From ea398e28739e25651ede7ddf5aeb57cbcbc8ca7d Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Tue, 14 Jun 2016 11:13:21 +0200 Subject: [PATCH] regulator: pwm: Support extra continuous mode cases The continuous mode allows one to declare a PWM regulator without having to declare the voltage <-> dutycycle association table. It works fine as long as your voltage(dutycycle) function is linear, but also has the following constraints: - dutycycle for min_uV = 0% - dutycycle for max_uV = 100% - dutycycle for min_uV < dutycycle for max_uV While the linearity constraint is acceptable for now, we sometimes need to restrict of the PWM range (to limit the maximum/minimum voltage for example) or have a min_uV_dutycycle > max_uV_dutycycle (this could be tweaked with PWM polarity, but not all PWMs support inverted polarity). Add the pwm-dutycycle-range and pwm-dutycycle-unit DT properties to define such constraints. If those properties are not defined, the PWM regulator use the default pwm-dutycycle-range = <0 100> and pwm-dutycycle-unit = <100> values (existing behavior). Signed-off-by: Boris Brezillon Reviewed-by: Brian Norris Tested-by: Brian Norris Tested-by: Heiko Stuebner Acked-by: Mark Brown Signed-off-by: Thierry Reding --- drivers/regulator/pwm-regulator.c | 92 ++++++++++++++++++++++++++++++++++----- 1 file changed, 82 insertions(+), 10 deletions(-) diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c index ae0bebb..c2452424 100644 --- a/drivers/regulator/pwm-regulator.c +++ b/drivers/regulator/pwm-regulator.c @@ -22,6 +22,12 @@ #include #include +struct pwm_continuous_reg_data { + unsigned int min_uV_dutycycle; + unsigned int max_uV_dutycycle; + unsigned int dutycycle_unit; +}; + struct pwm_regulator_data { /* Shared */ struct pwm_device *pwm; @@ -29,6 +35,9 @@ struct pwm_regulator_data { /* Voltage table */ struct pwm_voltages *duty_cycle_table; + /* Continuous mode info */ + struct pwm_continuous_reg_data continuous; + /* regulator descriptor */ struct regulator_desc desc; @@ -145,32 +154,78 @@ static int pwm_regulator_is_enabled(struct regulator_dev *dev) static int pwm_regulator_get_voltage(struct regulator_dev *rdev) { struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; + unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; + unsigned int duty_unit = drvdata->continuous.dutycycle_unit; int min_uV = rdev->constraints->min_uV; - int diff = rdev->constraints->max_uV - min_uV; + int max_uV = rdev->constraints->max_uV; + int diff_uV = max_uV - min_uV; struct pwm_state pstate; + unsigned int diff_duty; + unsigned int voltage; pwm_get_state(drvdata->pwm, &pstate); - return min_uV + pwm_get_relative_duty_cycle(&pstate, diff); + voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit); + + /* + * The dutycycle for min_uV might be greater than the one for max_uV. + * This is happening when the user needs an inversed polarity, but the + * PWM device does not support inversing it in hardware. + */ + if (max_uV_duty < min_uV_duty) { + voltage = min_uV_duty - voltage; + diff_duty = min_uV_duty - max_uV_duty; + } else { + voltage = voltage - min_uV_duty; + diff_duty = max_uV_duty - min_uV_duty; + } + + voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty); + + return voltage + min_uV; } static int pwm_regulator_set_voltage(struct regulator_dev *rdev, - int min_uV, int max_uV, - unsigned *selector) + int req_min_uV, int req_max_uV, + unsigned int *selector) { struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; + unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; + unsigned int duty_unit = drvdata->continuous.dutycycle_unit; unsigned int ramp_delay = rdev->constraints->ramp_delay; - unsigned int req_diff = min_uV - rdev->constraints->min_uV; + int min_uV = rdev->constraints->min_uV; + int max_uV = rdev->constraints->max_uV; + int diff_uV = max_uV - min_uV; struct pwm_state pstate; - unsigned int diff; int old_uV = pwm_regulator_get_voltage(rdev); + unsigned int diff_duty; + unsigned int dutycycle; int ret; pwm_init_state(drvdata->pwm, &pstate); - diff = rdev->constraints->max_uV - rdev->constraints->min_uV; - /* We pass diff as the scale to get a uV precision. */ - pwm_set_relative_duty_cycle(&pstate, req_diff, diff); + /* + * The dutycycle for min_uV might be greater than the one for max_uV. + * This is happening when the user needs an inversed polarity, but the + * PWM device does not support inversing it in hardware. + */ + if (max_uV_duty < min_uV_duty) + diff_duty = min_uV_duty - max_uV_duty; + else + diff_duty = max_uV_duty - min_uV_duty; + + dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) * + diff_duty, + diff_uV); + + if (max_uV_duty < min_uV_duty) + dutycycle = min_uV_duty - dutycycle; + else + dutycycle = min_uV_duty + dutycycle; + + pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit); ret = pwm_apply_state(drvdata->pwm, &pstate); if (ret) { @@ -182,7 +237,7 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev, return 0; /* Ramp delay is in uV/uS. Adjust to uS and delay */ - ramp_delay = DIV_ROUND_UP(abs(min_uV - old_uV), ramp_delay); + ramp_delay = DIV_ROUND_UP(abs(req_min_uV - old_uV), ramp_delay); usleep_range(ramp_delay, ramp_delay + DIV_ROUND_UP(ramp_delay, 10)); return 0; @@ -255,11 +310,28 @@ static int pwm_regulator_init_table(struct platform_device *pdev, static int pwm_regulator_init_continuous(struct platform_device *pdev, struct pwm_regulator_data *drvdata) { + u32 dutycycle_range[2] = { 0, 100 }; + u32 dutycycle_unit = 100; + memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops, sizeof(drvdata->ops)); drvdata->desc.ops = &drvdata->ops; drvdata->desc.continuous_voltage_range = true; + of_property_read_u32_array(pdev->dev.of_node, + "pwm-dutycycle-range", + dutycycle_range, 2); + of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit", + &dutycycle_unit); + + if (dutycycle_range[0] > dutycycle_unit || + dutycycle_range[1] > dutycycle_unit) + return -EINVAL; + + drvdata->continuous.dutycycle_unit = dutycycle_unit; + drvdata->continuous.min_uV_dutycycle = dutycycle_range[0]; + drvdata->continuous.max_uV_dutycycle = dutycycle_range[1]; + return 0; } -- 2.7.4