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256 lines
6.3 KiB
256 lines
6.3 KiB
// 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 = rpi_firmware_get(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.of_node = np; |
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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 = of_match_ptr(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 <[email protected]>"); |
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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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