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bcm2835-gpio-exp: Driver for GPIO expander via mailbox service
Pi3 and Compute Module 3 have a GPIO expander that the VPU communicates with. There is a mailbox service that now allows control of this expander, so add a kernel driver that can make use of it. Pwr_led node added to device-tree for Pi3. Signed-off-by: Dave Stevenson <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,256 @@ | ||
| /* | ||
| * Broadcom expander GPIO driver | ||
| * | ||
| * Uses the firmware mailbox service to communicate with the | ||
| * GPIO expander on the VPU. | ||
| * | ||
| * Copyright (C) 2017 Raspberry Pi Trading Ltd. | ||
| * | ||
| * Author: Dave Stevenson <[email protected]> | ||
| * Based on gpio-bcm-virt.c by Dom Cobley <[email protected]> | ||
| * | ||
| * This program is free software; you can redistribute it and/or modify | ||
| * it under the terms of the GNU General Public License as published by | ||
| * the Free Software Foundation; either version 2 of the License, or | ||
| * (at your option) any later version. | ||
| */ | ||
|
|
||
| #include <linux/err.h> | ||
| #include <linux/gpio.h> | ||
| #include <linux/module.h> | ||
| #include <linux/platform_device.h> | ||
| #include <linux/dma-mapping.h> | ||
| #include <soc/bcm2835/raspberrypi-firmware.h> | ||
|
|
||
| #define MODULE_NAME "brcmexp-gpio" | ||
| #define NUM_GPIO 8 | ||
|
|
||
| struct brcmexp_gpio { | ||
| struct gpio_chip gc; | ||
| struct device *dev; | ||
| struct rpi_firmware *fw; | ||
| }; | ||
|
|
||
| struct gpio_set_config { | ||
| u32 gpio, direction, polarity, term_en, term_pull_up, state; | ||
| }; | ||
|
|
||
| struct gpio_get_config { | ||
| u32 gpio, direction, polarity, term_en, term_pull_up; | ||
| }; | ||
|
|
||
| struct gpio_get_set_state { | ||
| u32 gpio, state; | ||
| }; | ||
|
|
||
| static int brcmexp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off) | ||
| { | ||
| struct brcmexp_gpio *gpio; | ||
| struct gpio_get_config get; | ||
| int ret; | ||
|
|
||
| gpio = container_of(gc, struct brcmexp_gpio, gc); | ||
|
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||
| get.gpio = off + gpio->gc.base; /* GPIO to update */ | ||
|
|
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| ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, | ||
| &get, sizeof(get)); | ||
| if (ret) { | ||
| dev_err(gpio->dev, | ||
| "Failed to get GPIO %u config (%d)\n", off, ret); | ||
| return ret; | ||
| } | ||
| return get.polarity; | ||
| } | ||
|
|
||
| static int brcmexp_gpio_dir_in(struct gpio_chip *gc, unsigned int off) | ||
| { | ||
| struct brcmexp_gpio *gpio; | ||
| struct gpio_set_config set_in; | ||
| int ret; | ||
|
|
||
| gpio = container_of(gc, struct brcmexp_gpio, gc); | ||
|
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||
| set_in.gpio = off + gpio->gc.base; /* GPIO to update */ | ||
| set_in.direction = 0; /* Input */ | ||
| set_in.polarity = brcmexp_gpio_get_polarity(gc, off); | ||
| /* Retain existing setting */ | ||
| set_in.term_en = 0; /* termination disabled */ | ||
| set_in.term_pull_up = 0; /* n/a as termination disabled */ | ||
| set_in.state = 0; /* n/a as configured as an input */ | ||
|
|
||
| ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, | ||
| &set_in, sizeof(set_in)); | ||
| if (ret) { | ||
| dev_err(gpio->dev, | ||
| "Failed to set GPIO %u to input (%d)\n", | ||
| off, ret); | ||
| return ret; | ||
| } | ||
| return 0; | ||
| } | ||
|
|
||
| static int brcmexp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val) | ||
| { | ||
| struct brcmexp_gpio *gpio; | ||
| struct gpio_set_config set_out; | ||
| int ret; | ||
|
|
||
| gpio = container_of(gc, struct brcmexp_gpio, gc); | ||
|
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||
| set_out.gpio = off + gpio->gc.base; /* GPIO to update */ | ||
| set_out.direction = 1; /* Output */ | ||
| set_out.polarity = brcmexp_gpio_get_polarity(gc, off); | ||
| /* Retain existing setting */ | ||
| set_out.term_en = 0; /* n/a as an output */ | ||
| set_out.term_pull_up = 0; /* n/a as termination disabled */ | ||
| set_out.state = val; /* Output state */ | ||
|
|
||
| ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, | ||
| &set_out, sizeof(set_out)); | ||
| if (ret) { | ||
| dev_err(gpio->dev, | ||
| "Failed to set GPIO %u to output (%d)\n", off, ret); | ||
| return ret; | ||
| } | ||
| return 0; | ||
| } | ||
|
|
||
| static int brcmexp_gpio_get_direction(struct gpio_chip *gc, unsigned int off) | ||
| { | ||
| struct brcmexp_gpio *gpio; | ||
| struct gpio_get_config get; | ||
| int ret; | ||
|
|
||
| gpio = container_of(gc, struct brcmexp_gpio, gc); | ||
|
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| get.gpio = off + gpio->gc.base; /* GPIO to update */ | ||
|
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| ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, | ||
| &get, sizeof(get)); | ||
| if (ret) { | ||
| dev_err(gpio->dev, | ||
| "Failed to get GPIO %u config (%d)\n", off, ret); | ||
| return ret; | ||
| } | ||
| return get.direction ? GPIOF_DIR_OUT : GPIOF_DIR_IN; | ||
| } | ||
|
|
||
| static int brcmexp_gpio_get(struct gpio_chip *gc, unsigned int off) | ||
| { | ||
| struct brcmexp_gpio *gpio; | ||
| struct gpio_get_set_state get; | ||
| int ret; | ||
|
|
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| gpio = container_of(gc, struct brcmexp_gpio, gc); | ||
|
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| get.gpio = off + gpio->gc.base; /* GPIO to update */ | ||
| get.state = 0; /* storage for returned value */ | ||
|
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| ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE, | ||
| &get, sizeof(get)); | ||
| if (ret) { | ||
| dev_err(gpio->dev, | ||
| "Failed to get GPIO %u state (%d)\n", off, ret); | ||
| return ret; | ||
| } | ||
| return !!get.state; | ||
| } | ||
|
|
||
| static void brcmexp_gpio_set(struct gpio_chip *gc, unsigned int off, int val) | ||
| { | ||
| struct brcmexp_gpio *gpio; | ||
| struct gpio_get_set_state set; | ||
| int ret; | ||
|
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| gpio = container_of(gc, struct brcmexp_gpio, gc); | ||
|
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| off += gpio->gc.base; | ||
|
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| set.gpio = off + gpio->gc.base; /* GPIO to update */ | ||
| set.state = val; /* Output state */ | ||
|
|
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| ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE, | ||
| &set, sizeof(set)); | ||
| if (ret) | ||
| dev_err(gpio->dev, | ||
| "Failed to set GPIO %u state (%d)\n", off, ret); | ||
| } | ||
|
|
||
| static int brcmexp_gpio_probe(struct platform_device *pdev) | ||
| { | ||
| int err = 0; | ||
| struct device *dev = &pdev->dev; | ||
| struct device_node *np = dev->of_node; | ||
| struct device_node *fw_node; | ||
| struct rpi_firmware *fw; | ||
| struct brcmexp_gpio *ucb; | ||
|
|
||
| fw_node = of_parse_phandle(np, "firmware", 0); | ||
| if (!fw_node) { | ||
| dev_err(dev, "Missing firmware node\n"); | ||
| return -ENOENT; | ||
| } | ||
|
|
||
| fw = rpi_firmware_get(fw_node); | ||
| if (!fw) | ||
| return -EPROBE_DEFER; | ||
|
|
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| ucb = devm_kzalloc(dev, sizeof(*ucb), GFP_KERNEL); | ||
| if (!ucb) | ||
| return -EINVAL; | ||
|
|
||
| ucb->fw = fw; | ||
| ucb->dev = dev; | ||
| ucb->gc.label = MODULE_NAME; | ||
| ucb->gc.owner = THIS_MODULE; | ||
| ucb->gc.of_node = np; | ||
| ucb->gc.base = 128; | ||
| ucb->gc.ngpio = NUM_GPIO; | ||
|
|
||
| ucb->gc.direction_input = brcmexp_gpio_dir_in; | ||
| ucb->gc.direction_output = brcmexp_gpio_dir_out; | ||
| ucb->gc.get_direction = brcmexp_gpio_get_direction; | ||
| ucb->gc.get = brcmexp_gpio_get; | ||
| ucb->gc.set = brcmexp_gpio_set; | ||
| ucb->gc.can_sleep = true; | ||
|
|
||
| err = gpiochip_add(&ucb->gc); | ||
| if (err) | ||
| return err; | ||
|
|
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| platform_set_drvdata(pdev, ucb); | ||
|
|
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| return 0; | ||
| } | ||
|
|
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| static int brcmexp_gpio_remove(struct platform_device *pdev) | ||
| { | ||
| struct brcmexp_gpio *ucb = platform_get_drvdata(pdev); | ||
|
|
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| gpiochip_remove(&ucb->gc); | ||
|
|
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| return 0; | ||
| } | ||
|
|
||
| static const struct of_device_id __maybe_unused brcmexp_gpio_ids[] = { | ||
| { .compatible = "brcm,bcm2835-expgpio" }, | ||
| { } | ||
| }; | ||
| MODULE_DEVICE_TABLE(of, brcmexp_gpio_ids); | ||
|
|
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| static struct platform_driver brcmexp_gpio_driver = { | ||
| .driver = { | ||
| .name = MODULE_NAME, | ||
| .owner = THIS_MODULE, | ||
| .of_match_table = of_match_ptr(brcmexp_gpio_ids), | ||
| }, | ||
| .probe = brcmexp_gpio_probe, | ||
| .remove = brcmexp_gpio_remove, | ||
| }; | ||
| module_platform_driver(brcmexp_gpio_driver); | ||
|
|
||
| MODULE_LICENSE("GPL"); | ||
| MODULE_AUTHOR("Dave Stevenson <[email protected]>"); | ||
| MODULE_DESCRIPTION("brcm-exp GPIO driver"); | ||
| MODULE_ALIAS("platform:brcmexp-gpio"); |
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