From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754367AbbBAXsN (ORCPT ); Sun, 1 Feb 2015 18:48:13 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:56489 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751698AbbBAXsK (ORCPT ); Sun, 1 Feb 2015 18:48:10 -0500 From: Guenter Roeck To: Mark Brown Cc: Robert Rosengren , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Guenter Roeck , Jean Delvare Subject: [PATCH] regmap: Fix i2c word access when using SMBus access functions Date: Sun, 1 Feb 2015 15:48:01 -0800 Message-Id: <1422834481-6936-1-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 2.1.0 X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-CTCH-PVer: 0000001 X-CTCH-Spam: Unknown X-CTCH-VOD: Unknown X-CTCH-Flags: 0 X-CTCH-RefID: str=0001.0A020203.54CEBB39.00F9,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-CTCH-Score: 0.001 X-CTCH-ScoreCust: 0.000 X-CTCH-Rules: C_4847, X-CTCH-SenderID: linux@roeck-us.net X-CTCH-SenderID-Flags: 0 X-CTCH-SenderID-TotalMessages: 7 X-CTCH-SenderID-TotalSpam: 0 X-CTCH-SenderID-TotalSuspected: 0 X-CTCH-SenderID-TotalConfirmed: 0 X-CTCH-SenderID-TotalBulk: 0 X-CTCH-SenderID-TotalVirus: 0 X-CTCH-SenderID-TotalRecipients: 0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: mailgid no entry from get_relayhosts_entry X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org SMBUs access functions assume that 16 bit values are formatted as little endian numbers. The direct i2c access functions in regmap, however, assume that 16 bit values are formatted as big endian numbers. As a result, the current code returns different values if an i2c chip's 16 bit registers are accessed through i2c access functions vs. SMBus access functions. Use regmap_smbus_read_word_swapped and regmap_smbus_write_word_swapped for 16 bit SMBus accesses unless a chip is registered with val_format_endian set to REGMAP_ENDIAN_LITTLE. In the latter case, keep using regmap_smbus_write_word_data and regmap_smbus_read_word_data. Cc: Jean Delvare Signed-off-by: Guenter Roeck --- Might be a candidate for -stable, though as far as I can see there is currently no driver in the upstream kernel using regmap for 16-bit i2c accesses. drivers/base/regmap/regmap-i2c.c | 41 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c index 053150a..865f4f8 100644 --- a/drivers/base/regmap/regmap-i2c.c +++ b/drivers/base/regmap/regmap-i2c.c @@ -87,6 +87,42 @@ static struct regmap_bus regmap_smbus_word = { .reg_read = regmap_smbus_word_reg_read, }; +static int regmap_smbus_word_read_swapped(void *context, unsigned int reg, + unsigned int *val) +{ + struct device *dev = context; + struct i2c_client *i2c = to_i2c_client(dev); + int ret; + + if (reg > 0xff) + return -EINVAL; + + ret = i2c_smbus_read_word_swapped(i2c, reg); + if (ret < 0) + return ret; + + *val = ret; + + return 0; +} + +static int regmap_smbus_word_write_swapped(void *context, unsigned int reg, + unsigned int val) +{ + struct device *dev = context; + struct i2c_client *i2c = to_i2c_client(dev); + + if (val > 0xffff || reg > 0xff) + return -EINVAL; + + return i2c_smbus_write_word_swapped(i2c, reg, val); +} + +static struct regmap_bus regmap_smbus_word_swapped = { + .reg_write = regmap_smbus_word_write_swapped, + .reg_read = regmap_smbus_word_read_swapped, +}; + static int regmap_i2c_write(void *context, const void *data, size_t count) { struct device *dev = context; @@ -180,7 +216,10 @@ static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c, else if (config->val_bits == 16 && config->reg_bits == 8 && i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_WORD_DATA)) - return ®map_smbus_word; + if (config->val_format_endian == REGMAP_ENDIAN_LITTLE) + return ®map_smbus_word; + else + return ®map_smbus_word_swapped; else if (config->val_bits == 8 && config->reg_bits == 8 && i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) -- 2.1.0