From patchwork Fri Apr 18 20:11:41 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris BREZILLON X-Patchwork-Id: 4018441 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EE588BFF02 for ; Fri, 18 Apr 2014 20:14:44 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C7F4B203AB for ; Fri, 18 Apr 2014 20:14:43 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 95D37203AA for ; Fri, 18 Apr 2014 20:14:42 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WbF8t-0004Px-3O; Fri, 18 Apr 2014 20:12:11 +0000 Received: from top.free-electrons.com ([176.31.233.9] helo=mail.free-electrons.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WbF8q-0004Iu-8k for linux-arm-kernel@lists.infradead.org; Fri, 18 Apr 2014 20:12:09 +0000 Received: by mail.free-electrons.com (Postfix, from userid 106) id 579727D9; Fri, 18 Apr 2014 22:11:51 +0200 (CEST) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from localhost.localdomain (col31-4-88-188-80-5.fbx.proxad.net [88.188.80.5]) by mail.free-electrons.com (Postfix) with ESMTPSA id 618177A0; Fri, 18 Apr 2014 22:11:50 +0200 (CEST) From: Boris BREZILLON To: Mark Brown Subject: [PATCH v3] regmap: i2c: fallback to SMBus if the adapter does not support standard I2C Date: Fri, 18 Apr 2014 22:11:41 +0200 Message-Id: <1397851901-16390-1-git-send-email-boris.brezillon@free-electrons.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1397727612-32103-1-git-send-email-boris.brezillon@free-electrons.com> References: <1397727612-32103-1-git-send-email-boris.brezillon@free-electrons.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140418_131208_629944_87265DCE X-CRM114-Status: GOOD ( 15.48 ) X-Spam-Score: 0.3 (/) Cc: Boris BREZILLON , Lars-Peter Clausen , dev@linux-sunxi.org, Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Hans de Goede , Chen-Yu Tsai , linux-arm-kernel@lists.infradead.org, Shuge , Maxime Ripard , Carlo Caione , kevin@allwinnertech.com, Guenter Roeck X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Some I2C adapters are only compatible with the SMBus protocol and do not support standard I2C transfers. Fallback to SMBus transfers if we encounter such kind of adapters. The transfer type is chosen according to the val_bits field in the regmap config. Signed-off-by: Boris BREZILLON --- Changes since v2: - fix regmap_get_i2c_bus scope (declare as static) - fix reg width check in reg_read/write functions - add reg_bits check in regmap_get_i2c_bus function - drivers/base/regmap/regmap-i2c.c | 104 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 102 insertions(+), 2 deletions(-) diff --git a/drivers/base/regmap/regmap-i2c.c b/drivers/base/regmap/regmap-i2c.c index ebd1895..0a43211 100644 --- a/drivers/base/regmap/regmap-i2c.c +++ b/drivers/base/regmap/regmap-i2c.c @@ -14,6 +14,79 @@ #include #include + +static int regmap_smbus_byte_reg_read(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_byte_data(i2c, reg); + if (ret < 0) + return ret; + + *val = ret; + + return 0; +} + +static int regmap_smbus_byte_reg_write(void *context, unsigned int reg, + unsigned int val) +{ + struct device *dev = context; + struct i2c_client *i2c = to_i2c_client(dev); + + if (val > 0xff || reg > 0xff) + return -EINVAL; + + return i2c_smbus_write_byte_data(i2c, reg, val); +} + +static struct regmap_bus regmap_smbus_byte = { + .reg_write = regmap_smbus_byte_reg_write, + .reg_read = regmap_smbus_byte_reg_read, +}; + +static int regmap_smbus_word_reg_read(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_data(i2c, reg); + if (ret < 0) + return ret; + + *val = ret; + + return 0; +} + +static int regmap_smbus_word_reg_write(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_data(i2c, reg, val); +} + +static struct regmap_bus regmap_smbus_word = { + .reg_write = regmap_smbus_word_reg_write, + .reg_read = regmap_smbus_word_reg_read, +}; + static int regmap_i2c_write(void *context, const void *data, size_t count) { struct device *dev = context; @@ -97,6 +170,23 @@ static struct regmap_bus regmap_i2c = { .read = regmap_i2c_read, }; +static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c, + const struct regmap_config *config) +{ + if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C)) + return ®map_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; + else if (config->val_bits == 8 && config->reg_bits == 8 && + i2c_check_functionality(i2c->adapter, + I2C_FUNC_SMBUS_BYTE_DATA)) + return ®map_smbus_byte; + + return ERR_PTR(-ENOTSUPP); +} + /** * regmap_init_i2c(): Initialise register map * @@ -109,7 +199,12 @@ static struct regmap_bus regmap_i2c = { struct regmap *regmap_init_i2c(struct i2c_client *i2c, const struct regmap_config *config) { - return regmap_init(&i2c->dev, ®map_i2c, &i2c->dev, config); + const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config); + + if (IS_ERR(bus)) + return ERR_PTR(PTR_ERR(bus)); + + return regmap_init(&i2c->dev, bus, &i2c->dev, config); } EXPORT_SYMBOL_GPL(regmap_init_i2c); @@ -126,7 +221,12 @@ EXPORT_SYMBOL_GPL(regmap_init_i2c); struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c, const struct regmap_config *config) { - return devm_regmap_init(&i2c->dev, ®map_i2c, &i2c->dev, config); + const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config); + + if (IS_ERR(bus)) + return ERR_PTR(PTR_ERR(bus)); + + return devm_regmap_init(&i2c->dev, bus, &i2c->dev, config); } EXPORT_SYMBOL_GPL(devm_regmap_init_i2c);