From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: George Stark <gnstark@salutedevices.com>
Cc: neil.armstrong@linaro.org, khilman@baylibre.com,
jbrunet@baylibre.com, martin.blumenstingl@googlemail.com,
thierry.reding@gmail.com, hkallweit1@gmail.com,
linux-pwm@vger.kernel.org, linux-amlogic@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel@salutedevices.com,
Dmitry Rokosov <ddrokosov@salutedevices.com>
Subject: Re: [PATCH v2 2/2] pwm: meson: Add check for error from clk_round_rate()
Date: Wed, 24 Apr 2024 16:19:04 +0200 [thread overview]
Message-ID: <xb2prc5ewslr74eh22xo4heeiepeiu4rb72zekuatcuhp45p6s@nhwhnq26tthg> (raw)
In-Reply-To: <20240424132408.2565916-3-gnstark@salutedevices.com>
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On Wed, Apr 24, 2024 at 04:24:08PM +0300, George Stark wrote:
> clk_round_rate() can return not only zero if requested frequency can not
> be provided but also negative error code so add check for it too.
>
> Also change type of variable holding clk_round_rate() result from
> unsigned long to long. It's safe due to clk_round_rate() returns long.
>
> Fixes: 329db102a26d ("pwm: meson: make full use of common clock framework")
> Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
> Signed-off-by: George Stark <gnstark@salutedevices.com>
> ---
> drivers/pwm/pwm-meson.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
> index f4d70da621ec..d4228ac1e7ea 100644
> --- a/drivers/pwm/pwm-meson.c
> +++ b/drivers/pwm/pwm-meson.c
> @@ -148,7 +148,7 @@ static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm,
> struct meson_pwm *meson = to_meson_pwm(chip);
> struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm];
> unsigned int cnt, duty_cnt;
> - unsigned long fin_freq;
> + long fin_freq;
> u64 duty, period, freq;
>
> duty = state->duty_cycle;
> @@ -168,9 +168,10 @@ static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm,
> freq = ULONG_MAX;
>
> fin_freq = clk_round_rate(channel->clk, freq);
> - if (fin_freq == 0) {
> - dev_err(pwmchip_parent(chip), "invalid source clock frequency\n");
> - return -EINVAL;
> + if (fin_freq <= 0) {
> + dev_err(pwmchip_parent(chip),
> + "invalid source clock frequency %llu\n", freq);
> + return fin_freq ? fin_freq : -EINVAL;
> }
>
> dev_dbg(pwmchip_parent(chip), "fin_freq: %lu Hz\n", fin_freq);
^
With fin_freq now being unsigned, this ------------' should be a 'd'.
If you want to still extend your fixes series: A bit further below there
is
cnt = div_u64(fin_freq * period, NSEC_PER_SEC);
. The multiplication there might overflow. This should better use
mul_u64_u64_div_u64() (or one of it's variants).
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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prev parent reply other threads:[~2024-04-24 14:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 13:24 [PATCH v2 0/2] meson pwm small fixes George Stark
2024-04-24 13:24 ` [PATCH v2 1/2] pwm: meson: Drop unneeded check in .get_state() George Stark
2024-04-24 13:24 ` [PATCH v2 2/2] pwm: meson: Add check for error from clk_round_rate() George Stark
2024-04-24 14:19 ` Uwe Kleine-König [this message]
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