leds: add SGI IP30 led support

This patch implemenets a driver to support the front panel LEDs of
SGI Octane (IP30) workstations.

Reviewed-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

drivers/leds/Kconfig

@@ -846,6 +846,17 @@ config LEDS_TPS6105X
 	  It is a single boost converter primarily for white LEDs and
 	  audio amplifiers.
 
+config LEDS_IP30
+	tristate "LED support for SGI Octane machines"
+	depends on LEDS_CLASS
+	depends on SGI_MFD_IOC3
+	help
+	  This option enables support for the Red and White LEDs of
+	  SGI Octane machines.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-ip30.
+
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 

drivers/leds/Makefile

@@ -86,6 +86,7 @@ obj-$(CONFIG_LEDS_TI_LMU_COMMON)	+= leds-ti-lmu-common.o
 obj-$(CONFIG_LEDS_LM3697)		+= leds-lm3697.o
 obj-$(CONFIG_LEDS_LM36274)		+= leds-lm36274.o
 obj-$(CONFIG_LEDS_TPS6105X)		+= leds-tps6105x.o
+obj-$(CONFIG_LEDS_IP30)			+= leds-ip30.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_CR0014114)		+= leds-cr0014114.o

drivers/leds/leds-ip30.c

@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LED Driver for SGI Octane machines
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/leds.h>
+
+#define IP30_LED_SYSTEM	0
+#define IP30_LED_FAULT	1
+
+struct ip30_led {
+	struct led_classdev cdev;
+	u32 __iomem *reg;
+};
+
+static void ip30led_set(struct led_classdev *led_cdev,
+			enum led_brightness value)
+{
+	struct ip30_led *led = container_of(led_cdev, struct ip30_led, cdev);
+
+	writel(value, led->reg);
+}
+
+static int ip30led_create(struct platform_device *pdev, int num)
+{
+	struct resource *res;
+	struct ip30_led *data;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, num);
+	if (!res)
+		return -EBUSY;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->reg = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(data->reg))
+		return PTR_ERR(data->reg);
+
+
+	switch (num) {
+	case IP30_LED_SYSTEM:
+		data->cdev.name = "white:system";
+		break;
+	case IP30_LED_FAULT:
+		data->cdev.name = "red:fault";
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	data->cdev.brightness = readl(data->reg);
+	data->cdev.max_brightness = 1;
+	data->cdev.brightness_set = ip30led_set;
+
+	return devm_led_classdev_register(&pdev->dev, &data->cdev);
+}
+
+static int ip30led_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = ip30led_create(pdev, IP30_LED_SYSTEM);
+	if (ret < 0)
+		return ret;
+
+	return ip30led_create(pdev, IP30_LED_FAULT);
+}
+
+static struct platform_driver ip30led_driver = {
+	.probe		= ip30led_probe,
+	.driver		= {
+		.name		= "ip30-leds",
+	},
+};
+
+module_platform_driver(ip30led_driver);
+
+MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfer@suse.de>");
+MODULE_DESCRIPTION("SGI Octane LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ip30-leds");