| Message ID | 1464942192-25967-14-git-send-email-boris.brezillon@free-electrons.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Boris, On Fri, Jun 03, 2016 at 10:23:11AM +0200, Boris Brezillon wrote: > 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 <boris.brezillon@free-electrons.com> > --- > drivers/regulator/pwm-regulator.c | 80 ++++++++++++++++++++++++++++++++++----- > 1 file changed, 71 insertions(+), 9 deletions(-) > > diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c > index c39ecd1..2e70eb1 100644 > --- a/drivers/regulator/pwm-regulator.c > +++ b/drivers/regulator/pwm-regulator.c ... > @@ -132,31 +141,67 @@ 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); > + > + if (max_uV_duty < min_uV_duty) { I still might have appreciated a comment above this line (and similar in set_voltage()) to help explain why max can be less than min -- you have it in the commit message, but nowhere in the code. Not a big deal, and the code looks otherwise good: Reviewed-by: Brian Norris <briannorris@chromium.org> Tested-by: Brian Norris <briannorris@chromium.org> > + 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; > + unsigned int diff_duty; > + unsigned int dutycycle; > int ret; > > pwm_prepare_new_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); > + 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) { [...] Brian
On Fri, 3 Jun 2016 14:03:08 -0700 Brian Norris <briannorris@chromium.org> wrote: > Hi Boris, > > On Fri, Jun 03, 2016 at 10:23:11AM +0200, Boris Brezillon wrote: > > 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 <boris.brezillon@free-electrons.com> > > --- > > drivers/regulator/pwm-regulator.c | 80 ++++++++++++++++++++++++++++++++++----- > > 1 file changed, 71 insertions(+), 9 deletions(-) > > > > diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c > > index c39ecd1..2e70eb1 100644 > > --- a/drivers/regulator/pwm-regulator.c > > +++ b/drivers/regulator/pwm-regulator.c > > ... > > > @@ -132,31 +141,67 @@ 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); > > + > > + if (max_uV_duty < min_uV_duty) { > > I still might have appreciated a comment above this line (and similar > in set_voltage()) to help explain why max can be less than min -- you > have it in the commit message, but nowhere in the code. Not a big deal, > and the code looks otherwise good: Sure, I'll add more comments in the next version. Thanks, Boris > > Reviewed-by: Brian Norris <briannorris@chromium.org> > Tested-by: Brian Norris <briannorris@chromium.org> > > > > + 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; > > + unsigned int diff_duty; > > + unsigned int dutycycle; > > int ret; > > > > pwm_prepare_new_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); > > + 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) { > > [...] > > Brian
diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c index c39ecd1..2e70eb1 100644 --- a/drivers/regulator/pwm-regulator.c +++ b/drivers/regulator/pwm-regulator.c @@ -21,6 +21,12 @@ #include <linux/of_device.h> #include <linux/pwm.h> +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; @@ -28,6 +34,9 @@ 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; @@ -132,31 +141,67 @@ 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); + + 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; + unsigned int diff_duty; + unsigned int dutycycle; int ret; pwm_prepare_new_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); + 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) { @@ -237,11 +282,28 @@ 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; }
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 <boris.brezillon@free-electrons.com> --- drivers/regulator/pwm-regulator.c | 80 ++++++++++++++++++++++++++++++++++----- 1 file changed, 71 insertions(+), 9 deletions(-)