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- /*
- * Custom GPIO-based I2C driver
- *
- * Copyright (C) 2007-2008 Gabor Juhos <juhosg@openwrt.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * ---------------------------------------------------------------------------
- *
- * The behaviour of this driver can be altered by setting some parameters
- * from the insmod command line.
- *
- * The following parameters are adjustable:
- *
- * bus0 These four arguments can be arrays of
- * bus1 1-8 unsigned integers as follows:
- * bus2
- * bus3 <id>,<sda>,<scl>,<udelay>,<timeout>,<sda_od>,<scl_od>,<scl_oo>
- *
- * where:
- *
- * <id> ID to used as device_id for the corresponding bus (required)
- * <sda> GPIO pin ID to used for SDA (required)
- * <scl> GPIO pin ID to used for SCL (required)
- * <udelay> signal toggle delay.
- * <timeout> clock stretching timeout.
- * <sda_od> SDA is configured as open drain.
- * <scl_od> SCL is configured as open drain.
- * <scl_oo> SCL output drivers cannot be turned off.
- *
- * See include/i2c-gpio.h for more information about the parameters.
- *
- * If this driver is built into the kernel, you can use the following kernel
- * command line parameters, with the same values as the corresponding module
- * parameters listed above:
- *
- * i2c-gpio-custom.bus0
- * i2c-gpio-custom.bus1
- * i2c-gpio-custom.bus2
- * i2c-gpio-custom.bus3
- */
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/platform_device.h>
- #include <linux/i2c-gpio.h>
- #define DRV_NAME "i2c-gpio-custom"
- #define DRV_DESC "Custom GPIO-based I2C driver"
- #define DRV_VERSION "0.1.1"
- #define PFX DRV_NAME ": "
- #define BUS_PARAM_ID 0
- #define BUS_PARAM_SDA 1
- #define BUS_PARAM_SCL 2
- #define BUS_PARAM_UDELAY 3
- #define BUS_PARAM_TIMEOUT 4
- #define BUS_PARAM_SDA_OD 5
- #define BUS_PARAM_SCL_OD 6
- #define BUS_PARAM_SCL_OO 7
- #define BUS_PARAM_REQUIRED 3
- #define BUS_PARAM_COUNT 8
- #define BUS_COUNT_MAX 4
- static unsigned int bus0[BUS_PARAM_COUNT] __initdata;
- static unsigned int bus1[BUS_PARAM_COUNT] __initdata;
- static unsigned int bus2[BUS_PARAM_COUNT] __initdata;
- static unsigned int bus3[BUS_PARAM_COUNT] __initdata;
- static unsigned int bus_nump[BUS_COUNT_MAX] __initdata;
- #define BUS_PARM_DESC \
- " config -> id,sda,scl[,udelay,timeout,sda_od,scl_od,scl_oo]"
- module_param_array(bus0, uint, &bus_nump[0], 0);
- MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC);
- module_param_array(bus1, uint, &bus_nump[1], 0);
- MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC);
- module_param_array(bus2, uint, &bus_nump[2], 0);
- MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC);
- module_param_array(bus3, uint, &bus_nump[3], 0);
- MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC);
- static struct platform_device *devices[BUS_COUNT_MAX];
- static unsigned int nr_devices;
- static void i2c_gpio_custom_cleanup(void)
- {
- int i;
- for (i = 0; i < nr_devices; i++)
- if (devices[i])
- platform_device_put(devices[i]);
- }
- static int __init i2c_gpio_custom_add_one(unsigned int id, unsigned int *params)
- {
- struct platform_device *pdev;
- struct i2c_gpio_platform_data pdata;
- int err;
- if (!bus_nump[id])
- return 0;
- if (bus_nump[id] < BUS_PARAM_REQUIRED) {
- printk(KERN_ERR PFX "not enough parameters for bus%d\n", id);
- err = -EINVAL;
- goto err;
- }
- pdev = platform_device_alloc("i2c-gpio", params[BUS_PARAM_ID]);
- if (!pdev) {
- err = -ENOMEM;
- goto err;
- }
- pdata.sda_pin = params[BUS_PARAM_SDA];
- pdata.scl_pin = params[BUS_PARAM_SCL];
- pdata.udelay = params[BUS_PARAM_UDELAY];
- pdata.timeout = params[BUS_PARAM_TIMEOUT];
- pdata.sda_is_open_drain = params[BUS_PARAM_SDA_OD] != 0;
- pdata.scl_is_open_drain = params[BUS_PARAM_SCL_OD] != 0;
- pdata.scl_is_output_only = params[BUS_PARAM_SCL_OO] != 0;
- err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
- if (err)
- goto err_put;
- err = platform_device_add(pdev);
- if (err)
- goto err_put;
- devices[nr_devices++] = pdev;
- return 0;
- err_put:
- platform_device_put(pdev);
- err:
- return err;
- }
- static int __init i2c_gpio_custom_probe(void)
- {
- int err;
- printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
- err = i2c_gpio_custom_add_one(0, bus0);
- if (err)
- goto err;
- err = i2c_gpio_custom_add_one(1, bus1);
- if (err)
- goto err;
- err = i2c_gpio_custom_add_one(2, bus2);
- if (err)
- goto err;
- err = i2c_gpio_custom_add_one(3, bus3);
- if (err)
- goto err;
- if (!nr_devices) {
- printk(KERN_ERR PFX "no bus parameter(s) specified\n");
- err = -ENODEV;
- goto err;
- }
- return 0;
- err:
- i2c_gpio_custom_cleanup();
- return err;
- }
- #ifdef MODULE
- static int __init i2c_gpio_custom_init(void)
- {
- return i2c_gpio_custom_probe();
- }
- module_init(i2c_gpio_custom_init);
- static void __exit i2c_gpio_custom_exit(void)
- {
- i2c_gpio_custom_cleanup();
- }
- module_exit(i2c_gpio_custom_exit);
- #else
- subsys_initcall(i2c_gpio_custom_probe);
- #endif /* MODULE*/
- MODULE_LICENSE("GPL v2");
- MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org >");
- MODULE_DESCRIPTION(DRV_DESC);
- MODULE_VERSION(DRV_VERSION);
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