1 files changed, 181 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-ixp4xx.c b/drivers/i2c/busses/i2c-ixp4xx.c
new file mode 100644
index 000000000000..8c55eafc3a09
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ixp4xx.c
@@ -0,0 +1,181 @@
+/*
+ * drivers/i2c/i2c-adap-ixp4xx.c
+ *
+ * Intel's IXP4xx XScale NPU chipsets (IXP420, 421, 422, 425) do not have
+ * an on board I2C controller but provide 16 GPIO pins that are often
+ * used to create an I2C bus. This driver provides an i2c_adapter 
+ * interface that plugs in under algo_bit and drives the GPIO pins
+ * as instructed by the alogorithm driver.
+ *
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ *
+ * Copyright (c) 2003-2004 MontaVista Software Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public 
+ * License version 2. This program is licensed "as is" without any 
+ * warranty of any kind, whether express or implied.
+ *
+ * NOTE: Since different platforms will use different GPIO pins for
+ *       I2C, this driver uses an IXP4xx-specific platform_data
+ *       pointer to pass the GPIO numbers to the driver. This 
+ *       allows us to support all the different IXP4xx platforms
+ *       w/o having to put #ifdefs in this driver.
+ *
+ *       See arch/arm/mach-ixp4xx/ixdp425.c for an example of building a 
+ *       device list and filling in the ixp4xx_i2c_pins data structure 
+ *       that is passed as the platform_data to this driver.
+ */
+
+#include <linux/config.h>
+#ifdef CONFIG_I2C_DEBUG_BUS
+#define DEBUG   1
+#endif
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+
+#include <asm/hardware.h>       /* Pick up IXP4xx-specific bits */
+
+static inline int ixp4xx_scl_pin(void *data)
+{
+        return ((struct ixp4xx_i2c_pins*)data)->scl_pin;
+}
+
+static inline int ixp4xx_sda_pin(void *data)
+{
+        return ((struct ixp4xx_i2c_pins*)data)->sda_pin;
+}
+
+static void ixp4xx_bit_setscl(void *data, int val)
+{
+        gpio_line_set(ixp4xx_scl_pin(data), 0);
+        gpio_line_config(ixp4xx_scl_pin(data),
+                val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT );
+}
+
+static void ixp4xx_bit_setsda(void *data, int val)
+{
+        gpio_line_set(ixp4xx_sda_pin(data), 0);
+        gpio_line_config(ixp4xx_sda_pin(data),
+                val ? IXP4XX_GPIO_IN : IXP4XX_GPIO_OUT );
+}
+
+static int ixp4xx_bit_getscl(void *data)
+{
+        int scl;
+
+        gpio_line_config(ixp4xx_scl_pin(data), IXP4XX_GPIO_IN );
+        gpio_line_get(ixp4xx_scl_pin(data), &scl);
+
+        return scl;
+}       
+
+static int ixp4xx_bit_getsda(void *data)
+{
+        int sda;
+
+        gpio_line_config(ixp4xx_sda_pin(data), IXP4XX_GPIO_IN );
+        gpio_line_get(ixp4xx_sda_pin(data), &sda);
+
+        return sda;
+}       
+
+struct ixp4xx_i2c_data {
+        struct ixp4xx_i2c_pins *gpio_pins;
+        struct i2c_adapter adapter;
+        struct i2c_algo_bit_data algo_data;
+};
+
+static int ixp4xx_i2c_remove(struct device *dev)
+{
+        struct platform_device *plat_dev = to_platform_device(dev);
+        struct ixp4xx_i2c_data *drv_data = dev_get_drvdata(&plat_dev->dev);
+
+        dev_set_drvdata(&plat_dev->dev, NULL);
+
+        i2c_bit_del_bus(&drv_data->adapter);
+
+        kfree(drv_data);
+
+        return 0;
+}
+
+static int ixp4xx_i2c_probe(struct device *dev)
+{
+        int err;
+        struct platform_device *plat_dev = to_platform_device(dev);
+        struct ixp4xx_i2c_pins *gpio = plat_dev->dev.platform_data;
+        struct ixp4xx_i2c_data *drv_data = 
+                kmalloc(sizeof(struct ixp4xx_i2c_data), GFP_KERNEL);
+
+        if(!drv_data)
+                return -ENOMEM;
+
+        memzero(drv_data, sizeof(struct ixp4xx_i2c_data));
+        drv_data->gpio_pins = gpio;
+
+        /*
+         * We could make a lot of these structures static, but
+         * certain platforms may have multiple GPIO-based I2C
+         * buses for various device domains, so we need per-device
+         * algo_data->data. 
+         */
+        drv_data->algo_data.data = gpio;
+        drv_data->algo_data.setsda = ixp4xx_bit_setsda;
+        drv_data->algo_data.setscl = ixp4xx_bit_setscl;
+        drv_data->algo_data.getsda = ixp4xx_bit_getsda;
+        drv_data->algo_data.getscl = ixp4xx_bit_getscl;
+        drv_data->algo_data.udelay = 10;
+        drv_data->algo_data.mdelay = 10;
+        drv_data->algo_data.timeout = 100;
+
+        drv_data->adapter.id = I2C_HW_B_IXP4XX;
+        drv_data->adapter.algo_data = &drv_data->algo_data;
+
+        drv_data->adapter.dev.parent = &plat_dev->dev;
+
+        gpio_line_config(gpio->scl_pin, IXP4XX_GPIO_IN);
+        gpio_line_config(gpio->sda_pin, IXP4XX_GPIO_IN);
+        gpio_line_set(gpio->scl_pin, 0);
+        gpio_line_set(gpio->sda_pin, 0);
+
+        if ((err = i2c_bit_add_bus(&drv_data->adapter) != 0)) {
+                printk(KERN_ERR "ERROR: Could not install %s\n", dev->bus_id);
+
+                kfree(drv_data);
+                return err;
+        }
+
+        dev_set_drvdata(&plat_dev->dev, drv_data);
+
+        return 0;
+}
+
+static struct device_driver ixp4xx_i2c_driver = {
+        .name           = "IXP4XX-I2C",
+        .bus            = &platform_bus_type,
+        .probe          = ixp4xx_i2c_probe,
+        .remove         = ixp4xx_i2c_remove,
+};
+
+static int __init ixp4xx_i2c_init(void)
+{
+        return driver_register(&ixp4xx_i2c_driver);
+}
+
+static void __exit ixp4xx_i2c_exit(void)
+{
+        driver_unregister(&ixp4xx_i2c_driver);
+}
+
+module_init(ixp4xx_i2c_init);
+module_exit(ixp4xx_i2c_exit);
+
+MODULE_DESCRIPTION("GPIO-based I2C adapter for IXP4xx systems");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
+