Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932135Ab3FER7w (ORCPT ); Wed, 5 Jun 2013 13:59:52 -0400 Received: from kdh-gw.itdev.co.uk ([89.21.227.133]:58795 "EHLO hermes.kdh.itdev.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757086Ab3FERsL (ORCPT ); Wed, 5 Jun 2013 13:48:11 -0400 From: Nick Dyer To: Dmitry Torokhov , Daniel Kurtz , Henrik Rydberg , Joonyoung Shim , Alan.Bowens@atmel.com, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, pmeerw@pmeerw.net, bleung@chromium.org, olofj@chromium.org Cc: Nick Dyer Subject: [PATCH 40/53] Input: atmel_mxt_ts - implement I2C retries Date: Wed, 5 Jun 2013 18:37:33 +0100 Message-Id: <1370453866-16534-41-git-send-email-nick.dyer@itdev.co.uk> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1370453866-16534-1-git-send-email-nick.dyer@itdev.co.uk> References: <1370453866-16534-1-git-send-email-nick.dyer@itdev.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2980 Lines: 105 Some maXTouch chips (eg mXT1386) will not respond on the first I2C request when they are in a sleep state. It must be retried after a delay for the chip to wake up. Signed-off-by: Nick Dyer --- drivers/input/touchscreen/atmel_mxt_ts.c | 45 ++++++++++++++++++++---------- 1 file changed, 30 insertions(+), 15 deletions(-) diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c index bd8971e..5a195be 100644 --- a/drivers/input/touchscreen/atmel_mxt_ts.c +++ b/drivers/input/touchscreen/atmel_mxt_ts.c @@ -197,6 +197,7 @@ struct t9_range { #define MXT_CRC_TIMEOUT 1000 /* msec */ #define MXT_FW_RESET_TIME 3000 /* msec */ #define MXT_FW_CHG_TIMEOUT 300 /* msec */ +#define MXT_WAKEUP_TIME 25 /* msec */ /* Command to unlock bootloader */ #define MXT_UNLOCK_CMD_MSB 0xaa @@ -569,6 +570,7 @@ static int __mxt_read_reg(struct i2c_client *client, struct i2c_msg xfer[2]; u8 buf[2]; int ret; + bool retry = false; buf[0] = reg & 0xff; buf[1] = (reg >> 8) & 0xff; @@ -585,17 +587,22 @@ static int __mxt_read_reg(struct i2c_client *client, xfer[1].len = len; xfer[1].buf = val; - ret = i2c_transfer(client->adapter, xfer, 2); - if (ret == 2) { - ret = 0; - } else { - if (ret >= 0) - ret = -EIO; - dev_err(&client->dev, "%s: i2c transfer failed (%d)\n", - __func__, ret); +retry_read: + ret = i2c_transfer(client->adapter, xfer, ARRAY_SIZE(xfer)); + if (ret != ARRAY_SIZE(xfer)) { + if (!retry) { + dev_dbg(&client->dev, "%s: i2c retry\n", __func__); + msleep(MXT_WAKEUP_TIME); + retry = true; + goto retry_read; + } else { + dev_err(&client->dev, "%s: i2c transfer failed (%d)\n", + __func__, ret); + return -EIO; + } } - return ret; + return 0; } static int __mxt_write_reg(struct i2c_client *client, u16 reg, u16 len, @@ -604,6 +611,7 @@ static int __mxt_write_reg(struct i2c_client *client, u16 reg, u16 len, u8 *buf; size_t count; int ret; + bool retry = false; count = len + 2; buf = kmalloc(count, GFP_KERNEL); @@ -614,14 +622,21 @@ static int __mxt_write_reg(struct i2c_client *client, u16 reg, u16 len, buf[1] = (reg >> 8) & 0xff; memcpy(&buf[2], val, len); +retry_write: ret = i2c_master_send(client, buf, count); - if (ret == count) { - ret = 0; - } else { - if (ret >= 0) + if (ret != count) { + if (!retry) { + dev_dbg(&client->dev, "%s: i2c retry\n", __func__); + msleep(MXT_WAKEUP_TIME); + retry = true; + goto retry_write; + } else { + dev_err(&client->dev, "%s: i2c send failed (%d)\n", + __func__, ret); ret = -EIO; - dev_err(&client->dev, "%s: i2c send failed (%d)\n", - __func__, ret); + } + } else { + ret = 0; } kfree(buf); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/