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/regmap.h>
17
18 /* XRA1403 registers */
19 #define XRA_GSR 0x00 /* GPIO State */
20 #define XRA_OCR 0x02 /* Output Control */
21 #define XRA_PIR 0x04 /* Input Polarity Inversion */
22 #define XRA_GCR 0x06 /* GPIO Configuration */
23 #define XRA_PUR 0x08 /* Input Internal Pull-up Resistor Enable/Disable */
24 #define XRA_IER 0x0A /* Input Interrupt Enable */
25 #define XRA_TSCR 0x0C /* Output Three-State Control */
26 #define XRA_ISR 0x0E /* Input Interrupt Status */
27 #define XRA_REIR 0x10 /* Input Rising Edge Interrupt Enable */
28 #define XRA_FEIR 0x12 /* Input Falling Edge Interrupt Enable */
29 #define XRA_IFR 0x14 /* Input Filter Enable/Disable */
30 #define XRA_LAST 0x15 /* Bounds */
31
32 struct xra1403 {
33 struct gpio_chip chip;
34 struct regmap *regmap;
35 };
36
37 static const struct regmap_config xra1403_regmap_cfg = {
38 .reg_bits = 7,
39 .pad_bits = 1,
40 .val_bits = 8,
41
42 .max_register = XRA_LAST,
43 };
44
to_reg(unsigned int reg,unsigned int offset)45 static unsigned int to_reg(unsigned int reg, unsigned int offset)
46 {
47 return reg + (offset > 7);
48 }
49
xra1403_direction_input(struct gpio_chip * chip,unsigned int offset)50 static int xra1403_direction_input(struct gpio_chip *chip, unsigned int offset)
51 {
52 struct xra1403 *xra = gpiochip_get_data(chip);
53
54 return regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
55 BIT(offset % 8), BIT(offset % 8));
56 }
57
xra1403_direction_output(struct gpio_chip * chip,unsigned int offset,int value)58 static int xra1403_direction_output(struct gpio_chip *chip, unsigned int offset,
59 int value)
60 {
61 int ret;
62 struct xra1403 *xra = gpiochip_get_data(chip);
63
64 ret = regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
65 BIT(offset % 8), 0);
66 if (ret)
67 return ret;
68
69 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
70 BIT(offset % 8), value ? BIT(offset % 8) : 0);
71
72 return ret;
73 }
74
xra1403_get_direction(struct gpio_chip * chip,unsigned int offset)75 static int xra1403_get_direction(struct gpio_chip *chip, unsigned int offset)
76 {
77 int ret;
78 unsigned int val;
79 struct xra1403 *xra = gpiochip_get_data(chip);
80
81 ret = regmap_read(xra->regmap, to_reg(XRA_GCR, offset), &val);
82 if (ret)
83 return ret;
84
85 if (val & BIT(offset % 8))
86 return GPIO_LINE_DIRECTION_IN;
87
88 return GPIO_LINE_DIRECTION_OUT;
89 }
90
xra1403_get(struct gpio_chip * chip,unsigned int offset)91 static int xra1403_get(struct gpio_chip *chip, unsigned int offset)
92 {
93 int ret;
94 unsigned int val;
95 struct xra1403 *xra = gpiochip_get_data(chip);
96
97 ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val);
98 if (ret)
99 return ret;
100
101 return !!(val & BIT(offset % 8));
102 }
103
xra1403_set(struct gpio_chip * chip,unsigned int offset,int value)104 static void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)
105 {
106 int ret;
107 struct xra1403 *xra = gpiochip_get_data(chip);
108
109 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
110 BIT(offset % 8), value ? BIT(offset % 8) : 0);
111 if (ret)
112 dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n",
113 offset, ret);
114 }
115
116 #ifdef CONFIG_DEBUG_FS
xra1403_dbg_show(struct seq_file * s,struct gpio_chip * chip)117 static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)
118 {
119 int reg;
120 struct xra1403 *xra = gpiochip_get_data(chip);
121 int value[XRA_LAST];
122 int i;
123 const char *label;
124 unsigned int gcr;
125 unsigned int gsr;
126
127 seq_puts(s, "xra reg:");
128 for (reg = 0; reg <= XRA_LAST; reg++)
129 seq_printf(s, " %2.2x", reg);
130 seq_puts(s, "\n value:");
131 for (reg = 0; reg < XRA_LAST; reg++) {
132 regmap_read(xra->regmap, reg, &value[reg]);
133 seq_printf(s, " %2.2x", value[reg]);
134 }
135 seq_puts(s, "\n");
136
137 gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];
138 gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];
139 for_each_requested_gpio(chip, i, label) {
140 seq_printf(s, " gpio-%-3d (%-12s) %s %s\n",
141 chip->base + i, label,
142 (gcr & BIT(i)) ? "in" : "out",
143 (gsr & BIT(i)) ? "hi" : "lo");
144 }
145 }
146 #else
147 #define xra1403_dbg_show NULL
148 #endif
149
xra1403_probe(struct spi_device * spi)150 static int xra1403_probe(struct spi_device *spi)
151 {
152 struct xra1403 *xra;
153 struct gpio_desc *reset_gpio;
154 int ret;
155
156 xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);
157 if (!xra)
158 return -ENOMEM;
159
160 /* bring the chip out of reset if reset pin is provided*/
161 reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
162 if (IS_ERR(reset_gpio))
163 dev_warn(&spi->dev, "Could not get reset-gpios\n");
164
165 xra->chip.direction_input = xra1403_direction_input;
166 xra->chip.direction_output = xra1403_direction_output;
167 xra->chip.get_direction = xra1403_get_direction;
168 xra->chip.get = xra1403_get;
169 xra->chip.set = xra1403_set;
170
171 xra->chip.dbg_show = xra1403_dbg_show;
172
173 xra->chip.ngpio = 16;
174 xra->chip.label = "xra1403";
175
176 xra->chip.base = -1;
177 xra->chip.can_sleep = true;
178 xra->chip.parent = &spi->dev;
179 xra->chip.owner = THIS_MODULE;
180
181 xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);
182 if (IS_ERR(xra->regmap)) {
183 ret = PTR_ERR(xra->regmap);
184 dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);
185 return ret;
186 }
187
188 return devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);
189 }
190
191 static const struct spi_device_id xra1403_ids[] = {
192 { "xra1403" },
193 {},
194 };
195 MODULE_DEVICE_TABLE(spi, xra1403_ids);
196
197 static const struct of_device_id xra1403_spi_of_match[] = {
198 { .compatible = "exar,xra1403" },
199 {},
200 };
201 MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);
202
203 static struct spi_driver xra1403_driver = {
204 .probe = xra1403_probe,
205 .id_table = xra1403_ids,
206 .driver = {
207 .name = "xra1403",
208 .of_match_table = xra1403_spi_of_match,
209 },
210 };
211
212 module_spi_driver(xra1403_driver);
213
214 MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");
215 MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");
216 MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");
217 MODULE_LICENSE("GPL v2");
218