From patchwork Tue Aug 28 21:34:23 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Aaro Koskinen X-Patchwork-Id: 1382541 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id A1783DF283 for ; Tue, 28 Aug 2012 21:34:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753359Ab2H1Vee (ORCPT ); Tue, 28 Aug 2012 17:34:34 -0400 Received: from filtteri2.pp.htv.fi ([213.243.153.185]:43267 "EHLO filtteri2.pp.htv.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753231Ab2H1Vea (ORCPT ); Tue, 28 Aug 2012 17:34:30 -0400 Received: from localhost (localhost [127.0.0.1]) by filtteri2.pp.htv.fi (Postfix) with ESMTP id 2B06D19B7D4; Wed, 29 Aug 2012 00:34:28 +0300 (EEST) X-Virus-Scanned: Debian amavisd-new at pp.htv.fi Received: from smtp6.welho.com ([213.243.153.40]) by localhost (filtteri2.pp.htv.fi [213.243.153.185]) (amavisd-new, port 10024) with ESMTP id HX3E-FzhmMiQ; Wed, 29 Aug 2012 00:34:27 +0300 (EEST) Received: from blackmetal.bb.dnainternet.fi (212-149-209-232.bb.dnainternet.fi [212.149.209.232]) by smtp6.welho.com (Postfix) with ESMTP id A72CF5BC005; Wed, 29 Aug 2012 00:34:27 +0300 (EEST) From: Aaro Koskinen To: linux-omap@vger.kernel.org Cc: linux-i2c@vger.kernel.org Subject: =?UTF-8?q?=5BRFC=20PATCH=201/5=5D=20i2c=3A=20introduce=20i2c-cbus=20driver?= Date: Wed, 29 Aug 2012 00:34:23 +0300 Message-Id: <1346189667-32330-2-git-send-email-aaro.koskinen@iki.fi> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1346189667-32330-1-git-send-email-aaro.koskinen@iki.fi> References: <1346189667-32330-1-git-send-email-aaro.koskinen@iki.fi> MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org Add i2c driver to enable access to devices behind CBUS on Nokia Internet Tablets. Signed-off-by: Aaro Koskinen Cc: linux-i2c@vger.kernel.org Acked-by: Tony Lindgren Acked-by: Felipe Balbi --- drivers/i2c/busses/Kconfig | 10 ++ drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-cbus.c | 342 +++++++++++++++++++++++++++++++++++++++++ include/linux/i2c-cbus.h | 27 ++++ 4 files changed, 380 insertions(+), 0 deletions(-) create mode 100644 drivers/i2c/busses/i2c-cbus.c create mode 100644 include/linux/i2c-cbus.h diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index b4aaa1b..184ef43 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -331,6 +331,16 @@ config I2C_BLACKFIN_TWI_CLK_KHZ help The unit of the TWI clock is kHz. +config I2C_CBUS + tristate "CBUS I2C driver" + depends on GENERIC_GPIO + help + Support for CBUS access using I2C API. Mostly relevant for Nokia + Internet Tablets (770, N800 and N810). + + This driver can also be built as a module. If so, the module + will be called i2c-cbus. + config I2C_CPM tristate "Freescale CPM1 or CPM2 (MPC8xx/826x)" depends on (CPM1 || CPM2) && OF_I2C diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index ce3c2be..44dbfd1 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -31,6 +31,7 @@ obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o obj-$(CONFIG_I2C_AT91) += i2c-at91.o obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o +obj-$(CONFIG_I2C_CBUS) += i2c-cbus.o obj-$(CONFIG_I2C_CPM) += i2c-cpm.o obj-$(CONFIG_I2C_DAVINCI) += i2c-davinci.o obj-$(CONFIG_I2C_DESIGNWARE_PLATFORM) += i2c-designware-platform.o diff --git a/drivers/i2c/busses/i2c-cbus.c b/drivers/i2c/busses/i2c-cbus.c new file mode 100644 index 0000000..3cc5be4 --- /dev/null +++ b/drivers/i2c/busses/i2c-cbus.c @@ -0,0 +1,342 @@ +/* + * CBUS I2C driver for Nokia Internet Tablets. + * + * Copyright (C) 2004-2010 Nokia Corporation + * + * Based on code written by Juha Yrjölä, David Weinehall, Mikko Ylinen and + * Felipe Balbi. Converted to I2C driver by Aaro Koskinen. + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file "COPYING" in the main directory of this + * archive for more details. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct cbus_host { + /* host lock */ + spinlock_t lock; + + struct device *dev; + + int clk_gpio; + int dat_gpio; + int sel_gpio; +}; + +/** + * cbus_send_bit - sends one bit over the bus + * @host: the host we're using + * @bit: one bit of information to send + * @input: whether to set data pin as input after sending + */ +static int cbus_send_bit(struct cbus_host *host, unsigned bit, + unsigned input) +{ + int ret = 0; + + gpio_set_value(host->dat_gpio, bit ? 1 : 0); + gpio_set_value(host->clk_gpio, 1); + + /* The data bit is read on the rising edge of CLK */ + if (input) + ret = gpio_direction_input(host->dat_gpio); + + gpio_set_value(host->clk_gpio, 0); + + return ret; +} + +/** + * cbus_send_data - sends @len amount of data over the bus + * @host: the host we're using + * @data: the data to send + * @len: size of the transfer + * @input: whether to set data pin as input after sending + */ +static int cbus_send_data(struct cbus_host *host, unsigned data, unsigned len, + unsigned input) +{ + int ret = 0; + int i; + + for (i = len; i > 0; i--) { + ret = cbus_send_bit(host, data & (1 << (i - 1)), + input && (i == 1)); + if (ret < 0) + goto out; + } + +out: + return ret; +} + +/** + * cbus_receive_bit - receives one bit from the bus + * @host: the host we're using + */ +static int cbus_receive_bit(struct cbus_host *host) +{ + int ret; + + gpio_set_value(host->clk_gpio, 1); + ret = gpio_get_value(host->dat_gpio); + if (ret < 0) + goto out; + gpio_set_value(host->clk_gpio, 0); + +out: + return ret; +} + +/** + * cbus_receive_word - receives 16-bit word from the bus + * @host: the host we're using + */ +static int cbus_receive_word(struct cbus_host *host) +{ + int ret = 0; + int i; + + for (i = 16; i > 0; i--) { + int bit = cbus_receive_bit(host); + + if (bit < 0) + goto out; + + if (bit) + ret |= 1 << (i - 1); + } + +out: + return ret; +} + +/** + * cbus_transfer - transfers data over the bus + * @host: the host we're using + * @rw: read/write flag + * @dev: device address + * @reg: register address + * @data: if @rw == I2C_SBUS_WRITE data to send otherwise 0 + */ +static int cbus_transfer(struct cbus_host *host, char rw, unsigned dev, + unsigned reg, unsigned data) +{ + unsigned long flags; + int ret; + + /* We don't want interrupts disturbing our transfer */ + spin_lock_irqsave(&host->lock, flags); + + /* Reset state and start of transfer, SEL stays down during transfer */ + gpio_set_value(host->sel_gpio, 0); + + /* Set the DAT pin to output */ + gpio_direction_output(host->dat_gpio, 1); + + /* Send the device address */ + ret = cbus_send_data(host, dev, 3, 0); + if (ret < 0) { + dev_dbg(host->dev, "failed sending device addr\n"); + goto out; + } + + /* Send the rw flag */ + ret = cbus_send_bit(host, rw == I2C_SMBUS_READ, 0); + if (ret < 0) { + dev_dbg(host->dev, "failed sending read/write flag\n"); + goto out; + } + + /* Send the device address */ + ret = cbus_send_data(host, reg, 5, rw == I2C_SMBUS_READ); + if (ret < 0) { + dev_dbg(host->dev, "failed sending register addr\n"); + goto out; + } + + if (rw == I2C_SMBUS_WRITE) { + ret = cbus_send_data(host, data, 16, 0); + if (ret < 0) { + dev_dbg(host->dev, "failed sending data\n"); + goto out; + } + } else { + gpio_set_value(host->clk_gpio, 1); + + ret = cbus_receive_word(host); + if (ret < 0) { + dev_dbg(host->dev, "failed receiving data\n"); + goto out; + } + } + + /* Indicate end of transfer, SEL goes up until next transfer */ + gpio_set_value(host->sel_gpio, 1); + gpio_set_value(host->clk_gpio, 1); + gpio_set_value(host->clk_gpio, 0); + +out: + spin_unlock_irqrestore(&host->lock, flags); + + return ret; +} + +static int cbus_i2c_smbus_xfer(struct i2c_adapter *adapter, + u16 addr, + unsigned short flags, + char read_write, + u8 command, + int size, + union i2c_smbus_data *data) +{ + struct cbus_host *chost = i2c_get_adapdata(adapter); + int ret; + + if (size != I2C_SMBUS_WORD_DATA) + return -EINVAL; + + ret = cbus_transfer(chost, read_write == I2C_SMBUS_READ, addr, + command, data->word); + if (ret < 0) + return ret; + + if (read_write == I2C_SMBUS_READ) + data->word = ret; + + return 0; +} + +static u32 cbus_i2c_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_SMBUS_READ_WORD_DATA | I2C_FUNC_SMBUS_WRITE_WORD_DATA; +} + +static const struct i2c_algorithm cbus_i2c_algo = { + .smbus_xfer = cbus_i2c_smbus_xfer, + .functionality = cbus_i2c_func, +}; + +static int cbus_i2c_remove(struct platform_device *pdev) +{ + struct i2c_adapter *adapter = platform_get_drvdata(pdev); + struct cbus_host *chost = i2c_get_adapdata(adapter); + int ret; + + ret = i2c_del_adapter(adapter); + if (ret) + return ret; + gpio_free(chost->clk_gpio); + gpio_free(chost->dat_gpio); + gpio_free(chost->sel_gpio); + kfree(chost); + kfree(adapter); + platform_set_drvdata(pdev, NULL); + + return 0; +} + +static int cbus_i2c_probe(struct platform_device *pdev) +{ + struct i2c_cbus_platform_data *pdata = pdev->dev.platform_data; + struct i2c_adapter *adapter; + struct cbus_host *chost; + struct gpio gpios[3]; + int ret; + + adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL); + if (!adapter) { + ret = -ENOMEM; + goto error; + } + + chost = kzalloc(sizeof(*chost), GFP_KERNEL); + if (!chost) { + ret = -ENOMEM; + goto error_mem; + } + + adapter->owner = THIS_MODULE; + adapter->class = I2C_CLASS_HWMON; + adapter->dev.parent = &pdev->dev; + adapter->nr = pdev->id; + adapter->timeout = HZ; + adapter->algo = &cbus_i2c_algo; + strlcpy(adapter->name, "CBUS I2C adapter", sizeof(adapter->name)); + + spin_lock_init(&chost->lock); + chost->dev = &pdev->dev; + + gpios[0].gpio = chost->clk_gpio = pdata->clk_gpio; + gpios[0].flags = GPIOF_OUT_INIT_LOW; + gpios[0].label = "CBUS clk"; + + gpios[1].gpio = chost->dat_gpio = pdata->dat_gpio; + gpios[1].flags = GPIOF_IN; + gpios[1].label = "CBUS data"; + + gpios[2].gpio = chost->sel_gpio = pdata->sel_gpio; + gpios[2].flags = GPIOF_OUT_INIT_HIGH; + gpios[2].label = "CBUS sel"; + + ret = gpio_request_array(gpios, ARRAY_SIZE(gpios)); + if (ret) + goto error_gpio; + + gpio_set_value(chost->clk_gpio, 1); + gpio_set_value(chost->clk_gpio, 0); + + i2c_set_adapdata(adapter, chost); + platform_set_drvdata(pdev, adapter); + + ret = i2c_add_numbered_adapter(adapter); + if (ret) + goto error_i2c; + + return 0; + +error_i2c: + gpio_free_array(gpios, ARRAY_SIZE(gpios)); +error_gpio: + kfree(chost); +error_mem: + kfree(adapter); +error: + return ret; +} + +static struct platform_driver cbus_i2c_driver = { + .probe = cbus_i2c_probe, + .remove = cbus_i2c_remove, + .driver = { + .owner = THIS_MODULE, + .name = "i2c-cbus", + }, +}; +module_platform_driver(cbus_i2c_driver); + +MODULE_ALIAS("platform:i2c-cbus"); +MODULE_DESCRIPTION("CBUS I2C driver"); +MODULE_AUTHOR("Juha Yrjölä"); +MODULE_AUTHOR("David Weinehall"); +MODULE_AUTHOR("Mikko Ylinen"); +MODULE_AUTHOR("Felipe Balbi "); +MODULE_AUTHOR("Aaro Koskinen "); +MODULE_LICENSE("GPL"); diff --git a/include/linux/i2c-cbus.h b/include/linux/i2c-cbus.h new file mode 100644 index 0000000..636d726 --- /dev/null +++ b/include/linux/i2c-cbus.h @@ -0,0 +1,27 @@ +/* + * i2c-cbus.h - CBUS I2C platform_data definition + * + * Copyright (C) 2004-2009 Nokia Corporation + * + * Written by Felipe Balbi and Aaro Koskinen. + * + * This file is subject to the terms and conditions of the GNU General + * Public License. See the file "COPYING" in the main directory of this + * archive for more details. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef __INCLUDE_LINUX_I2C_CBUS_H +#define __INCLUDE_LINUX_I2C_CBUS_H + +struct i2c_cbus_platform_data { + int dat_gpio; + int clk_gpio; + int sel_gpio; +}; + +#endif /* __INCLUDE_LINUX_I2C_CBUS_H */