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