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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/i2c/busses/i2c-ixp2000.c
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/i2c/busses/i2c-ixp2000.c')
-rw-r--r--drivers/i2c/busses/i2c-ixp2000.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-ixp2000.c b/drivers/i2c/busses/i2c-ixp2000.c
new file mode 100644
index 00000000000..21cd54d0230
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ixp2000.c
@@ -0,0 +1,171 @@
1/*
2 * drivers/i2c/busses/i2c-ixp2000.c
3 *
4 * I2C adapter for IXP2000 systems using GPIOs for I2C bus
5 *
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>
9 *
10 * Copyright (c) 2003-2004 MontaVista Software Inc.
11 *
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.
15 *
16 * From Jeff Daly:
17 *
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.
23 *
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.
27 */
28
29#include <linux/config.h>
30#ifdef CONFIG_I2C_DEBUG_BUS
31#define DEBUG 1
32#endif
33
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>
40
41#include <asm/hardware.h> /* Pick up IXP42000-specific bits */
42
43static inline int ixp2000_scl_pin(void *data)
44{
45 return ((struct ixp2000_i2c_pins*)data)->scl_pin;
46}
47
48static inline int ixp2000_sda_pin(void *data)
49{
50 return ((struct ixp2000_i2c_pins*)data)->sda_pin;
51}
52
53
54static void ixp2000_bit_setscl(void *data, int val)
55{
56 int i = 5000;
57
58 if (val) {
59 gpio_line_config(ixp2000_scl_pin(data), GPIO_IN);
60 while(!gpio_line_get(ixp2000_scl_pin(data)) && i--);
61 } else {
62 gpio_line_config(ixp2000_scl_pin(data), GPIO_OUT);
63 }
64}
65
66static void ixp2000_bit_setsda(void *data, int val)
67{
68 if (val) {
69 gpio_line_config(ixp2000_sda_pin(data), GPIO_IN);
70 } else {
71 gpio_line_config(ixp2000_sda_pin(data), GPIO_OUT);
72 }
73}
74
75static int ixp2000_bit_getscl(void *data)
76{
77 return gpio_line_get(ixp2000_scl_pin(data));
78}
79
80static int ixp2000_bit_getsda(void *data)
81{
82 return gpio_line_get(ixp2000_sda_pin(data));
83}
84
85struct ixp2000_i2c_data {
86 struct ixp2000_i2c_pins *gpio_pins;
87 struct i2c_adapter adapter;
88 struct i2c_algo_bit_data algo_data;
89};
90
91static int ixp2000_i2c_remove(struct device *dev)
92{
93 struct platform_device *plat_dev = to_platform_device(dev);
94 struct ixp2000_i2c_data *drv_data = dev_get_drvdata(&plat_dev->dev);
95
96 dev_set_drvdata(&plat_dev->dev, NULL);
97
98 i2c_bit_del_bus(&drv_data->adapter);
99
100 kfree(drv_data);
101
102 return 0;
103}
104
105static int ixp2000_i2c_probe(struct device *dev)
106{
107 int err;
108 struct platform_device *plat_dev = to_platform_device(dev);
109 struct ixp2000_i2c_pins *gpio = plat_dev->dev.platform_data;
110 struct ixp2000_i2c_data *drv_data =
111 kmalloc(sizeof(struct ixp2000_i2c_data), GFP_KERNEL);
112
113 if (!drv_data)
114 return -ENOMEM;
115 memzero(drv_data, sizeof(*drv_data));
116 drv_data->gpio_pins = gpio;
117
118 drv_data->algo_data.data = gpio;
119 drv_data->algo_data.setsda = ixp2000_bit_setsda;
120 drv_data->algo_data.setscl = ixp2000_bit_setscl;
121 drv_data->algo_data.getsda = ixp2000_bit_getsda;
122 drv_data->algo_data.getscl = ixp2000_bit_getscl;
123 drv_data->algo_data.udelay = 6;
124 drv_data->algo_data.mdelay = 6;
125 drv_data->algo_data.timeout = 100;
126
127 drv_data->adapter.id = I2C_HW_B_IXP2000,
128 drv_data->adapter.algo_data = &drv_data->algo_data,
129
130 drv_data->adapter.dev.parent = &plat_dev->dev;
131
132 gpio_line_config(gpio->sda_pin, GPIO_IN);
133 gpio_line_config(gpio->scl_pin, GPIO_IN);
134 gpio_line_set(gpio->scl_pin, 0);
135 gpio_line_set(gpio->sda_pin, 0);
136
137 if ((err = i2c_bit_add_bus(&drv_data->adapter)) != 0) {
138 dev_err(dev, "Could not install, error %d\n", err);
139 kfree(drv_data);
140 return err;
141 }
142
143 dev_set_drvdata(&plat_dev->dev, drv_data);
144
145 return 0;
146}
147
148static struct device_driver ixp2000_i2c_driver = {
149 .name = "IXP2000-I2C",
150 .bus = &platform_bus_type,
151 .probe = ixp2000_i2c_probe,
152 .remove = ixp2000_i2c_remove,
153};
154
155static int __init ixp2000_i2c_init(void)
156{
157 return driver_register(&ixp2000_i2c_driver);
158}
159
160static void __exit ixp2000_i2c_exit(void)
161{
162 driver_unregister(&ixp2000_i2c_driver);
163}
164
165module_init(ixp2000_i2c_init);
166module_exit(ixp2000_i2c_exit);
167
168MODULE_AUTHOR ("Deepak Saxena <dsaxena@plexity.net>");
169MODULE_DESCRIPTION("IXP2000 GPIO-based I2C bus driver");
170MODULE_LICENSE("GPL");
171