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![Julia Lawall](/assets/img/avatar_default.png)
These structures are only used to copy into other structures, so declare them as const. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @r disable optional_qualifier@ identifier i; position p; @@ static struct gpio_chip i@p = { ... }; @ok@ identifier r.i; expression e; position p; @@ e = i@p; @bad@ position p != {r.p,ok.p}; identifier r.i; struct gpio_chip e; @@ e@i@p @depends on !bad disable optional_qualifier@ identifier r.i; @@ static +const struct gpio_chip i = { ... }; // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Acked-by: Joachim Eastwood <manabian@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
190 lines
4.8 KiB
C
190 lines
4.8 KiB
C
/*
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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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return !(reg & TS4900_GPIO_OE);
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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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const struct of_device_id *match;
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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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match = of_match_device(ts4900_gpio_of_match_table, &client->dev);
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if (!match)
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return -EINVAL;
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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)match->data;
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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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