diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-ixp2000.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-ixp2000.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-ixp2000.c b/drivers/i2c/busses/i2c-ixp2000.c new file mode 100644 index 000000000000..21cd54d02302 --- /dev/null +++ b/drivers/i2c/busses/i2c-ixp2000.c @@ -0,0 +1,171 @@ +/* + * drivers/i2c/busses/i2c-ixp2000.c + * + * I2C adapter for IXP2000 systems using GPIOs for I2C bus + * + * Author: Deepak Saxena <dsaxena@plexity.net> + * Based on IXDP2400 code by: Naeem M. Afzal <naeem.m.afzal@intel.com> + * Made generic by: Jeff Daly <jeffrey.daly@intel.com> + * + * 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. + * + * From Jeff Daly: + * + * I2C adapter driver for Intel IXDP2xxx platforms. This should work for any + * IXP2000 platform if it uses the HW GPIO in the same manner. Basically, + * SDA and SCL GPIOs have external pullups. Setting the respective GPIO to + * an input will make the signal a '1' via the pullup. Setting them to + * outputs will pull them down. + * + * The GPIOs are open drain signals and are used as configuration strap inputs + * during power-up so there's generally a buffer on the board that needs to be + * 'enabled' to drive the GPIOs. + */ + +#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 IXP42000-specific bits */ + +static inline int ixp2000_scl_pin(void *data) +{ + return ((struct ixp2000_i2c_pins*)data)->scl_pin; +} + +static inline int ixp2000_sda_pin(void *data) +{ + return ((struct ixp2000_i2c_pins*)data)->sda_pin; +} + + +static void ixp2000_bit_setscl(void *data, int val) +{ + int i = 5000; + + if (val) { + gpio_line_config(ixp2000_scl_pin(data), GPIO_IN); + while(!gpio_line_get(ixp2000_scl_pin(data)) && i--); + } else { + gpio_line_config(ixp2000_scl_pin(data), GPIO_OUT); + } +} + +static void ixp2000_bit_setsda(void *data, int val) +{ + if (val) { + gpio_line_config(ixp2000_sda_pin(data), GPIO_IN); + } else { + gpio_line_config(ixp2000_sda_pin(data), GPIO_OUT); + } +} + +static int ixp2000_bit_getscl(void *data) +{ + return gpio_line_get(ixp2000_scl_pin(data)); +} + +static int ixp2000_bit_getsda(void *data) +{ + return gpio_line_get(ixp2000_sda_pin(data)); +} + +struct ixp2000_i2c_data { + struct ixp2000_i2c_pins *gpio_pins; + struct i2c_adapter adapter; + struct i2c_algo_bit_data algo_data; +}; + +static int ixp2000_i2c_remove(struct device *dev) +{ + struct platform_device *plat_dev = to_platform_device(dev); + struct ixp2000_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 ixp2000_i2c_probe(struct device *dev) +{ + int err; + struct platform_device *plat_dev = to_platform_device(dev); + struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data; + struct ixp2000_i2c_data *drv_data = + kmalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL); + + if (!drv_data) + return -ENOMEM; + memzero(drv_data, sizeof(*drv_data)); + drv_data->gpio_pins = gpio; + + drv_data->algo_data.data = gpio; + drv_data->algo_data.setsda = ixp2000_bit_setsda; + drv_data->algo_data.setscl = ixp2000_bit_setscl; + drv_data->algo_data.getsda = ixp2000_bit_getsda; + drv_data->algo_data.getscl = ixp2000_bit_getscl; + drv_data->algo_data.udelay = 6; + drv_data->algo_data.mdelay = 6; + drv_data->algo_data.timeout = 100; + + drv_data->adapter.id = I2C_HW_B_IXP2000, + drv_data->adapter.algo_data = &drv_data->algo_data, + + drv_data->adapter.dev.parent = &plat_dev->dev; + + gpio_line_config(gpio->sda_pin, GPIO_IN); + gpio_line_config(gpio->scl_pin, 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) { + dev_err(dev, "Could not install, error %d\n", err); + kfree(drv_data); + return err; + } + + dev_set_drvdata(&plat_dev->dev, drv_data); + + return 0; +} + +static struct device_driver ixp2000_i2c_driver = { + .name = "IXP2000-I2C", + .bus = &platform_bus_type, + .probe = ixp2000_i2c_probe, + .remove = ixp2000_i2c_remove, +}; + +static int __init ixp2000_i2c_init(void) +{ + return driver_register(&ixp2000_i2c_driver); +} + +static void __exit ixp2000_i2c_exit(void) +{ + driver_unregister(&ixp2000_i2c_driver); +} + +module_init(ixp2000_i2c_init); +module_exit(ixp2000_i2c_exit); + +MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>"); +MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver"); +MODULE_LICENSE("GPL"); + |