OpenWrt – Rev 1
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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/version.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 18, 0)
#include <linux/i2c-gpio.h>
#else
#include <linux/platform_data/i2c-gpio.h>
#endif
#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);