drivers/gpio/gpio-xra1403.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * GPIO driver for EXAR XRA1403 16-bit GPIO expander
0004  *
0005  * Copyright (c) 2017, General Electric Company
0006  */
0007
0008 #include <linux/bitops.h>
0009 #include <linux/gpio/driver.h>
0010 #include <linux/kernel.h>
0011 #include <linux/module.h>
0012 #include <linux/mutex.h>
0013 #include <linux/of_device.h>
0014 #include <linux/of_gpio.h>
0015 #include <linux/seq_file.h>
0016 #include <linux/spi/spi.h>
0017 #include <linux/regmap.h>
0018
0019 /* XRA1403 registers */
0020 #define XRA_GSR   0x00 /* GPIO State */
0021 #define XRA_OCR   0x02 /* Output Control */
0022 #define XRA_PIR   0x04 /* Input Polarity Inversion */
0023 #define XRA_GCR   0x06 /* GPIO Configuration */
0024 #define XRA_PUR   0x08 /* Input Internal Pull-up Resistor Enable/Disable */
0025 #define XRA_IER   0x0A /* Input Interrupt Enable */
0026 #define XRA_TSCR  0x0C /* Output Three-State Control */
0027 #define XRA_ISR   0x0E /* Input Interrupt Status */
0028 #define XRA_REIR  0x10 /* Input Rising Edge Interrupt Enable */
0029 #define XRA_FEIR  0x12 /* Input Falling Edge Interrupt Enable */
0030 #define XRA_IFR   0x14 /* Input Filter Enable/Disable */
0031 #define XRA_LAST  0x15 /* Bounds */
0032
0033 struct xra1403 {
0034     struct gpio_chip  chip;
0035     struct regmap     *regmap;
0036 };
0037
0038 static const struct regmap_config xra1403_regmap_cfg = {
0039         .reg_bits = 7,
0040         .pad_bits = 1,
0041         .val_bits = 8,
0042
0043         .max_register = XRA_LAST,
0044 };
0045
0046 static unsigned int to_reg(unsigned int reg, unsigned int offset)
0047 {
0048     return reg + (offset > 7);
0049 }
0050
0051 static int xra1403_direction_input(struct gpio_chip *chip, unsigned int offset)
0052 {
0053     struct xra1403 *xra = gpiochip_get_data(chip);
0054
0055     return regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
0056             BIT(offset % 8), BIT(offset % 8));
0057 }
0058
0059 static int xra1403_direction_output(struct gpio_chip *chip, unsigned int offset,
0060                     int value)
0061 {
0062     int ret;
0063     struct xra1403 *xra = gpiochip_get_data(chip);
0064
0065     ret = regmap_update_bits(xra->regmap, to_reg(XRA_GCR, offset),
0066             BIT(offset % 8), 0);
0067     if (ret)
0068         return ret;
0069
0070     ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
0071             BIT(offset % 8), value ? BIT(offset % 8) : 0);
0072
0073     return ret;
0074 }
0075
0076 static int xra1403_get_direction(struct gpio_chip *chip, unsigned int offset)
0077 {
0078     int ret;
0079     unsigned int val;
0080     struct xra1403 *xra = gpiochip_get_data(chip);
0081
0082     ret = regmap_read(xra->regmap, to_reg(XRA_GCR, offset), &val);
0083     if (ret)
0084         return ret;
0085
0086     if (val & BIT(offset % 8))
0087         return GPIO_LINE_DIRECTION_IN;
0088
0089     return GPIO_LINE_DIRECTION_OUT;
0090 }
0091
0092 static int xra1403_get(struct gpio_chip *chip, unsigned int offset)
0093 {
0094     int ret;
0095     unsigned int val;
0096     struct xra1403 *xra = gpiochip_get_data(chip);
0097
0098     ret = regmap_read(xra->regmap, to_reg(XRA_GSR, offset), &val);
0099     if (ret)
0100         return ret;
0101
0102     return !!(val & BIT(offset % 8));
0103 }
0104
0105 static void xra1403_set(struct gpio_chip *chip, unsigned int offset, int value)
0106 {
0107     int ret;
0108     struct xra1403 *xra = gpiochip_get_data(chip);
0109
0110     ret = regmap_update_bits(xra->regmap, to_reg(XRA_OCR, offset),
0111             BIT(offset % 8), value ? BIT(offset % 8) : 0);
0112     if (ret)
0113         dev_err(chip->parent, "Failed to set pin: %d, ret: %d\n",
0114                 offset, ret);
0115 }
0116
0117 #ifdef CONFIG_DEBUG_FS
0118 static void xra1403_dbg_show(struct seq_file *s, struct gpio_chip *chip)
0119 {
0120     int reg;
0121     struct xra1403 *xra = gpiochip_get_data(chip);
0122     int value[XRA_LAST];
0123     int i;
0124     const char *label;
0125     unsigned int gcr;
0126     unsigned int gsr;
0127
0128     seq_puts(s, "xra reg:");
0129     for (reg = 0; reg <= XRA_LAST; reg++)
0130         seq_printf(s, " %2.2x", reg);
0131     seq_puts(s, "\n  value:");
0132     for (reg = 0; reg < XRA_LAST; reg++) {
0133         regmap_read(xra->regmap, reg, &value[reg]);
0134         seq_printf(s, " %2.2x", value[reg]);
0135     }
0136     seq_puts(s, "\n");
0137
0138     gcr = value[XRA_GCR + 1] << 8 | value[XRA_GCR];
0139     gsr = value[XRA_GSR + 1] << 8 | value[XRA_GSR];
0140     for_each_requested_gpio(chip, i, label) {
0141         seq_printf(s, " gpio-%-3d (%-12s) %s %s\n",
0142                chip->base + i, label,
0143                (gcr & BIT(i)) ? "in" : "out",
0144                (gsr & BIT(i)) ? "hi" : "lo");
0145     }
0146 }
0147 #else
0148 #define xra1403_dbg_show NULL
0149 #endif
0150
0151 static int xra1403_probe(struct spi_device *spi)
0152 {
0153     struct xra1403 *xra;
0154     struct gpio_desc *reset_gpio;
0155     int ret;
0156
0157     xra = devm_kzalloc(&spi->dev, sizeof(*xra), GFP_KERNEL);
0158     if (!xra)
0159         return -ENOMEM;
0160
0161     /* bring the chip out of reset if reset pin is provided*/
0162     reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_LOW);
0163     if (IS_ERR(reset_gpio))
0164         dev_warn(&spi->dev, "Could not get reset-gpios\n");
0165
0166     xra->chip.direction_input = xra1403_direction_input;
0167     xra->chip.direction_output = xra1403_direction_output;
0168     xra->chip.get_direction = xra1403_get_direction;
0169     xra->chip.get = xra1403_get;
0170     xra->chip.set = xra1403_set;
0171
0172     xra->chip.dbg_show = xra1403_dbg_show;
0173
0174     xra->chip.ngpio = 16;
0175     xra->chip.label = "xra1403";
0176
0177     xra->chip.base = -1;
0178     xra->chip.can_sleep = true;
0179     xra->chip.parent = &spi->dev;
0180     xra->chip.owner = THIS_MODULE;
0181
0182     xra->regmap = devm_regmap_init_spi(spi, &xra1403_regmap_cfg);
0183     if (IS_ERR(xra->regmap)) {
0184         ret = PTR_ERR(xra->regmap);
0185         dev_err(&spi->dev, "Failed to allocate regmap: %d\n", ret);
0186         return ret;
0187     }
0188
0189     return devm_gpiochip_add_data(&spi->dev, &xra->chip, xra);
0190 }
0191
0192 static const struct spi_device_id xra1403_ids[] = {
0193     { "xra1403" },
0194     {},
0195 };
0196 MODULE_DEVICE_TABLE(spi, xra1403_ids);
0197
0198 static const struct of_device_id xra1403_spi_of_match[] = {
0199     { .compatible = "exar,xra1403" },
0200     {},
0201 };
0202 MODULE_DEVICE_TABLE(of, xra1403_spi_of_match);
0203
0204 static struct spi_driver xra1403_driver = {
0205     .probe    = xra1403_probe,
0206     .id_table = xra1403_ids,
0207     .driver   = {
0208         .name           = "xra1403",
0209         .of_match_table = of_match_ptr(xra1403_spi_of_match),
0210     },
0211 };
0212
0213 module_spi_driver(xra1403_driver);
0214
0215 MODULE_AUTHOR("Nandor Han <nandor.han@ge.com>");
0216 MODULE_AUTHOR("Semi Malinen <semi.malinen@ge.com>");
0217 MODULE_DESCRIPTION("GPIO expander driver for EXAR XRA1403");
0218 MODULE_LICENSE("GPL v2");