From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabio Estevam Subject: [PATCH v2] i2c: i2c-mxs: Use DMA mode even for small transfers Date: Mon, 1 Jul 2013 18:14:21 -0300 Message-ID: <1372713261-20551-1-git-send-email-festevam@gmail.com> Return-path: Sender: stable-owner@vger.kernel.org To: wsa@the-dreams.de Cc: marex@denx.de, shawn.guo@linaro.org, kernel@pengutronix.de, linux-i2c@vger.kernel.org, alexandre.belloni@free-electrons.com, to-fleischer@t-online.de, Fabio Estevam , stable@vger.kernel.org List-Id: linux-i2c@vger.kernel.org From: Fabio Estevam Recently we have been seing some reports about PIO mode not working properly. - http://www.spinics.net/lists/linux-i2c/msg11985.html - http://marc.info/?l=linux-i2c&m=137235593101385&w=2 - https://lkml.org/lkml/2013/6/24/430 Let's use DMA mode even for small transfers. Without this patch, i2c reads the incorrect sgtl5000 version on a mx28evk when touchscreen is enabled: [ 5.856270] sgtl5000 0-000a: Device with ID register 0 is not a sgtl5000 [ 9.877307] sgtl5000 0-000a: ASoC: failed to probe CODEC -19 [ 9.883528] mxs-sgtl5000 sound.12: ASoC: failed to instantiate card -19 [ 9.892955] mxs-sgtl5000 sound.12: snd_soc_register_card failed (-19) Cc: Signed-off-by: Fabio Estevam --- Applies against 3.10 Changes since v1: - Keep the PIO code drivers/i2c/busses/i2c-mxs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c index 2039f23..6d8094d 100644 --- a/drivers/i2c/busses/i2c-mxs.c +++ b/drivers/i2c/busses/i2c-mxs.c @@ -494,7 +494,7 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, * based on this empirical measurement and a lot of previous frobbing. */ i2c->cmd_err = 0; - if (msg->len < 8) { + if (0) { /* disable PIO mode until a proper fix is made */ ret = mxs_i2c_pio_setup_xfer(adap, msg, flags); if (ret) mxs_i2c_reset(i2c); -- 1.8.1.2