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) ? 1 : 0;
123}
124
125/**
126 * sama5d2_piobu_direction_input() - gpiochip direction_input
127 */
128static int sama5d2_piobu_direction_input(struct gpio_chip *chip,
129 unsigned int pin)
130{
131 return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION, PIOBU_IN);
132}
133
134/**
135 * sama5d2_piobu_direction_output() - gpiochip direction_output
136 */
137static int sama5d2_piobu_direction_output(struct gpio_chip *chip,
138 unsigned int pin, int value)
139{
140 unsigned int val = PIOBU_OUT;
141
142 if (value)
143 val |= PIOBU_HIGH;
144
145 return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION | PIOBU_SOD,
146 val);
147}
148
149/**
150 * sama5d2_piobu_get() - gpiochip get
151 */
152static int sama5d2_piobu_get(struct gpio_chip *chip, unsigned int pin)
153{
154 /* if pin is input, read value from PDS else read from SOD */
155 int ret = sama5d2_piobu_get_direction(chip, pin);
156
157 if (ret == 1)
158 ret = sama5d2_piobu_read_value(chip, pin, PIOBU_PDS);
159 else if (!ret)
160 ret = sama5d2_piobu_read_value(chip, pin, PIOBU_SOD);
161
162 if (ret < 0)
163 return ret;
164
165 return !!ret;
166}
167
168/**
169 * sama5d2_piobu_set() - gpiochip set
170 */
171static void sama5d2_piobu_set(struct gpio_chip *chip, unsigned int pin,
172 int value)
173{
174 if (!value)
175 value = PIOBU_LOW;
176 else
177 value = PIOBU_HIGH;
178
179 sama5d2_piobu_write_value(chip, pin, PIOBU_SOD, value);
180}
181
182static int sama5d2_piobu_probe(struct platform_device *pdev)
183{
184 struct sama5d2_piobu *piobu;
185 int ret, i;
186
187 piobu = devm_kzalloc(&pdev->dev, sizeof(*piobu), GFP_KERNEL);
188 if (!piobu)
189 return -ENOMEM;
190
191 platform_set_drvdata(pdev, piobu);
192 piobu->chip.label = pdev->name;
193 piobu->chip.parent = &pdev->dev;
194 piobu->chip.of_node = pdev->dev.of_node;
195 piobu->chip.owner = THIS_MODULE,
196 piobu->chip.get_direction = sama5d2_piobu_get_direction,
197 piobu->chip.direction_input = sama5d2_piobu_direction_input,
198 piobu->chip.direction_output = sama5d2_piobu_direction_output,
199 piobu->chip.get = sama5d2_piobu_get,
200 piobu->chip.set = sama5d2_piobu_set,
201 piobu->chip.base = -1,
202 piobu->chip.ngpio = PIOBU_NUM,
203 piobu->chip.can_sleep = 0,
204
205 piobu->regmap = syscon_node_to_regmap(pdev->dev.of_node);
206 if (IS_ERR(piobu->regmap)) {
207 dev_err(&pdev->dev, "Failed to get syscon regmap %ld\n",
208 PTR_ERR(piobu->regmap));
209 return PTR_ERR(piobu->regmap);
210 }
211
212 ret = devm_gpiochip_add_data(&pdev->dev, &piobu->chip, piobu);
213 if (ret) {
214 dev_err(&pdev->dev, "Failed to add gpiochip %d\n", ret);
215 return ret;
216 }
217
218 for (i = 0; i < PIOBU_NUM; ++i) {
219 ret = sama5d2_piobu_setup_pin(&piobu->chip, i);
220 if (ret) {
221 dev_err(&pdev->dev, "Failed to setup pin: %d %d\n",
222 i, ret);
223 return ret;
224 }
225 }
226
227 return 0;
228}
229
230static const struct of_device_id sama5d2_piobu_ids[] = {
231 { .compatible = "atmel,sama5d2-secumod" },
232 {},
233};
234MODULE_DEVICE_TABLE(of, sama5d2_piobu_ids);
235
236static struct platform_driver sama5d2_piobu_driver = {
237 .driver = {
238 .name = "sama5d2-piobu",
239 .of_match_table = of_match_ptr(sama5d2_piobu_ids)
240 },
241 .probe = sama5d2_piobu_probe,
242};
243
244module_platform_driver(sama5d2_piobu_driver);
245
246MODULE_VERSION("1.0");
247MODULE_LICENSE("GPL v2");
248MODULE_DESCRIPTION("SAMA5D2 PIOBU controller driver");
249MODULE_AUTHOR("Andrei Stefanescu <andrei.stefanescu@microchip.com>");
250