linux-kernel - Re: [PATCH] i2c: imx: add retries for i2c-0 on Ventana boards

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Message-ID: <20160708210714.GK16643@pengutronix.de>
Date:	Fri, 8 Jul 2016 23:07:14 +0200
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Tim Harvey <tharvey@...eworks.com>,
	Wolfram Sang <wsa@...-dreams.de>
Cc:	Fabio Estevam <fabio.estevam@...escale.com>,
	linux-i2c@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] i2c: imx: add retries for i2c-0 on Ventana boards

Hello Tim, hello Wolfram,

On Fri, Jul 08, 2016 at 12:49:04PM -0700, Tim Harvey wrote:
> On Thu, Jul 7, 2016 at 11:28 PM, Uwe Kleine-König
> <u.kleine-koenig@...gutronix.de> wrote:
> > Hello Tim,
> >
> > On Thu, Jul 07, 2016 at 07:03:49AM -0700, Tim Harvey wrote:
> >> Gateworks Ventana IMX6 based boards have a Gateworks System Controller [1]
> >> (gsc) device that can NAK i2c transactions when its busy in an ADC loop. As
> >> this is always on i2c-0 we will add retries for that bus for any Ventana
> >> board.
> >
> > The right thing is to fix the drivers IMHO.
> >
> The issue I have is that the i2c device emulates several other devices
> with existing drivers (pca953x, ds1672, at24) and those drivers don't
> have any retry mechanism in place for a retry.
> 
> Maybe if I converted those drivers to use regmap I could implement a
> regmap with retries in the mfd driver for my device?

Wolfram: what do you think?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |