1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MEN 16Z127 GPIO driver
4 *
5 * Copyright (C) 2016 MEN Mikroelektronik GmbH (www.men.de)
6 */
7
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/io.h>
11#include <linux/err.h>
12#include <linux/mcb.h>
13#include <linux/bitops.h>
14#include <linux/gpio/driver.h>
15
16#define MEN_Z127_CTRL	0x00
17#define MEN_Z127_PSR	0x04
18#define MEN_Z127_IRQR	0x08
19#define MEN_Z127_GPIODR	0x0c
20#define MEN_Z127_IER1	0x10
21#define MEN_Z127_IER2	0x14
22#define MEN_Z127_DBER	0x18
23#define MEN_Z127_ODER	0x1C
24#define GPIO_TO_DBCNT_REG(gpio)	((gpio * 4) + 0x80)
25
26#define MEN_Z127_DB_MIN_US	50
27/* 16 bit compare register. Each bit represents 50us */
28#define MEN_Z127_DB_MAX_US	(0xffff * MEN_Z127_DB_MIN_US)
29#define MEN_Z127_DB_IN_RANGE(db)	((db >= MEN_Z127_DB_MIN_US) && \
30					 (db <= MEN_Z127_DB_MAX_US))
31
32struct men_z127_gpio {
33	struct gpio_chip gc;
34	void __iomem *reg_base;
35	struct resource *mem;
36};
37
38static int men_z127_debounce(struct gpio_chip *gc, unsigned gpio,
39			     unsigned debounce)
40{
41	struct men_z127_gpio *priv = gpiochip_get_data(gc);
42	struct device *dev = gc->parent;
43	unsigned int rnd;
44	u32 db_en, db_cnt;
45
46	if (!MEN_Z127_DB_IN_RANGE(debounce)) {
47		dev_err(dev, "debounce value %u out of range", debounce);
48		return -EINVAL;
49	}
50
51	if (debounce > 0) {
52		/* round up or down depending on MSB-1 */
53		rnd = fls(debounce) - 1;
54
55		if (rnd && (debounce & BIT(rnd - 1)))
56			debounce = roundup(debounce, MEN_Z127_DB_MIN_US);
57		else
58			debounce = rounddown(debounce, MEN_Z127_DB_MIN_US);
59
60		if (debounce > MEN_Z127_DB_MAX_US)
61			debounce = MEN_Z127_DB_MAX_US;
62
63		/* 50us per register unit */
64		debounce /= 50;
65	}
66
67	raw_spin_lock(&gc->bgpio_lock);
68
69	db_en = readl(priv->reg_base + MEN_Z127_DBER);
70
71	if (debounce == 0) {
72		db_en &= ~BIT(gpio);
73		db_cnt = 0;
74	} else {
75		db_en |= BIT(gpio);
76		db_cnt = debounce;
77	}
78
79	writel(db_en, priv->reg_base + MEN_Z127_DBER);
80	writel(db_cnt, priv->reg_base + GPIO_TO_DBCNT_REG(gpio));
81
82	raw_spin_unlock(&gc->bgpio_lock);
83
84	return 0;
85}
86
87static int men_z127_set_single_ended(struct gpio_chip *gc,
88				     unsigned offset,
89				     enum pin_config_param param)
90{
91	struct men_z127_gpio *priv = gpiochip_get_data(gc);
92	u32 od_en;
93
94	raw_spin_lock(&gc->bgpio_lock);
95	od_en = readl(priv->reg_base + MEN_Z127_ODER);
96
97	if (param == PIN_CONFIG_DRIVE_OPEN_DRAIN)
98		od_en |= BIT(offset);
99	else
100		/* Implicitly PIN_CONFIG_DRIVE_PUSH_PULL */
101		od_en &= ~BIT(offset);
102
103	writel(od_en, priv->reg_base + MEN_Z127_ODER);
104	raw_spin_unlock(&gc->bgpio_lock);
105
106	return 0;
107}
108
109static int men_z127_set_config(struct gpio_chip *gc, unsigned offset,
110			       unsigned long config)
111{
112	enum pin_config_param param = pinconf_to_config_param(config);
113
114	switch (param) {
115	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
116	case PIN_CONFIG_DRIVE_PUSH_PULL:
117		return men_z127_set_single_ended(gc, offset, param);
118
119	case PIN_CONFIG_INPUT_DEBOUNCE:
120		return men_z127_debounce(gc, offset,
121			pinconf_to_config_argument(config));
122
123	default:
124		break;
125	}
126
127	return -ENOTSUPP;
128}
129
130static int men_z127_probe(struct mcb_device *mdev,
131			  const struct mcb_device_id *id)
132{
133	struct men_z127_gpio *men_z127_gpio;
134	struct device *dev = &mdev->dev;
135	int ret;
136
137	men_z127_gpio = devm_kzalloc(dev, sizeof(struct men_z127_gpio),
138				     GFP_KERNEL);
139	if (!men_z127_gpio)
140		return -ENOMEM;
141
142	men_z127_gpio->mem = mcb_request_mem(mdev, dev_name(dev));
143	if (IS_ERR(men_z127_gpio->mem)) {
144		dev_err(dev, "failed to request device memory");
145		return PTR_ERR(men_z127_gpio->mem);
146	}
147
148	men_z127_gpio->reg_base = ioremap(men_z127_gpio->mem->start,
149					  resource_size(men_z127_gpio->mem));
150	if (men_z127_gpio->reg_base == NULL) {
151		ret = -ENXIO;
152		goto err_release;
153	}
154
155	mcb_set_drvdata(mdev, men_z127_gpio);
156
157	ret = bgpio_init(&men_z127_gpio->gc, &mdev->dev, 4,
158			 men_z127_gpio->reg_base + MEN_Z127_PSR,
159			 men_z127_gpio->reg_base + MEN_Z127_CTRL,
160			 NULL,
161			 men_z127_gpio->reg_base + MEN_Z127_GPIODR,
162			 NULL, 0);
163	if (ret)
164		goto err_unmap;
165
166	men_z127_gpio->gc.set_config = men_z127_set_config;
167
168	ret = gpiochip_add_data(&men_z127_gpio->gc, men_z127_gpio);
169	if (ret) {
170		dev_err(dev, "failed to register MEN 16Z127 GPIO controller");
171		goto err_unmap;
172	}
173
174	dev_info(dev, "MEN 16Z127 GPIO driver registered");
175
176	return 0;
177
178err_unmap:
179	iounmap(men_z127_gpio->reg_base);
180err_release:
181	mcb_release_mem(men_z127_gpio->mem);
182	return ret;
183}
184
185static void men_z127_remove(struct mcb_device *mdev)
186{
187	struct men_z127_gpio *men_z127_gpio = mcb_get_drvdata(mdev);
188
189	gpiochip_remove(&men_z127_gpio->gc);
190	iounmap(men_z127_gpio->reg_base);
191	mcb_release_mem(men_z127_gpio->mem);
192}
193
194static const struct mcb_device_id men_z127_ids[] = {
195	{ .device = 0x7f },
196	{ }
197};
198MODULE_DEVICE_TABLE(mcb, men_z127_ids);
199
200static struct mcb_driver men_z127_driver = {
201	.driver = {
202		.name = "z127-gpio",
203	},
204	.probe = men_z127_probe,
205	.remove = men_z127_remove,
206	.id_table = men_z127_ids,
207};
208module_mcb_driver(men_z127_driver);
209
210MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
211MODULE_DESCRIPTION("MEN 16z127 GPIO Controller");
212MODULE_LICENSE("GPL v2");
213MODULE_ALIAS("mcb:16z127");
214MODULE_IMPORT_NS(MCB);
215