[RFC v2 1/3] ath79: add gpio-latch driver for Mikrotik RouterBoards

Denis Kalashnikov denis281089 at gmail.com
Fri May 21 04:05:01 PDT 2021


This is a slighty modified version of ar71xx gpio-latch driver
written by Gabor Juhos <juhosg at openwrt.org>.

Changes:
* DTS support,
* New gpio API (gpiod_*).

Signed-off-by: Denis Kalashnikov <denis281089 at gmail.com>
---

Changelog:

v1-->v2:
- Don't use MFD driver API anymore.

---
 .../ath79/files/drivers/gpio/gpio-latch.c     | 225 ++++++++++++++++++
 .../patches-5.10/939-mikrotik-rb91x.patch     |  25 ++
 .../patches-5.4/939-mikrotik-rb91x.patch      |  23 ++
 3 files changed, 273 insertions(+)
 create mode 100644 target/linux/ath79/files/drivers/gpio/gpio-latch.c
 create mode 100644 target/linux/ath79/patches-5.10/939-mikrotik-rb91x.patch
 create mode 100644 target/linux/ath79/patches-5.4/939-mikrotik-rb91x.patch

diff --git a/target/linux/ath79/files/drivers/gpio/gpio-latch.c b/target/linux/ath79/files/drivers/gpio/gpio-latch.c
new file mode 100644
index 0000000000..cb80b29052
--- /dev/null
+++ b/target/linux/ath79/files/drivers/gpio/gpio-latch.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  GPIO latch driver
+ *
+ *  Copyright (C) 2014 Gabor Juhos <juhosg at openwrt.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
+
+#define GPIO_LATCH_DRIVER_NAME  "gpio-latch"
+#define GPIO_LATCH_LINES 9
+
+struct gpio_latch_chip {
+	struct gpio_chip gc;
+	struct mutex mutex;
+	struct mutex latch_mutex;
+	bool latch_enabled;
+	int le_gpio;
+	bool le_active_low;
+	struct gpio_desc **gpios;
+};
+
+static inline struct gpio_latch_chip *to_gpio_latch_chip(struct gpio_chip *gc)
+{
+	return container_of(gc, struct gpio_latch_chip, gc);
+}
+
+static void gpio_latch_lock(struct gpio_latch_chip *glc, bool enable)
+{
+	mutex_lock(&glc->mutex);
+
+	if (enable)
+		glc->latch_enabled = true;
+
+	if (glc->latch_enabled)
+		mutex_lock(&glc->latch_mutex);
+}
+
+static void gpio_latch_unlock(struct gpio_latch_chip *glc, bool disable)
+{
+	if (glc->latch_enabled)
+		mutex_unlock(&glc->latch_mutex);
+
+	if (disable)
+		glc->latch_enabled = true;
+
+	mutex_unlock(&glc->mutex);
+}
+
+static int
+gpio_latch_get(struct gpio_chip *gc, unsigned offset)
+{
+	struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
+	int ret;
+
+	gpio_latch_lock(glc, false);
+	ret = gpiod_get_value(glc->gpios[offset]);
+	gpio_latch_unlock(glc, false);
+
+	return ret;
+}
+
+static void
+gpio_latch_set(struct gpio_chip *gc, unsigned offset, int value)
+{
+	struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
+	bool enable_latch = false;
+	bool disable_latch = false;
+
+	if (offset == glc->le_gpio) {
+		enable_latch = value ^ glc->le_active_low;
+		disable_latch = !enable_latch;
+	}
+
+	gpio_latch_lock(glc, enable_latch);
+	gpiod_set_value(glc->gpios[offset], value);
+	gpio_latch_unlock(glc, disable_latch);
+}
+
+static int
+gpio_latch_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+	struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
+	int ret;
+
+	gpio_latch_lock(glc, false);
+	ret = gpiod_direction_input(glc->gpios[offset]);
+	gpio_latch_unlock(glc, false);
+
+	return ret;
+}
+
+static int
+gpio_latch_direction_output(struct gpio_chip *gc, unsigned offset, int value)
+{
+	struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
+	bool enable_latch = false;
+	bool disable_latch = false;
+	int ret;
+
+	if (offset == glc->le_gpio) {
+		enable_latch = value ^ glc->le_active_low;
+		disable_latch = !enable_latch;
+	}
+
+	gpio_latch_lock(glc, enable_latch);
+	ret = gpiod_direction_output(glc->gpios[offset], value);
+	gpio_latch_unlock(glc, disable_latch);
+
+	return ret;
+}
+
+static int gpio_latch_probe(struct platform_device *pdev)
+{
+	struct gpio_latch_chip *glc;
+	struct gpio_chip *gc;
+	struct device *dev = &pdev->dev;
+	struct device_node *of_node = dev->of_node;
+	struct gpio_descs *gpios;
+	int i;
+	enum of_gpio_flags flags;
+
+	glc = devm_kzalloc(dev, sizeof(*glc), GFP_KERNEL);
+	if (!glc)
+		return -ENOMEM;
+
+	mutex_init(&glc->mutex);
+	mutex_init(&glc->latch_mutex);
+
+	gpios = devm_gpiod_get_array(dev, NULL, 0);
+	if (IS_ERR(gpios)) {
+		dev_err(dev, "failed to get gpios: %d\n", (int)gpios);
+		return -EINVAL;
+	}
+	glc->gpios = gpios->desc;
+
+	if (gpios->ndescs != GPIO_LATCH_LINES) {
+		dev_err(dev, "gpios count must be %d\n", GPIO_LATCH_LINES);
+		return -EINVAL;
+	}
+
+	glc->le_gpio = of_get_named_gpio_flags(of_node, "latch-enable-gpios", 0,
+		&flags);
+	if (glc->le_gpio < 0) {
+		dev_err(dev,
+		  "could not read required 'latch-enable-gpios' property: %d\n",
+		  glc->le_gpio);
+		return -EINVAL;
+	}
+	glc->le_active_low = (flags == OF_GPIO_ACTIVE_LOW) ? true : false;
+
+	for (i = 0; i < gpios->ndescs; i++) {
+		if (glc->le_gpio == desc_to_gpio(glc->gpios[i])) {
+			glc->le_gpio = i;
+			break;
+		}
+	}
+
+	if (i == gpios->ndescs) {
+		dev_err(dev, "latch-enable-gpio must be in gpios list\n");
+		return -EINVAL;
+	}
+
+	gc = &glc->gc;
+	gc->label = GPIO_LATCH_DRIVER_NAME;
+	gc->can_sleep = true;
+	gc->base = -1;
+	gc->ngpio = gpios->ndescs;
+	gc->get = gpio_latch_get;
+	gc->set = gpio_latch_set;
+	gc->direction_input = gpio_latch_direction_input,
+	gc->direction_output = gpio_latch_direction_output;
+	gc->of_node = of_node;
+
+	platform_set_drvdata(pdev, glc);
+
+	i = gpiochip_add(&glc->gc);
+	if (i) {
+		dev_err(dev, "gpiochip_add() failed: %d\n", i);
+		return i;
+	}
+
+	return 0;
+}
+
+static int gpio_latch_remove(struct platform_device *pdev)
+{
+	struct gpio_latch_chip *glc = platform_get_drvdata(pdev);
+
+	gpiochip_remove(&glc->gc);
+	return 0;
+}
+
+static const struct of_device_id gpio_latch_match[] = {
+	{ .compatible = GPIO_LATCH_DRIVER_NAME },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, gpio_latch_match);
+
+static struct platform_driver gpio_latch_driver = {
+	.probe = gpio_latch_probe,
+	.remove = gpio_latch_remove,
+	.driver = {
+		.name = GPIO_LATCH_DRIVER_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = gpio_latch_match,
+	},
+};
+
+module_platform_driver(gpio_latch_driver);
+
+MODULE_DESCRIPTION("GPIO latch driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
+MODULE_AUTHOR("Denis Kalashnikov <denis281089 at gmail.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" GPIO_LATCH_DRIVER_NAME);
diff --git a/target/linux/ath79/patches-5.10/939-mikrotik-rb91x.patch b/target/linux/ath79/patches-5.10/939-mikrotik-rb91x.patch
new file mode 100644
index 0000000000..9f6441cc3c
--- /dev/null
+++ b/target/linux/ath79/patches-5.10/939-mikrotik-rb91x.patch
@@ -0,0 +1,25 @@
+--- a/drivers/gpio/Kconfig
++++ b/drivers/gpio/Kconfig
+@@ -1524,6 +1524,12 @@ config GPIO_RB4XX
+ 	help
+ 	  GPIO driver for Mikrotik Routerboard RB4xx series.
+ 
++config GPIO_LATCH
++	tristate "Support for GPIO on latch on Mikrotik RouterBoards"
++	depends on ATH79
++	help
++	  GPIO driver for latch on Mikrotik Routerboards.
++
+ endmenu
+ 
+ menu "SPI GPIO expanders"
+--- a/drivers/gpio/Makefile
++++ b/drivers/gpio/Makefile
+@@ -72,6 +72,7 @@ obj-$(CONFIG_GPIO_IT87)			+= gpio-it87.o
+ obj-$(CONFIG_GPIO_IXP4XX)		+= gpio-ixp4xx.o
+ obj-$(CONFIG_GPIO_JANZ_TTL)		+= gpio-janz-ttl.o
+ obj-$(CONFIG_GPIO_KEMPLD)		+= gpio-kempld.o
++obj-$(CONFIG_GPIO_LATCH)		+= gpio-latch.o
+ obj-$(CONFIG_GPIO_LOGICVC)		+= gpio-logicvc.o
+ obj-$(CONFIG_GPIO_LOONGSON1)		+= gpio-loongson1.o
+ obj-$(CONFIG_GPIO_LOONGSON)		+= gpio-loongson.o
diff --git a/target/linux/ath79/patches-5.4/939-mikrotik-rb91x.patch b/target/linux/ath79/patches-5.4/939-mikrotik-rb91x.patch
new file mode 100644
index 0000000000..94b98445e9
--- /dev/null
+++ b/target/linux/ath79/patches-5.4/939-mikrotik-rb91x.patch
@@ -0,0 +1,23 @@
+--- a/drivers/gpio/Kconfig
++++ b/drivers/gpio/Kconfig
+@@ -130,6 +130,10 @@ config GPIO_ATH79
+ 	  Select this option to enable GPIO driver for
+ 	  Atheros AR71XX/AR724X/AR913X SoC devices.
+ 
++config GPIO_LATCH
++	tristate "Mikrotik GPIO latch driver"
++	depends on ATH79
++
+ config GPIO_RASPBERRYPI_EXP
+ 	tristate "Raspberry Pi 3 GPIO Expander"
+ 	default RASPBERRYPI_FIRMWARE
+--- a/drivers/gpio/Makefile
++++ b/drivers/gpio/Makefile
+@@ -67,6 +67,7 @@ obj-$(CONFIG_GPIO_IT87)			+= gpio-it87.o
+ obj-$(CONFIG_GPIO_IXP4XX)		+= gpio-ixp4xx.o
+ obj-$(CONFIG_GPIO_JANZ_TTL)		+= gpio-janz-ttl.o
+ obj-$(CONFIG_GPIO_KEMPLD)		+= gpio-kempld.o
++obj-$(CONFIG_GPIO_LATCH)		+= gpio-latch.o
+ obj-$(CONFIG_GPIO_LOONGSON1)		+= gpio-loongson1.o
+ obj-$(CONFIG_GPIO_LOONGSON)		+= gpio-loongson.o
+ obj-$(CONFIG_GPIO_LP3943)		+= gpio-lp3943.o
-- 
2.26.3




More information about the openwrt-devel mailing list