drivers/gpio/gpio-xra1403.c

   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");