ChangeSet 1.1557.61.6, 2004/02/17 15:00:40-08:00, dsaxena@plexity.net [PATCH] I2C: Support for IXP42x GPIO-based I2C Following is an updated patch to add support for using the GPIO lines on an Intel IXP42x SOC for I2C. Changes since last patch include: - Cleanups as per Jean Delvare's comments - Rename functions as 42x instead of 425 - Change the comments at the top of the file to better reflect the purpose of this driver. This code has been tested with the eeprom client driver and worked w/o any problems. drivers/i2c/busses/Kconfig | 11 ++ drivers/i2c/busses/Makefile | 1 drivers/i2c/busses/i2c-ixp42x.c | 180 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 192 insertions(+) diff -Nru a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig --- a/drivers/i2c/busses/Kconfig Mon Mar 15 14:37:32 2004 +++ b/drivers/i2c/busses/Kconfig Mon Mar 15 14:37:32 2004 @@ -144,6 +144,17 @@ This support is also available as a module. If so, the module will be called i2c-ite. +config I2C_IXP42X + tristate "IXP42x GPIO-Based I2C Interface" + depends on I2C && ARCH_IXP425 + select I2C_ALGOBIT + help + Say Y here if you have an Intel IXP42x(420,421,422,425) based + system and are using GPIO lines for an I2C bus. + + This support is also available as a module. If so, the module + will be called i2c-ixp42x. + config I2C_KEYWEST tristate "Powermac Keywest I2C interface" depends on I2C && PPC_PMAC diff -Nru a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile --- a/drivers/i2c/busses/Makefile Mon Mar 15 14:37:32 2004 +++ b/drivers/i2c/busses/Makefile Mon Mar 15 14:37:32 2004 @@ -15,6 +15,7 @@ obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o obj-$(CONFIG_I2C_ISA) += i2c-isa.o obj-$(CONFIG_I2C_ITE) += i2c-ite.o +obj-$(CONFIG_I2C_IXP42X) += i2c-ixp42x.o obj-$(CONFIG_I2C_KEYWEST) += i2c-keywest.o obj-$(CONFIG_I2C_NFORCE2) += i2c-nforce2.o obj-$(CONFIG_I2C_PHILIPSPAR) += i2c-philips-par.o diff -Nru a/drivers/i2c/busses/i2c-ixp42x.c b/drivers/i2c/busses/i2c-ixp42x.c --- /dev/null Wed Dec 31 16:00:00 1969 +++ b/drivers/i2c/busses/i2c-ixp42x.c Mon Mar 15 14:37:32 2004 @@ -0,0 +1,180 @@ +/* + * drivers/i2c/i2c-adap-ixp42x.c + * + * Intel's IXP42x 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 + * + * 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 IXP42x-specific platform_data + * pointer to pass the GPIO numbers to the driver. This + * allows us to support all the different IXP42x platforms + * w/o having to put #ifdefs in this driver. + * + * See arch/arm/mach-ixp42x/ixdp425.c for an example of building a + * device list and filling in the ixp42x_i2c_pins data structure + * that is passed as the platform_data to this driver. + */ + +#include +#ifdef CONFIG_I2C_DEBUG_BUS +#define DEBUG 1 +#endif + +#include +#include +#include +#include +#include + +#include /* Pick up IXP42x-specific bits */ + +static inline int ixp42x_scl_pin(void *data) +{ + return ((struct ixp42x_i2c_pins*)data)->scl_pin; +} + +static inline int ixp42x_sda_pin(void *data) +{ + return ((struct ixp42x_i2c_pins*)data)->sda_pin; +} + +static void ixp42x_bit_setscl(void *data, int val) +{ + gpio_line_set(ixp42x_scl_pin(data), 0); + gpio_line_config(ixp42x_scl_pin(data), + val ? IXP425_GPIO_IN : IXP425_GPIO_OUT ); +} + +static void ixp42x_bit_setsda(void *data, int val) +{ + gpio_line_set(ixp42x_sda_pin(data), 0); + gpio_line_config(ixp42x_sda_pin(data), + val ? IXP425_GPIO_IN : IXP425_GPIO_OUT ); +} + +static int ixp42x_bit_getscl(void *data) +{ + int scl; + + gpio_line_config(ixp42x_scl_pin(data), IXP425_GPIO_IN ); + gpio_line_get(ixp42x_scl_pin(data), &scl); + + return scl; +} + +static int ixp42x_bit_getsda(void *data) +{ + int sda; + + gpio_line_config(ixp42x_sda_pin(data), IXP425_GPIO_IN ); + gpio_line_get(ixp42x_sda_pin(data), &sda); + + return sda; +} + +struct ixp42x_i2c_data { + struct ixp42x_i2c_pins *gpio_pins; + struct i2c_adapter adapter; + struct i2c_algo_bit_data algo_data; +}; + +static int ixp42x_i2c_remove(struct device *dev) +{ + struct platform_device *plat_dev = to_platform_device(dev); + struct ixp42x_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 ixp42x_i2c_probe(struct device *dev) +{ + int err; + struct platform_device *plat_dev = to_platform_device(dev); + struct ixp42x_i2c_pins *gpio = plat_dev->dev.platform_data; + struct ixp42x_i2c_data *drv_data = + kmalloc(sizeof(struct ixp42x_i2c_data), GFP_KERNEL); + + if(!drv_data) + return -ENOMEM; + + memzero(drv_data, sizeof(struct ixp42x_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 = ixp42x_bit_setsda; + drv_data->algo_data.setscl = ixp42x_bit_setscl; + drv_data->algo_data.getsda = ixp42x_bit_getsda; + drv_data->algo_data.getscl = ixp42x_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_IXP425, + drv_data->adapter.algo_data = &drv_data->algo_data, + + drv_data->adapter.dev.parent = &plat_dev->dev; + + gpio_line_config(gpio->scl_pin, IXP425_GPIO_IN); + gpio_line_config(gpio->sda_pin, IXP425_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 ixp42x_i2c_driver = { + .name = "IXP42X-I2C", + .bus = &platform_bus_type, + .probe = ixp42x_i2c_probe, + .remove = ixp42x_i2c_remove, +}; + +static int __init ixp42x_i2c_init(void) +{ + return driver_register(&ixp42x_i2c_driver); +} + +static void __exit ixp42x_i2c_exit(void) +{ + driver_unregister(&ixp42x_i2c_driver); +} + +module_init(ixp42x_i2c_init); +module_exit(ixp42x_i2c_exit); + +MODULE_DESCRIPTION("GPIO-based I2C driver for IXP42x systems"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Deepak Saxena "); +