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![Zhu Wang](/assets/img/avatar_default.png)
The driver depends on CONFIG_OF, so it is not necessary to use of_match_ptr() here, and __maybe_unused can also be removed. Even for drivers that do not depend on CONFIG_OF, it's almost always better to leave out the of_match_ptr(), since the only thing it can possibly do is to save a few bytes of .text if a driver can be used both with and without it. Signed-off-by: Zhu Wang <wangzhu9@huawei.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
255 lines
6.2 KiB
C
255 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Raspberry Pi 3 expander GPIO driver
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*
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* Uses the firmware mailbox service to communicate with the
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* GPIO expander on the VPU.
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*
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* Copyright (C) 2017 Raspberry Pi Trading Ltd.
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*/
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#include <linux/err.h>
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#include <linux/gpio/driver.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <soc/bcm2835/raspberrypi-firmware.h>
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#define MODULE_NAME "raspberrypi-exp-gpio"
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#define NUM_GPIO 8
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#define RPI_EXP_GPIO_BASE 128
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#define RPI_EXP_GPIO_DIR_IN 0
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#define RPI_EXP_GPIO_DIR_OUT 1
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struct rpi_exp_gpio {
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struct gpio_chip gc;
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struct rpi_firmware *fw;
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};
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/* VC4 firmware mailbox interface data structures */
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struct gpio_set_config {
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u32 gpio;
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u32 direction;
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u32 polarity;
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u32 term_en;
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u32 term_pull_up;
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u32 state;
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};
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struct gpio_get_config {
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u32 gpio;
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u32 direction;
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u32 polarity;
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u32 term_en;
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u32 term_pull_up;
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};
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struct gpio_get_set_state {
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u32 gpio;
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u32 state;
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};
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static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off)
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{
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struct rpi_exp_gpio *gpio;
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struct gpio_get_config get;
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int ret;
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gpio = gpiochip_get_data(gc);
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get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
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ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
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&get, sizeof(get));
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if (ret || get.gpio != 0) {
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dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n",
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off, ret, get.gpio);
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return ret ? ret : -EIO;
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}
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return get.polarity;
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}
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static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off)
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{
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struct rpi_exp_gpio *gpio;
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struct gpio_set_config set_in;
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int ret;
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gpio = gpiochip_get_data(gc);
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set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
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set_in.direction = RPI_EXP_GPIO_DIR_IN;
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set_in.term_en = 0; /* termination disabled */
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set_in.term_pull_up = 0; /* n/a as termination disabled */
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set_in.state = 0; /* n/a as configured as an input */
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ret = rpi_exp_gpio_get_polarity(gc, off);
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if (ret < 0)
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return ret;
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set_in.polarity = ret; /* Retain existing setting */
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ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
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&set_in, sizeof(set_in));
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if (ret || set_in.gpio != 0) {
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dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n",
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off, ret, set_in.gpio);
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return ret ? ret : -EIO;
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}
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return 0;
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}
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static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val)
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{
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struct rpi_exp_gpio *gpio;
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struct gpio_set_config set_out;
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int ret;
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gpio = gpiochip_get_data(gc);
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set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
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set_out.direction = RPI_EXP_GPIO_DIR_OUT;
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set_out.term_en = 0; /* n/a as an output */
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set_out.term_pull_up = 0; /* n/a as termination disabled */
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set_out.state = val; /* Output state */
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ret = rpi_exp_gpio_get_polarity(gc, off);
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if (ret < 0)
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return ret;
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set_out.polarity = ret; /* Retain existing setting */
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ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG,
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&set_out, sizeof(set_out));
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if (ret || set_out.gpio != 0) {
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dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n",
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off, ret, set_out.gpio);
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return ret ? ret : -EIO;
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}
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return 0;
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}
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static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off)
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{
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struct rpi_exp_gpio *gpio;
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struct gpio_get_config get;
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int ret;
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gpio = gpiochip_get_data(gc);
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get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
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ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG,
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&get, sizeof(get));
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if (ret || get.gpio != 0) {
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dev_err(gc->parent,
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"Failed to get GPIO %u config (%d %x)\n", off, ret,
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get.gpio);
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return ret ? ret : -EIO;
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}
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if (get.direction)
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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 rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off)
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{
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struct rpi_exp_gpio *gpio;
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struct gpio_get_set_state get;
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int ret;
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gpio = gpiochip_get_data(gc);
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get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
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get.state = 0; /* storage for returned value */
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ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE,
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&get, sizeof(get));
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if (ret || get.gpio != 0) {
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dev_err(gc->parent,
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"Failed to get GPIO %u state (%d %x)\n", off, ret,
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get.gpio);
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return ret ? ret : -EIO;
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}
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return !!get.state;
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}
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static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val)
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{
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struct rpi_exp_gpio *gpio;
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struct gpio_get_set_state set;
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int ret;
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gpio = gpiochip_get_data(gc);
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set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */
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set.state = val; /* Output state */
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ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE,
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&set, sizeof(set));
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if (ret || set.gpio != 0)
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dev_err(gc->parent,
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"Failed to set GPIO %u state (%d %x)\n", off, ret,
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set.gpio);
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}
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static int rpi_exp_gpio_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct device_node *fw_node;
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struct rpi_firmware *fw;
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struct rpi_exp_gpio *rpi_gpio;
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fw_node = of_get_parent(np);
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if (!fw_node) {
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dev_err(dev, "Missing firmware node\n");
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return -ENOENT;
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}
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fw = devm_rpi_firmware_get(&pdev->dev, fw_node);
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of_node_put(fw_node);
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if (!fw)
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return -EPROBE_DEFER;
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rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL);
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if (!rpi_gpio)
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return -ENOMEM;
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rpi_gpio->fw = fw;
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rpi_gpio->gc.parent = dev;
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rpi_gpio->gc.label = MODULE_NAME;
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rpi_gpio->gc.owner = THIS_MODULE;
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rpi_gpio->gc.base = -1;
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rpi_gpio->gc.ngpio = NUM_GPIO;
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rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in;
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rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out;
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rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction;
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rpi_gpio->gc.get = rpi_exp_gpio_get;
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rpi_gpio->gc.set = rpi_exp_gpio_set;
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rpi_gpio->gc.can_sleep = true;
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return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio);
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}
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static const struct of_device_id rpi_exp_gpio_ids[] = {
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{ .compatible = "raspberrypi,firmware-gpio" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids);
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static struct platform_driver rpi_exp_gpio_driver = {
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.driver = {
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.name = MODULE_NAME,
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.of_match_table = rpi_exp_gpio_ids,
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},
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.probe = rpi_exp_gpio_probe,
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};
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module_platform_driver(rpi_exp_gpio_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>");
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MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver");
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MODULE_ALIAS("platform:rpi-exp-gpio");
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