diff options
Diffstat (limited to 'package/system/i2c-gpio-custom/src/i2c-gpio-custom.c')
| -rw-r--r-- | package/system/i2c-gpio-custom/src/i2c-gpio-custom.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/package/system/i2c-gpio-custom/src/i2c-gpio-custom.c b/package/system/i2c-gpio-custom/src/i2c-gpio-custom.c new file mode 100644 index 000000000..76ab5f39c --- /dev/null +++ b/package/system/i2c-gpio-custom/src/i2c-gpio-custom.c @@ -0,0 +1,198 @@ +/* + * 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); |