2 * drivers/i2c/busses/i2c-ixp2000.c
4 * I2C adapter for IXP2000 systems using GPIOs for I2C bus
6 * Author: Deepak Saxena <dsaxena@plexity.net>
7 * Based on IXDP2400 code by: Naeem M. Afzal <naeem.m.afzal@intel.com>
8 * Made generic by: Jeff Daly <jeffrey.daly@intel.com>
10 * Copyright (c) 2003-2004 MontaVista Software Inc.
12 * This file is licensed under the terms of the GNU General Public
13 * License version 2. This program is licensed "as is" without any
14 * warranty of any kind, whether express or implied.
18 * I2C adapter driver for Intel IXDP2xxx platforms. This should work for any
19 * IXP2000 platform if it uses the HW GPIO in the same manner. Basically,
20 * SDA and SCL GPIOs have external pullups. Setting the respective GPIO to
21 * an input will make the signal a '1' via the pullup. Setting them to
22 * outputs will pull them down.
24 * The GPIOs are open drain signals and are used as configuration strap inputs
25 * during power-up so there's generally a buffer on the board that needs to be
26 * 'enabled' to drive the GPIOs.
29 #include <linux/kernel.h>
30 #include <linux/init.h>
31 #include <linux/platform_device.h>
32 #include <linux/module.h>
33 #include <linux/i2c.h>
34 #include <linux/i2c-algo-bit.h>
35 #include <linux/slab.h>
37 #include <mach/hardware.h> /* Pick up IXP2000-specific bits */
38 #include <mach/gpio.h>
40 static inline int ixp2000_scl_pin(void *data
)
42 return ((struct ixp2000_i2c_pins
*)data
)->scl_pin
;
45 static inline int ixp2000_sda_pin(void *data
)
47 return ((struct ixp2000_i2c_pins
*)data
)->sda_pin
;
51 static void ixp2000_bit_setscl(void *data
, int val
)
56 gpio_line_config(ixp2000_scl_pin(data
), GPIO_IN
);
57 while(!gpio_line_get(ixp2000_scl_pin(data
)) && i
--);
59 gpio_line_config(ixp2000_scl_pin(data
), GPIO_OUT
);
63 static void ixp2000_bit_setsda(void *data
, int val
)
66 gpio_line_config(ixp2000_sda_pin(data
), GPIO_IN
);
68 gpio_line_config(ixp2000_sda_pin(data
), GPIO_OUT
);
72 static int ixp2000_bit_getscl(void *data
)
74 return gpio_line_get(ixp2000_scl_pin(data
));
77 static int ixp2000_bit_getsda(void *data
)
79 return gpio_line_get(ixp2000_sda_pin(data
));
82 struct ixp2000_i2c_data
{
83 struct ixp2000_i2c_pins
*gpio_pins
;
84 struct i2c_adapter adapter
;
85 struct i2c_algo_bit_data algo_data
;
88 static int ixp2000_i2c_remove(struct platform_device
*plat_dev
)
90 struct ixp2000_i2c_data
*drv_data
= platform_get_drvdata(plat_dev
);
92 platform_set_drvdata(plat_dev
, NULL
);
94 i2c_del_adapter(&drv_data
->adapter
);
101 static int ixp2000_i2c_probe(struct platform_device
*plat_dev
)
104 struct ixp2000_i2c_pins
*gpio
= plat_dev
->dev
.platform_data
;
105 struct ixp2000_i2c_data
*drv_data
=
106 kzalloc(sizeof(struct ixp2000_i2c_data
), GFP_KERNEL
);
110 drv_data
->gpio_pins
= gpio
;
112 drv_data
->algo_data
.data
= gpio
;
113 drv_data
->algo_data
.setsda
= ixp2000_bit_setsda
;
114 drv_data
->algo_data
.setscl
= ixp2000_bit_setscl
;
115 drv_data
->algo_data
.getsda
= ixp2000_bit_getsda
;
116 drv_data
->algo_data
.getscl
= ixp2000_bit_getscl
;
117 drv_data
->algo_data
.udelay
= 6;
118 drv_data
->algo_data
.timeout
= HZ
;
120 strlcpy(drv_data
->adapter
.name
, plat_dev
->dev
.driver
->name
,
121 sizeof(drv_data
->adapter
.name
));
122 drv_data
->adapter
.algo_data
= &drv_data
->algo_data
,
124 drv_data
->adapter
.dev
.parent
= &plat_dev
->dev
;
126 gpio_line_config(gpio
->sda_pin
, GPIO_IN
);
127 gpio_line_config(gpio
->scl_pin
, GPIO_IN
);
128 gpio_line_set(gpio
->scl_pin
, 0);
129 gpio_line_set(gpio
->sda_pin
, 0);
131 if ((err
= i2c_bit_add_bus(&drv_data
->adapter
)) != 0) {
132 dev_err(&plat_dev
->dev
, "Could not install, error %d\n", err
);
137 platform_set_drvdata(plat_dev
, drv_data
);
142 static struct platform_driver ixp2000_i2c_driver
= {
143 .probe
= ixp2000_i2c_probe
,
144 .remove
= ixp2000_i2c_remove
,
146 .name
= "IXP2000-I2C",
147 .owner
= THIS_MODULE
,
151 static int __init
ixp2000_i2c_init(void)
153 return platform_driver_register(&ixp2000_i2c_driver
);
156 static void __exit
ixp2000_i2c_exit(void)
158 platform_driver_unregister(&ixp2000_i2c_driver
);
161 module_init(ixp2000_i2c_init
);
162 module_exit(ixp2000_i2c_exit
);
164 MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>");
165 MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver");
166 MODULE_LICENSE("GPL");
167 MODULE_ALIAS("platform:IXP2000-I2C");