplied and then re-worked within the same patch-set. The submission in the previous patch is the tried and tested (i.e. in real releases) method written by ST. This patch contains a simplification provided later. It looks and performs better, but doesn't have the same time-under-test that the original method does. The idea is that we keep some history in order to provide an easy way back i.e. revert. Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/regulator/pwm-regulator.c27
1 files changed, 7 insertions, 20 deletions
diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index dac145db305c..d5cb267fa192 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -93,26 +93,13 @@ static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
/**
* Continuous voltage call-backs
*/
-static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev,
- int volt_mV)
+static int pwm_voltage_to_duty_cycle(struct regulator_dev *rdev, int req_uV)
{
- struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
- int min_mV = rdev->constraints->min_uV / 1000;
- int max_mV = rdev->constraints->max_uV / 1000;
- int max_duty_cycle = drvdata->max_duty_cycle;
- int vdiff = min_mV - max_mV;
- int pwm_code;
- int tmp;
-
- tmp = ((max_duty_cycle - min_mV) * max_duty_cycle) / vdiff;
- pwm_code = ((tmp + max_duty_cycle) * volt_mV) / vdiff;
-
- if (pwm_code < 0)
- pwm_code = 0;
- if (pwm_code > max_duty_cycle)
- pwm_code = max_duty_cycle;
-
- return pwm_code * 100 / max_duty_cycle;
+ int min_uV = rdev->constraints->min_uV;
+ int max_uV = rdev->constraints->max_uV;
+ int diff = max_uV - min_uV;
+
+ return 100 - ((((req_uV * 100) - (min_uV * 100)) / diff));
}
static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
@@ -131,7 +118,7 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
int duty_cycle;
int ret;
- duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV / 1000);
+ duty_cycle = pwm_voltage_to_duty_cycle(rdev, min_uV);
ret = pwm_config(drvdata->pwm,
(drvdata->pwm->period / 100) * duty_cycle,
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