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/module.h>
 12#include <linux/mutex.h>
 13#include <linux/of_device.h>
 14#include <linux/of_gpio.h>
 15#include <linux/seq_file.h>
 16#include <linux/spi/spi.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 void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)
106{
107	int ret;
108	struct xra1403 *xra = gpiochip_get_data(chip);
109
110	ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
111			BIT(offset % 8), value ? BIT(offset % 8) : 0);
112	if (ret)
113		dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n",
114				offset, ret);
115}
116
117#ifdef CONFIG_DEBUG_FS
118static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)
119{
120	int reg;
121	struct xra1403 *xra = gpiochip_get_data(chip);
122	int value[XRA_LAST];
123	int i;
124	const char *label;
125	unsigned int gcr;
126	unsigned int gsr;
127
128	seq_puts(s, "xra reg:");
129	for (reg = 0; reg <= XRA_LAST; reg++)
130		seq_printf(s, " %2.2x", reg);
131	seq_puts(s, "\n  value:");
132	for (reg = 0; reg < XRA_LAST; reg++) {
133		regmap_read(xra->regmap, reg, &value[reg]);
134		seq_printf(s, " %2.2x", value[reg]);
135	}
136	seq_puts(s, "\n");
137
138	gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];
139	gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];
140	for_each_requested_gpio(chip, i, label) {
141		seq_printf(s, " gpio-%-3d (%-12s) %s %s\n",
142			   chip->base + i, label,
143			   (gcr & BIT(i)) ? "in" : "out",
144			   (gsr & BIT(i)) ? "hi" : "lo");
145	}
146}
147#else
148#define xra1403_dbg_show NULL
149#endif
150
151static int xra1403_probe(struct spi_device *spi)
152{
153	struct xra1403 *xra;
154	struct gpio_desc *reset_gpio;
155	int ret;
156
157	xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);
158	if (!xra)
159		return -ENOMEM;
160
161	/* bring the chip out of reset if reset pin is provided*/
162	reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
163	if (IS_ERR(reset_gpio))
164		dev_warn(&spi->dev, "Could not get reset-gpios\n");
165
166	xra->chip.direction_input = xra1403_direction_input;
167	xra->chip.direction_output = xra1403_direction_output;
168	xra->chip.get_direction = xra1403_get_direction;
169	xra->chip.get = xra1403_get;
170	xra->chip.set = xra1403_set;
171
172	xra->chip.dbg_show = xra1403_dbg_show;
173
174	xra->chip.ngpio = 16;
175	xra->chip.label = "xra1403";
176
177	xra->chip.base = -1;
178	xra->chip.can_sleep = true;
179	xra->chip.parent = &spi->dev;
180	xra->chip.owner = THIS_MODULE;
181
182	xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);
183	if (IS_ERR(xra->regmap)) {
184		ret = PTR_ERR(xra->regmap);
185		dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);
186		return ret;
187	}
188
189	ret = devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);
190	if (ret < 0) {
191		dev_err(&spi->dev, "Unable to register gpiochip\n");
192		return ret;
193	}
194
195	spi_set_drvdata(spi, xra);
196
197	return 0;
198}
199
200static const struct spi_device_id xra1403_ids[] = {
201	{ "xra1403" },
202	{},
203};
204MODULE_DEVICE_TABLE(spi, xra1403_ids);
205
206static const struct of_device_id xra1403_spi_of_match[] = {
207	{ .compatible = "exar,xra1403" },
208	{},
209};
210MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);
211
212static struct spi_driver xra1403_driver = {
213	.probe    = xra1403_probe,
214	.id_table = xra1403_ids,
215	.driver   = {
216		.name           = "xra1403",
217		.of_match_table = of_match_ptr(xra1403_spi_of_match),
218	},
219};
220
221module_spi_driver(xra1403_driver);
222
223MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");
224MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");
225MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");
226MODULE_LICENSE("GPL v2");