From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Baruch Siach <baruch@tkos.co.il>
Cc: "Thierry Reding" <thierry.reding@gmail.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Lee Jones" <lee.jones@linaro.org>,
"Linus Walleij" <linus.walleij@linaro.org>,
"Russell King" <linux@armlinux.org.uk>,
"Andrew Lunn" <andrew@lunn.ch>,
"Gregory Clement" <gregory.clement@bootlin.com>,
"Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>,
"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
"Chris Packham" <chris.packham@alliedtelesis.co.nz>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Ralph Sennhauser" <ralph.sennhauser@gmail.com>,
linux-pwm@vger.kernel.org,
linux-gpio <linux-gpio@vger.kernel.org>,
arm-soc <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 1/5] gpio: mvebu: fix pwm .get_state period calculation
Date: Tue, 19 Jan 2021 12:00:18 +0100 [thread overview]
Message-ID: <CAMpxmJU1mjek0rEzr34xFdPHDTuEe9i9wjwiLp=UezXKYNtcwQ@mail.gmail.com> (raw)
In-Reply-To: <588373a200d20da0fa6c2a6c7f1928b4818097e9.1610882271.git.baruch@tkos.co.il>
On Sun, Jan 17, 2021 at 2:17 PM Baruch Siach <baruch@tkos.co.il> wrote:
>
> The period is the sum of on and off values. That is, calculate period as
>
> ($on + $off) / clkrate
>
> instead of
>
> $off / clkrate - $on / clkrate
>
> that makes no sense.
>
> Reported-by: Russell King <linux@armlinux.org.uk>
> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Fixes: 757642f9a584e ("gpio: mvebu: Add limited PWM support")
> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
> ---
> drivers/gpio/gpio-mvebu.c | 19 ++++++++-----------
> 1 file changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
> index 672681a976f5..a912a8fed197 100644
> --- a/drivers/gpio/gpio-mvebu.c
> +++ b/drivers/gpio/gpio-mvebu.c
> @@ -676,20 +676,17 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
> else
> state->duty_cycle = 1;
>
> + val = (unsigned long long) u; /* on duration */
> regmap_read(mvpwm->regs, mvebu_pwmreg_blink_off_duration(mvpwm), &u);
> - val = (unsigned long long) u * NSEC_PER_SEC;
> + val += (unsigned long long) u; /* period = on + off duration */
> + val *= NSEC_PER_SEC;
> do_div(val, mvpwm->clk_rate);
> - if (val < state->duty_cycle) {
> + if (val > UINT_MAX)
> + state->period = UINT_MAX;
> + else if (val)
> + state->period = val;
> + else
> state->period = 1;
> - } else {
> - val -= state->duty_cycle;
> - if (val > UINT_MAX)
> - state->period = UINT_MAX;
> - else if (val)
> - state->period = val;
> - else
> - state->period = 1;
> - }
>
> regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u);
> if (u)
> --
> 2.29.2
>
I applied this for fixes and will send out a PR to Linus T this week.
Once that's upstream I'll apply the rest for the next release.
Bartosz
next prev parent reply other threads:[~2021-01-19 14:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-17 13:17 [PATCH v4 0/5] gpio: mvebu: pwm fixes and improvements Baruch Siach
2021-01-17 13:17 ` [PATCH v4 1/5] gpio: mvebu: fix pwm .get_state period calculation Baruch Siach
2021-01-19 11:00 ` Bartosz Golaszewski [this message]
2021-01-17 13:17 ` [PATCH v4 2/5] gpio: mvebu: improve pwm period calculation accuracy Baruch Siach
2021-01-17 13:17 ` [PATCH v4 3/5] gpio: mvebu: make pwm .get_state closer to idempotent Baruch Siach
2021-01-17 13:17 ` [PATCH v4 4/5] gpio: mvebu: don't limit pwm period/duty_cycle to UINT_MAX Baruch Siach
2021-01-17 13:17 ` [PATCH v4 5/5] gpio: mvebu: improve handling of pwm zero on/off values Baruch Siach
2021-01-19 19:39 ` Uwe Kleine-König
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