| /* |
| * Digital I/O driver for Technologic Systems I2C FPGA Core |
| * |
| * Copyright (C) 2015 Technologic Systems |
| * Copyright (C) 2016 Savoir-Faire Linux |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed "as is" WITHOUT ANY WARRANTY of any |
| * kind, whether expressed or implied; without even the implied warranty |
| * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License version 2 for more details. |
| */ |
| |
| #include <linux/gpio/driver.h> |
| #include <linux/i2c.h> |
| #include <linux/of_device.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); |
| |
| /* |
| * This will clear the output enable bit, the other bits are |
| * dontcare when this is cleared |
| */ |
| return regmap_write(priv->regmap, offset, 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); |
| int ret; |
| |
| 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, |
| const struct i2c_device_id *id) |
| { |
| 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"); |