blob: a68e199d579d58c099203886eaabd3479c0e35cf [file] [log] [blame]
Andreas Wernerf436bc22016-02-29 19:44:43 +01001/*
2 * MEN 16Z127 GPIO driver
3 *
4 * Copyright (C) 2016 MEN Mikroelektronik GmbH (www.men.de)
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; version 2 of the License.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/io.h>
14#include <linux/err.h>
15#include <linux/mcb.h>
16#include <linux/bitops.h>
17#include <linux/gpio/driver.h>
18
19#define MEN_Z127_CTRL 0x00
20#define MEN_Z127_PSR 0x04
21#define MEN_Z127_IRQR 0x08
22#define MEN_Z127_GPIODR 0x0c
23#define MEN_Z127_IER1 0x10
24#define MEN_Z127_IER2 0x14
25#define MEN_Z127_DBER 0x18
26#define MEN_Z127_ODER 0x1C
27#define GPIO_TO_DBCNT_REG(gpio) ((gpio * 4) + 0x80)
28
29#define MEN_Z127_DB_MIN_US 50
30/* 16 bit compare register. Each bit represents 50us */
31#define MEN_Z127_DB_MAX_US (0xffff * MEN_Z127_DB_MIN_US)
32#define MEN_Z127_DB_IN_RANGE(db) ((db >= MEN_Z127_DB_MIN_US) && \
33 (db <= MEN_Z127_DB_MAX_US))
34
35struct men_z127_gpio {
36 struct gpio_chip gc;
37 void __iomem *reg_base;
38 struct mcb_device *mdev;
39 struct resource *mem;
40 spinlock_t lock;
41};
42
43static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
44 unsigned debounce)
45{
46 struct men_z127_gpio *priv = gpiochip_get_data(gc);
47 struct device *dev = &priv->mdev->dev;
48 unsigned int rnd;
49 u32 db_en, db_cnt;
50
51 if (!MEN_Z127_DB_IN_RANGE(debounce)) {
52 dev_err(dev, "debounce value %u out of range", debounce);
53 return -EINVAL;
54 }
55
56 if (debounce > 0) {
57 /* round up or down depending on MSB-1 */
58 rnd = fls(debounce) - 1;
59
60 if (rnd && (debounce & BIT(rnd - 1)))
61 debounce = round_up(debounce, MEN_Z127_DB_MIN_US);
62 else
63 debounce = round_down(debounce, MEN_Z127_DB_MIN_US);
64
65 if (debounce > MEN_Z127_DB_MAX_US)
66 debounce = MEN_Z127_DB_MAX_US;
67
68 /* 50us per register unit */
69 debounce /= 50;
70 }
71
72 spin_lock(&priv->lock);
73
74 db_en = readl(priv->reg_base + MEN_Z127_DBER);
75
76 if (debounce == 0) {
77 db_en &= ~BIT(gpio);
78 db_cnt = 0;
79 } else {
80 db_en |= BIT(gpio);
81 db_cnt = debounce;
82 }
83
84 writel(db_en, priv->reg_base + MEN_Z127_DBER);
85 writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio));
86
87 spin_unlock(&priv->lock);
88
89 return 0;
90}
91
92static int men_z127_request(struct gpio_chip *gc, unsigned gpio_pin)
93{
94 struct men_z127_gpio *priv = gpiochip_get_data(gc);
95 u32 od_en;
96
97 if (gpio_pin >= gc->ngpio)
98 return -EINVAL;
99
100 spin_lock(&priv->lock);
101 od_en = readl(priv->reg_base + MEN_Z127_ODER);
102
103 if (gpiochip_line_is_open_drain(gc, gpio_pin))
104 od_en |= BIT(gpio_pin);
105 else
106 od_en &= ~BIT(gpio_pin);
107
108 writel(od_en, priv->reg_base + MEN_Z127_ODER);
109 spin_unlock(&priv->lock);
110
111 return 0;
112}
113
114static int men_z127_probe(struct mcb_device *mdev,
115 const struct mcb_device_id *id)
116{
117 struct men_z127_gpio *men_z127_gpio;
118 struct device *dev = &mdev->dev;
119 int ret;
120
121 men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio),
122 GFP_KERNEL);
123 if (!men_z127_gpio)
124 return -ENOMEM;
125
126 men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev));
127 if (IS_ERR(men_z127_gpio->mem)) {
128 dev_err(dev, "failed to request device memory");
129 return PTR_ERR(men_z127_gpio->mem);
130 }
131
132 men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start,
133 resource_size(men_z127_gpio->mem));
134 if (men_z127_gpio->reg_base == NULL) {
135 ret = -ENXIO;
136 goto err_release;
137 }
138
139 men_z127_gpio->mdev = mdev;
140 mcb_set_drvdata(mdev, men_z127_gpio);
141
142 ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4,
143 men_z127_gpio->reg_base + MEN_Z127_PSR,
144 men_z127_gpio->reg_base + MEN_Z127_CTRL,
145 NULL,
146 men_z127_gpio->reg_base + MEN_Z127_GPIODR,
147 NULL, 0);
148 if (ret)
149 goto err_unmap;
150
151 men_z127_gpio->gc.set_debounce = men_z127_debounce;
152 men_z127_gpio->gc.request = men_z127_request;
153
154 ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio);
155 if (ret) {
156 dev_err(dev, "failed to register MEN 16Z127 GPIO controller");
157 goto err_unmap;
158 }
159
160 dev_info(dev, "MEN 16Z127 GPIO driver registered");
161
162 return 0;
163
164err_unmap:
165 iounmap(men_z127_gpio->reg_base);
166err_release:
167 mcb_release_mem(men_z127_gpio->mem);
168 return ret;
169}
170
171static void men_z127_remove(struct mcb_device *mdev)
172{
173 struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev);
174
175 gpiochip_remove(&men_z127_gpio->gc);
176 iounmap(men_z127_gpio->reg_base);
177 mcb_release_mem(men_z127_gpio->mem);
178}
179
180static const struct mcb_device_id men_z127_ids[] = {
181 { .device = 0x7f },
182 { }
183};
184MODULE_DEVICE_TABLE(mcb, men_z127_ids);
185
186static struct mcb_driver men_z127_driver = {
187 .driver = {
188 .name = "z127-gpio",
189 .owner = THIS_MODULE,
190 },
191 .probe = men_z127_probe,
192 .remove = men_z127_remove,
193 .id_table = men_z127_ids,
194};
195module_mcb_driver(men_z127_driver);
196
197MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
198MODULE_DESCRIPTION("MEN 16z127 GPIO Controller");
199MODULE_LICENSE("GPL v2");
200MODULE_ALIAS("mcb:16z127");