From: Brian Norris <briannorris@chromium.org>
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Thierry Reding <thierry.reding@gmail.com>,
linux-pwm@vger.kernel.org, Mark Brown <broonie@kernel.org>,
Liam Girdwood <lgirdwood@gmail.com>,
Heiko Stuebner <heiko@sntech.de>,
linux-rockchip@lists.infradead.org,
Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Milo Kim <milo.kim@ti.com>,
Doug Anderson <dianders@google.com>,
Caesar Wang <wxt@rock-chips.com>,
Stephen Barber <smbarber@chromium.org>,
Srinivas Kandagatla <srinivas.kandagatla@gmail.com>,
Maxime Coquelin <maxime.coquelin@st.com>,
Patrice Chotard <patrice.chotard@st.com>,
kernel@stlinux.com, Laxman Dewangan <ldewangan@nvidia.com>
Subject: Re: [PATCH 10/14] regulator: pwm: Switch to the atomic PWM API
Date: Fri, 3 Jun 2016 13:50:28 -0700 [thread overview]
Message-ID: <20160603205028.GH124478@google.com> (raw)
In-Reply-To: <1464942192-25967-11-git-send-email-boris.brezillon@free-electrons.com>
+ Laxman
Hi,
On Fri, Jun 03, 2016 at 10:23:08AM +0200, Boris Brezillon wrote:
> Use the atomic API wherever appropriate and get rid of pwm_apply_args()
> call (the reference period and polarity are now explicitly set when
> calling pwm_apply_state()).
>
> We also make use of the pwm_set_relative_duty_cycle() helper to ease
> relative to absolute duty_cycle conversion.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
> drivers/regulator/pwm-regulator.c | 38 ++++++++++----------------------------
> 1 file changed, 10 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
> index 524b43f..bf033fd 100644
> --- a/drivers/regulator/pwm-regulator.c
> +++ b/drivers/regulator/pwm-regulator.c
> @@ -59,16 +59,14 @@ static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
> unsigned selector)
> {
> struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
> - struct pwm_args pargs;
> - int dutycycle;
> + struct pwm_state pstate;
> int ret;
>
> - pwm_get_args(drvdata->pwm, &pargs);
> + pwm_prepare_new_state(drvdata->pwm, &pstate);
> + pwm_set_relative_duty_cycle(&pstate,
> + drvdata->duty_cycle_table[selector].dutycycle, 100);
>
> - dutycycle = (pargs.period *
> - drvdata->duty_cycle_table[selector].dutycycle) / 100;
> -
> - ret = pwm_config(drvdata->pwm, dutycycle, pargs.period);
> + ret = pwm_apply_state(drvdata->pwm, &pstate);
> if (ret) {
> dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
> return ret;
> @@ -126,34 +124,18 @@ 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;
> unsigned int req_diff = min_uV - rdev->constraints->min_uV;
> + struct pwm_state pstate;
> unsigned int diff;
> - unsigned int duty_pulse;
> - u64 req_period;
> - u32 rem;
> int ret;
>
> - pwm_get_args(drvdata->pwm, &pargs);
> + pwm_prepare_new_state(drvdata->pwm, &pstate);
> 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);
> - }
> + /* We pass diff as the scale to get a uV precision. */
> + pwm_set_relative_duty_cycle(&pstate, req_diff, diff);
Notably, you're dropping much of Laxman's commit fd786fb0276a ("regulator:
pwm: Try to avoid voltage error in duty cycle calculation"), but I
believe the DIV_ROUND_CLOSEST_ULL() in pwm_set_relative_duty_cycle()
solves his problem better.
>
> - ret = pwm_config(drvdata->pwm, duty_pulse, pargs.period);
> + ret = pwm_apply_state(drvdata->pwm, &pstate);
> if (ret) {
> dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
> return ret;
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
next prev parent reply other threads:[~2016-06-03 20:50 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-03 8:22 [PATCH 00/14] regulator: pwm: various improvements Boris Brezillon
2016-06-03 8:22 ` [PATCH 01/14] pwm: Add new helpers to create/manipulate PWM states Boris Brezillon
2016-06-03 8:23 ` [PATCH 02/14] regulator: pwm: Drop unneeded pwm_enable() call Boris Brezillon
2016-06-03 11:08 ` Applied "regulator: pwm: Drop unneeded pwm_enable() call" to the regulator tree Mark Brown
2016-06-03 8:23 ` [PATCH 03/14] pwm: rockchip: Fix period and duty_cycle approximation Boris Brezillon
2016-06-03 20:03 ` Brian Norris
2016-06-04 6:19 ` Boris Brezillon
2016-06-07 17:25 ` Brian Norris
2016-06-03 8:23 ` [PATCH 04/14] pwm: rockchip: Add support for hardware readout Boris Brezillon
2016-06-03 20:07 ` Brian Norris
2016-06-03 20:20 ` Brian Norris
2016-06-04 6:24 ` Boris Brezillon
2016-06-07 17:26 ` Brian Norris
2016-06-03 8:23 ` [PATCH 05/14] pwm: rockchip: Avoid glitches on already running PWMs Boris Brezillon
2016-06-03 20:28 ` Brian Norris
2016-06-04 6:26 ` Boris Brezillon
2016-06-03 8:23 ` [PATCH 06/14] pwm: rockchip: Add support for atomic update Boris Brezillon
2016-06-03 20:37 ` Brian Norris
2016-06-03 8:23 ` [PATCH 07/14] pwm: sti: Add support for hardware readout Boris Brezillon
2016-06-03 8:23 ` [PATCH 08/14] pwm: sti: Avoid glitches on already running PWMs Boris Brezillon
2016-06-03 20:38 ` Brian Norris
2016-06-03 8:23 ` [PATCH 09/14] regulator: pwm: Adjust PWM config at probe time Boris Brezillon
2016-06-03 20:41 ` Brian Norris
2016-06-03 8:23 ` [PATCH 10/14] regulator: pwm: Switch to the atomic PWM API Boris Brezillon
2016-06-03 20:50 ` Brian Norris [this message]
2016-06-04 6:28 ` Boris Brezillon
2016-06-06 6:14 ` Laxman Dewangan
2016-06-03 8:23 ` [PATCH 11/14] regulator: pwm: properly initialize the ->state field Boris Brezillon
2016-06-03 20:51 ` Brian Norris
2016-06-03 8:23 ` [PATCH 12/14] regulator: pwm: Retrieve correct voltage Boris Brezillon
2016-06-03 20:55 ` Brian Norris
2016-06-03 8:23 ` [PATCH 13/14] regulator: pwm: Support extra continuous mode cases Boris Brezillon
2016-06-03 21:03 ` Brian Norris
2016-06-04 6:30 ` Boris Brezillon
2016-06-03 8:23 ` [PATCH 14/14] regulator: pwm: Document pwm-dutycycle-unit and pwm-dutycycle-range Boris Brezillon
2016-06-03 21:04 ` Brian Norris
2016-06-06 14:09 ` Rob Herring
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