[PATCH 3/4] bcm2835-gpio-exp: Driver for GPIO expander via mailbox service
Baruch Siach
baruch at tkos.co.il
Tue Jan 2 05:19:20 PST 2018
From: Dave Stevenson <dave.stevenson at raspberrypi.org>
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.
Signed-off-by: Dave Stevenson <dave.stevenson at raspberrypi.org>
Signed-off-by: Baruch Siach <baruch at tkos.co.il>
---
drivers/gpio/Kconfig | 7 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-bcm-exp.c | 254 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 262 insertions(+)
create mode 100644 drivers/gpio/gpio-bcm-exp.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d6a8e851ad13..e2aab64ea772 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -128,6 +128,13 @@ config GPIO_AXP209
help
Say yes to enable GPIO support for the AXP209 PMIC
+config GPIO_BCM_EXP
+ bool "Broadcom Exp GPIO"
+ depends on OF_GPIO && RASPBERRYPI_FIRMWARE && (ARCH_BCM2835 || COMPILE_TEST)
+ help
+ Turn on GPIO support for Broadcom chips 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 4bc24febb889..c5f481b1d53c 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_GPIO_ARIZONA) += gpio-arizona.o
obj-$(CONFIG_GPIO_ATH79) += gpio-ath79.o
obj-$(CONFIG_GPIO_ASPEED) += gpio-aspeed.o
obj-$(CONFIG_GPIO_AXP209) += gpio-axp209.o
+obj-$(CONFIG_GPIO_BCM_EXP) += gpio-bcm-exp.o
obj-$(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-bcm-exp.c b/drivers/gpio/gpio-bcm-exp.c
new file mode 100644
index 000000000000..d68adafaee4a
--- /dev/null
+++ b/drivers/gpio/gpio-bcm-exp.c
@@ -0,0 +1,254 @@
+/*
+ * 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 <dave.stevenson at raspberrypi.org>
+ * Based on gpio-bcm-virt.c by Dom Cobley <popcornmix at gmail.com>
+ *
+ * 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);
+
+ get.gpio = off + gpio->gc.base; /* GPIO to update */
+
+ 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);
+
+ 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);
+
+ 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);
+
+ get.gpio = off + gpio->gc.base; /* GPIO to update */
+
+ 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;
+
+ gpio = container_of(gc, struct brcmexp_gpio, gc);
+
+ get.gpio = off + gpio->gc.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) {
+ 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;
+
+ gpio = container_of(gc, struct brcmexp_gpio, gc);
+
+ set.gpio = off + gpio->gc.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)
+ 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;
+
+ 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;
+
+ platform_set_drvdata(pdev, ucb);
+
+ return 0;
+}
+
+static int brcmexp_gpio_remove(struct platform_device *pdev)
+{
+ struct brcmexp_gpio *ucb = platform_get_drvdata(pdev);
+
+ gpiochip_remove(&ucb->gc);
+
+ return 0;
+}
+
+static const struct of_device_id __maybe_unused brcmexp_gpio_ids[] = {
+ { .compatible = "brcm,bcm2835-expgpio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, brcmexp_gpio_ids);
+
+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 <dave.stevenson at raspberrypi.org>");
+MODULE_DESCRIPTION("brcm-exp GPIO driver");
+MODULE_ALIAS("platform:brcmexp-gpio");
--
2.15.1
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