diff options
Diffstat (limited to 'drivers/gpio/gpio-ts4900.c')
| -rw-r--r-- | drivers/gpio/gpio-ts4900.c | 60 |
1 files changed, 35 insertions, 25 deletions
diff --git a/drivers/gpio/gpio-ts4900.c b/drivers/gpio/gpio-ts4900.c index 1da8d0586329..d9ee8fc77ccd 100644 --- a/drivers/gpio/gpio-ts4900.c +++ b/drivers/gpio/gpio-ts4900.c @@ -1,23 +1,15 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Digital I/O driver for Technologic Systems I2C FPGA Core * - * Copyright (C) 2015 Technologic Systems + * Copyright (C) 2015, 2018 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/property.h> #include <linux/regmap.h> #define DEFAULT_PIN_NUMBER 32 @@ -44,7 +36,10 @@ static int ts4900_gpio_get_direction(struct gpio_chip *chip, regmap_read(priv->regmap, offset, ®); - return !(reg & TS4900_GPIO_OE); + 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, @@ -53,18 +48,34 @@ static int ts4900_gpio_direction_input(struct gpio_chip *chip, 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 + * 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_write(priv->regmap, offset, 0); + 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); @@ -84,16 +95,16 @@ static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset) return !!(reg & priv->input_bit); } -static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset, - int value) +static int 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); + return regmap_update_bits(priv->regmap, offset, + TS4900_GPIO_OUT, TS4900_GPIO_OUT); + + return regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0); } static const struct regmap_config ts4900_regmap_config = { @@ -125,14 +136,13 @@ static const struct of_device_id ts4900_gpio_of_match_table[] = { }; MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table); -static int ts4900_gpio_probe(struct i2c_client *client, - const struct i2c_device_id *id) +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)) + if (device_property_read_u32(&client->dev, "ngpios", &ngpio)) ngpio = DEFAULT_PIN_NUMBER; priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); @@ -143,7 +153,7 @@ static int ts4900_gpio_probe(struct i2c_client *client, 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->input_bit = (uintptr_t)device_get_match_data(&client->dev); priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config); if (IS_ERR(priv->regmap)) { |