From: Sascha Hauer <s.hauer@pengutronix.de>
To: Lukasz Majewski <l.majewski@majess.pl>
Cc: Thierry Reding <thierry.reding@gmail.com>,
Stefan Agner <stefan@agner.ch>,
Boris Brezillon <boris.brezillon@free-electrons.com>,
linux-pwm@vger.kernel.org,
Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>,
linux-kernel@vger.kernel.org, kernel@pengutronix.de,
Fabio Estevam <fabio.estevam@nxp.com>,
Fabio Estevam <festevam@gmail.com>,
Lothar Wassmann <LW@karo-electronics.de>
Subject: Re: [PATCH 1/6] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation
Date: Tue, 25 Oct 2016 07:54:54 +0200 [thread overview]
Message-ID: <20161025055454.emytytmcg6d23jdd@pengutronix.de> (raw)
In-Reply-To: <1477259146-19167-2-git-send-email-l.majewski@majess.pl>
On Sun, Oct 23, 2016 at 11:45:41PM +0200, Lukasz Majewski wrote:
> The code has been rewritten to remove "generic" calls to
> imx_pwm_{enable|disable|config}.
>
> Such approach would facilitate switch to atomic PWM (a.k.a ->apply())
> implementation.
>
> Suggested-by: Stefan Agner <stefan@agner.ch>
> Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
> ---
> drivers/pwm/pwm-imx.c | 46 ++++++++++++++++++++++++++++++++++------------
> 1 file changed, 34 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
> index c37d223..83e43d5 100644
> --- a/drivers/pwm/pwm-imx.c
> +++ b/drivers/pwm/pwm-imx.c
> @@ -66,8 +66,6 @@ struct imx_chip {
> static int imx_pwm_config_v1(struct pwm_chip *chip,
> struct pwm_device *pwm, int duty_ns, int period_ns)
> {
> - struct imx_chip *imx = to_imx_chip(chip);
> -
> /*
> * The PWM subsystem allows for exact frequencies. However,
> * I cannot connect a scope on my device to the PWM line and
> @@ -85,26 +83,52 @@ static int imx_pwm_config_v1(struct pwm_chip *chip,
> * both the prescaler (/1 .. /128) and then by CLKSEL
> * (/2 .. /16).
> */
> + struct imx_chip *imx = to_imx_chip(chip);
> u32 max = readl(imx->mmio_base + MX1_PWMP);
> u32 p = max * duty_ns / period_ns;
> + int ret;
> +
> + ret = clk_prepare_enable(imx->clk_ipg);
> + if (ret)
> + return ret;
> +
> writel(max - p, imx->mmio_base + MX1_PWMS);
>
> + clk_disable_unprepare(imx->clk_ipg);
> +
> return 0;
> }
>
> -static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable)
> +static int imx_pwm_enable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
> {
> struct imx_chip *imx = to_imx_chip(chip);
> + int ret;
> u32 val;
>
> + ret = clk_prepare_enable(imx->clk_ipg);
> + if (ret)
> + return ret;
> +
> val = readl(imx->mmio_base + MX1_PWMC);
> + val |= MX1_PWMC_EN;
> + writel(val, imx->mmio_base + MX1_PWMC);
>
> - if (enable)
> - val |= MX1_PWMC_EN;
> - else
> - val &= ~MX1_PWMC_EN;
> + clk_disable_unprepare(imx->clk_per);
This looks wrong. You start by enabling clk_ipg which is needed for
register access, but then end with disabling clk_per which is needed for
driving the actual PWM output. This function should probably enable
clk_per on entry and enable clk_ipg while accessing registers.
Sascha
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next prev parent reply other threads:[~2016-10-25 5:55 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-23 21:45 [PATCH 0/6] pwm: imx: Provide atomic operation for IMX PWM driver Lukasz Majewski
2016-10-23 21:45 ` [PATCH 1/6] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation Lukasz Majewski
2016-10-24 15:21 ` Boris Brezillon
2016-10-25 5:54 ` Sascha Hauer [this message]
2016-10-25 6:27 ` Boris Brezillon
2016-10-25 6:32 ` Sascha Hauer
2016-10-25 6:42 ` Boris Brezillon
2016-10-25 6:55 ` Lukasz Majewski
2016-10-23 21:45 ` [PATCH 2/6] pwm: imx: Move PWMv2 software reset code to a separate function Lukasz Majewski
2016-10-24 15:23 ` Boris Brezillon
2016-10-24 21:02 ` Lukasz Majewski
2016-10-23 21:45 ` [PATCH 3/6] pwm: imx: Move PWMv2 wait for fifo slot " Lukasz Majewski
2016-10-24 15:23 ` Boris Brezillon
2016-10-23 21:45 ` [PATCH 4/6] pwm: imx: Provide atomic PWM support for IMXv2 PWM Lukasz Majewski
2016-10-24 15:25 ` Boris Brezillon
2016-10-23 21:45 ` [PATCH 5/6] pwm: imx: Remove redundant IMX PWMv2 code Lukasz Majewski
2016-10-24 15:27 ` Boris Brezillon
2016-10-23 21:45 ` [PATCH 6/6] pwm: imx: Introduce "polarity_supported" flag to PWMv2 driver Lukasz Majewski
2016-10-24 15:28 ` Boris Brezillon
2016-10-24 15:34 ` Boris Brezillon
2016-10-24 21:14 ` Lukasz Majewski
2016-10-25 6:37 ` Boris Brezillon
2016-10-25 6:58 ` Lukasz Majewski
2016-10-24 15:36 ` [PATCH 0/6] pwm: imx: Provide atomic operation for IMX PWM driver Boris Brezillon
2016-10-24 21:26 ` Lukasz Majewski
2016-10-25 3:41 ` Stefan Agner
2016-10-25 7:07 ` Lukasz Majewski
2016-10-25 17:08 ` Fabio Estevam
2016-10-25 17:09 ` Fabio Estevam
2016-10-27 5:59 ` Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 00/11] " Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 01/11] pwm: print error messages with pr_err() instead of pr_debug() Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 02/11] pwm: imx: remove ipg clock Lukasz Majewski
2016-12-27 7:26 ` Stefan Agner
2016-12-27 7:54 ` Lukasz Majewski
2016-12-28 22:01 ` Lukasz Majewski
2016-12-29 7:22 ` Stefan Agner
2016-12-29 10:06 ` Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 03/11] pwm: imx: Add separate set of pwm ops for PWMv1 and PWMv2 Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 04/11] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 05/11] pwm: imx: Move PWMv2 software reset code to a separate function Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 06/11] pwm: imx: Move PWMv2 wait for fifo slot " Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 07/11] pwm: imx: Provide atomic PWM support for i.MX PWMv2 Lukasz Majewski
2016-12-29 16:21 ` Boris Brezillon
2016-12-29 16:45 ` Lukasz Majewski
2016-12-29 17:08 ` Boris Brezillon
2017-01-03 11:43 ` Lukasz Majewski
2017-01-03 12:46 ` Boris Brezillon
2017-01-03 17:29 ` Stefan Agner
2017-01-03 19:35 ` Boris Brezillon
2017-01-03 22:01 ` Lukasz Majewski
2017-01-03 22:18 ` Boris Brezillon
2017-01-03 22:46 ` Lukasz Majewski
2017-01-03 23:34 ` Boris Brezillon
2017-01-04 11:29 ` Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 08/11] pwm: imx: Remove redundant i.MX PWMv2 code Lukasz Majewski
2016-12-26 22:55 ` [PATCH v3 RESEND 09/11] pwm: core: make the PWM_POLARITY flag in DTB optional Lukasz Majewski
2016-12-26 22:56 ` [PATCH v3 RESEND 10/11] pwm: imx: doc: Update imx-pwm.txt documentation entry Lukasz Majewski
2016-12-26 22:56 ` [PATCH v3 RESEND 11/11] pwm: imx: Add polarity inversion support to i.MX's PWMv2 Lukasz Majewski
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