6 files changed, 407 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/i2c/i2c-cbus-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-cbus-gpio.txt
new file mode 100644
index 000000000000..8ce9cd2855b5
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-cbus-gpio.txt
@@ -0,0 +1,27 @@
+Device tree bindings for i2c-cbus-gpio driver
+
+Required properties:
+        - compatible = "i2c-cbus-gpio";
+        - gpios: clk, dat, sel
+        - #address-cells = <1>;
+        - #size-cells = <0>;
+
+Optional properties:
+        - child nodes conforming to i2c bus binding
+
+Example:
+
+i2c@0 {
+        compatible = "i2c-cbus-gpio";
+        gpios = <&gpio 66 0 /* clk */
+                 &gpio 65 0 /* dat */
+                 &gpio 64 0 /* sel */
+                >;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        retu-mfd: retu@1 {
+                compatible = "retu-mfd";
+                reg = <0x1>;
+        };
+};
diff --git a/arch/arm/mach-omap2/board-n8x0.c b/arch/arm/mach-omap2/board-n8x0.c
index d95f727ca39a..bbfd74263c42 100644
--- a/arch/arm/mach-omap2/board-n8x0.c
+++ b/arch/arm/mach-omap2/board-n8x0.c
@@ -16,10 +16,12 @@
 #include <linux/gpio.h>
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/irq.h>
 #include <linux/stddef.h>
 #include <linux/i2c.h>
 #include <linux/spi/spi.h>
 #include <linux/usb/musb.h>
+#include <linux/platform_data/i2c-cbus-gpio.h>
 #include <linux/platform_data/spi-omap2-mcspi.h>
 #include <linux/platform_data/mtd-onenand-omap2.h>
 #include <sound/tlv320aic3x.h>
@@ -39,6 +41,45 @@
 #define TUSB6010_GPIO_ENABLE    0
 #define TUSB6010_DMACHAN        0x3f
 
+#if defined(CONFIG_I2C_CBUS_GPIO) || defined(CONFIG_I2C_CBUS_GPIO_MODULE)
+static struct i2c_cbus_platform_data n8x0_cbus_data = {
+        .clk_gpio = 66,
+        .dat_gpio = 65,
+        .sel_gpio = 64,
+};
+
+static struct platform_device n8x0_cbus_device = {
+        .name   = "i2c-cbus-gpio",
+        .id     = 3,
+        .dev    = {
+                .platform_data = &n8x0_cbus_data,
+        },
+};
+
+static struct i2c_board_info n8x0_i2c_board_info_3[] __initdata = {
+        {
+                I2C_BOARD_INFO("retu-mfd", 0x01),
+        },
+};
+
+static void __init n8x0_cbus_init(void)
+{
+        const int retu_irq_gpio = 108;
+
+        if (gpio_request_one(retu_irq_gpio, GPIOF_IN, "Retu IRQ"))
+                return;
+        irq_set_irq_type(gpio_to_irq(retu_irq_gpio), IRQ_TYPE_EDGE_RISING);
+        n8x0_i2c_board_info_3[0].irq = gpio_to_irq(retu_irq_gpio);
+        i2c_register_board_info(3, n8x0_i2c_board_info_3,
+                                ARRAY_SIZE(n8x0_i2c_board_info_3));
+        platform_device_register(&n8x0_cbus_device);
+}
+#else /* CONFIG_I2C_CBUS_GPIO */
+static void __init n8x0_cbus_init(void)
+{
+}
+#endif /* CONFIG_I2C_CBUS_GPIO */
+
 #if defined(CONFIG_USB_MUSB_TUSB6010) || defined(CONFIG_USB_MUSB_TUSB6010_MODULE)
 /*
  * Enable or disable power to TUSB6010. When enabling, turn on 3.3 V and
@@ -677,6 +718,7 @@ static void __init n8x0_init_machine(void)
         gpmc_onenand_init(board_onenand_data);
         n8x0_mmc_init();
         n8x0_usb_init();
+        n8x0_cbus_init();
 }
 
 MACHINE_START(NOKIA_N800, "Nokia N800")
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index e9df4612b7eb..e949edf644d4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -337,6 +337,16 @@ config I2C_BLACKFIN_TWI_CLK_KHZ
         help
           The unit of the TWI clock is kHz.
 
+config I2C_CBUS_GPIO
+        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-gpio.
+
 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 395b516ffa08..f9e3e0b5c827 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-$(CONFIG_I2C_CBUS_GPIO)     += i2c-cbus-gpio.o
 obj-$(CONFIG_I2C_CPM)           += i2c-cpm.o
 obj-$(CONFIG_I2C_DAVINCI)       += i2c-davinci.o
 obj-$(CONFIG_I2C_DESIGNWARE_CORE)       += i2c-designware-core.o
diff --git a/drivers/i2c/busses/i2c-cbus-gpio.c b/drivers/i2c/busses/i2c-cbus-gpio.c
new file mode 100644
index 000000000000..98386d659318
--- /dev/null
+++ b/drivers/i2c/busses/i2c-cbus-gpio.c
@@ -0,0 +1,300 @@
+/*
+ * 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 <linux/io.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/i2c-cbus-gpio.h>
+
+/*
+ * Bit counts are derived from Nokia implementation. These should be checked
+ * if other CBUS implementations appear.
+ */
+#define CBUS_ADDR_BITS  3
+#define CBUS_REG_BITS   5
+
+struct cbus_host {
+        spinlock_t      lock;           /* host 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
+ */
+static void cbus_send_bit(struct cbus_host *host, unsigned bit)
+{
+        gpio_set_value(host->dat_gpio, bit ? 1 : 0);
+        gpio_set_value(host->clk_gpio, 1);
+        gpio_set_value(host->clk_gpio, 0);
+}
+
+/**
+ * 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
+ */
+static void cbus_send_data(struct cbus_host *host, unsigned data, unsigned len)
+{
+        int i;
+
+        for (i = len; i > 0; i--)
+                cbus_send_bit(host, data & (1 << (i - 1)));
+}
+
+/**
+ * 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);
+        gpio_set_value(host->clk_gpio, 0);
+        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)
+                        return bit;
+
+                if (bit)
+                        ret |= 1 << (i - 1);
+        }
+        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 */
+        cbus_send_data(host, dev, CBUS_ADDR_BITS);
+
+        /* Send the rw flag */
+        cbus_send_bit(host, rw == I2C_SMBUS_READ);
+
+        /* Send the register address */
+        cbus_send_data(host, reg, CBUS_REG_BITS);
+
+        if (rw == I2C_SMBUS_WRITE) {
+                cbus_send_data(host, data, 16);
+                ret = 0;
+        } else {
+                ret = gpio_direction_input(host->dat_gpio);
+                if (ret) {
+                        dev_dbg(host->dev, "failed setting direction\n");
+                        goto out;
+                }
+                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);
+
+        return i2c_del_adapter(adapter);
+}
+
+static int cbus_i2c_probe(struct platform_device *pdev)
+{
+        struct i2c_adapter *adapter;
+        struct cbus_host *chost;
+        int ret;
+
+        adapter = devm_kzalloc(&pdev->dev, sizeof(struct i2c_adapter),
+                               GFP_KERNEL);
+        if (!adapter)
+                return -ENOMEM;
+
+        chost = devm_kzalloc(&pdev->dev, sizeof(*chost), GFP_KERNEL);
+        if (!chost)
+                return -ENOMEM;
+
+        if (pdev->dev.of_node) {
+                struct device_node *dnode = pdev->dev.of_node;
+                if (of_gpio_count(dnode) != 3)
+                        return -ENODEV;
+                chost->clk_gpio = of_get_gpio(dnode, 0);
+                chost->dat_gpio = of_get_gpio(dnode, 1);
+                chost->sel_gpio = of_get_gpio(dnode, 2);
+        } else if (pdev->dev.platform_data) {
+                struct i2c_cbus_platform_data *pdata = pdev->dev.platform_data;
+                chost->clk_gpio = pdata->clk_gpio;
+                chost->dat_gpio = pdata->dat_gpio;
+                chost->sel_gpio = pdata->sel_gpio;
+        } else {
+                return -ENODEV;
+        }
+
+        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;
+
+        ret = devm_gpio_request_one(&pdev->dev, chost->clk_gpio,
+                                    GPIOF_OUT_INIT_LOW, "CBUS clk");
+        if (ret)
+                return ret;
+
+        ret = devm_gpio_request_one(&pdev->dev, chost->dat_gpio, GPIOF_IN,
+                                    "CBUS data");
+        if (ret)
+                return ret;
+
+        ret = devm_gpio_request_one(&pdev->dev, chost->sel_gpio,
+                                    GPIOF_OUT_INIT_HIGH, "CBUS sel");
+        if (ret)
+                return ret;
+
+        i2c_set_adapdata(adapter, chost);
+        platform_set_drvdata(pdev, adapter);
+
+        return i2c_add_numbered_adapter(adapter);
+}
+
+#if defined(CONFIG_OF)
+static const struct of_device_id i2c_cbus_dt_ids[] = {
+        { .compatible = "i2c-cbus-gpio", },
+        { }
+};
+MODULE_DEVICE_TABLE(of, i2c_cbus_dt_ids);
+#endif
+
+static struct platform_driver cbus_i2c_driver = {
+        .probe  = cbus_i2c_probe,
+        .remove = cbus_i2c_remove,
+        .driver = {
+                .owner  = THIS_MODULE,
+                .name   = "i2c-cbus-gpio",
+        },
+};
+module_platform_driver(cbus_i2c_driver);
+
+MODULE_ALIAS("platform:i2c-cbus-gpio");
+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 <aaro.koskinen@iki.fi>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_data/i2c-cbus-gpio.h b/include/linux/platform_data/i2c-cbus-gpio.h
new file mode 100644
index 000000000000..6faa992a9502
--- /dev/null
+++ b/include/linux/platform_data/i2c-cbus-gpio.h
@@ -0,0 +1,27 @@
+/*
+ * i2c-cbus-gpio.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_GPIO_H
+#define __INCLUDE_LINUX_I2C_CBUS_GPIO_H
+
+struct i2c_cbus_platform_data {
+        int dat_gpio;
+        int clk_gpio;
+        int sel_gpio;
+};
+
+#endif /* __INCLUDE_LINUX_I2C_CBUS_GPIO_H */