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 33 struct xra1403 { 34 struct gpio_chip chip; 35 struct regmap *regmap; 36 }; 37 38 static 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 46 static unsigned int to_reg(unsigned int reg, unsigned int offset) 47 { 48 return reg + (offset > 7); 49 } 50 51 static 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 59 static 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 76 static 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 return !!(val & BIT(offset % 8)); 87 } 88 89 static int xra1403_get(struct gpio_chip *chip, unsigned int offset) 90 { 91 int ret; 92 unsigned int val; 93 struct xra1403 *xra = gpiochip_get_data(chip); 94 95 ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val); 96 if (ret) 97 return ret; 98 99 return !!(val & BIT(offset % 8)); 100 } 101 102 static void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value) 103 { 104 int ret; 105 struct xra1403 *xra = gpiochip_get_data(chip); 106 107 ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset), 108 BIT(offset % 8), value ? BIT(offset % 8) : 0); 109 if (ret) 110 dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n", 111 offset, ret); 112 } 113 114 #ifdef CONFIG_DEBUG_FS 115 static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip) 116 { 117 int reg; 118 struct xra1403 *xra = gpiochip_get_data(chip); 119 int value[XRA_LAST]; 120 int i; 121 unsigned int gcr; 122 unsigned int gsr; 123 124 seq_puts(s, "xra reg:"); 125 for (reg = 0; reg <= XRA_LAST; reg++) 126 seq_printf(s, " %2.2x", reg); 127 seq_puts(s, "\n value:"); 128 for (reg = 0; reg < XRA_LAST; reg++) { 129 regmap_read(xra->regmap, reg, &value[reg]); 130 seq_printf(s, " %2.2x", value[reg]); 131 } 132 seq_puts(s, "\n"); 133 134 gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR]; 135 gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR]; 136 for (i = 0; i < chip->ngpio; i++) { 137 const char *label = gpiochip_is_requested(chip, i); 138 139 if (!label) 140 continue; 141 142 seq_printf(s, " gpio-%-3d (%-12s) %s %s\n", 143 chip->base + i, label, 144 (gcr & BIT(i)) ? "in" : "out", 145 (gsr & BIT(i)) ? "hi" : "lo"); 146 } 147 } 148 #else 149 #define xra1403_dbg_show NULL 150 #endif 151 152 static int xra1403_probe(struct spi_device *spi) 153 { 154 struct xra1403 *xra; 155 struct gpio_desc *reset_gpio; 156 int ret; 157 158 xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL); 159 if (!xra) 160 return -ENOMEM; 161 162 /* bring the chip out of reset if reset pin is provided*/ 163 reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW); 164 if (IS_ERR(reset_gpio)) 165 dev_warn(&spi->dev, "Could not get reset-gpios\n"); 166 167 xra->chip.direction_input = xra1403_direction_input; 168 xra->chip.direction_output = xra1403_direction_output; 169 xra->chip.get_direction = xra1403_get_direction; 170 xra->chip.get = xra1403_get; 171 xra->chip.set = xra1403_set; 172 173 xra->chip.dbg_show = xra1403_dbg_show; 174 175 xra->chip.ngpio = 16; 176 xra->chip.label = "xra1403"; 177 178 xra->chip.base = -1; 179 xra->chip.can_sleep = true; 180 xra->chip.parent = &spi->dev; 181 xra->chip.owner = THIS_MODULE; 182 183 xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg); 184 if (IS_ERR(xra->regmap)) { 185 ret = PTR_ERR(xra->regmap); 186 dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret); 187 return ret; 188 } 189 190 ret = devm_gpiochip_add_data(&spi->dev, &xra->chip, xra); 191 if (ret < 0) { 192 dev_err(&spi->dev, "Unable to register gpiochip\n"); 193 return ret; 194 } 195 196 spi_set_drvdata(spi, xra); 197 198 return 0; 199 } 200 201 static const struct spi_device_id xra1403_ids[] = { 202 { "xra1403" }, 203 {}, 204 }; 205 MODULE_DEVICE_TABLE(spi, xra1403_ids); 206 207 static const struct of_device_id xra1403_spi_of_match[] = { 208 { .compatible = "exar,xra1403" }, 209 {}, 210 }; 211 MODULE_DEVICE_TABLE(of, xra1403_spi_of_match); 212 213 static struct spi_driver xra1403_driver = { 214 .probe = xra1403_probe, 215 .id_table = xra1403_ids, 216 .driver = { 217 .name = "xra1403", 218 .of_match_table = of_match_ptr(xra1403_spi_of_match), 219 }, 220 }; 221 222 module_spi_driver(xra1403_driver); 223 224 MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>"); 225 MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>"); 226 MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403"); 227 MODULE_LICENSE("GPL v2"); 228