From: Matthias Brugger <matthias.bgg@gmail.com>
To: Fabien Parent <fparent@baylibre.com>,
linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-pwm@vger.kernel.org
Cc: robh+dt@kernel.org, lee.jones@linaro.org,
u.kleine-koenig@pengutronix.de, thierry.reding@gmail.com
Subject: Re: [PATCH 2/5] pwm: pwm-mediatek: always use bus clock
Date: Mon, 19 Oct 2020 16:27:38 +0200 [thread overview]
Message-ID: <0f2dc182-868c-43c3-8ae8-999e7cf1d986@gmail.com> (raw)
In-Reply-To: <20201019140705.1518822-3-fparent@baylibre.com>
On 19/10/2020 16:07, Fabien Parent wrote:
> The MediaTek PWM IP can sometimes use the 26MHz source clock to generate
> the PWM signal, but the driver currently assumes that we always use
> the PWM bus clock to generate the PWM signal.
>
> This commit modifies the PWM driver in order to force the PWM IP to
> always use the bus clock as source clock.
>
> I do not have the datasheet of all the MediaTek SoC, so I don't know
> if the register to choose the source clk is present in all the SoCs
> or only in subset. As a consequence I made this change optional by
> using a platform data paremeter to says whether this register is
> supported or not. On all the SoC I don't have the datasheet
> (MT2712, MT7622, MT7623, MT7628, MT7629) I kept the behavior
> to be the same as before this change.
>
> Signed-off-by: Fabien Parent <fparent@baylibre.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
> ---
> drivers/pwm/pwm-mediatek.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
> index ab001ce55178..108881619aea 100644
> --- a/drivers/pwm/pwm-mediatek.c
> +++ b/drivers/pwm/pwm-mediatek.c
> @@ -30,12 +30,14 @@
> #define PWM45DWIDTH_FIXUP 0x30
> #define PWMTHRES 0x30
> #define PWM45THRES_FIXUP 0x34
> +#define PWM_CK_26M_SEL 0x210
>
> #define PWM_CLK_DIV_MAX 7
>
> struct pwm_mediatek_of_data {
> unsigned int num_pwms;
> bool pwm45_fixup;
> + bool has_ck_26m_sel;
> };
>
> /**
> @@ -132,6 +134,10 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
> if (ret < 0)
> return ret;
>
> + /* Make sure we use the bus clock and not the 26MHz clock */
> + if (pc->soc->has_ck_26m_sel)
> + writel(0, pc->regs + PWM_CK_26M_SEL);
> +
> /* Using resolution in picosecond gets accuracy higher */
> resolution = (u64)NSEC_PER_SEC * 1000;
> do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm]));
> @@ -281,31 +287,37 @@ static int pwm_mediatek_remove(struct platform_device *pdev)
> static const struct pwm_mediatek_of_data mt2712_pwm_data = {
> .num_pwms = 8,
> .pwm45_fixup = false,
> + .has_ck_26m_sel = false,
> };
>
> static const struct pwm_mediatek_of_data mt7622_pwm_data = {
> .num_pwms = 6,
> .pwm45_fixup = false,
> + .has_ck_26m_sel = false,
> };
>
> static const struct pwm_mediatek_of_data mt7623_pwm_data = {
> .num_pwms = 5,
> .pwm45_fixup = true,
> + .has_ck_26m_sel = false,
> };
>
> static const struct pwm_mediatek_of_data mt7628_pwm_data = {
> .num_pwms = 4,
> .pwm45_fixup = true,
> + .has_ck_26m_sel = false,
> };
>
> static const struct pwm_mediatek_of_data mt7629_pwm_data = {
> .num_pwms = 1,
> .pwm45_fixup = false,
> + .has_ck_26m_sel = false,
> };
>
> static const struct pwm_mediatek_of_data mt8516_pwm_data = {
> .num_pwms = 5,
> .pwm45_fixup = false,
> + .has_ck_26m_sel = true,
> };
>
> static const struct of_device_id pwm_mediatek_of_match[] = {
>
next prev parent reply other threads:[~2020-10-19 14:27 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-19 14:07 [PATCH 0/5] Add PWM support for MT8183 EVB Fabien Parent
2020-10-19 14:07 ` [PATCH 1/5] dt-bindings: pwm: pwm-mediatek: Add documentation for MT8183 SoC Fabien Parent
2020-10-19 14:31 ` Matthias Brugger
2020-10-26 13:38 ` Rob Herring
2020-10-19 14:07 ` [PATCH 2/5] pwm: pwm-mediatek: always use bus clock Fabien Parent
2020-10-19 14:27 ` Matthias Brugger [this message]
2020-10-19 14:07 ` [PATCH 3/5] pwm: pwm-mediatek: Add MT8183 SoC support Fabien Parent
2020-10-19 14:30 ` Matthias Brugger
2020-10-19 14:07 ` [PATCH 4/5] arm64: dts: mediatek: mt8183: add pwm node Fabien Parent
2020-10-19 14:07 ` [PATCH 5/5] arm64: dts: mediatek: mt8183-evb: add PWM support Fabien Parent
2020-11-11 20:27 ` [PATCH 0/5] Add PWM support for MT8183 EVB Thierry Reding
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