[PATCH 07/10] leds: i2cs: Add I2CS FPGA leds driver

[Pantelis Antoniou]

From: Georgi Vlaev <gvlaev@xxxxxxxxxxx>

Add support for the FRU faceplate status LEDs (OK, FAIL,
ACTIVE, STANDBY) controlled by the Juniper I2CS FPGA. This
driver is a jnx-i2cs-core client.

Signed-off-by: Georgi Vlaev <gvlaev@xxxxxxxxxxx>
[Ported from Juniper kernel]
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
---
 drivers/leds/Kconfig         |   9 ++
 drivers/leds/Makefile        |   1 +
 drivers/leds/leds-jnx-i2cs.c | 219 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 229 insertions(+)
 create mode 100644 drivers/leds/leds-jnx-i2cs.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 7a628c6..45c6612 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -659,6 +659,15 @@ config LEDS_MLXCPLD
 	  This option enabled support for the LEDs on the Mellanox
 	  boards. Say Y to enabled these.
 
+config LEDS_JNX_I2CS
+	tristate "LED support for the Juniper Networks I2CS FPGA"
+	depends on LEDS_CLASS && I2C
+	select REGMAP_I2C
+	help
+	  This option enables support for the FRU faceplate status
+	  LEDs (OK, FAIL, ACTIVE, STANDBY) controlled by the Juniper
+	  I2CS FPGA.
+
 comment "LED Triggers"
 source "drivers/leds/trigger/Kconfig"
 
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 3965070..1ce2d0b 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -71,6 +71,7 @@ obj-$(CONFIG_LEDS_IS31FL319X)		+= leds-is31fl319x.o
 obj-$(CONFIG_LEDS_IS31FL32XX)		+= leds-is31fl32xx.o
 obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
 obj-$(CONFIG_LEDS_MLXCPLD)		+= leds-mlxcpld.o
+obj-$(CONFIG_LEDS_JNX_I2CS)		+= leds-jnx-i2cs.o
 
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
diff --git a/drivers/leds/leds-jnx-i2cs.c b/drivers/leds/leds-jnx-i2cs.c
new file mode 100644
index 0000000..c2d7274
--- /dev/null
+++ b/drivers/leds/leds-jnx-i2cs.c
@@ -0,0 +1,219 @@
+/*
+ * Juniper Networks I2CS FPGA LEDs driver
+ *
+ * Copyright (C) 2016 Juniper Networks
+ * Author: Georgi Vlaev <gvlaev@xxxxxxxxxxx>
+ *
+ * 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/module.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+#include <linux/delay.h>
+#include <linux/leds.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/jnx-i2cs-core.h>
+
+#define FRU_LEDS	4 /* Total LEDs (active, fail, ok, standby) */
+#define HW_BLINK_LEDS	3 /* LEDs with hw blink cap (standby not supported) */
+
+/*
+ * I2CS fru_led [0x12]
+ *
+ * bit 6   | bit 5    | bit 4   |...                        | bit 0
+ * blink_ok|blink_fail|blink_act|led_standby|led_ok|led_fail|led_act
+ */
+
+/* TODO: Use the regmap from the parent MFD */
+static struct regmap_config i2cs_leds_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = I2CS_SPARE_OE,
+};
+
+struct i2cs_led {
+	struct led_classdev lc;
+	struct regmap *regmap;
+	struct work_struct work;
+	int blink;
+	int on;
+	int bit;
+};
+
+struct i2cs_led_data {
+	int num_leds;
+	struct i2cs_led *leds;
+};
+
+static void jnx_i2cs_leds_work(struct work_struct *work)
+{
+	struct i2cs_led *led = container_of(work, struct i2cs_led, work);
+
+	int mask = (BIT(led->bit) << 4) | BIT(led->bit);
+	int value = ((led->blink << led->bit) << 4) | (led->on << led->bit);
+
+	regmap_update_bits(led->regmap, I2CS_FRU_LED, mask, value & 0x7f);
+}
+
+static void jnx_i2cs_leds_brightness_set(struct led_classdev *lc,
+				 enum led_brightness brightness)
+{
+	struct i2cs_led *led = container_of(lc, struct i2cs_led, lc);
+
+	led->on = (brightness != LED_OFF);
+	led->blink = 0; /* always turn off hw blink on brightness_set() */
+	schedule_work(&led->work);
+}
+
+static int jnx_i2cs_leds_blink_set(struct led_classdev *lc,
+				   unsigned long *delay_on,
+				   unsigned long *delay_off)
+{
+	struct i2cs_led *led = container_of(lc, struct i2cs_led, lc);
+
+	led->blink = (*delay_on > 0);
+	led->on = led->blink; /* 'on' bit should be set if blinking */
+	schedule_work(&led->work);
+
+	return 0;
+}
+
+static int jnx_i2cs_leds_init_one(struct device *dev, struct device_node *np,
+				  struct i2cs_led_data *ild,
+				  struct regmap *regmap, int num)
+{
+	struct i2cs_led *led;
+	const char *string;
+	bool hw_blink;
+	int ret;
+	u32 reg;
+
+	ret = of_property_read_u32(np, "reg", &reg);
+	if (ret || reg >= FRU_LEDS)
+		return -ENODEV;
+
+	led = &ild->leds[num];
+	led->bit = reg;
+	led->regmap = regmap;
+
+	if (!of_property_read_string(np, "label", &string))
+		led->lc.name = string;
+	else
+		led->lc.name = np->name;
+
+	if (!of_property_read_string(np, "linux,default-trigger", &string))
+		led->lc.default_trigger = string;
+
+	led->lc.brightness = LED_OFF;
+	led->lc.brightness_set = jnx_i2cs_leds_brightness_set;
+	if (led->bit <= HW_BLINK_LEDS) {
+		hw_blink = of_property_read_bool(np, "hw-blink");
+		if (hw_blink)
+			led->lc.blink_set = jnx_i2cs_leds_blink_set;
+	}
+
+	ret = devm_led_classdev_register(dev, &led->lc);
+	if (ret)
+		return ret;
+
+	INIT_WORK(&led->work, jnx_i2cs_leds_work);
+
+	return 0;
+}
+
+static int jnx_i2cs_leds_of_init(struct device *dev, struct i2cs_led_data *ild)
+{
+	struct device_node *child, *np = dev->of_node;
+	struct regmap *regmap;
+	struct i2c_client *client;
+	int ret, num_leds, i = 0;
+
+	if (!dev->parent)
+		return -ENODEV;
+
+	client = i2c_verify_client(dev->parent);
+	if (!client)
+		return -ENODEV;
+
+	regmap = devm_regmap_init_i2c(client, &i2cs_leds_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(dev, "Failed to allocate register map\n");
+		return PTR_ERR(regmap);
+	}
+
+	num_leds = of_get_child_count(np);
+	if (!num_leds || num_leds > FRU_LEDS)
+		return -ENODEV;
+
+	ild->num_leds = num_leds;
+	ild->leds = devm_kzalloc(dev, sizeof(struct i2cs_led) * num_leds,
+				 GFP_KERNEL);
+	if (!ild->leds)
+		return -ENOMEM;
+
+	for_each_child_of_node(np, child) {
+		ret = jnx_i2cs_leds_init_one(dev, child, ild, regmap, i++);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int jnx_i2cs_leds_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct i2cs_led_data *ild;
+	int ret;
+
+	ild = devm_kzalloc(dev, sizeof(*ild), GFP_KERNEL);
+	if (!ild)
+		return -ENOMEM;
+
+	ret = jnx_i2cs_leds_of_init(dev, ild);
+	if (ret < 0)
+		return ret;
+
+	platform_set_drvdata(pdev, ild);
+
+	return 0;
+}
+
+static int jnx_i2cs_leds_remove(struct platform_device *pdev)
+{
+	struct i2cs_led_data *ild = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < ild->num_leds; i++) {
+		devm_led_classdev_unregister(&pdev->dev, &ild->leds[i].lc);
+		cancel_work_sync(&ild->leds[i].work);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id jnx_i2cs_leds_match[] = {
+	{ .compatible = "jnx,leds-i2cs", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, jnx_i2cs_leds_match);
+
+static struct platform_driver jnx_i2cs_leds_driver = {
+	.driver = {
+		.name  = "leds-i2cs",
+		.of_match_table = jnx_i2cs_leds_match,
+	},
+	.probe = jnx_i2cs_leds_probe,
+	.remove = jnx_i2cs_leds_remove,
+};
+
+module_platform_driver(jnx_i2cs_leds_driver);
+
+MODULE_DESCRIPTION("Juniper Networks I2CS leds driver");
+MODULE_AUTHOR("Georgi Vlaev <gvlaev@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
-- 
1.9.1