drivers/gpio/gpio-xra1403.c

   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");