1/*
2 * GPIO driver for EXAR XRA1403 16-bit GPIO expander
3 *
4 * Copyright (c) 2017, General Electric Company
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19#include <linux/bitops.h>
20#include <linux/gpio/driver.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/mutex.h>
24#include <linux/of_device.h>
25#include <linux/of_gpio.h>
26#include <linux/seq_file.h>
27#include <linux/spi/spi.h>
28#include <linux/regmap.h>
29
30/* XRA1403 registers */
31#define XRA_GSR 0x00 /* GPIO State */
32#define XRA_OCR 0x02 /* Output Control */
33#define XRA_PIR 0x04 /* Input Polarity Inversion */
34#define XRA_GCR 0x06 /* GPIO Configuration */
35#define XRA_PUR 0x08 /* Input Internal Pull-up Resistor Enable/Disable */
36#define XRA_IER 0x0A /* Input Interrupt Enable */
37#define XRA_TSCR 0x0C /* Output Three-State Control */
38#define XRA_ISR 0x0E /* Input Interrupt Status */
39#define XRA_REIR 0x10 /* Input Rising Edge Interrupt Enable */
40#define XRA_FEIR 0x12 /* Input Falling Edge Interrupt Enable */
41#define XRA_IFR 0x14 /* Input Filter Enable/Disable */
42#define XRA_LAST 0x15 /* Bounds */
43
44struct xra1403 {
45 struct gpio_chip chip;
46 struct regmap *regmap;
47};
48
49static const struct regmap_config xra1403_regmap_cfg = {
50 .reg_bits = 7,
51 .pad_bits = 1,
52 .val_bits = 8,
53
54 .max_register = XRA_LAST,
55};
56
57static unsigned int to_reg(unsigned int reg, unsigned int offset)
58{
59 return reg + (offset > 7);
60}
61
62static int xra1403_direction_input(struct gpio_chip *chip, unsigned int offset)
63{
64 struct xra1403 *xra = gpiochip_get_data(chip);
65
66 return regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
67 BIT(offset % 8), BIT(offset % 8));
68}
69
70static int xra1403_direction_output(struct gpio_chip *chip, unsigned int offset,
71 int value)
72{
73 int ret;
74 struct xra1403 *xra = gpiochip_get_data(chip);
75
76 ret = regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
77 BIT(offset % 8), 0);
78 if (ret)
79 return ret;
80
81 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
82 BIT(offset % 8), value ? BIT(offset % 8) : 0);
83
84 return ret;
85}
86
87static int xra1403_get_direction(struct gpio_chip *chip, unsigned int offset)
88{
89 int ret;
90 unsigned int val;
91 struct xra1403 *xra = gpiochip_get_data(chip);
92
93 ret = regmap_read(xra->regmap, to_reg(XRA_GCR, offset), &val);
94 if (ret)
95 return ret;
96
97 return !!(val & BIT(offset % 8));
98}
99
100static int xra1403_get(struct gpio_chip *chip, unsigned int offset)
101{
102 int ret;
103 unsigned int val;
104 struct xra1403 *xra = gpiochip_get_data(chip);
105
106 ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val);
107 if (ret)
108 return ret;
109
110 return !!(val & BIT(offset % 8));
111}
112
113static void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)
114{
115 int ret;
116 struct xra1403 *xra = gpiochip_get_data(chip);
117
118 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
119 BIT(offset % 8), value ? BIT(offset % 8) : 0);
120 if (ret)
121 dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n",
122 offset, ret);
123}
124
125#ifdef CONFIG_DEBUG_FS
126static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)
127{
128 int reg;
129 struct xra1403 *xra = gpiochip_get_data(chip);
130 int value[XRA_LAST];
131 int i;
132 unsigned int gcr;
133 unsigned int gsr;
134
135 seq_puts(s, "xra reg:");
136 for (reg = 0; reg <= XRA_LAST; reg++)
137 seq_printf(s, " %2.2x", reg);
138 seq_puts(s, "\n value:");
139 for (reg = 0; reg < XRA_LAST; reg++) {
140 regmap_read(xra->regmap, reg, &value[reg]);
141 seq_printf(s, " %2.2x", value[reg]);
142 }
143 seq_puts(s, "\n");
144
145 gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];
146 gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];
147 for (i = 0; i < chip->ngpio; i++) {
148 const char *label = gpiochip_is_requested(chip, i);
149
150 if (!label)
151 continue;
152
153 seq_printf(s, " gpio-%-3d (%-12s) %s %s\n",
154 chip->base + i, label,
155 (gcr & BIT(i)) ? "in" : "out",
156 (gsr & BIT(i)) ? "hi" : "lo");
157 }
158}
159#else
160#define xra1403_dbg_show NULL
161#endif
162
163static int xra1403_probe(struct spi_device *spi)
164{
165 struct xra1403 *xra;
166 struct gpio_desc *reset_gpio;
167 int ret;
168
169 xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);
170 if (!xra)
171 return -ENOMEM;
172
173 /* bring the chip out of reset if reset pin is provided*/
174 reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
175 if (IS_ERR(reset_gpio))
176 dev_warn(&spi->dev, "Could not get reset-gpios\n");
177
178 xra->chip.direction_input = xra1403_direction_input;
179 xra->chip.direction_output = xra1403_direction_output;
180 xra->chip.get_direction = xra1403_get_direction;
181 xra->chip.get = xra1403_get;
182 xra->chip.set = xra1403_set;
183
184 xra->chip.dbg_show = xra1403_dbg_show;
185
186 xra->chip.ngpio = 16;
187 xra->chip.label = "xra1403";
188
189 xra->chip.base = -1;
190 xra->chip.can_sleep = true;
191 xra->chip.parent = &spi->dev;
192 xra->chip.owner = THIS_MODULE;
193
194 xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);
195 if (IS_ERR(xra->regmap)) {
196 ret = PTR_ERR(xra->regmap);
197 dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);
198 return ret;
199 }
200
201 ret = devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);
202 if (ret < 0) {
203 dev_err(&spi->dev, "Unable to register gpiochip\n");
204 return ret;
205 }
206
207 spi_set_drvdata(spi, xra);
208
209 return 0;
210}
211
212static const struct spi_device_id xra1403_ids[] = {
213 { "xra1403" },
214 {},
215};
216MODULE_DEVICE_TABLE(spi, xra1403_ids);
217
218static const struct of_device_id xra1403_spi_of_match[] = {
219 { .compatible = "exar,xra1403" },
220 {},
221};
222MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);
223
224static struct spi_driver xra1403_driver = {
225 .probe = xra1403_probe,
226 .id_table = xra1403_ids,
227 .driver = {
228 .name = "xra1403",
229 .of_match_table = of_match_ptr(xra1403_spi_of_match),
230 },
231};
232
233module_spi_driver(xra1403_driver);
234
235MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");
236MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");
237MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");
238MODULE_LICENSE("GPL v2");
239