Hi Vasan,
On 07/16/2015 08:54 AM, Vasant Hegde wrote:
On 07/14/2015 02:30 PM, Jacek Anaszewski wrote:
Hi Vasant,
Jacek,
Thanks for the update. I think that we have still room
for improvements, please look at my comments below.
Thanks for the detailed review.
You're welcome.
.../...
@@ -0,0 +1,24 @@
+Device Tree binding for LEDs on IBM Power Systems
+-------------------------------------------------
+
Please start with:
---------
Required properties:
- compatible : Should be "ibm,opal-v3-led".
Each location code of FRU/Enclosure must be expressed in the
form of a sub-node.
Required properties for the sub nodes:
- led-types : Supported LED types (attention/identify/fault) provided
in the form of string array.
---------
or something of this flavour. The example should be at the end.
Fixed.
+The 'leds' node under '/ibm,opal' lists service indicators available in the
+system and their capabilities.
+
+leds {
+ compatible = "ibm,opal-v3-led";
+ led-mode = "lightpath";
What about led-mode property? If it is generated by firmware I think,
that this should be mentioned somehow.
Yes.. Its generated by firmware. Added this property to documentation file.
+
+ U78C9.001.RST0027-P1-C1 {
+ led-types = "identify", "fault";
+ };
+ ...
+ ...
+};
+
+Each node under 'leds' node describes location code of FRU/Enclosure.
+
+compatible : should be : "ibm,opal-v3-led".
Second colon was redundant here.
I have added as
- compatible : "ibm,opal-v3-led".
Please retain "Should be :".
+
+The properties under each node:
+
+ led-types : Supported LED types (attention/identify/fault).
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 4191614..4f56c7a 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -505,6 +505,17 @@ config LEDS_BLINKM
This option enables support for the BlinkM RGB LED connected
through I2C. Say Y to enable support for the BlinkM LED.
+config LEDS_POWERNV
+ tristate "LED support for PowerNV Platform"
+ depends on LEDS_CLASS
+ depends on PPC_POWERNV
+ depends on OF
+ help
+ This option enables support for the system LEDs present on
+ PowerNV platforms. Say 'y' to enable this support in kernel.
+ To compile this driver as a module, choose 'm' here: the module
+ will be called leds-powernv.
+
config LEDS_SYSCON
bool "LED support for LEDs on system controllers"
depends on LEDS_CLASS=y
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index bf46093..480814a 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_LEDS_SYSCON) += leds-syscon.o
obj-$(CONFIG_LEDS_VERSATILE) += leds-versatile.o
obj-$(CONFIG_LEDS_MENF21BMC) += leds-menf21bmc.o
obj-$(CONFIG_LEDS_PM8941_WLED) += leds-pm8941-wled.o
+obj-$(CONFIG_LEDS_POWERNV) += leds-powernv.o
# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
diff --git a/drivers/leds/leds-powernv.c b/drivers/leds/leds-powernv.c
new file mode 100644
index 0000000..b5a307c
--- /dev/null
+++ b/drivers/leds/leds-powernv.c
@@ -0,0 +1,463 @@
+/*
+ * PowerNV LED Driver
+ *
+ * Copyright IBM Corp. 2015
+ *
+ * Author: Vasant Hegde <hegdevasant@xxxxxxxxxxxxxxxxxx>
+ * Author: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
+ *
+ * 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/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>
+
+/*
+ * 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.
+ */
+static bool led_disabled;
+
+/* 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, POWERNV_LED_TYPE_IDENTIFY},
+ {OPAL_SLOT_LED_TYPE_FAULT, POWERNV_LED_TYPE_FAULT},
+ {OPAL_SLOT_LED_TYPE_ATTN, POWERNV_LED_TYPE_ATTENTION},
+ {-1, NULL},
+};
+
+/*
+ * LED set routines have been implemented as work queue tasks scheduled
+ * on the global work queue. Individual task calls OPAL interface to set
+ * the LED state which might sleep for some time.
+ */
+struct powernv_led_data {
+ struct led_classdev cdev;
+ enum led_brightness value; /* Brightness value */
+ struct mutex lock;
+ struct work_struct work_led; /* LED update workqueue */
+};
+
+struct powernv_leds_priv {
+ int num_leds;
+ struct powernv_led_data powernv_leds[];
+};
+
+
+static inline int sizeof_powernv_leds_priv(int num_leds)
+{
+ return sizeof(struct powernv_leds_priv) +
+ (sizeof(struct powernv_led_data) * num_leds);
+}
+
+/* Returns OPAL_SLOT_LED_TYPE_* for given led type string */
+static int powernv_get_led_type(struct led_classdev *led_cdev)
+{
+ char *desc;
+ int i;
+
+ desc = strstr(led_cdev->name, ":");
+ if (!desc)
+ return -1;
+ desc++;
+ if (!desc)
+ return -1;
+
+ for (i = 0; i < ARRAY_SIZE(led_type_map); i++)
+ if (!strcmp(led_type_map[i].desc, desc))
+ return led_type_map[i].type;
+
+ return -1;
+}
+
+/* This function gets LED location code for given LED classdev */
+static char *powernv_get_location_code(struct led_classdev *led_cdev)
+{
+ char *loc_code;
+ char *colon;
+
+ /* Location code of the LED */
+ loc_code = kasprintf(GFP_KERNEL, "%s", led_cdev->name);
+ if (!loc_code) {
+ dev_err(led_cdev->dev,
+ "%s: Memory allocation failed\n", __func__);
+ return NULL;
+ }
+
+ colon = strstr(loc_code, ":");
+ if (!colon) {
+ kfree(loc_code);
+ return NULL;
+ }
+
+ *colon = '\0';
+ return loc_code;
+}
+
+/*
+ * 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 void powernv_led_set(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ char *loc_code;
+ int rc, token, led_type;
+ u64 led_mask, led_value = 0;
+ __be64 max_led_type;
+ struct opal_msg msg;
+
+ led_type = powernv_get_led_type(led_cdev);
+ if (led_type == -1)
+ return;
Please parse the led type once upon initialization and add related
property to the struct powernv_led_data that will hold the value.
I thought we can get location code and type using class dev name itself. Hence I
didn't add these two properties to structure..
This way you are doing extra work for parsing the name each time
the brightness is set.
Do you want me to add them to structure itself?
Yes, please add them.
+ loc_code = powernv_get_location_code(led_cdev);
+ if (!loc_code)
+ return;
The same situation as in case of led type.
+ /* Prepare for the OPAL call */
+ max_led_type = cpu_to_be64(OPAL_SLOT_LED_TYPE_MAX);
This value could be also calculated only once.
Yeah. May be I can move this to powernv_leds_priv structure.
+ led_mask = OPAL_SLOT_LED_STATE_ON << 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(led_cdev->dev,
+ "%s: Couldn't get OPAL async token\n",
+ __func__);
+ goto out_loc;
+ }
+
+ rc = opal_leds_set_ind(token, loc_code,
+ led_mask, led_value, &max_led_type);
+ if (rc != OPAL_ASYNC_COMPLETION) {
+ dev_err(led_cdev->dev,
+ "%s: OPAL set LED call failed for %s [rc=%d]\n",
+ __func__, loc_code, rc);
+ goto out_token;
+ }
+
+ rc = opal_async_wait_response(token, &msg);
+ if (rc) {
+ dev_err(led_cdev->dev,
+ "%s: Failed to wait for the async response [rc=%d]\n",
+ __func__, rc);
+ goto out_token;
+ }
+
+ rc = be64_to_cpu(msg.params[1]);
+ if (rc != OPAL_SUCCESS)
+ dev_err(led_cdev->dev,
+ "%s : OAPL async call returned failed [rc=%d]\n",
+ __func__, rc);
+
+out_token:
+ opal_async_release_token(token);
+
+out_loc:
+ kfree(loc_code);
+}
+
+/*
+ * This function fetches the LED state for a given LED type for
+ * mentioned LED classdev structure.
+ */
+static enum led_brightness powernv_led_get(struct led_classdev *led_cdev)
+{
+ char *loc_code;
+ int rc, led_type;
+ __be64 led_mask, led_value, max_led_type;
+
+ led_type = powernv_get_led_type(led_cdev);
+ if (led_type == -1)
+ return LED_OFF;
+
+ loc_code = powernv_get_location_code(led_cdev);
+ if (!loc_code)
+ return LED_OFF;
+
+ /* Fetch all LED status */
+ led_mask = cpu_to_be64(0);
+ led_value = cpu_to_be64(0);
+ max_led_type = cpu_to_be64(OPAL_SLOT_LED_TYPE_MAX);
+
+ rc = opal_leds_get_ind(loc_code, &led_mask, &led_value, &max_led_type);
+ if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
+ dev_err(led_cdev->dev,
+ "%s: OPAL get led call failed [rc=%d]\n",
+ __func__, rc);
+ goto led_fail;
+ }
+
+ led_mask = be64_to_cpu(led_mask);
+ led_value = be64_to_cpu(led_value);
be64_to_cpu result should be assigned to the variable of u64/s64 type.
PowerNV platform is capable of running both big/little endian mode.. But
presently our firmware is big endian. These variable contains big endian values.
Hence I have created as __be64 .. (This is the convention we follow in other
places as well).
It is correct that the argument is of __be64 type, but be64_to_cpu
returns u64 type, whereas you assign it to __be64.
+ /* LED status available */
+ if (!((led_mask >> led_type) & OPAL_SLOT_LED_STATE_ON)) {
+ dev_err(led_cdev->dev,
+ "%s: LED status not available for %s\n",
+ __func__, led_cdev->name);
+ goto led_fail;
+ }
+
+ /* LED status value */
+ if ((led_value >> led_type) & OPAL_SLOT_LED_STATE_ON) {
+ kfree(loc_code);
+ return LED_FULL;
+ }
+
+led_fail:
+ kfree(loc_code);
+ return LED_OFF;
+}
+
+/* Execute LED set task for given led classdev */
+static void powernv_deferred_led_set(struct work_struct *work)
+{
+ struct powernv_led_data *powernv_led =
+ container_of(work, struct powernv_led_data, work_led);
+
+ mutex_lock(&powernv_led->lock);
+ powernv_led_set(&powernv_led->cdev, powernv_led->value);
+ mutex_unlock(&powernv_led->lock);
+}
+
+/*
+ * LED classdev 'brightness_get' function. This schedules work
+ * to update LED state.
+ */
+static void 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);
+
+ /* Do not modify LED in unload path */
+ if (led_disabled)
+ return;
+
+ /* Prepare the request */
+ powernv_led->value = value;
+
+ /* Schedule the new task */
+ schedule_work(&powernv_led->work_led);
+}
+
+/* LED classdev 'brightness_get' function */
+static enum led_brightness
+powernv_brightness_get(struct led_classdev *led_cdev)
+{
+ return powernv_led_get(led_cdev);
+}
+
+
+/*
+ * 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_name, const char *led_type_desc)
+{
+ int rc;
+
+ /* Create the name for classdev */
+ powernv_led->cdev.name = kasprintf(GFP_KERNEL, "%s:%s",
+ led_name, led_type_desc);
Please use devm_kasprintf.
Done.
+ if (!powernv_led->cdev.name) {
+ dev_err(dev,
+ "%s: Memory allocation failed for classdev name\n",
+ __func__);
+ return -ENOMEM;
+ }
+
+ /* Make sure LED type is supported */
+ if (powernv_get_led_type(&powernv_led->cdev) == -1) {
+ kfree(powernv_led->cdev.name);
+ return -EINVAL;
+ }
+
+ powernv_led->cdev.brightness_set = powernv_brightness_set;
+ powernv_led->cdev.brightness_get = powernv_brightness_get;
+ powernv_led->cdev.brightness = LED_OFF;
+ powernv_led->cdev.max_brightness = LED_FULL;
+
+ mutex_init(&powernv_led->lock);
+ INIT_WORK(&powernv_led->work_led, powernv_deferred_led_set);
+
+ /* Register the classdev */
+ rc = led_classdev_register(dev, &powernv_led->cdev);
devm_led_classdev_register is also available.
Looks like most of the existing drivers are using led_classdev_register function..
Which one is preferred here?
It is quite new API, but it is now preferable.
+ if (rc) {
+ dev_err(dev, "%s: Classdev registration failed for %s\n",
+ __func__, powernv_led->cdev.name);
+ kfree(powernv_led->cdev.name);
+ }
+
+ return rc;
+}
+
+/* Unregister classdev structure for any given LED */
+static void powernv_led_delete(struct powernv_led_data *powernv_led)
+{
+ led_classdev_unregister(&powernv_led->cdev);
+}
This function is redundant.
Like powernv_led_create, I just added this function ... hoping this will improve
code readability.
Will remove this function.
+/* 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_leds_priv *priv, int num_leds)
+{
+ const char *cur = NULL;
+ int i, rc = -1;
+ struct property *p;
+ struct device_node *np;
+ struct powernv_led_data *powernv_led;
+ struct device *dev = &pdev->dev;
+
+ for_each_child_of_node(led_node, np) {
+ p = of_find_property(np, "led-types", NULL);
+ if (!p)
+ continue;
+
+ while ((cur = of_prop_next_string(p, cur)) != NULL) {
+ powernv_led = &priv->powernv_leds[priv->num_leds++];
+ if (priv->num_leds > num_leds) {
+ rc = -ENOMEM;
+ goto classdev_fail;
+ }
+ rc = powernv_led_create(dev,
+ powernv_led, np->name, cur);
+ if (rc)
+ goto classdev_fail;
+ } /* while end */
+ }
+
+ platform_set_drvdata(pdev, priv);
+ return rc;
+
+classdev_fail:
+ for (i = priv->num_leds - 2; i > 0; i--)
Why do you leave element with id == 0 unreleased?
It was my mistake. Fixed.
+ powernv_led_delete(&priv->powernv_leds[i]);
+
+ return rc;
+}
+
+/*
+ * We want to populate LED device for each LED type. Hence we
+ * have to calculate count explicitly.
+ */
+static int powernv_leds_count(struct device_node *led_node)
+{
+ const char *cur = NULL;
+ int num_leds = 0;
+ struct property *p;
+ struct device_node *np;
+
+ for_each_child_of_node(led_node, np) {
+ p = of_find_property(np, "led-types", NULL);
+ if (!p)
+ continue;
+
+ while ((cur = of_prop_next_string(p, cur)) != NULL)
+ num_leds++;
+ }
+
+ return num_leds;
+}
Does it mean that if the node exists but does't have led-types
property we are not going to register it?
Yes.. No point in registering location code ..which doesn't have led-types
property.
I assume that this is
firmware which generates the nodes, otherwise it would make
no sense to have the node, am I right?
That correct. Our firmware generates this property.
Thanks for the clarification.
+/* Platform driver probe */
+static int powernv_led_probe(struct platform_device *pdev)
+{
+ int num_leds;
+ struct device_node *led_node;
+ struct powernv_leds_priv *priv;
+
+ led_node = of_find_node_by_path("/ibm,opal/leds");
+ if (!led_node) {
+ dev_err(&pdev->dev,
+ "%s: LED parent device node not found\n", __func__);
+ return -EINVAL;
+ }
+
+ num_leds = powernv_leds_count(led_node);
+ if (num_leds <= 0) {
+ dev_err(&pdev->dev,
+ "%s: No location code found under LED node\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ priv = devm_kzalloc(&pdev->dev,
+ sizeof_powernv_leds_priv(num_leds),
+ GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ return powernv_led_classdev(pdev, led_node, priv, num_leds);
+}
+
+/* Platform driver remove */
+static int powernv_led_remove(struct platform_device *pdev)
+{
+ int i;
+ struct powernv_led_data *powernv_led;
+ struct powernv_leds_priv *priv;
+
+ /* Disable LED operation */
+ led_disabled = true;
+
+ priv = platform_get_drvdata(pdev);
+
+ for (i = 0; i < priv->num_leds; i++) {
+ powernv_led = &priv->powernv_leds[i];
+ powernv_led_delete(powernv_led);
+ flush_work(&powernv_led->work_led);
+ }
You are missing mutex_destroy here.
Oh yeah.. I missed it. Fixed.
-Vasant
--
Best Regards,
Jacek Anaszewski
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