diff options
| -rw-r--r-- | drivers/gpio/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/gpio/Makefile | 1 | ||||
| -rw-r--r-- | drivers/gpio/gpio-raspberrypi-exp.c | 252 |
3 files changed, 262 insertions, 0 deletions
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 8dbb228..fd0562a 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -122,6 +122,15 @@ config GPIO_ATH79 Select this option to enable GPIO driver for Atheros AR71XX/AR724X/AR913X SoC devices. +config GPIO_RASPBERRYPI_EXP + tristate "Raspberry Pi 3 GPIO Expander" + default RASPBERRYPI_FIRMWARE + depends on OF_GPIO + depends on (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || COMPILE_TEST + help + Turn on GPIO support for the expander on Raspberry Pi 3 boards, using + the firmware mailbox to communicate with VideoCore on BCM283x chips. + config GPIO_BCM_KONA bool "Broadcom Kona GPIO" depends on OF_GPIO && (ARCH_BCM_MOBILE || COMPILE_TEST) diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index cccb0d4..76dc0a0 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -32,6 +32,7 @@ obj-$(CONFIG_GPIO_AMDPT) += gpio-amdpt.o obj-$(CONFIG_GPIO_ARIZONA) += gpio-arizona.o obj-$(CONFIG_GPIO_ATH79) += gpio-ath79.o obj-$(CONFIG_GPIO_ASPEED) += gpio-aspeed.o +obj-$(CONFIG_GPIO_RASPBERRYPI_EXP) += gpio-raspberrypi-exp.o obj-$(CONFIG_GPIO_BCM_KONA) += gpio-bcm-kona.o obj-$(CONFIG_GPIO_BD9571MWV) += gpio-bd9571mwv.o obj-$(CONFIG_GPIO_BRCMSTB) += gpio-brcmstb.o diff --git a/drivers/gpio/gpio-raspberrypi-exp.c b/drivers/gpio/gpio-raspberrypi-exp.c new file mode 100644 index 0000000..d6d36d5 --- /dev/null +++ b/drivers/gpio/gpio-raspberrypi-exp.c @@ -0,0 +1,252 @@ +// 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; + } + return !get.direction; +} + +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); + 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"); |
