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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 | // SPDX-License-Identifier: GPL-2.0 /* * Digital I/O driver for Technologic Systems I2C FPGA Core * * Copyright (C) 2015, 2018 Technologic Systems * Copyright (C) 2016 Savoir-Faire Linux */ #include <linux/gpio/driver.h> #include <linux/i2c.h> #include <linux/of.h> #include <linux/module.h> #include <linux/regmap.h> #define DEFAULT_PIN_NUMBER 32 /* * Register bits used by the GPIO device * Some boards, such as TS-7970 do not have a separate input bit */ #define TS4900_GPIO_OE 0x01 #define TS4900_GPIO_OUT 0x02 #define TS4900_GPIO_IN 0x04 #define TS7970_GPIO_IN 0x02 struct ts4900_gpio_priv { struct regmap *regmap; struct gpio_chip gpio_chip; unsigned int input_bit; }; static int ts4900_gpio_get_direction(struct gpio_chip *chip, unsigned int offset) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); unsigned int reg; regmap_read(priv->regmap, offset, ®); if (reg & TS4900_GPIO_OE) return GPIO_LINE_DIRECTION_OUT; return GPIO_LINE_DIRECTION_IN; } static int ts4900_gpio_direction_input(struct gpio_chip *chip, unsigned int offset) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); /* * Only clear the OE bit here, requires a RMW. Prevents a potential issue * with OE and DAT getting to the physical pin at different times. */ return regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OE, 0); } static int ts4900_gpio_direction_output(struct gpio_chip *chip, unsigned int offset, int value) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); unsigned int reg; int ret; /* * If changing from an input to an output, we need to first set the * GPIO's DAT bit to what is requested and then set the OE bit. This * prevents a glitch that can occur on the IO line. */ regmap_read(priv->regmap, offset, ®); if (!(reg & TS4900_GPIO_OE)) { if (value) reg = TS4900_GPIO_OUT; else reg &= ~TS4900_GPIO_OUT; regmap_write(priv->regmap, offset, reg); } if (value) ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE | TS4900_GPIO_OUT); else ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE); return ret; } static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); unsigned int reg; regmap_read(priv->regmap, offset, ®); return !!(reg & priv->input_bit); } static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset, int value) { struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); if (value) regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, TS4900_GPIO_OUT); else regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0); } static const struct regmap_config ts4900_regmap_config = { .reg_bits = 16, .val_bits = 8, }; static const struct gpio_chip template_chip = { .label = "ts4900-gpio", .owner = THIS_MODULE, .get_direction = ts4900_gpio_get_direction, .direction_input = ts4900_gpio_direction_input, .direction_output = ts4900_gpio_direction_output, .get = ts4900_gpio_get, .set = ts4900_gpio_set, .base = -1, .can_sleep = true, }; static const struct of_device_id ts4900_gpio_of_match_table[] = { { .compatible = "technologic,ts4900-gpio", .data = (void *)TS4900_GPIO_IN, }, { .compatible = "technologic,ts7970-gpio", .data = (void *)TS7970_GPIO_IN, }, { /* sentinel */ }, }; MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table); static int ts4900_gpio_probe(struct i2c_client *client) { struct ts4900_gpio_priv *priv; u32 ngpio; int ret; if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio)) ngpio = DEFAULT_PIN_NUMBER; priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->gpio_chip = template_chip; priv->gpio_chip.label = "ts4900-gpio"; priv->gpio_chip.ngpio = ngpio; priv->gpio_chip.parent = &client->dev; priv->input_bit = (uintptr_t)of_device_get_match_data(&client->dev); priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config); if (IS_ERR(priv->regmap)) { ret = PTR_ERR(priv->regmap); dev_err(&client->dev, "Failed to allocate register map: %d\n", ret); return ret; } ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv); if (ret < 0) { dev_err(&client->dev, "Unable to register gpiochip\n"); return ret; } i2c_set_clientdata(client, priv); return 0; } static const struct i2c_device_id ts4900_gpio_id_table[] = { { "ts4900-gpio", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table); static struct i2c_driver ts4900_gpio_driver = { .driver = { .name = "ts4900-gpio", .of_match_table = ts4900_gpio_of_match_table, }, .probe = ts4900_gpio_probe, .id_table = ts4900_gpio_id_table, }; module_i2c_driver(ts4900_gpio_driver); MODULE_AUTHOR("Technologic Systems"); MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core"); MODULE_LICENSE("GPL"); |