summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-sama5d2-piobu.c
blob: 3e95da717fc9a73ff32e39bae4bd269b14debb72 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
// SPDX-License-Identifier: GPL-2.0
/*
 * SAMA5D2 PIOBU GPIO controller
 *
 * Copyright (C) 2018 Microchip Technology Inc. and its subsidiaries
 *
 * Author: Andrei Stefanescu <andrei.stefanescu@microchip.com>
 *
 */
#include <linux/bits.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#define PIOBU_NUM 8
#define PIOBU_REG_SIZE 4

/*
 * backup mode protection register for tamper detection
 * normal mode protection register for tamper detection
 * wakeup signal generation
 */
#define PIOBU_BMPR 0x7C
#define PIOBU_NMPR 0x80
#define PIOBU_WKPR 0x90

#define PIOBU_BASE 0x18 /* PIOBU offset from SECUMOD base register address. */

#define PIOBU_DET_OFFSET 16

/* In the datasheet this bit is called OUTPUT */
#define PIOBU_DIRECTION BIT(8)
#define PIOBU_OUT BIT(8)
#define PIOBU_IN 0

#define PIOBU_SOD BIT(9)
#define PIOBU_PDS BIT(10)

#define PIOBU_HIGH BIT(9)
#define PIOBU_LOW 0

struct sama5d2_piobu {
	struct gpio_chip chip;
	struct regmap *regmap;
};

/*
 * sama5d2_piobu_setup_pin() - prepares a pin for set_direction call
 *
 * Do not consider pin for tamper detection (normal and backup modes)
 * Do not consider pin as tamper wakeup interrupt source
 */
static int sama5d2_piobu_setup_pin(struct gpio_chip *chip, unsigned int pin)
{
	int ret;
	struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
						   chip);
	unsigned int mask = BIT(PIOBU_DET_OFFSET + pin);

	ret = regmap_update_bits(piobu->regmap, PIOBU_BMPR, mask, 0);
	if (ret)
		return ret;

	ret = regmap_update_bits(piobu->regmap, PIOBU_NMPR, mask, 0);
	if (ret)
		return ret;

	return regmap_update_bits(piobu->regmap, PIOBU_WKPR, mask, 0);
}

/*
 * sama5d2_piobu_write_value() - writes value & mask at the pin's PIOBU register
 */
static int sama5d2_piobu_write_value(struct gpio_chip *chip, unsigned int pin,
				     unsigned int mask, unsigned int value)
{
	int reg;
	struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
						   chip);

	reg = PIOBU_BASE + pin * PIOBU_REG_SIZE;

	return regmap_update_bits(piobu->regmap, reg, mask, value);
}

/*
 * sama5d2_piobu_read_value() - read the value with masking from the pin's PIOBU
 *			      register
 */
static int sama5d2_piobu_read_value(struct gpio_chip *chip, unsigned int pin,
				    unsigned int mask)
{
	struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
						   chip);
	unsigned int val, reg;
	int ret;

	reg = PIOBU_BASE + pin * PIOBU_REG_SIZE;
	ret = regmap_read(piobu->regmap, reg, &val);
	if (ret < 0)
		return ret;

	return val & mask;
}

/*
 * sama5d2_piobu_get_direction() - gpiochip get_direction
 */
static int sama5d2_piobu_get_direction(struct gpio_chip *chip,
				       unsigned int pin)
{
	int ret = sama5d2_piobu_read_value(chip, pin, PIOBU_DIRECTION);

	if (ret < 0)
		return ret;

	return (ret == PIOBU_IN) ? GPIO_LINE_DIRECTION_IN :
				   GPIO_LINE_DIRECTION_OUT;
}

/*
 * sama5d2_piobu_direction_input() - gpiochip direction_input
 */
static int sama5d2_piobu_direction_input(struct gpio_chip *chip,
					 unsigned int pin)
{
	return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION, PIOBU_IN);
}

/*
 * sama5d2_piobu_direction_output() - gpiochip direction_output
 */
static int sama5d2_piobu_direction_output(struct gpio_chip *chip,
					  unsigned int pin, int value)
{
	unsigned int val = PIOBU_OUT;

	if (value)
		val |= PIOBU_HIGH;

	return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION | PIOBU_SOD,
					 val);
}

/*
 * sama5d2_piobu_get() - gpiochip get
 */
static int sama5d2_piobu_get(struct gpio_chip *chip, unsigned int pin)
{
	/* if pin is input, read value from PDS else read from SOD */
	int ret = sama5d2_piobu_get_direction(chip, pin);

	if (ret == GPIO_LINE_DIRECTION_IN)
		ret = sama5d2_piobu_read_value(chip, pin, PIOBU_PDS);
	else if (ret == GPIO_LINE_DIRECTION_OUT)
		ret = sama5d2_piobu_read_value(chip, pin, PIOBU_SOD);

	if (ret < 0)
		return ret;

	return !!ret;
}

/*
 * sama5d2_piobu_set() - gpiochip set
 */
static void sama5d2_piobu_set(struct gpio_chip *chip, unsigned int pin,
			      int value)
{
	if (!value)
		value = PIOBU_LOW;
	else
		value = PIOBU_HIGH;

	sama5d2_piobu_write_value(chip, pin, PIOBU_SOD, value);
}

static int sama5d2_piobu_probe(struct platform_device *pdev)
{
	struct sama5d2_piobu *piobu;
	int ret, i;

	piobu = devm_kzalloc(&pdev->dev, sizeof(*piobu), GFP_KERNEL);
	if (!piobu)
		return -ENOMEM;

	platform_set_drvdata(pdev, piobu);
	piobu->chip.label = pdev->name;
	piobu->chip.parent = &pdev->dev;
	piobu->chip.owner = THIS_MODULE,
	piobu->chip.get_direction = sama5d2_piobu_get_direction,
	piobu->chip.direction_input = sama5d2_piobu_direction_input,
	piobu->chip.direction_output = sama5d2_piobu_direction_output,
	piobu->chip.get = sama5d2_piobu_get,
	piobu->chip.set = sama5d2_piobu_set,
	piobu->chip.base = -1,
	piobu->chip.ngpio = PIOBU_NUM,
	piobu->chip.can_sleep = 0,

	piobu->regmap = syscon_node_to_regmap(pdev->dev.of_node);
	if (IS_ERR(piobu->regmap)) {
		dev_err(&pdev->dev, "Failed to get syscon regmap %ld\n",
			PTR_ERR(piobu->regmap));
		return PTR_ERR(piobu->regmap);
	}

	ret = devm_gpiochip_add_data(&pdev->dev, &piobu->chip, piobu);
	if (ret) {
		dev_err(&pdev->dev, "Failed to add gpiochip %d\n", ret);
		return ret;
	}

	for (i = 0; i < PIOBU_NUM; ++i) {
		ret = sama5d2_piobu_setup_pin(&piobu->chip, i);
		if (ret) {
			dev_err(&pdev->dev, "Failed to setup pin: %d %d\n",
				i, ret);
			return ret;
		}
	}

	return 0;
}

static const struct of_device_id sama5d2_piobu_ids[] = {
	{ .compatible = "atmel,sama5d2-secumod" },
	{},
};
MODULE_DEVICE_TABLE(of, sama5d2_piobu_ids);

static struct platform_driver sama5d2_piobu_driver = {
	.driver = {
		.name		= "sama5d2-piobu",
		.of_match_table	= of_match_ptr(sama5d2_piobu_ids)
	},
	.probe = sama5d2_piobu_probe,
};

module_platform_driver(sama5d2_piobu_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("SAMA5D2 PIOBU controller driver");
MODULE_AUTHOR("Andrei Stefanescu <andrei.stefanescu@microchip.com>");