1 files changed, 349 insertions, 0 deletions
diff --git a/drivers/leds/leds-powernv.c b/drivers/leds/leds-powernv.c
new file mode 100644
index 000000000..743e2cdd0
--- /dev/null
+++ b/drivers/leds/leds-powernv.c
@@ -0,0 +1,349 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PowerNV LED Driver
+ *
+ * Copyright IBM Corp. 2015
+ *
+ * Author: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
+ * Author: Anshuman Khandual <khandual@linux.vnet.ibm.com>
+ */
+
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <asm/opal.h>
+
+/* Map LED type to description. */
+struct led_type_map {
+	const int	type;
+	const char	*desc;
+};
+static const struct led_type_map led_type_map[] = {
+	{OPAL_SLOT_LED_TYPE_ID,		"identify"},
+	{OPAL_SLOT_LED_TYPE_FAULT,	"fault"},
+	{OPAL_SLOT_LED_TYPE_ATTN,	"attention"},
+	{-1,				NULL},
+};
+
+struct powernv_led_common {
+	/*
+	 * By default unload path resets all the LEDs. But on PowerNV
+	 * platform we want to retain LED state across reboot as these
+	 * are controlled by firmware. Also service processor can modify
+	 * the LEDs independent of OS. Hence avoid resetting LEDs in
+	 * unload path.
+	 */
+	bool		led_disabled;
+
+	/* Max supported LED type */
+	__be64		max_led_type;
+
+	/* glabal lock */
+	struct mutex	lock;
+};
+
+/* PowerNV LED data */
+struct powernv_led_data {
+	struct led_classdev	cdev;
+	char			*loc_code;	/* LED location code */
+	int			led_type;	/* OPAL_SLOT_LED_TYPE_* */
+
+	struct powernv_led_common *common;
+};
+
+
+/* Returns OPAL_SLOT_LED_TYPE_* for given led type string */
+static int powernv_get_led_type(const char *led_type_desc)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(led_type_map); i++)
+		if (!strcmp(led_type_map[i].desc, led_type_desc))
+			return led_type_map[i].type;
+
+	return -1;
+}
+
+/*
+ * This commits the state change of the requested LED through an OPAL call.
+ * This function is called from work queue task context when ever it gets
+ * scheduled. This function can sleep at opal_async_wait_response call.
+ */
+static int powernv_led_set(struct powernv_led_data *powernv_led,
+			    enum led_brightness value)
+{
+	int rc, token;
+	u64 led_mask, led_value = 0;
+	__be64 max_type;
+	struct opal_msg msg;
+	struct device *dev = powernv_led->cdev.dev;
+	struct powernv_led_common *powernv_led_common = powernv_led->common;
+
+	/* Prepare for the OPAL call */
+	max_type = powernv_led_common->max_led_type;
+	led_mask = OPAL_SLOT_LED_STATE_ON << powernv_led->led_type;
+	if (value)
+		led_value = led_mask;
+
+	/* OPAL async call */
+	token = opal_async_get_token_interruptible();
+	if (token < 0) {
+		if (token != -ERESTARTSYS)
+			dev_err(dev, "%s: Couldn't get OPAL async token\n",
+				__func__);
+		return token;
+	}
+
+	rc = opal_leds_set_ind(token, powernv_led->loc_code,
+			       led_mask, led_value, &max_type);
+	if (rc != OPAL_ASYNC_COMPLETION) {
+		dev_err(dev, "%s: OPAL set LED call failed for %s [rc=%d]\n",
+			__func__, powernv_led->loc_code, rc);
+		goto out_token;
+	}
+
+	rc = opal_async_wait_response(token, &msg);
+	if (rc) {
+		dev_err(dev,
+			"%s: Failed to wait for the async response [rc=%d]\n",
+			__func__, rc);
+		goto out_token;
+	}
+
+	rc = opal_get_async_rc(msg);
+	if (rc != OPAL_SUCCESS)
+		dev_err(dev, "%s : OAPL async call returned failed [rc=%d]\n",
+			__func__, rc);
+
+out_token:
+	opal_async_release_token(token);
+	return rc;
+}
+
+/*
+ * This function fetches the LED state for a given LED type for
+ * mentioned LED classdev structure.
+ */
+static enum led_brightness powernv_led_get(struct powernv_led_data *powernv_led)
+{
+	int rc;
+	__be64 mask, value, max_type;
+	u64 led_mask, led_value;
+	struct device *dev = powernv_led->cdev.dev;
+	struct powernv_led_common *powernv_led_common = powernv_led->common;
+
+	/* Fetch all LED status */
+	mask = cpu_to_be64(0);
+	value = cpu_to_be64(0);
+	max_type = powernv_led_common->max_led_type;
+
+	rc = opal_leds_get_ind(powernv_led->loc_code,
+			       &mask, &value, &max_type);
+	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
+		dev_err(dev, "%s: OPAL get led call failed [rc=%d]\n",
+			__func__, rc);
+		return LED_OFF;
+	}
+
+	led_mask = be64_to_cpu(mask);
+	led_value = be64_to_cpu(value);
+
+	/* LED status available */
+	if (!((led_mask >> powernv_led->led_type) & OPAL_SLOT_LED_STATE_ON)) {
+		dev_err(dev, "%s: LED status not available for %s\n",
+			__func__, powernv_led->cdev.name);
+		return LED_OFF;
+	}
+
+	/* LED status value */
+	if ((led_value >> powernv_led->led_type) & OPAL_SLOT_LED_STATE_ON)
+		return LED_FULL;
+
+	return LED_OFF;
+}
+
+/*
+ * LED classdev 'brightness_get' function. This schedules work
+ * to update LED state.
+ */
+static int powernv_brightness_set(struct led_classdev *led_cdev,
+				   enum led_brightness value)
+{
+	struct powernv_led_data *powernv_led =
+		container_of(led_cdev, struct powernv_led_data, cdev);
+	struct powernv_led_common *powernv_led_common = powernv_led->common;
+	int rc;
+
+	/* Do not modify LED in unload path */
+	if (powernv_led_common->led_disabled)
+		return 0;
+
+	mutex_lock(&powernv_led_common->lock);
+	rc = powernv_led_set(powernv_led, value);
+	mutex_unlock(&powernv_led_common->lock);
+
+	return rc;
+}
+
+/* LED classdev 'brightness_get' function */
+static enum led_brightness powernv_brightness_get(struct led_classdev *led_cdev)
+{
+	struct powernv_led_data *powernv_led =
+		container_of(led_cdev, struct powernv_led_data, cdev);
+
+	return powernv_led_get(powernv_led);
+}
+
+/*
+ * This function registers classdev structure for any given type of LED on
+ * a given child LED device node.
+ */
+static int powernv_led_create(struct device *dev,
+			      struct powernv_led_data *powernv_led,
+			      const char *led_type_desc)
+{
+	int rc;
+
+	/* Make sure LED type is supported */
+	powernv_led->led_type = powernv_get_led_type(led_type_desc);
+	if (powernv_led->led_type == -1) {
+		dev_warn(dev, "%s: No support for led type : %s\n",
+			 __func__, led_type_desc);
+		return -EINVAL;
+	}
+
+	/* Create the name for classdev */
+	powernv_led->cdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s:%s",
+						powernv_led->loc_code,
+						led_type_desc);
+	if (!powernv_led->cdev.name)
+		return -ENOMEM;
+
+	powernv_led->cdev.brightness_set_blocking = powernv_brightness_set;
+	powernv_led->cdev.brightness_get = powernv_brightness_get;
+	powernv_led->cdev.brightness = LED_OFF;
+	powernv_led->cdev.max_brightness = LED_FULL;
+
+	/* Register the classdev */
+	rc = devm_led_classdev_register(dev, &powernv_led->cdev);
+	if (rc) {
+		dev_err(dev, "%s: Classdev registration failed for %s\n",
+			__func__, powernv_led->cdev.name);
+	}
+
+	return rc;
+}
+
+/* Go through LED device tree node and register LED classdev structure */
+static int powernv_led_classdev(struct platform_device *pdev,
+				struct device_node *led_node,
+				struct powernv_led_common *powernv_led_common)
+{
+	const char *cur = NULL;
+	int rc = -1;
+	struct property *p;
+	struct device_node *np;
+	struct powernv_led_data *powernv_led;
+	struct device *dev = &pdev->dev;
+
+	for_each_available_child_of_node(led_node, np) {
+		p = of_find_property(np, "led-types", NULL);
+
+		while ((cur = of_prop_next_string(p, cur)) != NULL) {
+			powernv_led = devm_kzalloc(dev, sizeof(*powernv_led),
+						   GFP_KERNEL);
+			if (!powernv_led) {
+				of_node_put(np);
+				return -ENOMEM;
+			}
+
+			powernv_led->common = powernv_led_common;
+			powernv_led->loc_code = (char *)np->name;
+
+			rc = powernv_led_create(dev, powernv_led, cur);
+			if (rc) {
+				of_node_put(np);
+				return rc;
+			}
+		} /* while end */
+	}
+
+	return rc;
+}
+
+/* Platform driver probe */
+static int powernv_led_probe(struct platform_device *pdev)
+{
+	struct device_node *led_node;
+	struct powernv_led_common *powernv_led_common;
+	struct device *dev = &pdev->dev;
+	int rc;
+
+	led_node = of_find_node_by_path("/ibm,opal/leds");
+	if (!led_node) {
+		dev_err(dev, "%s: LED parent device node not found\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	powernv_led_common = devm_kzalloc(dev, sizeof(*powernv_led_common),
+					  GFP_KERNEL);
+	if (!powernv_led_common) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	mutex_init(&powernv_led_common->lock);
+	powernv_led_common->max_led_type = cpu_to_be64(OPAL_SLOT_LED_TYPE_MAX);
+
+	platform_set_drvdata(pdev, powernv_led_common);
+
+	rc = powernv_led_classdev(pdev, led_node, powernv_led_common);
+out:
+	of_node_put(led_node);
+	return rc;
+}
+
+/* Platform driver remove */
+static int powernv_led_remove(struct platform_device *pdev)
+{
+	struct powernv_led_common *powernv_led_common;
+
+	/* Disable LED operation */
+	powernv_led_common = platform_get_drvdata(pdev);
+	powernv_led_common->led_disabled = true;
+
+	/* Destroy lock */
+	mutex_destroy(&powernv_led_common->lock);
+
+	dev_info(&pdev->dev, "PowerNV led module unregistered\n");
+	return 0;
+}
+
+/* Platform driver property match */
+static const struct of_device_id powernv_led_match[] = {
+	{
+		.compatible	= "ibm,opal-v3-led",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, powernv_led_match);
+
+static struct platform_driver powernv_led_driver = {
+	.probe	= powernv_led_probe,
+	.remove = powernv_led_remove,
+	.driver = {
+		.name = "powernv-led-driver",
+		.of_match_table = powernv_led_match,
+	},
+};
+
+module_platform_driver(powernv_led_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("PowerNV LED driver");
+MODULE_AUTHOR("Vasant Hegde <hegdevasant@linux.vnet.ibm.com>");