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 if (val & BIT(offset % 8)) 87 return GPIO_LINE_DIRECTION_IN; 88 89 return GPIO_LINE_DIRECTION_OUT; 90 } 91 92 static 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 } 104 105 static 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 118 static 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 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 (i = 0; i < chip->ngpio; i++) { 140 const char *label = gpiochip_is_requested(chip, i); 141 142 if (!label) 143 continue; 144 145 seq_printf(s, " gpio-%-3d (%-12s) %s %s\n", 146 chip->base + i, label, 147 (gcr & BIT(i)) ? "in" : "out", 148 (gsr & BIT(i)) ? "hi" : "lo"); 149 } 150 } 151 #else 152 #define xra1403_dbg_show NULL 153 #endif 154 155 static int xra1403_probe(struct spi_device *spi) 156 { 157 struct xra1403 *xra; 158 struct gpio_desc *reset_gpio; 159 int ret; 160 161 xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL); 162 if (!xra) 163 return -ENOMEM; 164 165 /* bring the chip out of reset if reset pin is provided*/ 166 reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW); 167 if (IS_ERR(reset_gpio)) 168 dev_warn(&spi->dev, "Could not get reset-gpios\n"); 169 170 xra->chip.direction_input = xra1403_direction_input; 171 xra->chip.direction_output = xra1403_direction_output; 172 xra->chip.get_direction = xra1403_get_direction; 173 xra->chip.get = xra1403_get; 174 xra->chip.set = xra1403_set; 175 176 xra->chip.dbg_show = xra1403_dbg_show; 177 178 xra->chip.ngpio = 16; 179 xra->chip.label = "xra1403"; 180 181 xra->chip.base = -1; 182 xra->chip.can_sleep = true; 183 xra->chip.parent = &spi->dev; 184 xra->chip.owner = THIS_MODULE; 185 186 xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg); 187 if (IS_ERR(xra->regmap)) { 188 ret = PTR_ERR(xra->regmap); 189 dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret); 190 return ret; 191 } 192 193 ret = devm_gpiochip_add_data(&spi->dev, &xra->chip, xra); 194 if (ret < 0) { 195 dev_err(&spi->dev, "Unable to register gpiochip\n"); 196 return ret; 197 } 198 199 spi_set_drvdata(spi, xra); 200 201 return 0; 202 } 203 204 static const struct spi_device_id xra1403_ids[] = { 205 { "xra1403" }, 206 {}, 207 }; 208 MODULE_DEVICE_TABLE(spi, xra1403_ids); 209 210 static const struct of_device_id xra1403_spi_of_match[] = { 211 { .compatible = "exar,xra1403" }, 212 {}, 213 }; 214 MODULE_DEVICE_TABLE(of, xra1403_spi_of_match); 215 216 static struct spi_driver xra1403_driver = { 217 .probe = xra1403_probe, 218 .id_table = xra1403_ids, 219 .driver = { 220 .name = "xra1403", 221 .of_match_table = of_match_ptr(xra1403_spi_of_match), 222 }, 223 }; 224 225 module_spi_driver(xra1403_driver); 226 227 MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>"); 228 MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>"); 229 MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403"); 230 MODULE_LICENSE("GPL v2"); 231