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Guenter Roeckd22fcde2013-06-23 21:00:05 -07001/*
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
33struct 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 */
42static 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)
Brunner Michael2e7f6122013-07-31 20:55:39 +020049 status |= KEMPLD_GPIO_MASK(bit);
Guenter Roeckd22fcde2013-06-23 21:00:05 -070050 else
Brunner Michael2e7f6122013-07-31 20:55:39 +020051 status &= ~KEMPLD_GPIO_MASK(bit);
Guenter Roeckd22fcde2013-06-23 21:00:05 -070052 kempld_write8(pld, reg, status);
53}
54
55static 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
Brunner Michael2e7f6122013-07-31 20:55:39 +020063 return !!(status & KEMPLD_GPIO_MASK(bit));
Guenter Roeckd22fcde2013-06-23 21:00:05 -070064}
65
66static 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
Brunner Michael2e7f6122013-07-31 20:55:39 +020072 return kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), offset);
Guenter Roeckd22fcde2013-06-23 21:00:05 -070073}
74
75static void kempld_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
76{
77 struct kempld_gpio_data *gpio
78 = container_of(chip, struct kempld_gpio_data, chip);
79 struct kempld_device_data *pld = gpio->pld;
80
81 kempld_get_mutex(pld);
Brunner Michael2e7f6122013-07-31 20:55:39 +020082 kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
Guenter Roeckd22fcde2013-06-23 21:00:05 -070083 kempld_release_mutex(pld);
84}
85
86static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
87{
88 struct kempld_gpio_data *gpio
89 = container_of(chip, struct kempld_gpio_data, chip);
90 struct kempld_device_data *pld = gpio->pld;
91
92 kempld_get_mutex(pld);
Brunner Michael2e7f6122013-07-31 20:55:39 +020093 kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 0);
Guenter Roeckd22fcde2013-06-23 21:00:05 -070094 kempld_release_mutex(pld);
95
96 return 0;
97}
98
99static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
100 int value)
101{
102 struct kempld_gpio_data *gpio
103 = container_of(chip, struct kempld_gpio_data, chip);
104 struct kempld_device_data *pld = gpio->pld;
105
106 kempld_get_mutex(pld);
Brunner Michael2e7f6122013-07-31 20:55:39 +0200107 kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
108 kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 1);
Guenter Roeckd22fcde2013-06-23 21:00:05 -0700109 kempld_release_mutex(pld);
110
111 return 0;
112}
113
114static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
115{
116 struct kempld_gpio_data *gpio
117 = container_of(chip, struct kempld_gpio_data, chip);
118 struct kempld_device_data *pld = gpio->pld;
119
Brunner Michael2e7f6122013-07-31 20:55:39 +0200120 return kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), offset);
Guenter Roeckd22fcde2013-06-23 21:00:05 -0700121}
122
123static int kempld_gpio_pincount(struct kempld_device_data *pld)
124{
125 u16 evt, evt_back;
126
127 kempld_get_mutex(pld);
128
129 /* Backup event register as it might be already initialized */
130 evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
131 /* Clear event register */
132 kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
133 /* Read back event register */
134 evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
135 /* Restore event register */
136 kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);
137
138 kempld_release_mutex(pld);
139
140 return evt ? __ffs(evt) : 16;
141}
142
143static int kempld_gpio_probe(struct platform_device *pdev)
144{
145 struct device *dev = &pdev->dev;
146 struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
Jingoo Hane56aee12013-07-30 17:08:05 +0900147 struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
Guenter Roeckd22fcde2013-06-23 21:00:05 -0700148 struct kempld_gpio_data *gpio;
149 struct gpio_chip *chip;
150 int ret;
151
152 if (pld->info.spec_major < 2) {
153 dev_err(dev,
154 "Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
155 return -ENODEV;
156 }
157
158 gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
159 if (gpio == NULL)
160 return -ENOMEM;
161
162 gpio->pld = pld;
163
164 platform_set_drvdata(pdev, gpio);
165
166 chip = &gpio->chip;
167 chip->label = "gpio-kempld";
168 chip->owner = THIS_MODULE;
169 chip->dev = dev;
Linus Walleij9fb1f392013-12-04 14:42:46 +0100170 chip->can_sleep = true;
Guenter Roeckd22fcde2013-06-23 21:00:05 -0700171 if (pdata && pdata->gpio_base)
172 chip->base = pdata->gpio_base;
173 else
174 chip->base = -1;
175 chip->direction_input = kempld_gpio_direction_input;
176 chip->direction_output = kempld_gpio_direction_output;
177 chip->get_direction = kempld_gpio_get_direction;
178 chip->get = kempld_gpio_get;
179 chip->set = kempld_gpio_set;
180 chip->ngpio = kempld_gpio_pincount(pld);
181 if (chip->ngpio == 0) {
182 dev_err(dev, "No GPIO pins detected\n");
183 return -ENODEV;
184 }
185
186 ret = gpiochip_add(chip);
187 if (ret) {
188 dev_err(dev, "Could not register GPIO chip\n");
189 return ret;
190 }
191
192 dev_info(dev, "GPIO functionality initialized with %d pins\n",
193 chip->ngpio);
194
195 return 0;
196}
197
198static int kempld_gpio_remove(struct platform_device *pdev)
199{
200 struct kempld_gpio_data *gpio = platform_get_drvdata(pdev);
201
202 return gpiochip_remove(&gpio->chip);
203}
204
205static struct platform_driver kempld_gpio_driver = {
206 .driver = {
Michael Brunner81e9df22013-08-09 17:33:06 +0200207 .name = "kempld-gpio",
Guenter Roeckd22fcde2013-06-23 21:00:05 -0700208 .owner = THIS_MODULE,
209 },
210 .probe = kempld_gpio_probe,
211 .remove = kempld_gpio_remove,
212};
213
214module_platform_driver(kempld_gpio_driver);
215
216MODULE_DESCRIPTION("KEM PLD GPIO Driver");
217MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
218MODULE_LICENSE("GPL");
Axel Lin9288eca2014-04-12 12:45:18 +0800219MODULE_ALIAS("platform:kempld-gpio");