]>
Commit | Line | Data |
---|---|---|
d22fcde0 GR |
1 | /* |
2 | * Kontron PLD GPIO driver | |
3 | * | |
4 | * Copyright (c) 2010-2013 Kontron Europe GmbH | |
5 | * Author: Michael Brunner <michael.brunner@kontron.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License 2 as published | |
9 | * by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | */ | |
16 | ||
17 | #include <linux/init.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/bitops.h> | |
21 | #include <linux/errno.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/gpio.h> | |
24 | #include <linux/mfd/kempld.h> | |
25 | ||
26 | #define KEMPLD_GPIO_MAX_NUM 16 | |
27 | #define KEMPLD_GPIO_MASK(x) (1 << ((x) % 8)) | |
28 | #define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8) | |
29 | #define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8) | |
30 | #define KEMPLD_GPIO_EVT_LVL_EDGE 0x46 | |
31 | #define KEMPLD_GPIO_IEN 0x4A | |
32 | ||
33 | struct kempld_gpio_data { | |
34 | struct gpio_chip chip; | |
35 | struct kempld_device_data *pld; | |
36 | }; | |
37 | ||
38 | /* | |
39 | * Set or clear GPIO bit | |
40 | * kempld_get_mutex must be called prior to calling this function. | |
41 | */ | |
42 | static void kempld_gpio_bitop(struct kempld_device_data *pld, | |
43 | u8 reg, u8 bit, u8 val) | |
44 | { | |
45 | u8 status; | |
46 | ||
47 | status = kempld_read8(pld, reg); | |
48 | if (val) | |
49 | status |= (1 << bit); | |
50 | else | |
51 | status &= ~(1 << bit); | |
52 | kempld_write8(pld, reg, status); | |
53 | } | |
54 | ||
55 | static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit) | |
56 | { | |
57 | u8 status; | |
58 | ||
59 | kempld_get_mutex(pld); | |
60 | status = kempld_read8(pld, reg); | |
61 | kempld_release_mutex(pld); | |
62 | ||
63 | return !!(status & (1 << bit)); | |
64 | } | |
65 | ||
66 | static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset) | |
67 | { | |
68 | struct kempld_gpio_data *gpio | |
69 | = container_of(chip, struct kempld_gpio_data, chip); | |
70 | struct kempld_device_data *pld = gpio->pld; | |
71 | ||
72 | return kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), | |
73 | KEMPLD_GPIO_MASK(offset)); | |
74 | } | |
75 | ||
76 | static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value) | |
77 | { | |
78 | struct kempld_gpio_data *gpio | |
79 | = container_of(chip, struct kempld_gpio_data, chip); | |
80 | struct kempld_device_data *pld = gpio->pld; | |
81 | ||
82 | kempld_get_mutex(pld); | |
83 | kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), | |
84 | KEMPLD_GPIO_MASK(offset), value); | |
85 | kempld_release_mutex(pld); | |
86 | } | |
87 | ||
88 | static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset) | |
89 | { | |
90 | struct kempld_gpio_data *gpio | |
91 | = container_of(chip, struct kempld_gpio_data, chip); | |
92 | struct kempld_device_data *pld = gpio->pld; | |
93 | ||
94 | kempld_get_mutex(pld); | |
95 | kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), | |
96 | KEMPLD_GPIO_MASK(offset), 0); | |
97 | kempld_release_mutex(pld); | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset, | |
103 | int value) | |
104 | { | |
105 | struct kempld_gpio_data *gpio | |
106 | = container_of(chip, struct kempld_gpio_data, chip); | |
107 | struct kempld_device_data *pld = gpio->pld; | |
108 | ||
109 | kempld_get_mutex(pld); | |
110 | kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), | |
111 | KEMPLD_GPIO_MASK(offset), value); | |
112 | kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), | |
113 | KEMPLD_GPIO_MASK(offset), 1); | |
114 | kempld_release_mutex(pld); | |
115 | ||
116 | return 0; | |
117 | } | |
118 | ||
119 | static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset) | |
120 | { | |
121 | struct kempld_gpio_data *gpio | |
122 | = container_of(chip, struct kempld_gpio_data, chip); | |
123 | struct kempld_device_data *pld = gpio->pld; | |
124 | ||
125 | return kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), | |
126 | KEMPLD_GPIO_MASK(offset)); | |
127 | } | |
128 | ||
129 | static int kempld_gpio_pincount(struct kempld_device_data *pld) | |
130 | { | |
131 | u16 evt, evt_back; | |
132 | ||
133 | kempld_get_mutex(pld); | |
134 | ||
135 | /* Backup event register as it might be already initialized */ | |
136 | evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE); | |
137 | /* Clear event register */ | |
138 | kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000); | |
139 | /* Read back event register */ | |
140 | evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE); | |
141 | /* Restore event register */ | |
142 | kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back); | |
143 | ||
144 | kempld_release_mutex(pld); | |
145 | ||
146 | return evt ? __ffs(evt) : 16; | |
147 | } | |
148 | ||
149 | static int kempld_gpio_probe(struct platform_device *pdev) | |
150 | { | |
151 | struct device *dev = &pdev->dev; | |
152 | struct kempld_device_data *pld = dev_get_drvdata(dev->parent); | |
153 | struct kempld_platform_data *pdata = pld->dev->platform_data; | |
154 | struct kempld_gpio_data *gpio; | |
155 | struct gpio_chip *chip; | |
156 | int ret; | |
157 | ||
158 | if (pld->info.spec_major < 2) { | |
159 | dev_err(dev, | |
160 | "Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n"); | |
161 | return -ENODEV; | |
162 | } | |
163 | ||
164 | gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL); | |
165 | if (gpio == NULL) | |
166 | return -ENOMEM; | |
167 | ||
168 | gpio->pld = pld; | |
169 | ||
170 | platform_set_drvdata(pdev, gpio); | |
171 | ||
172 | chip = &gpio->chip; | |
173 | chip->label = "gpio-kempld"; | |
174 | chip->owner = THIS_MODULE; | |
175 | chip->dev = dev; | |
176 | chip->can_sleep = 1; | |
177 | if (pdata && pdata->gpio_base) | |
178 | chip->base = pdata->gpio_base; | |
179 | else | |
180 | chip->base = -1; | |
181 | chip->direction_input = kempld_gpio_direction_input; | |
182 | chip->direction_output = kempld_gpio_direction_output; | |
183 | chip->get_direction = kempld_gpio_get_direction; | |
184 | chip->get = kempld_gpio_get; | |
185 | chip->set = kempld_gpio_set; | |
186 | chip->ngpio = kempld_gpio_pincount(pld); | |
187 | if (chip->ngpio == 0) { | |
188 | dev_err(dev, "No GPIO pins detected\n"); | |
189 | return -ENODEV; | |
190 | } | |
191 | ||
192 | ret = gpiochip_add(chip); | |
193 | if (ret) { | |
194 | dev_err(dev, "Could not register GPIO chip\n"); | |
195 | return ret; | |
196 | } | |
197 | ||
198 | dev_info(dev, "GPIO functionality initialized with %d pins\n", | |
199 | chip->ngpio); | |
200 | ||
201 | return 0; | |
202 | } | |
203 | ||
204 | static int kempld_gpio_remove(struct platform_device *pdev) | |
205 | { | |
206 | struct kempld_gpio_data *gpio = platform_get_drvdata(pdev); | |
207 | ||
208 | return gpiochip_remove(&gpio->chip); | |
209 | } | |
210 | ||
211 | static struct platform_driver kempld_gpio_driver = { | |
212 | .driver = { | |
213 | .name = "gpio-kempld", | |
214 | .owner = THIS_MODULE, | |
215 | }, | |
216 | .probe = kempld_gpio_probe, | |
217 | .remove = kempld_gpio_remove, | |
218 | }; | |
219 | ||
220 | module_platform_driver(kempld_gpio_driver); | |
221 | ||
222 | MODULE_DESCRIPTION("KEM PLD GPIO Driver"); | |
223 | MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>"); | |
224 | MODULE_LICENSE("GPL"); | |
225 | MODULE_ALIAS("platform:gpio-kempld"); |