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 44 struct xra1403 { 45 struct gpio_chip chip; 46 struct regmap *regmap; 47 }; 48 49 static 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 57 static unsigned int to_reg(unsigned int reg, unsigned int offset) 58 { 59 return reg + (offset > 7); 60 } 61 62 static 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 70 static 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 87 static 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 } 99 100 static 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 } 112 113 static 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 126 static 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 162 163 static 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 } 211 212 static const struct spi_device_id xra1403_ids[] = { 213 { "xra1403" }, 214 {}, 215 }; 216 MODULE_DEVICE_TABLE(spi, xra1403_ids); 217 218 static const struct of_device_id xra1403_spi_of_match[] = { 219 { .compatible = "exar,xra1403" }, 220 {}, 221 }; 222 MODULE_DEVICE_TABLE(of, xra1403_spi_of_match); 223 224 static 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 }; 232 233 module_spi_driver(xra1403_driver); 234 235 MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>"); 236 MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>"); 237 MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403"); 238 MODULE_LICENSE("GPL v2"); 239