From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966086AbbBCSBk (ORCPT ); Tue, 3 Feb 2015 13:01:40 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:58101 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933924AbbBCSBg (ORCPT ); Tue, 3 Feb 2015 13:01:36 -0500 From: Guenter Roeck To: Mark Brown Cc: linux-kernel@vger.kernel.org, Guenter Roeck , Jean Delvare Subject: [PATCH v2 2/2] regmap: Fix i2c word access when using SMBus access functions Date: Tue, 3 Feb 2015 10:01:19 -0800 Message-Id: <1422986479-14723-2-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1422986479-14723-1-git-send-email-linux@roeck-us.net> References: <1422986479-14723-1-git-send-email-linux@roeck-us.net> 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=0001.0A020202.54D10CFD.02CE,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: 5 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 if a chip is configured as REGMAP_ENDIAN_BIG. If the chip is configured as REGMAP_ENDIAN_LITTLE, keep using regmap_smbus_write_word_data and regmap_smbus_read_word_data. Otherwise reject registration if the controller does not support direct i2c accesses. Cc: Jean Delvare Signed-off-by: Guenter Roeck --- v2: SMBUs -> SMBus, 16 bit -> 16-bit in commit log Use regmap_get_val_endian to get configured chip endianness Only accept REGMAP_ENDIAN_LITTLE and REGMAP_ENDIAN_BIG for SMBus 16-bit accesses drivers/base/regmap/regmap-i2c.c | 46 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 45 insertions(+), 1 deletion(-) diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c index 053150a..4b76e33 100644 --- a/drivers/base/regmap/regmap-i2c.c +++ b/drivers/base/regmap/regmap-i2c.c @@ -14,6 +14,7 @@ #include #include +#include "internal.h" static int regmap_smbus_byte_reg_read(void *context, unsigned int reg, unsigned int *val) @@ -87,6 +88,42 @@ 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 +217,14 @@ 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; + switch (regmap_get_val_endian(&i2c->dev, NULL, config)) { + case REGMAP_ENDIAN_LITTLE: + return ®map_smbus_word; + case REGMAP_ENDIAN_BIG: + return ®map_smbus_word_swapped; + default: /* everything else is not supported */ + break; + } else if (config->val_bits == 8 && config->reg_bits == 8 && i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) -- 2.1.0