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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: linux-pwm@vger.kernel.org,
	Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>,
	Lukasz Majewski <l.majewski@majess.pl>,
	linux-kernel@vger.kernel.org, Stefan Agner <stefan@agner.ch>,
	Thierry Reding <thierry.reding@gmail.com>,
	kernel@pengutronix.de, Fabio Estevam <fabio.estevam@nxp.com>,
	Philipp Zabel <pza@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	Lothar Wassmann <LW@karo-electronics.de>
Subject: Re: [PATCH v2 03/10] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation
Date: Tue, 1 Nov 2016 09:59:35 +0100	[thread overview]
Message-ID: <20161101085935.4fitl2u6hkt63ro6@pengutronix.de> (raw)
In-Reply-To: <20161031092937.im5epytgorcd5fbm@pengutronix.de>

On Mon, Oct 31, 2016 at 10:29:37AM +0100, Sascha Hauer wrote:
> > accesses. This is true for the ->config() callback, but not for the
> > ->set_enable() callback. Given that the ipg clock is not consistently
> > enabled for all register accesses we can assume that either it is not
> > required at all or that the current code does not work.
> > Remove the ipg clock code for now so that it's no longer in the way of
> > refactoring the driver.
> 
> For reference:
> 
> I verified on i.MX53 and i.MX25 that the ipg clock provided to the pwm
> driver is not needed when accessing registers. I would have to verify
> that on i.MX27 aswell, but I do not have a board handy at the moment.

Also on i.MX27 disabling the PWMs ipg_clk does not disable register
accesses.

Sascha

> 
> The current assumption as discussed by Philipp and me is that the ipg
> clk is only needed when the pwm output is driven by the ipg clk
> (MX3_PWMCR[16:17] = MX3_PWMCR_CLKSRC_IPG)
> 
> Sascha
> 
> -- 
> Pengutronix e.K.                           |                             |
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> 
> 

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

  parent reply	other threads:[~2016-11-01  8:59 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-27  6:29 [PATCH v2 00/10] pwm: imx: Provide atomic operation for IMX PWM driver Lukasz Majewski
2016-10-27  6:29 ` [PATCH v2 01/10] pwm: print error messages with pr_err() instead of pr_debug() Lukasz Majewski
2016-10-27  6:29 ` [PATCH v2 02/10] pwm: imx: Add separate set of pwm ops for PWMv1 and PWMv2 Lukasz Majewski
2016-10-27  6:29 ` [PATCH v2 03/10] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation Lukasz Majewski
2016-10-27  7:40   ` Boris Brezillon
2016-10-27  8:22     ` Lukasz Majewski
2016-10-31  5:59     ` Sascha Hauer
2016-10-31  5:59       ` Sascha Hauer
2016-10-31  8:06       ` Lukasz Majewski
2016-10-31  9:24         ` Sascha Hauer
2016-10-31  9:29       ` Sascha Hauer
2016-10-31 11:58         ` Lukasz Majewski
2016-11-01  5:57         ` Lukasz Majewski
2016-11-01  7:17           ` Sascha Hauer
2016-11-01  8:20             ` Lukasz Majewski
2016-11-01  8:59         ` Sascha Hauer [this message]
2016-11-02  7:18       ` Lothar Waßmann
2016-11-02  7:36         ` Sascha Hauer
2016-11-02  7:56           ` Lothar Waßmann
2016-11-02  8:06             ` Sascha Hauer
2016-11-02  8:51               ` Lothar Waßmann
2016-11-02  9:34                 ` Philipp Zabel
2016-10-27  6:29 ` [PATCH v2 04/10] pwm: imx: Move PWMv2 software reset code to a separate function Lukasz Majewski
2016-11-03  9:34   ` Philipp Zabel
2016-10-27  6:29 ` [PATCH v2 05/10] pwm: imx: Move PWMv2 wait for fifo slot " Lukasz Majewski
2016-10-27  6:29 ` [PATCH v2 06/10] pwm: imx: Provide atomic PWM support for i.MX PWMv2 Lukasz Majewski
2016-10-27  6:29 ` [PATCH v2 07/10] pwm: imx: Remove redundant i.MX PWMv2 code Lukasz Majewski
2016-10-27  6:29 ` [PATCH v2 08/10] pwm: core: make the PWM_POLARITY flag in DTB optional Lukasz Majewski
2016-10-27  6:29 ` [PATCH v2 10/10] pwm: imx: Add polarity inversion support to i.MX's PWMv2 Lukasz Majewski

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