Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 | /*
* 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/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/slab.h>
#include <mach/hardware.h> /* Pick up IXP2000-specific bits */
#include <mach/gpio-ixp2000.h>
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 platform_device *plat_dev)
{
struct ixp2000_i2c_data *drv_data = platform_get_drvdata(plat_dev);
platform_set_drvdata(plat_dev, NULL);
i2c_del_adapter(&drv_data->adapter);
kfree(drv_data);
return 0;
}
static int ixp2000_i2c_probe(struct platform_device *plat_dev)
{
int err;
struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data;
struct ixp2000_i2c_data *drv_data =
kzalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL);
if (!drv_data)
return -ENOMEM;
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.timeout = HZ;
strlcpy(drv_data->adapter.name, plat_dev->dev.driver->name,
sizeof(drv_data->adapter.name));
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(&plat_dev->dev, "Could not install, error %d\n", err);
kfree(drv_data);
return err;
}
platform_set_drvdata(plat_dev, drv_data);
return 0;
}
static struct platform_driver ixp2000_i2c_driver = {
.probe = ixp2000_i2c_probe,
.remove = ixp2000_i2c_remove,
.driver = {
.name = "IXP2000-I2C",
.owner = THIS_MODULE,
},
};
module_platform_driver(ixp2000_i2c_driver);
MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:IXP2000-I2C");
|