tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Kontron PLD GPIO driver
4 *
5 * Copyright (c) 2010-2013 Kontron Europe GmbH
6 * Author: Michael Brunner <michael.brunner@kontron.com>
7 */
8
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/bitops.h>
13#include <linux/errno.h>
14#include <linux/platform_device.h>
15#include <linux/gpio/driver.h>
16#include <linux/mfd/kempld.h>
17
18#define KEMPLD_GPIO_MAX_NUM 16
19#define KEMPLD_GPIO_MASK(x) (BIT((x) % 8))
20#define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)
21#define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)
22#define KEMPLD_GPIO_EVT_LVL_EDGE 0x46
23#define KEMPLD_GPIO_IEN 0x4A
24
25struct kempld_gpio_data {
26 struct gpio_chip chip;
27 struct kempld_device_data *pld;
28};
29
30/*
31 * Set or clear GPIO bit
32 * kempld_get_mutex must be called prior to calling this function.
33 */
34static void kempld_gpio_bitop(struct kempld_device_data *pld,
35 u8 reg, u8 bit, u8 val)
36{
37 u8 status;
38
39 status = kempld_read8(pld, reg);
40 if (val)
41 status |= KEMPLD_GPIO_MASK(bit);
42 else
43 status &= ~KEMPLD_GPIO_MASK(bit);
44 kempld_write8(pld, reg, status);
45}
46
47static int kempld_gpio_get_bit(struct kempld_device_data *pld, u8 reg, u8 bit)
48{
49 u8 status;
50
51 kempld_get_mutex(pld);
52 status = kempld_read8(pld, reg);
53 kempld_release_mutex(pld);
54
55 return !!(status & KEMPLD_GPIO_MASK(bit));
56}
57
58static int kempld_gpio_get(struct gpio_chip *chip, unsigned offset)
59{
60 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
61 struct kempld_device_data *pld = gpio->pld;
62
63 return !!kempld_gpio_get_bit(pld, KEMPLD_GPIO_LVL_NUM(offset), offset);
64}
65
66static int kempld_gpio_set(struct gpio_chip *chip, unsigned int offset,
67 int value)
68{
69 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
70 struct kempld_device_data *pld = gpio->pld;
71
72 kempld_get_mutex(pld);
73 kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
74 kempld_release_mutex(pld);
75
76 return 0;
77}
78
79static int kempld_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
80{
81 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
82 struct kempld_device_data *pld = gpio->pld;
83
84 kempld_get_mutex(pld);
85 kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 0);
86 kempld_release_mutex(pld);
87
88 return 0;
89}
90
91static int kempld_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
92 int value)
93{
94 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
95 struct kempld_device_data *pld = gpio->pld;
96
97 kempld_get_mutex(pld);
98 kempld_gpio_bitop(pld, KEMPLD_GPIO_LVL_NUM(offset), offset, value);
99 kempld_gpio_bitop(pld, KEMPLD_GPIO_DIR_NUM(offset), offset, 1);
100 kempld_release_mutex(pld);
101
102 return 0;
103}
104
105static int kempld_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
106{
107 struct kempld_gpio_data *gpio = gpiochip_get_data(chip);
108 struct kempld_device_data *pld = gpio->pld;
109
110 if (kempld_gpio_get_bit(pld, KEMPLD_GPIO_DIR_NUM(offset), offset))
111 return GPIO_LINE_DIRECTION_OUT;
112
113 return GPIO_LINE_DIRECTION_IN;
114}
115
116static int kempld_gpio_pincount(struct kempld_device_data *pld)
117{
118 u16 evt, evt_back;
119
120 kempld_get_mutex(pld);
121
122 /* Backup event register as it might be already initialized */
123 evt_back = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
124 /* Clear event register */
125 kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, 0x0000);
126 /* Read back event register */
127 evt = kempld_read16(pld, KEMPLD_GPIO_EVT_LVL_EDGE);
128 /* Restore event register */
129 kempld_write16(pld, KEMPLD_GPIO_EVT_LVL_EDGE, evt_back);
130
131 kempld_release_mutex(pld);
132
133 return evt ? __ffs(evt) : 16;
134}
135
136static int kempld_gpio_probe(struct platform_device *pdev)
137{
138 struct device *dev = &pdev->dev;
139 struct kempld_device_data *pld = dev_get_drvdata(dev->parent);
140 struct kempld_platform_data *pdata = dev_get_platdata(pld->dev);
141 struct kempld_gpio_data *gpio;
142 struct gpio_chip *chip;
143 int ret;
144
145 if (pld->info.spec_major < 2) {
146 dev_err(dev,
147 "Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
148 return -ENODEV;
149 }
150
151 gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
152 if (!gpio)
153 return -ENOMEM;
154
155 gpio->pld = pld;
156
157 platform_set_drvdata(pdev, gpio);
158
159 chip = &gpio->chip;
160 chip->label = "gpio-kempld";
161 chip->owner = THIS_MODULE;
162 chip->parent = dev;
163 chip->can_sleep = true;
164 if (pdata && pdata->gpio_base)
165 chip->base = pdata->gpio_base;
166 else
167 chip->base = -1;
168 chip->direction_input = kempld_gpio_direction_input;
169 chip->direction_output = kempld_gpio_direction_output;
170 chip->get_direction = kempld_gpio_get_direction;
171 chip->get = kempld_gpio_get;
172 chip->set = kempld_gpio_set;
173 chip->ngpio = kempld_gpio_pincount(pld);
174 if (chip->ngpio == 0) {
175 dev_err(dev, "No GPIO pins detected\n");
176 return -ENODEV;
177 }
178
179 ret = devm_gpiochip_add_data(dev, chip, gpio);
180 if (ret) {
181 dev_err(dev, "Could not register GPIO chip\n");
182 return ret;
183 }
184
185 dev_info(dev, "GPIO functionality initialized with %d pins\n",
186 chip->ngpio);
187
188 return 0;
189}
190
191static struct platform_driver kempld_gpio_driver = {
192 .driver = {
193 .name = "kempld-gpio",
194 },
195 .probe = kempld_gpio_probe,
196};
197
198module_platform_driver(kempld_gpio_driver);
199
200MODULE_DESCRIPTION("KEM PLD GPIO Driver");
201MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
202MODULE_LICENSE("GPL");
203MODULE_ALIAS("platform:kempld-gpio");