[PATCH v7 3/3] leds/powernv: Add driver for PowerNV platform
Jacek Anaszewski
jacek.anaszewski at gmail.com
Thu Jul 23 17:55:39 AEST 2015
Hi Vasant,
Thanks for the update.
On 22.07.2015 16:52, Vasant Hegde wrote:
> This patch implements LED driver for PowerNV platform using the existing
> generic LED class framework.
>
> PowerNV platform has below type of LEDs:
> - System attention
> Indicates there is a problem with the system that needs attention.
> - Identify
> Helps the user locate/identify a particular FRU or resource in the
> system.
> - Fault
> Indicates there is a problem with the FRU or resource at the
> location with which the indicator is associated.
>
> We register classdev structures for all individual LEDs detected on the
> system through LED specific device tree nodes. Device tree nodes specify
> what all kind of LEDs present on the same location code. It registers
> LED classdev structure for each of them.
>
> All the system LEDs can be found in the same regular path /sys/class/leds/.
> We don't use LED colors. We use LED node and led-types property to form
> LED classdev. Our LEDs have names in this format.
>
> <location_code>:<attention|identify|fault>
>
> Any positive brightness value would turn on the LED and a zero value would
> turn off the LED. The driver will return LED_FULL (255) for any turned on
> LED and LED_OFF (0) for any turned off LED.
>
> As per the LED class framework, the 'brightness_set' function should not
> sleep. Hence these functions have been implemented through global work
> queue tasks which might sleep on OPAL async call completion.
>
> The platform level implementation of LED get and set state has been
> achieved through OPAL calls. These calls are made available for the
> driver by exporting from architecture specific codes.
>
> Signed-off-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
> Signed-off-by: Anshuman Khandual <khandual at linux.vnet.ibm.com>
> Acked-by: Stewart Smith <stewart at linux.vnet.ibm.com>
> Tested-by: Stewart Smith <stewart at linux.vnet.ibm.com>
> ---
> .../devicetree/bindings/leds/leds-powernv.txt | 26 ++
> drivers/leds/Kconfig | 11 +
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-powernv.c | 342 +++++++++++++++++++++
> 4 files changed, 380 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/leds/leds-powernv.txt
> create mode 100644 drivers/leds/leds-powernv.c
>
> diff --git a/Documentation/devicetree/bindings/leds/leds-powernv.txt b/Documentation/devicetree/bindings/leds/leds-powernv.txt
> new file mode 100644
> index 0000000..6665569
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-powernv.txt
> @@ -0,0 +1,26 @@
> +Device Tree binding for LEDs on IBM Power Systems
> +-------------------------------------------------
> +
> +Required properties:
> +- compatible : Should be "ibm,opal-v3-led".
> +- led-mode : Should be "lightpath" or "guidinglight".
> +
> +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.
> +
> +Example:
> +
> +leds {
> + compatible = "ibm,opal-v3-led";
> + led-mode = "lightpath";
> +
> + U78C9.001.RST0027-P1-C1 {
> + led-types = "identify", "fault";
> + };
> + ...
> + ...
> +};
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 9ad35f7..f218cc3a 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -560,6 +560,17 @@ 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 8d6a24a..6a943d1 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -65,6 +65,7 @@ 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_KTD2692) += leds-ktd2692.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..9e70291
> --- /dev/null
> +++ b/drivers/leds/leds-powernv.c
> @@ -0,0 +1,342 @@
> +/*
> + * PowerNV LED Driver
> + *
> + * Copyright IBM Corp. 2015
> + *
> + * Author: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
> + * Author: Anshuman Khandual <khandual at linux.vnet.ibm.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/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},
> +};
> +
> +/* PowerNV LED data */
> +struct powernv_led_data {
> + struct led_classdev cdev;
> + char *loc_code; /* LED location code */
> + int led_type; /* OPAL_SLOT_LED_TYPE_* */
> + enum led_brightness value; /* Brightness value */
You don't need 'value' as brightness value is already stored in
cdev.brightness.
> +
> + __be64 *max_led_type; /* Max supported LED type */
> + struct mutex *lock; /* glabal lock */
> +};
> +
> +
> +/* 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 void powernv_led_set(struct powernv_led_data *powernv_led)
> +{
> + int rc, token;
> + u64 led_mask, led_value = 0;
> + __be64 max_type;
> + struct opal_msg msg;
> + struct device *dev = powernv_led->cdev.dev;
> +
> + /* Prepare for the OPAL call */
> + max_type = *(powernv_led->max_led_type);
> + led_mask = OPAL_SLOT_LED_STATE_ON << powernv_led->led_type;
> + if (powernv_led->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;
> + }
> +
> + 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 = be64_to_cpu(msg.params[1]);
> + 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);
> +}
> +
> +/*
> + * 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;
> +
> + /* Fetch all LED status */
> + mask = cpu_to_be64(0);
> + value = cpu_to_be64(0);
> + max_type = *(powernv_led->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 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;
> +
> + return powernv_led_set(powernv_led);
Isn't mutex_lock/unlock missing here?
> +}
> +
> +/* 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) {
> + dev_err(dev,
> + "%s: Memory allocation failed for classdev name\n",
> + __func__);
> + return -ENOMEM;
> + }
> +
> + 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;
> +
> + /* 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,
> + __be64 *max_led_type, struct mutex *lock)
> +{
> + 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_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 = devm_kzalloc(dev, sizeof(*powernv_led),
> + GFP_KERNEL);
> + if (!powernv_led)
> + return -ENOMEM;
> +
> + powernv_led->loc_code = (char *)np->name;
> + powernv_led->max_led_type = max_led_type;
> + powernv_led->lock = lock;
> +
> + rc = powernv_led_create(dev, powernv_led, cur);
> + if (rc)
> + return rc;
> + } /* while end */
> + }
> +
> + return rc;
> +}
> +
> +/* Platform driver probe */
> +static int powernv_led_probe(struct platform_device *pdev)
> +{
> + __be64 *max_led_type;
> + struct mutex *lock;
> + struct device_node *led_node;
> + struct device *dev = &pdev->dev;
> +
> + 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;
> + }
> +
> + lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
> + if (!lock)
> + return -ENOMEM;
> +
> + max_led_type = devm_kzalloc(dev, sizeof(*max_led_type), GFP_KERNEL);
> + if (!max_led_type)
> + return -ENOMEM;
> +
> + mutex_init(lock);
> + *max_led_type = cpu_to_be64(OPAL_SLOT_LED_TYPE_MAX);
> +
> + platform_set_drvdata(pdev, lock);
Setting only lock as drvdata looks odd to me and I haven't noticed
anyone doing that.
I'd prefer to put lock, led_disabled and max_led_type in a common
struct and set it as drvdata. I know that I accepted this design, but
I didn't take into account these details.
> + return powernv_led_classdev(pdev, led_node, max_led_type, lock);
> +}
> +
> +/* Platform driver remove */
> +static int powernv_led_remove(struct platform_device *pdev)
> +{
> + struct mutex *lock = platform_get_drvdata(pdev);
> +
> + /* Disable LED operation */
> + led_disabled = true;
> +
> + mutex_destroy(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",
> + .owner = THIS_MODULE,
> + .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 at linux.vnet.ibm.com>");
>
--
Best Regards,
Jacek Anaszewski
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