path: root/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/0041-Enable-passthrough-based-gpio-character-device.patch

From d34efc982a9206db87da49be3d9b1e20f59be56f Mon Sep 17 00:00:00 2001
From: Kuiying Wang <kuiying.wang@intel.com>
Date: Thu, 31 Jan 2019 17:47:39 +0800
Subject: [PATCH] Enable passthrough based gpio character device.

Signed-off-by: Kuiying Wang <kuiying.wang@intel.com>
---
 drivers/gpio/gpio-aspeed.c              | 47 ++++++++++++++++++++++-
 drivers/gpio/gpiolib.c                  | 51 +++++++++++++++++++++++--
 drivers/gpio/gpiolib.h                  |  1 +
 include/linux/gpio/consumer.h           |  9 +++++
 include/linux/pinctrl/pinconf-generic.h |  2 +
 include/uapi/linux/gpio.h               |  1 +
 6 files changed, 106 insertions(+), 5 deletions(-)

diff --git a/drivers/gpio/gpio-aspeed.c b/drivers/gpio/gpio-aspeed.c
index 2342e154029b..06fd95197684 100644
--- a/drivers/gpio/gpio-aspeed.c
+++ b/drivers/gpio/gpio-aspeed.c
@@ -17,9 +17,11 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/spinlock.h>
 #include <linux/string.h>
 
@@ -58,6 +60,7 @@ struct aspeed_gpio {
 	struct gpio_chip chip;
 	spinlock_t lock;
 	void __iomem *base;
+	struct regmap *scu;
 	int irq;
 	const struct aspeed_gpio_config *config;
 
@@ -91,6 +94,13 @@ struct aspeed_gpio_bank {
  *       and thus can be used to read back what was last written
  *       reliably.
  */
+#define SCU8C				0x8C /* Multi-function Pin Control #4 */
+#define PASS_THROUGH1		32
+#define PASS_THROUGH2		34
+#define PASS_THROUGH2_MASK	0x2000
+#define PASS_THROUGH1_MASK	0x1000
+#define PASS_THROUGH2_ON 	0x2000
+#define PASS_THROUGH1_ON 	0x1000
 
 static const int debounce_timers[4] = { 0x00, 0x50, 0x54, 0x58 };
 
@@ -988,12 +998,38 @@ static int set_debounce(struct gpio_chip *chip, unsigned int offset,
 	return disable_debounce(chip, offset);
 }
 
+static int aspeed_gpio_pass_through(struct gpio_chip *chip, unsigned int offset,
+				    unsigned long param)
+{
+	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
+	u32 value;
+
+	if (!gpio->scu)
+		return -ENOTSUPP;
+	if (param == PIN_CONFIG_PASS_THROUGH_ENABLE){
+		if (offset == PASS_THROUGH2){
+			regmap_update_bits(gpio->scu, SCU8C, PASS_THROUGH2_MASK, PASS_THROUGH2_ON);
+		} else if (offset == PASS_THROUGH1){
+			regmap_update_bits(gpio->scu, SCU8C, PASS_THROUGH1_MASK, PASS_THROUGH1_ON);
+		}
+	} else if (param == PIN_CONFIG_PASS_THROUGH_DISABLE){
+		if (offset == PASS_THROUGH2){
+			regmap_update_bits(gpio->scu, SCU8C, PASS_THROUGH2_MASK, ~(PASS_THROUGH2_ON));
+		} else if (offset == PASS_THROUGH1){
+			regmap_update_bits(gpio->scu, SCU8C, PASS_THROUGH1_MASK, ~(PASS_THROUGH1_ON));
+		}
+	} else {
+		return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
 static int aspeed_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 				  unsigned long config)
 {
 	unsigned long param = pinconf_to_config_param(config);
 	u32 arg = pinconf_to_config_argument(config);
-
 	if (param == PIN_CONFIG_INPUT_DEBOUNCE)
 		return set_debounce(chip, offset, arg);
 	else if (param == PIN_CONFIG_BIAS_DISABLE ||
@@ -1006,6 +1042,9 @@ static int aspeed_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 		return -ENOTSUPP;
 	else if (param == PIN_CONFIG_PERSIST_STATE)
 		return aspeed_gpio_reset_tolerance(chip, offset, arg);
+	else if (param == PIN_CONFIG_PASS_THROUGH_ENABLE ||
+			param == PIN_CONFIG_PASS_THROUGH_DISABLE)
+		return aspeed_gpio_pass_through(chip, offset, param);
 
 	return -ENOTSUPP;
 }
@@ -1167,7 +1206,11 @@ static int __init aspeed_gpio_probe(struct platform_device *pdev)
 	gpio->base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(gpio->base))
 		return PTR_ERR(gpio->base);
-
+	gpio->scu = syscon_regmap_lookup_by_compatible("aspeed,ast2500-scu");
+	if (IS_ERR(gpio->scu)) {
+		dev_err(&pdev->dev, "Failed to find SCU regmap\n");
+		gpio->scu = NULL;
+	}
 	spin_lock_init(&gpio->lock);
 
 	gpio_id = of_match_node(aspeed_gpio_of_table, pdev->dev.of_node);
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a8e01d99919c..21eeca17583d 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -419,6 +419,7 @@ struct linehandle_state {
 	GPIOHANDLE_REQUEST_OUTPUT | \
 	GPIOHANDLE_REQUEST_ACTIVE_LOW | \
 	GPIOHANDLE_REQUEST_OPEN_DRAIN | \
+	GPIOHANDLE_REQUEST_PASS_THROUGH | \
 	GPIOHANDLE_REQUEST_OPEN_SOURCE)
 
 static long linehandle_ioctl(struct file *filep, unsigned int cmd,
@@ -519,7 +520,6 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 		return -EINVAL;
 
 	lflags = handlereq.flags;
-
 	/* Return an error if an unknown flag is set */
 	if (lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
 		return -EINVAL;
@@ -579,6 +579,8 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 			set_bit(FLAG_OPEN_DRAIN, &desc->flags);
 		if (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE)
 			set_bit(FLAG_OPEN_SOURCE, &desc->flags);
+		if (lflags & GPIOHANDLE_REQUEST_PASS_THROUGH)
+			set_bit(FLAG_PASS_THROUGH, &desc->flags);
 
 		ret = gpiod_set_transitory(desc, false);
 		if (ret < 0)
@@ -598,6 +600,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 			ret = gpiod_direction_input(desc);
 			if (ret)
 				goto out_free_descs;
+		} else if (lflags & GPIOHANDLE_REQUEST_PASS_THROUGH) {
+			int val = !!handlereq.default_values[i];
+			ret = gpiod_direction_pass_through(desc, val);
+			if (ret)
+				goto out_free_descs;
 		}
 		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
 			offset);
@@ -1010,7 +1017,6 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	struct gpio_device *gdev = filp->private_data;
 	struct gpio_chip *chip = gdev->chip;
 	void __user *ip = (void __user *)arg;
-
 	/* We fail any subsequent ioctl():s when the chip is gone */
 	if (!chip)
 		return -ENODEV;
@@ -1018,7 +1024,6 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	/* Fill in the struct and pass to userspace */
 	if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
 		struct gpiochip_info chipinfo;
-
 		memset(&chipinfo, 0, sizeof(chipinfo));
 
 		strncpy(chipinfo.name, dev_name(&gdev->dev),
@@ -2643,6 +2648,46 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 }
 EXPORT_SYMBOL_GPL(gpiod_direction_output);
 
+/**
+ * gpiod_direction_pass_through - set the GPIO direction to pass-through
+ * @desc:	GPIO to set to pass-through
+ *
+ * Set the direction of the passed GPIO to passthrough.
+ *
+ * Return 0 in case of success, else an error code.
+ */
+int gpiod_direction_pass_through(struct gpio_desc *desc, int val)
+{
+	struct gpio_chip *gc;
+
+	VALIDATE_DESC(desc);
+	/* GPIOs used for IRQs shall not be set as pass-through */
+	if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
+		gpiod_err(desc,
+			  "%s: tried to set a GPIO tied to an IRQ as pass-through\n",
+			  __func__);
+		return -EIO;
+	}
+	gc = desc->gdev->chip;
+	val = !!val;
+	if (test_bit(FLAG_PASS_THROUGH, &desc->flags)) {
+		if (val)
+			gpio_set_drive_single_ended(gc, gpio_chip_hwgpio(desc),
+						PIN_CONFIG_PASS_THROUGH_ENABLE);
+		else
+			gpio_set_drive_single_ended(gc, gpio_chip_hwgpio(desc),
+						PIN_CONFIG_PASS_THROUGH_DISABLE);
+	} else {
+		gpiod_err(desc,
+			  "%s: desc->flags is not set to FLAG_PASS_THROUGH\n",
+			  __func__);
+		return -EIO;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gpiod_direction_pass_through);
+
 /**
  * gpiod_set_debounce - sets @debounce time for a GPIO
  * @desc: descriptor of the GPIO for which to set debounce time
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index a7e49fef73d4..b143ee47870a 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -210,6 +210,7 @@ struct gpio_desc {
 #define FLAG_IS_OUT	1
 #define FLAG_EXPORT	2	/* protected by sysfs_lock */
 #define FLAG_SYSFS	3	/* exported via /sys/class/gpio/control */
+#define FLAG_PASS_THROUGH 4 /*Gpio is passthrough type*/
 #define FLAG_ACTIVE_LOW	6	/* value has active low */
 #define FLAG_OPEN_DRAIN	7	/* Gpio is open drain type */
 #define FLAG_OPEN_SOURCE 8	/* Gpio is open source type */
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 21ddbe440030..96551839c191 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -99,6 +99,7 @@ void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs);
 int gpiod_get_direction(struct gpio_desc *desc);
 int gpiod_direction_input(struct gpio_desc *desc);
 int gpiod_direction_output(struct gpio_desc *desc, int value);
+int gpiod_direction_pass_through(struct gpio_desc *desc, int val);
 int gpiod_direction_output_raw(struct gpio_desc *desc, int value);
 
 /* Value get/set from non-sleeping context */
@@ -314,6 +315,14 @@ static inline int gpiod_direction_output(struct gpio_desc *desc, int value)
 	WARN_ON(1);
 	return -ENOSYS;
 }
+
+static inline int gpiod_direction_pass_through(struct gpio_desc *desc, int val)
+{
+	/* GPIO can never have been requested */
+	WARN_ON(1);
+	return -ENOSYS;
+}
+
 static inline int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
 {
 	/* GPIO can never have been requested */
diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h
index 6c0680641108..59f0cbabb685 100644
--- a/include/linux/pinctrl/pinconf-generic.h
+++ b/include/linux/pinctrl/pinconf-generic.h
@@ -124,6 +124,8 @@ enum pin_config_param {
 	PIN_CONFIG_SLEW_RATE,
 	PIN_CONFIG_SKEW_DELAY,
 	PIN_CONFIG_PERSIST_STATE,
+	PIN_CONFIG_PASS_THROUGH_ENABLE,
+	PIN_CONFIG_PASS_THROUGH_DISABLE,
 	PIN_CONFIG_END = 0x7F,
 	PIN_CONFIG_MAX = 0xFF,
 };
diff --git a/include/uapi/linux/gpio.h b/include/uapi/linux/gpio.h
index 1bf6e6df084b..384ced158412 100644
--- a/include/uapi/linux/gpio.h
+++ b/include/uapi/linux/gpio.h
@@ -62,6 +62,7 @@ struct gpioline_info {
 #define GPIOHANDLE_REQUEST_ACTIVE_LOW	(1UL << 2)
 #define GPIOHANDLE_REQUEST_OPEN_DRAIN	(1UL << 3)
 #define GPIOHANDLE_REQUEST_OPEN_SOURCE	(1UL << 4)
+#define GPIOHANDLE_REQUEST_PASS_THROUGH	(1UL << 5)
 
 /**
  * struct gpiohandle_request - Information about a GPIO handle request
-- 
2.19.1