1/*
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 resource *mem;
39};
40
41static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
42 unsigned debounce)
43{
44 struct men_z127_gpio *priv = gpiochip_get_data(gc);
45 struct device *dev = gc->parent;
46 unsigned int rnd;
47 u32 db_en, db_cnt;
48
49 if (!MEN_Z127_DB_IN_RANGE(debounce)) {
50 dev_err(dev, "debounce value %u out of range", debounce);
51 return -EINVAL;
52 }
53
54 if (debounce > 0) {
55 /* round up or down depending on MSB-1 */
56 rnd = fls(debounce) - 1;
57
58 if (rnd && (debounce & BIT(rnd - 1)))
59 debounce = roundup(debounce, MEN_Z127_DB_MIN_US);
60 else
61 debounce = rounddown(debounce, MEN_Z127_DB_MIN_US);
62
63 if (debounce > MEN_Z127_DB_MAX_US)
64 debounce = MEN_Z127_DB_MAX_US;
65
66 /* 50us per register unit */
67 debounce /= 50;
68 }
69
70 spin_lock(&gc->bgpio_lock);
71
72 db_en = readl(priv->reg_base + MEN_Z127_DBER);
73
74 if (debounce == 0) {
75 db_en &= ~BIT(gpio);
76 db_cnt = 0;
77 } else {
78 db_en |= BIT(gpio);
79 db_cnt = debounce;
80 }
81
82 writel(db_en, priv->reg_base + MEN_Z127_DBER);
83 writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio));
84
85 spin_unlock(&gc->bgpio_lock);
86
87 return 0;
88}
89
90static int men_z127_set_single_ended(struct gpio_chip *gc,
91 unsigned offset,
92 enum pin_config_param param)
93{
94 struct men_z127_gpio *priv = gpiochip_get_data(gc);
95 u32 od_en;
96
97 spin_lock(&gc->bgpio_lock);
98 od_en = readl(priv->reg_base + MEN_Z127_ODER);
99
100 if (param == PIN_CONFIG_DRIVE_OPEN_DRAIN)
101 od_en |= BIT(offset);
102 else
103 /* Implicitly PIN_CONFIG_DRIVE_PUSH_PULL */
104 od_en &= ~BIT(offset);
105
106 writel(od_en, priv->reg_base + MEN_Z127_ODER);
107 spin_unlock(&gc->bgpio_lock);
108
109 return 0;
110}
111
112static int men_z127_set_config(struct gpio_chip *gc, unsigned offset,
113 unsigned long config)
114{
115 enum pin_config_param param = pinconf_to_config_param(config);
116
117 switch (param) {
118 case PIN_CONFIG_DRIVE_OPEN_DRAIN:
119 case PIN_CONFIG_DRIVE_PUSH_PULL:
120 return men_z127_set_single_ended(gc, offset, param);
121
122 case PIN_CONFIG_INPUT_DEBOUNCE:
123 return men_z127_debounce(gc, offset,
124 pinconf_to_config_argument(config));
125
126 default:
127 break;
128 }
129
130 return -ENOTSUPP;
131}
132
133static int men_z127_probe(struct mcb_device *mdev,
134 const struct mcb_device_id *id)
135{
136 struct men_z127_gpio *men_z127_gpio;
137 struct device *dev = &mdev->dev;
138 int ret;
139
140 men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio),
141 GFP_KERNEL);
142 if (!men_z127_gpio)
143 return -ENOMEM;
144
145 men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev));
146 if (IS_ERR(men_z127_gpio->mem)) {
147 dev_err(dev, "failed to request device memory");
148 return PTR_ERR(men_z127_gpio->mem);
149 }
150
151 men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start,
152 resource_size(men_z127_gpio->mem));
153 if (men_z127_gpio->reg_base == NULL) {
154 ret = -ENXIO;
155 goto err_release;
156 }
157
158 mcb_set_drvdata(mdev, men_z127_gpio);
159
160 ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4,
161 men_z127_gpio->reg_base + MEN_Z127_PSR,
162 men_z127_gpio->reg_base + MEN_Z127_CTRL,
163 NULL,
164 men_z127_gpio->reg_base + MEN_Z127_GPIODR,
165 NULL, 0);
166 if (ret)
167 goto err_unmap;
168
169 men_z127_gpio->gc.set_config = men_z127_set_config;
170
171 ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio);
172 if (ret) {
173 dev_err(dev, "failed to register MEN 16Z127 GPIO controller");
174 goto err_unmap;
175 }
176
177 dev_info(dev, "MEN 16Z127 GPIO driver registered");
178
179 return 0;
180
181err_unmap:
182 iounmap(men_z127_gpio->reg_base);
183err_release:
184 mcb_release_mem(men_z127_gpio->mem);
185 return ret;
186}
187
188static void men_z127_remove(struct mcb_device *mdev)
189{
190 struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev);
191
192 gpiochip_remove(&men_z127_gpio->gc);
193 iounmap(men_z127_gpio->reg_base);
194 mcb_release_mem(men_z127_gpio->mem);
195}
196
197static const struct mcb_device_id men_z127_ids[] = {
198 { .device = 0x7f },
199 { }
200};
201MODULE_DEVICE_TABLE(mcb, men_z127_ids);
202
203static struct mcb_driver men_z127_driver = {
204 .driver = {
205 .name = "z127-gpio",
206 },
207 .probe = men_z127_probe,
208 .remove = men_z127_remove,
209 .id_table = men_z127_ids,
210};
211module_mcb_driver(men_z127_driver);
212
213MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
214MODULE_DESCRIPTION("MEN 16z127 GPIO Controller");
215MODULE_LICENSE("GPL v2");
216MODULE_ALIAS("mcb:16z127");
217