tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * GPIO driver for EXAR XRA1403 16-bit GPIO expander
4 *
5 * Copyright (c) 2017, General Electric Company
6 */
7
8#include <linux/bitops.h>
9#include <linux/gpio/driver.h>
10#include <linux/kernel.h>
11#include <linux/mod_devicetable.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/seq_file.h>
15#include <linux/spi/spi.h>
16#include <linux/string_choices.h>
17#include <linux/regmap.h>
18
19/* XRA1403 registers */
20#define XRA_GSR 0x00 /* GPIO State */
21#define XRA_OCR 0x02 /* Output Control */
22#define XRA_PIR 0x04 /* Input Polarity Inversion */
23#define XRA_GCR 0x06 /* GPIO Configuration */
24#define XRA_PUR 0x08 /* Input Internal Pull-up Resistor Enable/Disable */
25#define XRA_IER 0x0A /* Input Interrupt Enable */
26#define XRA_TSCR 0x0C /* Output Three-State Control */
27#define XRA_ISR 0x0E /* Input Interrupt Status */
28#define XRA_REIR 0x10 /* Input Rising Edge Interrupt Enable */
29#define XRA_FEIR 0x12 /* Input Falling Edge Interrupt Enable */
30#define XRA_IFR 0x14 /* Input Filter Enable/Disable */
31#define XRA_LAST 0x15 /* Bounds */
32
33struct xra1403 {
34 struct gpio_chip chip;
35 struct regmap *regmap;
36};
37
38static const struct regmap_config xra1403_regmap_cfg = {
39 .reg_bits = 7,
40 .pad_bits = 1,
41 .val_bits = 8,
42
43 .max_register = XRA_LAST,
44};
45
46static unsigned int to_reg(unsigned int reg, unsigned int offset)
47{
48 return reg + (offset > 7);
49}
50
51static int xra1403_direction_input(struct gpio_chip *chip, unsigned int offset)
52{
53 struct xra1403 *xra = gpiochip_get_data(chip);
54
55 return regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
56 BIT(offset % 8), BIT(offset % 8));
57}
58
59static int xra1403_direction_output(struct gpio_chip *chip, unsigned int offset,
60 int value)
61{
62 int ret;
63 struct xra1403 *xra = gpiochip_get_data(chip);
64
65 ret = regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
66 BIT(offset % 8), 0);
67 if (ret)
68 return ret;
69
70 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
71 BIT(offset % 8), value ? BIT(offset % 8) : 0);
72
73 return ret;
74}
75
76static int xra1403_get_direction(struct gpio_chip *chip, unsigned int offset)
77{
78 int ret;
79 unsigned int val;
80 struct xra1403 *xra = gpiochip_get_data(chip);
81
82 ret = regmap_read(xra->regmap, to_reg(XRA_GCR, offset), &val);
83 if (ret)
84 return ret;
85
86 if (val & BIT(offset % 8))
87 return GPIO_LINE_DIRECTION_IN;
88
89 return GPIO_LINE_DIRECTION_OUT;
90}
91
92static int xra1403_get(struct gpio_chip *chip, unsigned int offset)
93{
94 int ret;
95 unsigned int val;
96 struct xra1403 *xra = gpiochip_get_data(chip);
97
98 ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val);
99 if (ret)
100 return ret;
101
102 return !!(val & BIT(offset % 8));
103}
104
105static int xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)
106{
107 struct xra1403 *xra = gpiochip_get_data(chip);
108
109 return regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
110 BIT(offset % 8),
111 value ? BIT(offset % 8) : 0);
112}
113
114#ifdef CONFIG_DEBUG_FS
115static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)
116{
117 int reg;
118 struct xra1403 *xra = gpiochip_get_data(chip);
119 int value[XRA_LAST];
120 int i;
121 const char *label;
122 unsigned int gcr;
123 unsigned int gsr;
124
125 seq_puts(s, "xra reg:");
126 for (reg = 0; reg <= XRA_LAST; reg++)
127 seq_printf(s, " %2.2x", reg);
128 seq_puts(s, "\n value:");
129 for (reg = 0; reg < XRA_LAST; reg++) {
130 regmap_read(xra->regmap, reg, &value[reg]);
131 seq_printf(s, " %2.2x", value[reg]);
132 }
133 seq_puts(s, "\n");
134
135 gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];
136 gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];
137 for_each_requested_gpio(chip, i, label) {
138 seq_printf(s, " gpio-%-3d (%-12s) %s %s\n", i, label,
139 (gcr & BIT(i)) ? "in" : "out",
140 str_hi_lo(gsr & BIT(i)));
141 }
142}
143#else
144#define xra1403_dbg_show NULL
145#endif
146
147static int xra1403_probe(struct spi_device *spi)
148{
149 struct xra1403 *xra;
150 struct gpio_desc *reset_gpio;
151 int ret;
152
153 xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);
154 if (!xra)
155 return -ENOMEM;
156
157 /* bring the chip out of reset if reset pin is provided*/
158 reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
159 if (IS_ERR(reset_gpio))
160 dev_warn(&spi->dev, "Could not get reset-gpios\n");
161
162 xra->chip.direction_input = xra1403_direction_input;
163 xra->chip.direction_output = xra1403_direction_output;
164 xra->chip.get_direction = xra1403_get_direction;
165 xra->chip.get = xra1403_get;
166 xra->chip.set = xra1403_set;
167
168 xra->chip.dbg_show = xra1403_dbg_show;
169
170 xra->chip.ngpio = 16;
171 xra->chip.label = "xra1403";
172
173 xra->chip.base = -1;
174 xra->chip.can_sleep = true;
175 xra->chip.parent = &spi->dev;
176 xra->chip.owner = THIS_MODULE;
177
178 xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);
179 if (IS_ERR(xra->regmap)) {
180 ret = PTR_ERR(xra->regmap);
181 dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);
182 return ret;
183 }
184
185 return devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);
186}
187
188static const struct spi_device_id xra1403_ids[] = {
189 { "xra1403" },
190 {},
191};
192MODULE_DEVICE_TABLE(spi, xra1403_ids);
193
194static const struct of_device_id xra1403_spi_of_match[] = {
195 { .compatible = "exar,xra1403" },
196 {},
197};
198MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);
199
200static struct spi_driver xra1403_driver = {
201 .probe = xra1403_probe,
202 .id_table = xra1403_ids,
203 .driver = {
204 .name = "xra1403",
205 .of_match_table = xra1403_spi_of_match,
206 },
207};
208
209module_spi_driver(xra1403_driver);
210
211MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");
212MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");
213MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");
214MODULE_LICENSE("GPL v2");