2 * GPIO driver for EXAR XRA1403 16-bit GPIO expander
4 * Copyright (c) 2017, General Electric Company
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.
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
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/>.
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>
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 */
44 struct gpio_chip chip;
45 struct regmap *regmap;
48 static const struct regmap_config xra1403_regmap_cfg = {
53 .max_register = XRA_IFR | 0x01,
56 static unsigned int to_reg(unsigned int reg, unsigned int offset)
58 return reg + (offset > 7);
61 static int xra1403_direction_input(struct gpio_chip *chip, unsigned int offset)
63 struct xra1403 *xra = gpiochip_get_data(chip);
65 return regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
66 BIT(offset % 8), BIT(offset % 8));
69 static int xra1403_direction_output(struct gpio_chip *chip, unsigned int offset,
73 struct xra1403 *xra = gpiochip_get_data(chip);
75 ret = regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
80 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
81 BIT(offset % 8), value ? BIT(offset % 8) : 0);
86 static int xra1403_get_direction(struct gpio_chip *chip, unsigned int offset)
90 struct xra1403 *xra = gpiochip_get_data(chip);
92 ret = regmap_read(xra->regmap, to_reg(XRA_GCR, offset), &val);
96 return !!(val & BIT(offset % 8));
99 static int xra1403_get(struct gpio_chip *chip, unsigned int offset)
103 struct xra1403 *xra = gpiochip_get_data(chip);
105 ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val);
109 return !!(val & BIT(offset % 8));
112 static void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)
115 struct xra1403 *xra = gpiochip_get_data(chip);
117 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
118 BIT(offset % 8), value ? BIT(offset % 8) : 0);
120 dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n",
124 #ifdef CONFIG_DEBUG_FS
125 static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)
128 struct xra1403 *xra = gpiochip_get_data(chip);
134 value = kmalloc_array(xra1403_regmap_cfg.max_register, sizeof(*value),
139 seq_puts(s, "xra reg:");
140 for (reg = 0; reg <= xra1403_regmap_cfg.max_register; reg++)
141 seq_printf(s, " %2.2x", reg);
142 seq_puts(s, "\n value:");
143 for (reg = 0; reg < xra1403_regmap_cfg.max_register; reg++) {
144 regmap_read(xra->regmap, reg, &value[reg]);
145 seq_printf(s, " %2.2x", value[reg]);
149 gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];
150 gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];
151 for (i = 0; i < chip->ngpio; i++) {
152 const char *label = gpiochip_is_requested(chip, i);
157 seq_printf(s, " gpio-%-3d (%-12s) %s %s\n",
158 chip->base + i, label,
159 (gcr & BIT(i)) ? "in" : "out",
160 (gsr & BIT(i)) ? "hi" : "lo");
165 #define xra1403_dbg_show NULL
168 static int xra1403_probe(struct spi_device *spi)
171 struct gpio_desc *reset_gpio;
174 xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);
178 /* bring the chip out of reset if reset pin is provided*/
179 reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
180 if (IS_ERR(reset_gpio))
181 dev_warn(&spi->dev, "Could not get reset-gpios\n");
183 xra->chip.direction_input = xra1403_direction_input;
184 xra->chip.direction_output = xra1403_direction_output;
185 xra->chip.get_direction = xra1403_get_direction;
186 xra->chip.get = xra1403_get;
187 xra->chip.set = xra1403_set;
189 xra->chip.dbg_show = xra1403_dbg_show;
191 xra->chip.ngpio = 16;
192 xra->chip.label = "xra1403";
195 xra->chip.can_sleep = true;
196 xra->chip.parent = &spi->dev;
197 xra->chip.owner = THIS_MODULE;
199 xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);
200 if (IS_ERR(xra->regmap)) {
201 ret = PTR_ERR(xra->regmap);
202 dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);
206 ret = devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);
208 dev_err(&spi->dev, "Unable to register gpiochip\n");
212 spi_set_drvdata(spi, xra);
217 static const struct spi_device_id xra1403_ids[] = {
221 MODULE_DEVICE_TABLE(spi, xra1403_ids);
223 static const struct of_device_id xra1403_spi_of_match[] = {
224 { .compatible = "exar,xra1403" },
227 MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);
229 static struct spi_driver xra1403_driver = {
230 .probe = xra1403_probe,
231 .id_table = xra1403_ids,
234 .of_match_table = of_match_ptr(xra1403_spi_of_match),
238 module_spi_driver(xra1403_driver);
240 MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");
241 MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");
242 MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");
243 MODULE_LICENSE("GPL v2");