2 * drivers/i2c/i2c-adap-ixp4xx.c
4 * Intel's IXP4xx XScale NPU chipsets (IXP420, 421, 422, 425) do not have
5 * an on board I2C controller but provide 16 GPIO pins that are often
6 * used to create an I2C bus. This driver provides an i2c_adapter
7 * interface that plugs in under algo_bit and drives the GPIO pins
8 * as instructed by the alogorithm driver.
10 * Author: Deepak Saxena <dsaxena@plexity.net>
12 * Copyright (c) 2003-2004 MontaVista Software Inc.
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
18 * NOTE: Since different platforms will use different GPIO pins for
19 * I2C, this driver uses an IXP4xx-specific platform_data
20 * pointer to pass the GPIO numbers to the driver. This
21 * allows us to support all the different IXP4xx platforms
22 * w/o having to put #ifdefs in this driver.
24 * See arch/arm/mach-ixp4xx/ixdp425.c for an example of building a
25 * device list and filling in the ixp4xx_i2c_pins data structure
26 * that is passed as the platform_data to this driver.
29 #include <linux/config.h>
30 #ifdef CONFIG_I2C_DEBUG_BUS
34 #include <linux/kernel.h>
35 #include <linux/init.h>
36 #include <linux/device.h>
37 #include <linux/module.h>
38 #include <linux/i2c.h>
39 #include <linux/i2c-algo-bit.h>
41 #include <asm/hardware.h> /* Pick up IXP4xx-specific bits */
43 static inline int ixp4xx_scl_pin(void *data
)
45 return ((struct ixp4xx_i2c_pins
*)data
)->scl_pin
;
48 static inline int ixp4xx_sda_pin(void *data
)
50 return ((struct ixp4xx_i2c_pins
*)data
)->sda_pin
;
53 static void ixp4xx_bit_setscl(void *data
, int val
)
55 gpio_line_set(ixp4xx_scl_pin(data
), 0);
56 gpio_line_config(ixp4xx_scl_pin(data
),
57 val
? IXP4XX_GPIO_IN
: IXP4XX_GPIO_OUT
);
60 static void ixp4xx_bit_setsda(void *data
, int val
)
62 gpio_line_set(ixp4xx_sda_pin(data
), 0);
63 gpio_line_config(ixp4xx_sda_pin(data
),
64 val
? IXP4XX_GPIO_IN
: IXP4XX_GPIO_OUT
);
67 static int ixp4xx_bit_getscl(void *data
)
71 gpio_line_config(ixp4xx_scl_pin(data
), IXP4XX_GPIO_IN
);
72 gpio_line_get(ixp4xx_scl_pin(data
), &scl
);
77 static int ixp4xx_bit_getsda(void *data
)
81 gpio_line_config(ixp4xx_sda_pin(data
), IXP4XX_GPIO_IN
);
82 gpio_line_get(ixp4xx_sda_pin(data
), &sda
);
87 struct ixp4xx_i2c_data
{
88 struct ixp4xx_i2c_pins
*gpio_pins
;
89 struct i2c_adapter adapter
;
90 struct i2c_algo_bit_data algo_data
;
93 static int ixp4xx_i2c_remove(struct device
*dev
)
95 struct platform_device
*plat_dev
= to_platform_device(dev
);
96 struct ixp4xx_i2c_data
*drv_data
= dev_get_drvdata(&plat_dev
->dev
);
98 dev_set_drvdata(&plat_dev
->dev
, NULL
);
100 i2c_bit_del_bus(&drv_data
->adapter
);
107 static int ixp4xx_i2c_probe(struct device
*dev
)
110 struct platform_device
*plat_dev
= to_platform_device(dev
);
111 struct ixp4xx_i2c_pins
*gpio
= plat_dev
->dev
.platform_data
;
112 struct ixp4xx_i2c_data
*drv_data
=
113 kmalloc(sizeof(struct ixp4xx_i2c_data
), GFP_KERNEL
);
118 memzero(drv_data
, sizeof(struct ixp4xx_i2c_data
));
119 drv_data
->gpio_pins
= gpio
;
122 * We could make a lot of these structures static, but
123 * certain platforms may have multiple GPIO-based I2C
124 * buses for various device domains, so we need per-device
127 drv_data
->algo_data
.data
= gpio
;
128 drv_data
->algo_data
.setsda
= ixp4xx_bit_setsda
;
129 drv_data
->algo_data
.setscl
= ixp4xx_bit_setscl
;
130 drv_data
->algo_data
.getsda
= ixp4xx_bit_getsda
;
131 drv_data
->algo_data
.getscl
= ixp4xx_bit_getscl
;
132 drv_data
->algo_data
.udelay
= 10;
133 drv_data
->algo_data
.mdelay
= 10;
134 drv_data
->algo_data
.timeout
= 100;
136 drv_data
->adapter
.id
= I2C_HW_B_IXP4XX
,
137 drv_data
->adapter
.algo_data
= &drv_data
->algo_data
,
139 drv_data
->adapter
.dev
.parent
= &plat_dev
->dev
;
141 gpio_line_config(gpio
->scl_pin
, IXP4XX_GPIO_IN
);
142 gpio_line_config(gpio
->sda_pin
, IXP4XX_GPIO_IN
);
143 gpio_line_set(gpio
->scl_pin
, 0);
144 gpio_line_set(gpio
->sda_pin
, 0);
146 if ((err
= i2c_bit_add_bus(&drv_data
->adapter
) != 0)) {
147 printk(KERN_ERR
"ERROR: Could not install %s\n", dev
->bus_id
);
153 dev_set_drvdata(&plat_dev
->dev
, drv_data
);
158 static struct device_driver ixp4xx_i2c_driver
= {
159 .name
= "IXP4XX-I2C",
160 .bus
= &platform_bus_type
,
161 .probe
= ixp4xx_i2c_probe
,
162 .remove
= ixp4xx_i2c_remove
,
165 static int __init
ixp4xx_i2c_init(void)
167 return driver_register(&ixp4xx_i2c_driver
);
170 static void __exit
ixp4xx_i2c_exit(void)
172 driver_unregister(&ixp4xx_i2c_driver
);
175 module_init(ixp4xx_i2c_init
);
176 module_exit(ixp4xx_i2c_exit
);
178 MODULE_DESCRIPTION("GPIO-based I2C adapter for IXP4xx systems");
179 MODULE_LICENSE("GPL");
180 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");