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188 lines
4.8 KiB
188 lines
4.8 KiB
/* |
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* Digital I/O driver for Technologic Systems I2C FPGA Core |
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* |
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* Copyright (C) 2015 Technologic Systems |
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* Copyright (C) 2016 Savoir-Faire Linux |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License version 2 as |
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* published by the Free Software Foundation. |
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* |
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any |
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* kind, whether expressed or implied; without even the implied warranty |
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License version 2 for more details. |
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*/ |
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#include <linux/gpio/driver.h> |
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#include <linux/i2c.h> |
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#include <linux/of_device.h> |
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#include <linux/module.h> |
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#include <linux/regmap.h> |
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#define DEFAULT_PIN_NUMBER 32 |
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/* |
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* Register bits used by the GPIO device |
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* Some boards, such as TS-7970 do not have a separate input bit |
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*/ |
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#define TS4900_GPIO_OE 0x01 |
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#define TS4900_GPIO_OUT 0x02 |
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#define TS4900_GPIO_IN 0x04 |
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#define TS7970_GPIO_IN 0x02 |
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struct ts4900_gpio_priv { |
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struct regmap *regmap; |
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struct gpio_chip gpio_chip; |
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unsigned int input_bit; |
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}; |
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static int ts4900_gpio_get_direction(struct gpio_chip *chip, |
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unsigned int offset) |
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{ |
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struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); |
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unsigned int reg; |
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regmap_read(priv->regmap, offset, ®); |
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if (reg & TS4900_GPIO_OE) |
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return GPIO_LINE_DIRECTION_OUT; |
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return GPIO_LINE_DIRECTION_IN; |
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} |
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static int ts4900_gpio_direction_input(struct gpio_chip *chip, |
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unsigned int offset) |
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{ |
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struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); |
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/* |
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* This will clear the output enable bit, the other bits are |
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* dontcare when this is cleared |
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*/ |
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return regmap_write(priv->regmap, offset, 0); |
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} |
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static int ts4900_gpio_direction_output(struct gpio_chip *chip, |
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unsigned int offset, int value) |
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{ |
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struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); |
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int ret; |
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if (value) |
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ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE | |
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TS4900_GPIO_OUT); |
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else |
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ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE); |
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return ret; |
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} |
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static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset) |
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{ |
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struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); |
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unsigned int reg; |
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regmap_read(priv->regmap, offset, ®); |
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return !!(reg & priv->input_bit); |
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} |
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static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset, |
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int value) |
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{ |
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struct ts4900_gpio_priv *priv = gpiochip_get_data(chip); |
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if (value) |
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regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, |
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TS4900_GPIO_OUT); |
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else |
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regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0); |
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} |
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static const struct regmap_config ts4900_regmap_config = { |
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.reg_bits = 16, |
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.val_bits = 8, |
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}; |
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static const struct gpio_chip template_chip = { |
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.label = "ts4900-gpio", |
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.owner = THIS_MODULE, |
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.get_direction = ts4900_gpio_get_direction, |
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.direction_input = ts4900_gpio_direction_input, |
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.direction_output = ts4900_gpio_direction_output, |
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.get = ts4900_gpio_get, |
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.set = ts4900_gpio_set, |
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.base = -1, |
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.can_sleep = true, |
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}; |
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static const struct of_device_id ts4900_gpio_of_match_table[] = { |
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{ |
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.compatible = "technologic,ts4900-gpio", |
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.data = (void *)TS4900_GPIO_IN, |
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}, { |
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.compatible = "technologic,ts7970-gpio", |
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.data = (void *)TS7970_GPIO_IN, |
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}, |
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{ /* sentinel */ }, |
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}; |
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MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table); |
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static int ts4900_gpio_probe(struct i2c_client *client, |
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const struct i2c_device_id *id) |
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{ |
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struct ts4900_gpio_priv *priv; |
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u32 ngpio; |
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int ret; |
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if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio)) |
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ngpio = DEFAULT_PIN_NUMBER; |
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priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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priv->gpio_chip = template_chip; |
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priv->gpio_chip.label = "ts4900-gpio"; |
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priv->gpio_chip.ngpio = ngpio; |
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priv->gpio_chip.parent = &client->dev; |
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priv->input_bit = (uintptr_t)of_device_get_match_data(&client->dev); |
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priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config); |
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if (IS_ERR(priv->regmap)) { |
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ret = PTR_ERR(priv->regmap); |
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dev_err(&client->dev, "Failed to allocate register map: %d\n", |
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ret); |
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return ret; |
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} |
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ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv); |
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if (ret < 0) { |
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dev_err(&client->dev, "Unable to register gpiochip\n"); |
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return ret; |
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} |
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i2c_set_clientdata(client, priv); |
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return 0; |
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} |
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static const struct i2c_device_id ts4900_gpio_id_table[] = { |
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{ "ts4900-gpio", }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table); |
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static struct i2c_driver ts4900_gpio_driver = { |
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.driver = { |
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.name = "ts4900-gpio", |
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.of_match_table = ts4900_gpio_of_match_table, |
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}, |
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.probe = ts4900_gpio_probe, |
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.id_table = ts4900_gpio_id_table, |
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}; |
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module_i2c_driver(ts4900_gpio_driver); |
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MODULE_AUTHOR("Technologic Systems"); |
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MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core"); |
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MODULE_LICENSE("GPL");
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