Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755836Ab2F1NMb (ORCPT ); Thu, 28 Jun 2012 09:12:31 -0400 Received: from mail-gg0-f202.google.com ([209.85.161.202]:61500 "EHLO mail-gg0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754102Ab2F1NIa (ORCPT ); Thu, 28 Jun 2012 09:08:30 -0400 From: Daniel Kurtz To: Dmitry Torokhov , Henrik Rydberg , Joonyoung Shim , Nick Dyer , Yufeng Shen Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Olof Johansson , Benson Leung , Daniel Kurtz Subject: [PATCH 11/23 v6] Input: atmel_mxt_ts - add variable length __mxt_write_reg Date: Thu, 28 Jun 2012 21:08:12 +0800 Message-Id: <1340888904-15620-12-git-send-email-djkurtz@chromium.org> X-Mailer: git-send-email 1.7.7.3 In-Reply-To: <1340888904-15620-1-git-send-email-djkurtz@chromium.org> References: <1340888904-15620-1-git-send-email-djkurtz@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2102 Lines: 72 The i2c bus requires 4 bytes to do a 1-byte write (1 byte i2c address + 2 byte offset + 1 byte data). By taking a length with writes, the driver can amortize transaction overhead by performing larger transactions where appropriate. This patch just sets up the new API. Later patches refactor writes to take advantage of the larger transactions. Signed-off-by: Daniel Kurtz --- drivers/input/touchscreen/atmel_mxt_ts.c | 23 ++++++++++++++++++----- 1 files changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c index a68b227..dd2577b 100644 --- a/drivers/input/touchscreen/atmel_mxt_ts.c +++ b/drivers/input/touchscreen/atmel_mxt_ts.c @@ -431,17 +431,24 @@ static int mxt_read_reg(struct i2c_client *client, u16 reg, u8 *val) return __mxt_read_reg(client, reg, 1, val); } -static int mxt_write_reg(struct i2c_client *client, u16 reg, u8 val) +static int __mxt_write_reg(struct i2c_client *client, u16 reg, u16 len, + const void *val) { - u8 buf[3]; + u8 *buf; + size_t count; int ret; + count = len + 2; + buf = kmalloc(count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + buf[0] = reg & 0xff; buf[1] = (reg >> 8) & 0xff; - buf[2] = val; + memcpy(&buf[2], val, len); - ret = i2c_master_send(client, buf, 3); - if (ret == 3) { + ret = i2c_master_send(client, buf, count); + if (ret == count) { ret = 0; } else { if (ret >= 0) @@ -450,9 +457,15 @@ static int mxt_write_reg(struct i2c_client *client, u16 reg, u8 val) __func__, ret); } + kfree(buf); return ret; } +static int mxt_write_reg(struct i2c_client *client, u16 reg, u8 val) +{ + return __mxt_write_reg(client, reg, 1, &val); +} + static int mxt_read_object_table(struct i2c_client *client, u16 reg, u8 *object_buf) { -- 1.7.7.3 -- 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/