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
  43 struct xra1403 {
  44         struct gpio_chip  chip;
  45         struct regmap     *regmap;
  46 };
  47
  48 static const struct regmap_config xra1403_regmap_cfg = {
  49                 .reg_bits = 7,
  50                 .pad_bits = 1,
  51                 .val_bits = 8,
  52
  53                 .max_register = XRA_IFR | 0x01,
  54 };
  55
  56 static unsigned int to_reg(unsigned int reg, unsigned int offset)
  57 {
  58         return reg + (offset > 7);
  59 }
  60
  61 static int xra1403_direction_input(struct gpio_chip *chip, unsigned int offset)
  62 {
  63         struct xra1403 *xra = gpiochip_get_data(chip);
  64
  65         return regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
  66                         BIT(offset % 8), BIT(offset % 8));
  67 }
  68
  69 static int xra1403_direction_output(struct gpio_chip *chip, unsigned int offset,
  70                                     int value)
  71 {
  72         int ret;
  73         struct xra1403 *xra = gpiochip_get_data(chip);
  74
  75         ret = regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
  76                         BIT(offset % 8), 0);
  77         if (ret)
  78                 return ret;
  79
  80         ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
  81                         BIT(offset % 8), value ? BIT(offset % 8) : 0);
  82
  83         return ret;
  84 }
  85
  86 static int xra1403_get_direction(struct gpio_chip *chip, unsigned int offset)
  87 {
  88         int ret;
  89         unsigned int val;
  90         struct xra1403 *xra = gpiochip_get_data(chip);
  91
  92         ret = regmap_read(xra->regmap, to_reg(XRA_GCR, offset), &val);
  93         if (ret)
  94                 return ret;
  95
  96         return !!(val & BIT(offset % 8));
  97 }
  98
  99 static int xra1403_get(struct gpio_chip *chip, unsigned int offset)
 100 {
 101         int ret;
 102         unsigned int val;
 103         struct xra1403 *xra = gpiochip_get_data(chip);
 104
 105         ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val);
 106         if (ret)
 107                 return ret;
 108
 109         return !!(val & BIT(offset % 8));
 110 }
 111
 112 static void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)
 113 {
 114         int ret;
 115         struct xra1403 *xra = gpiochip_get_data(chip);
 116
 117         ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
 118                         BIT(offset % 8), value ? BIT(offset % 8) : 0);
 119         if (ret)
 120                 dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n",
 121                                 offset, ret);
 122 }
 123
 124 #ifdef CONFIG_DEBUG_FS
 125 static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 126 {
 127         int reg;
 128         struct xra1403 *xra = gpiochip_get_data(chip);
 129         int value[xra1403_regmap_cfg.max_register];
 130         int i;
 131         unsigned int gcr;
 132         unsigned int gsr;
 133
 134         seq_puts(s, "xra reg:");
 135         for (reg = 0; reg <= xra1403_regmap_cfg.max_register; reg++)
 136                 seq_printf(s, " %2.2x", reg);
 137         seq_puts(s, "\n  value:");
 138         for (reg = 0; reg < xra1403_regmap_cfg.max_register; reg++) {
 139                 regmap_read(xra->regmap, reg, &value[reg]);
 140                 seq_printf(s, " %2.2x", value[reg]);
 141         }
 142         seq_puts(s, "\n");
 143
 144         gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];
 145         gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];
 146         for (i = 0; i < chip->ngpio; i++) {
 147                 const char *label = gpiochip_is_requested(chip, i);
 148
 149                 if (!label)
 150                         continue;
 151
 152                 seq_printf(s, " gpio-%-3d (%-12s) %s %s\n",
 153                            chip->base + i, label,
 154                            (gcr & BIT(i)) ? "in" : "out",
 155                            (gsr & BIT(i)) ? "hi" : "lo");
 156         }
 157 }
 158 #else
 159 #define xra1403_dbg_show NULL
 160 #endif
 161
 162 static int xra1403_probe(struct spi_device *spi)
 163 {
 164         struct xra1403 *xra;
 165         struct gpio_desc *reset_gpio;
 166         int ret;
 167
 168         xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);
 169         if (!xra)
 170                 return -ENOMEM;
 171
 172         /* bring the chip out of reset if reset pin is provided*/
 173         reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
 174         if (IS_ERR(reset_gpio))
 175                 dev_warn(&spi->dev, "Could not get reset-gpios\n");
 176
 177         xra->chip.direction_input = xra1403_direction_input;
 178         xra->chip.direction_output = xra1403_direction_output;
 179         xra->chip.get_direction = xra1403_get_direction;
 180         xra->chip.get = xra1403_get;
 181         xra->chip.set = xra1403_set;
 182
 183         xra->chip.dbg_show = xra1403_dbg_show;
 184
 185         xra->chip.ngpio = 16;
 186         xra->chip.label = "xra1403";
 187
 188         xra->chip.base = -1;
 189         xra->chip.can_sleep = true;
 190         xra->chip.parent = &spi->dev;
 191         xra->chip.owner = THIS_MODULE;
 192
 193         xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);
 194         if (IS_ERR(xra->regmap)) {
 195                 ret = PTR_ERR(xra->regmap);
 196                 dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);
 197                 return ret;
 198         }
 199
 200         ret = devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);
 201         if (ret < 0) {
 202                 dev_err(&spi->dev, "Unable to register gpiochip\n");
 203                 return ret;
 204         }
 205
 206         spi_set_drvdata(spi, xra);
 207
 208         return 0;
 209 }
 210
 211 static const struct spi_device_id xra1403_ids[] = {
 212         { "xra1403" },
 213         {},
 214 };
 215 MODULE_DEVICE_TABLE(spi, xra1403_ids);
 216
 217 static const struct of_device_id xra1403_spi_of_match[] = {
 218         { .compatible = "exar,xra1403" },
 219         {},
 220 };
 221 MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);
 222
 223 static struct spi_driver xra1403_driver = {
 224         .probe    = xra1403_probe,
 225         .id_table = xra1403_ids,
 226         .driver   = {
 227                 .name           = "xra1403",
 228                 .of_match_table = of_match_ptr(xra1403_spi_of_match),
 229         },
 230 };
 231
 232 module_spi_driver(xra1403_driver);
 233
 234 MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");
 235 MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");
 236 MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");
 237 MODULE_LICENSE("GPL v2");