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d6c3db83 AV |
1 | /* |
2 | * Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU | |
3 | * | |
4 | * Copyright (c) 2008 MontaVista Software, Inc. | |
5 | * | |
6 | * Author: Anton Vorontsov <avorontsov@ru.mvista.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | */ | |
13 | ||
14 | #include <linux/init.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/device.h> | |
18 | #include <linux/mutex.h> | |
19 | #include <linux/i2c.h> | |
20 | #include <linux/gpio.h> | |
21 | #include <linux/of.h> | |
22 | #include <linux/of_gpio.h> | |
5a0e3ad6 | 23 | #include <linux/slab.h> |
d6c3db83 AV |
24 | #include <asm/prom.h> |
25 | #include <asm/machdep.h> | |
26 | ||
27 | /* | |
28 | * I don't have specifications for the MCU firmware, I found this register | |
29 | * and bits positions by the trial&error method. | |
30 | */ | |
31 | #define MCU_REG_CTRL 0x20 | |
32 | #define MCU_CTRL_POFF 0x40 | |
33 | ||
34 | #define MCU_NUM_GPIO 2 | |
35 | ||
36 | struct mcu { | |
37 | struct mutex lock; | |
d6c3db83 | 38 | struct i2c_client *client; |
a19e3da5 | 39 | struct gpio_chip gc; |
d6c3db83 AV |
40 | u8 reg_ctrl; |
41 | }; | |
42 | ||
43 | static struct mcu *glob_mcu; | |
44 | ||
45 | static void mcu_power_off(void) | |
46 | { | |
47 | struct mcu *mcu = glob_mcu; | |
48 | ||
49 | pr_info("Sending power-off request to the MCU...\n"); | |
50 | mutex_lock(&mcu->lock); | |
51 | i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL, | |
52 | mcu->reg_ctrl | MCU_CTRL_POFF); | |
53 | mutex_unlock(&mcu->lock); | |
54 | } | |
55 | ||
56 | static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) | |
57 | { | |
a19e3da5 | 58 | struct mcu *mcu = container_of(gc, struct mcu, gc); |
d6c3db83 AV |
59 | u8 bit = 1 << (4 + gpio); |
60 | ||
61 | mutex_lock(&mcu->lock); | |
62 | if (val) | |
63 | mcu->reg_ctrl &= ~bit; | |
64 | else | |
65 | mcu->reg_ctrl |= bit; | |
66 | ||
67 | i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl); | |
68 | mutex_unlock(&mcu->lock); | |
69 | } | |
70 | ||
71 | static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) | |
72 | { | |
73 | mcu_gpio_set(gc, gpio, val); | |
74 | return 0; | |
75 | } | |
76 | ||
77 | static int mcu_gpiochip_add(struct mcu *mcu) | |
78 | { | |
79 | struct device_node *np; | |
a19e3da5 | 80 | struct gpio_chip *gc = &mcu->gc; |
d6c3db83 AV |
81 | |
82 | np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx"); | |
83 | if (!np) | |
84 | return -ENODEV; | |
85 | ||
86 | gc->owner = THIS_MODULE; | |
87 | gc->label = np->full_name; | |
88 | gc->can_sleep = 1; | |
89 | gc->ngpio = MCU_NUM_GPIO; | |
90 | gc->base = -1; | |
91 | gc->set = mcu_gpio_set; | |
92 | gc->direction_output = mcu_gpio_dir_out; | |
594fa265 | 93 | gc->of_node = np; |
d6c3db83 | 94 | |
594fa265 | 95 | return gpiochip_add(gc); |
d6c3db83 AV |
96 | } |
97 | ||
98 | static int mcu_gpiochip_remove(struct mcu *mcu) | |
99 | { | |
594fa265 | 100 | return gpiochip_remove(&mcu->gc); |
d6c3db83 AV |
101 | } |
102 | ||
103 | static int __devinit mcu_probe(struct i2c_client *client, | |
104 | const struct i2c_device_id *id) | |
105 | { | |
106 | struct mcu *mcu; | |
107 | int ret; | |
108 | ||
109 | mcu = kzalloc(sizeof(*mcu), GFP_KERNEL); | |
110 | if (!mcu) | |
111 | return -ENOMEM; | |
112 | ||
113 | mutex_init(&mcu->lock); | |
114 | mcu->client = client; | |
115 | i2c_set_clientdata(client, mcu); | |
116 | ||
117 | ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL); | |
118 | if (ret < 0) | |
119 | goto err; | |
120 | mcu->reg_ctrl = ret; | |
121 | ||
122 | ret = mcu_gpiochip_add(mcu); | |
123 | if (ret) | |
124 | goto err; | |
125 | ||
126 | /* XXX: this is potentially racy, but there is no lock for ppc_md */ | |
127 | if (!ppc_md.power_off) { | |
128 | glob_mcu = mcu; | |
129 | ppc_md.power_off = mcu_power_off; | |
130 | dev_info(&client->dev, "will provide power-off service\n"); | |
131 | } | |
132 | ||
133 | return 0; | |
134 | err: | |
135 | kfree(mcu); | |
136 | return ret; | |
137 | } | |
138 | ||
139 | static int __devexit mcu_remove(struct i2c_client *client) | |
140 | { | |
141 | struct mcu *mcu = i2c_get_clientdata(client); | |
142 | int ret; | |
143 | ||
144 | if (glob_mcu == mcu) { | |
145 | ppc_md.power_off = NULL; | |
146 | glob_mcu = NULL; | |
147 | } | |
148 | ||
149 | ret = mcu_gpiochip_remove(mcu); | |
150 | if (ret) | |
151 | return ret; | |
152 | i2c_set_clientdata(client, NULL); | |
153 | kfree(mcu); | |
154 | return 0; | |
155 | } | |
156 | ||
157 | static const struct i2c_device_id mcu_ids[] = { | |
158 | { "mcu-mpc8349emitx", }, | |
159 | {}, | |
160 | }; | |
161 | MODULE_DEVICE_TABLE(i2c, mcu_ids); | |
162 | ||
2ffe8c5f GL |
163 | static struct of_device_id mcu_of_match_table[] __devinitdata = { |
164 | { .compatible = "fsl,mcu-mpc8349emitx", }, | |
165 | { }, | |
166 | }; | |
167 | ||
d6c3db83 AV |
168 | static struct i2c_driver mcu_driver = { |
169 | .driver = { | |
170 | .name = "mcu-mpc8349emitx", | |
171 | .owner = THIS_MODULE, | |
2ffe8c5f | 172 | .of_match_table = mcu_of_match_table, |
d6c3db83 AV |
173 | }, |
174 | .probe = mcu_probe, | |
175 | .remove = __devexit_p(mcu_remove), | |
176 | .id_table = mcu_ids, | |
177 | }; | |
178 | ||
179 | static int __init mcu_init(void) | |
180 | { | |
181 | return i2c_add_driver(&mcu_driver); | |
182 | } | |
183 | module_init(mcu_init); | |
184 | ||
185 | static void __exit mcu_exit(void) | |
186 | { | |
187 | i2c_del_driver(&mcu_driver); | |
188 | } | |
189 | module_exit(mcu_exit); | |
190 | ||
191 | MODULE_DESCRIPTION("Power Management and GPIO expander driver for " | |
192 | "MPC8349E-mITX-compatible MCU"); | |
193 | MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>"); | |
194 | MODULE_LICENSE("GPL"); |