1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SAMA5D2 PIOBU GPIO controller
4 *
5 * Copyright (C) 2018 Microchip Technology Inc. and its subsidiaries
6 *
7 * Author: Andrei Stefanescu <andrei.stefanescu@microchip.com>
8 *
9 */
10#include <linux/bits.h>
11#include <linux/gpio/driver.h>
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/mfd/syscon.h>
15#include <linux/module.h>
16#include <linux/of.h>
17#include <linux/platform_device.h>
18#include <linux/regmap.h>
19
20#define PIOBU_NUM 8
21#define PIOBU_REG_SIZE 4
22
23/*
24 * backup mode protection register for tamper detection
25 * normal mode protection register for tamper detection
26 * wakeup signal generation
27 */
28#define PIOBU_BMPR 0x7C
29#define PIOBU_NMPR 0x80
30#define PIOBU_WKPR 0x90
31
32#define PIOBU_BASE 0x18 /* PIOBU offset from SECUMOD base register address. */
33
34#define PIOBU_DET_OFFSET 16
35
36/* In the datasheet this bit is called OUTPUT */
37#define PIOBU_DIRECTION BIT(8)
38#define PIOBU_OUT BIT(8)
39#define PIOBU_IN 0
40
41#define PIOBU_SOD BIT(9)
42#define PIOBU_PDS BIT(10)
43
44#define PIOBU_HIGH BIT(9)
45#define PIOBU_LOW 0
46
47struct sama5d2_piobu {
48	struct gpio_chip chip;
49	struct regmap *regmap;
50};
51
52/*
53 * sama5d2_piobu_setup_pin() - prepares a pin for set_direction call
54 *
55 * Do not consider pin for tamper detection (normal and backup modes)
56 * Do not consider pin as tamper wakeup interrupt source
57 */
58static int sama5d2_piobu_setup_pin(struct gpio_chip *chip, unsigned int pin)
59{
60	int ret;
61	struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
62						   chip);
63	unsigned int mask = BIT(PIOBU_DET_OFFSET + pin);
64
65	ret = regmap_update_bits(piobu->regmap, PIOBU_BMPR, mask, 0);
66	if (ret)
67		return ret;
68
69	ret = regmap_update_bits(piobu->regmap, PIOBU_NMPR, mask, 0);
70	if (ret)
71		return ret;
72
73	return regmap_update_bits(piobu->regmap, PIOBU_WKPR, mask, 0);
74}
75
76/*
77 * sama5d2_piobu_write_value() - writes value & mask at the pin's PIOBU register
78 */
79static int sama5d2_piobu_write_value(struct gpio_chip *chip, unsigned int pin,
80				     unsigned int mask, unsigned int value)
81{
82	int reg;
83	struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
84						   chip);
85
86	reg = PIOBU_BASE + pin * PIOBU_REG_SIZE;
87
88	return regmap_update_bits(piobu->regmap, reg, mask, value);
89}
90
91/*
92 * sama5d2_piobu_read_value() - read the value with masking from the pin's PIOBU
93 *			      register
94 */
95static int sama5d2_piobu_read_value(struct gpio_chip *chip, unsigned int pin,
96				    unsigned int mask)
97{
98	struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
99						   chip);
100	unsigned int val, reg;
101	int ret;
102
103	reg = PIOBU_BASE + pin * PIOBU_REG_SIZE;
104	ret = regmap_read(piobu->regmap, reg, &val);
105	if (ret < 0)
106		return ret;
107
108	return val & mask;
109}
110
111/*
112 * sama5d2_piobu_get_direction() - gpiochip get_direction
113 */
114static int sama5d2_piobu_get_direction(struct gpio_chip *chip,
115				       unsigned int pin)
116{
117	int ret = sama5d2_piobu_read_value(chip, pin, PIOBU_DIRECTION);
118
119	if (ret < 0)
120		return ret;
121
122	return (ret == PIOBU_IN) ? GPIO_LINE_DIRECTION_IN :
123				   GPIO_LINE_DIRECTION_OUT;
124}
125
126/*
127 * sama5d2_piobu_direction_input() - gpiochip direction_input
128 */
129static int sama5d2_piobu_direction_input(struct gpio_chip *chip,
130					 unsigned int pin)
131{
132	return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION, PIOBU_IN);
133}
134
135/*
136 * sama5d2_piobu_direction_output() - gpiochip direction_output
137 */
138static int sama5d2_piobu_direction_output(struct gpio_chip *chip,
139					  unsigned int pin, int value)
140{
141	unsigned int val = PIOBU_OUT;
142
143	if (value)
144		val |= PIOBU_HIGH;
145
146	return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION | PIOBU_SOD,
147					 val);
148}
149
150/*
151 * sama5d2_piobu_get() - gpiochip get
152 */
153static int sama5d2_piobu_get(struct gpio_chip *chip, unsigned int pin)
154{
155	/* if pin is input, read value from PDS else read from SOD */
156	int ret = sama5d2_piobu_get_direction(chip, pin);
157
158	if (ret == GPIO_LINE_DIRECTION_IN)
159		ret = sama5d2_piobu_read_value(chip, pin, PIOBU_PDS);
160	else if (ret == GPIO_LINE_DIRECTION_OUT)
161		ret = sama5d2_piobu_read_value(chip, pin, PIOBU_SOD);
162
163	if (ret < 0)
164		return ret;
165
166	return !!ret;
167}
168
169/*
170 * sama5d2_piobu_set() - gpiochip set
171 */
172static void sama5d2_piobu_set(struct gpio_chip *chip, unsigned int pin,
173			      int value)
174{
175	if (!value)
176		value = PIOBU_LOW;
177	else
178		value = PIOBU_HIGH;
179
180	sama5d2_piobu_write_value(chip, pin, PIOBU_SOD, value);
181}
182
183static int sama5d2_piobu_probe(struct platform_device *pdev)
184{
185	struct sama5d2_piobu *piobu;
186	int ret, i;
187
188	piobu = devm_kzalloc(&pdev->dev, sizeof(*piobu), GFP_KERNEL);
189	if (!piobu)
190		return -ENOMEM;
191
192	piobu->chip.label = pdev->name;
193	piobu->chip.parent = &pdev->dev;
194	piobu->chip.owner = THIS_MODULE,
195	piobu->chip.get_direction = sama5d2_piobu_get_direction,
196	piobu->chip.direction_input = sama5d2_piobu_direction_input,
197	piobu->chip.direction_output = sama5d2_piobu_direction_output,
198	piobu->chip.get = sama5d2_piobu_get,
199	piobu->chip.set = sama5d2_piobu_set,
200	piobu->chip.base = -1,
201	piobu->chip.ngpio = PIOBU_NUM,
202	piobu->chip.can_sleep = 0,
203
204	piobu->regmap = syscon_node_to_regmap(pdev->dev.of_node);
205	if (IS_ERR(piobu->regmap)) {
206		dev_err(&pdev->dev, "Failed to get syscon regmap %ld\n",
207			PTR_ERR(piobu->regmap));
208		return PTR_ERR(piobu->regmap);
209	}
210
211	ret = devm_gpiochip_add_data(&pdev->dev, &piobu->chip, piobu);
212	if (ret) {
213		dev_err(&pdev->dev, "Failed to add gpiochip %d\n", ret);
214		return ret;
215	}
216
217	for (i = 0; i < PIOBU_NUM; ++i) {
218		ret = sama5d2_piobu_setup_pin(&piobu->chip, i);
219		if (ret) {
220			dev_err(&pdev->dev, "Failed to setup pin: %d %d\n",
221				i, ret);
222			return ret;
223		}
224	}
225
226	return 0;
227}
228
229static const struct of_device_id sama5d2_piobu_ids[] = {
230	{ .compatible = "atmel,sama5d2-secumod" },
231	{},
232};
233MODULE_DEVICE_TABLE(of, sama5d2_piobu_ids);
234
235static struct platform_driver sama5d2_piobu_driver = {
236	.driver = {
237		.name		= "sama5d2-piobu",
238		.of_match_table	= sama5d2_piobu_ids,
239	},
240	.probe = sama5d2_piobu_probe,
241};
242
243module_platform_driver(sama5d2_piobu_driver);
244
245MODULE_LICENSE("GPL v2");
246MODULE_DESCRIPTION("SAMA5D2 PIOBU controller driver");
247MODULE_AUTHOR("Andrei Stefanescu <andrei.stefanescu@microchip.com>");
248