// SPDX-License-Identifier: GPL-2.0+ /* * Raspberry Pi 3 expander GPIO driver * * Uses the firmware mailbox service to communicate with the * GPIO expander on the VPU. * * Copyright (C) 2017 Raspberry Pi Trading Ltd. */ #include <linux/err.h> #include <linux/gpio/driver.h> #include <linux/module.h> #include <linux/platform_device.h> #include <soc/bcm2835/raspberrypi-firmware.h> #define MODULE_NAME "raspberrypi-exp-gpio" #define NUM_GPIO 8 #define RPI_EXP_GPIO_BASE 128 #define RPI_EXP_GPIO_DIR_IN 0 #define RPI_EXP_GPIO_DIR_OUT 1 struct rpi_exp_gpio { struct gpio_chip gc; struct rpi_firmware *fw; }; /* VC4 firmware mailbox interface data structures */ struct gpio_set_config { u32 gpio; u32 direction; u32 polarity; u32 term_en; u32 term_pull_up; u32 state; }; struct gpio_get_config { u32 gpio; u32 direction; u32 polarity; u32 term_en; u32 term_pull_up; }; struct gpio_get_set_state { u32 gpio; u32 state; }; static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_get_config get; int ret; gpio = gpiochip_get_data(gc); get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, &get, sizeof(get)); if (ret || get.gpio != 0) { dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n", off, ret, get.gpio); return ret ? ret : -EIO; } return get.polarity; } static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_set_config set_in; int ret; gpio = gpiochip_get_data(gc); set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ set_in.direction = RPI_EXP_GPIO_DIR_IN; 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_exp_gpio_get_polarity(gc, off); if (ret < 0) return ret; set_in.polarity = ret; /* Retain existing setting */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, &set_in, sizeof(set_in)); if (ret || set_in.gpio != 0) { dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n", off, ret, set_in.gpio); return ret ? ret : -EIO; } return 0; } static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val) { struct rpi_exp_gpio *gpio; struct gpio_set_config set_out; int ret; gpio = gpiochip_get_data(gc); set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ set_out.direction = RPI_EXP_GPIO_DIR_OUT; 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_exp_gpio_get_polarity(gc, off); if (ret < 0) return ret; set_out.polarity = ret; /* Retain existing setting */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, &set_out, sizeof(set_out)); if (ret || set_out.gpio != 0) { dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n", off, ret, set_out.gpio); return ret ? ret : -EIO; } return 0; } static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_get_config get; int ret; gpio = gpiochip_get_data(gc); get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, &get, sizeof(get)); if (ret || get.gpio != 0) { dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n", off, ret, get.gpio); return ret ? ret : -EIO; } if (get.direction) return GPIO_LINE_DIRECTION_OUT; return GPIO_LINE_DIRECTION_IN; } static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_get_set_state get; int ret; gpio = gpiochip_get_data(gc); get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ get.state = 0; /* storage for returned value */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE, &get, sizeof(get)); if (ret || get.gpio != 0) { dev_err(gc->parent, "Failed to get GPIO %u state (%d %x)\n", off, ret, get.gpio); return ret ? ret : -EIO; } return !!get.state; } static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val) { struct rpi_exp_gpio *gpio; struct gpio_get_set_state set; int ret; gpio = gpiochip_get_data(gc); set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ set.state = val; /* Output state */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE, &set, sizeof(set)); if (ret || set.gpio != 0) dev_err(gc->parent, "Failed to set GPIO %u state (%d %x)\n", off, ret, set.gpio); } static int rpi_exp_gpio_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; struct device_node *fw_node; struct rpi_firmware *fw; struct rpi_exp_gpio *rpi_gpio; fw_node = of_get_parent(np); if (!fw_node) { dev_err(dev, "Missing firmware node\n"); return -ENOENT; } fw = rpi_firmware_get(fw_node); of_node_put(fw_node); if (!fw) return -EPROBE_DEFER; rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL); if (!rpi_gpio) return -ENOMEM; rpi_gpio->fw = fw; rpi_gpio->gc.parent = dev; rpi_gpio->gc.label = MODULE_NAME; rpi_gpio->gc.owner = THIS_MODULE; rpi_gpio->gc.of_node = np; rpi_gpio->gc.base = -1; rpi_gpio->gc.ngpio = NUM_GPIO; rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in; rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out; rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction; rpi_gpio->gc.get = rpi_exp_gpio_get; rpi_gpio->gc.set = rpi_exp_gpio_set; rpi_gpio->gc.can_sleep = true; return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio); } static const struct of_device_id rpi_exp_gpio_ids[] = { { .compatible = "raspberrypi,firmware-gpio" }, { } }; MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids); static struct platform_driver rpi_exp_gpio_driver = { .driver = { .name = MODULE_NAME, .of_match_table = of_match_ptr(rpi_exp_gpio_ids), }, .probe = rpi_exp_gpio_probe, }; module_platform_driver(rpi_exp_gpio_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>"); MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver"); MODULE_ALIAS("platform:rpi-exp-gpio");