From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH] i2c: pca954x: put the mux to disconnected state after resume Date: Fri, 25 Jul 2014 09:15:19 +0200 Message-ID: <20140725091519.4e780494@endymion.delvare> References: <1406254559-5615-1-git-send-email-jszhang@marvell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1406254559-5615-1-git-send-email-jszhang-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jisheng Zhang Cc: wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org, paul.gortmaker-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hi Jisheng Zhang, On Fri, 25 Jul 2014 10:15:59 +0800, Jisheng Zhang wrote: > pca954x may be power lost during suspend, so after resume we also suffer > the issue fixed by commit cd823db8b1161ef0d756514d280715a576d65cc3, > > "pca954x power-on default is channel 0 connected. If multiple pca954x > muxes are connected to the same physical I2C bus, the parent bus will > see channel 0 devices behind both muxes by default." > > What's more, when resume bootloader may also operate the mux, so the > the channel connected after that may not be the one driver thought. > > We fix this problem by putting the mux to disconnected state and > clearing last_chan in the resume hook. > > Signed-off-by: Jisheng Zhang > --- > drivers/i2c/muxes/i2c-mux-pca954x.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c > index 9bd4212..c8c3d58 100644 > --- a/drivers/i2c/muxes/i2c-mux-pca954x.c > +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c > @@ -273,9 +273,23 @@ static int pca954x_remove(struct i2c_client *client) > return 0; > } > > +#ifdef CONFIG_PM_SLEEP > +static int pca954x_resume(struct device *dev) > +{ > + struct i2c_client *client = to_i2c_client(dev); > + struct pca954x *data = i2c_get_clientdata(client); > + > + data->last_chan = 0; > + return i2c_smbus_write_byte(client, 0); > +} > +#endif > + > +static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume); I think you must include for this. Other than this, the change looks reasonable, you can add: Reviewed-by: Jean Delvare (Please note my new e-mail address.) > + > static struct i2c_driver pca954x_driver = { > .driver = { > .name = "pca954x", > + .pm = &pca954x_pm, > .owner = THIS_MODULE, > }, > .probe = pca954x_probe, -- Jean Delvare SUSE L3 Support