[PATCH 1/2] led: add pca955x led support

Oleg.Karfich at wago.com Oleg.Karfich at wago.com
Tue Sep 4 23:20:39 PDT 2018


Signed-off-by: Oleg Karfich <oleg.karfich at wago.com>
---
 drivers/led/Kconfig       |   9 +
 drivers/led/Makefile      |   1 +
 drivers/led/led-pca955x.c | 421 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 431 insertions(+)
 create mode 100644 drivers/led/led-pca955x.c

diff --git a/drivers/led/Kconfig b/drivers/led/Kconfig
index 50f0d8f..2a5920a 100644
--- a/drivers/led/Kconfig
+++ b/drivers/led/Kconfig
@@ -31,4 +31,13 @@ config LED_TRIGGERS
 	  This allows to assign certain triggers like heartbeat or network
 	  activity to LEDs.
 
+config LED_PCA955X
+	bool "LED Support for PCA955x I2C chips"
+	depends on I2C
+	help
+	  This option enables support for LEDs connected to PCA955x
+	  LED driver chips accessed via the I2C bus.  Supported
+	  devices include PCA9550, PCA9551, PCA9552, and PCA9553.
+
+
 endif
diff --git a/drivers/led/Makefile b/drivers/led/Makefile
index 619bbcf..862e173 100644
--- a/drivers/led/Makefile
+++ b/drivers/led/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_LED) += core.o
 obj-$(CONFIG_LED_GPIO) += led-gpio.o
 obj-$(CONFIG_LED_PWM) += led-pwm.o
 obj-$(CONFIG_LED_TRIGGERS) += led-triggers.o
+obj-$(CONFIG_LED_TRIGGERS) += led-pca955x.o
diff --git a/drivers/led/led-pca955x.c b/drivers/led/led-pca955x.c
new file mode 100644
index 0000000..9c4f796
--- /dev/null
+++ b/drivers/led/led-pca955x.c
@@ -0,0 +1,421 @@
+/*
+ * Copyright 2007-2008 Extreme Engineering Solutions, Inc.
+ * Author: Nate Case <ncase at xes-inc.com>
+ *
+ * Copyright (C) 2018 WAGO Kontakttechnik GmbH & Co. KG <http://global.wago.com>
+ * Author: Oleg Karfich <oleg.karfich at wago.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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * This code was ported from linux-4.18 kernel driver.
+ * Orginal code with it's copyright info can be found in
+ * drivers/leds/leds-pca955x.c
+ *
+ * LED driver for various PCA955x I2C LED drivers
+ *
+ * Supported devices:
+ *
+ *	Device		Description		7-bit slave address
+ *	------		-----------		-------------------
+ *	PCA9550		2-bit driver		0x60 .. 0x61
+ *	PCA9551		8-bit driver		0x60 .. 0x67
+ *	PCA9552		16-bit driver		0x60 .. 0x67
+ *	PCA9553/01	4-bit driver		0x62
+ *	PCA9553/02	4-bit driver		0x63
+ *
+ * Philips PCA955x LED driver chips follow a register map as shown below:
+ *
+ *	Control Register		Description
+ *	----------------		-----------
+ *	0x0				Input register 0
+ *					..
+ *	NUM_INPUT_REGS - 1		Last Input register X
+ *
+ *	NUM_INPUT_REGS			Frequency prescaler 0
+ *	NUM_INPUT_REGS + 1		PWM register 0
+ *	NUM_INPUT_REGS + 2		Frequency prescaler 1
+ *	NUM_INPUT_REGS + 3		PWM register 1
+ *
+ *	NUM_INPUT_REGS + 4		LED selector 0
+ *	NUM_INPUT_REGS + 4
+ *	    + NUM_LED_REGS - 1		Last LED selector
+ *
+ *  where NUM_INPUT_REGS and NUM_LED_REGS vary depending on how many
+ *  bits the chip supports.
+ *
+  */
+
+#include <common.h>
+#include <init.h>
+#include <led.h>
+#include <malloc.h>
+#include <i2c/i2c.h>
+#include <of_device.h>
+
+/* LED select registers determine the source that drives LED outputs */
+#define PCA955X_LS_LED_ON	0x0	/* Output LOW */
+#define PCA955X_LS_LED_OFF	0x1	/* Output HI-Z */
+#define PCA955X_LS_BLINK0	0x2	/* Blink at PWM0 rate */
+#define PCA955X_LS_BLINK1	0x3	/* Blink at PWM1 rate */
+
+enum led_brightness {
+	LED_OFF		= 0,
+	LED_HALF	= 127,
+	LED_FULL	= 255,
+};
+
+enum pca955x_type {
+	pca9550,
+	pca9551,
+	pca9552,
+	pca9553,
+};
+
+struct pca955x_chipdef {
+	int	bits;
+	u8	slv_addr;	/* 7-bit slave address mask */
+	int	slv_addr_shift;	/* Number of bits to ignore */
+};
+
+static struct pca955x_chipdef pca955x_chipdefs[] = {
+	[pca9550] = {
+		.bits		= 2,
+		.slv_addr	= /* 110000x */ 0x60,
+		.slv_addr_shift	= 1,
+	},
+	[pca9551] = {
+		.bits		= 8,
+		.slv_addr	= /* 1100xxx */ 0x60,
+		.slv_addr_shift	= 3,
+	},
+	[pca9552] = {
+		.bits		= 16,
+		.slv_addr	= /* 1100xxx */ 0x60,
+		.slv_addr_shift	= 3,
+	},
+	[pca9553] = {
+		.bits		= 4,
+		.slv_addr	= /* 110001x */ 0x62,
+		.slv_addr_shift	= 1,
+	},
+};
+
+static const struct platform_device_id led_pca955x_id[] = {
+	{ "pca9550", pca9550 },
+	{ "pca9551", pca9551 },
+	{ "pca9552", pca9552 },
+	{ "pca9553", pca9553 },
+	{ }
+};
+
+struct pca955x {
+	struct pca955x_led *leds;
+	struct pca955x_chipdef	*chipdef;
+	struct i2c_client	*client;
+};
+
+struct pca955x_led {
+	struct pca955x	*pca955x;
+	struct led	led_cdev;
+	int		led_num;	/* 0 .. 15 potentially */
+	char		name[32];
+};
+
+struct pca955x_platform_data {
+	struct pca955x_led	*leds;
+	int			num_leds;
+};
+
+/* 8 bits per input register */
+static inline int pca95xx_num_input_regs(int bits)
+{
+	return (bits + 7) / 8;
+}
+
+/*
+ * Return an LED selector register value based on an existing one, with
+ * the appropriate 2-bit state value set for the given LED number (0-3).
+ */
+static inline u8 pca955x_ledsel(u8 oldval, int led_num, int state)
+{
+	return (oldval & (~(0x3 << (led_num << 1)))) |
+		((state & 0x3) << (led_num << 1));
+}
+
+/*
+ * Write to frequency prescaler register, used to program the
+ * period of the PWM output.  period = (PSCx + 1) / 38
+ */
+static int pca955x_write_psc(struct i2c_client *client, int n, u8 val)
+{
+	struct pca955x *pca955x = i2c_get_clientdata(client);
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client,
+		pca95xx_num_input_regs(pca955x->chipdef->bits) + 2*n,
+		val);
+	if (ret < 0)
+		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
+			__func__, n, val, ret);
+	return ret;
+}
+
+/*
+ * Write to PWM register, which determines the duty cycle of the
+ * output.  LED is OFF when the count is less than the value of this
+ * register, and ON when it is greater.  If PWMx == 0, LED is always OFF.
+ *
+ * Duty cycle is (256 - PWMx) / 256
+ */
+static int pca955x_write_pwm(struct i2c_client *client, int n, u8 val)
+{
+	struct pca955x *pca955x = i2c_get_clientdata(client);
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client,
+		pca95xx_num_input_regs(pca955x->chipdef->bits) + 1 + 2*n,
+		val);
+	if (ret < 0)
+		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
+			__func__, n, val, ret);
+	return ret;
+}
+
+/*
+ * Write to LED selector register, which determines the source that
+ * drives the LED output.
+ */
+static int pca955x_write_ls(struct i2c_client *client, int n, u8 val)
+{
+	struct pca955x *pca955x = i2c_get_clientdata(client);
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client,
+		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n,
+		val);
+	if (ret < 0)
+		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
+			__func__, n, val, ret);
+	return ret;
+}
+
+/*
+ * Read the LED selector register, which determines the source that
+ * drives the LED output.
+ */
+static int pca955x_read_ls(struct i2c_client *client, int n, u8 *val)
+{
+	struct pca955x *pca955x = i2c_get_clientdata(client);
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(client,
+		pca95xx_num_input_regs(pca955x->chipdef->bits) + 4 + n);
+	if (ret < 0) {
+		dev_err(&client->dev, "%s: reg 0x%x, err %d\n",
+			__func__, n, ret);
+		return ret;
+	}
+	*val = (u8)ret;
+	return 0;
+}
+
+static void pca955x_led_set(struct led *led_cdev, unsigned int value)
+{
+	struct pca955x_led *pca955x_led;
+	struct pca955x *pca955x;
+	u8 ls;
+	int chip_ls;	/* which LSx to use (0-3 potentially) */
+	int ls_led;	/* which set of bits within LSx to use (0-3) */
+	int ret;
+
+	pca955x_led = container_of(led_cdev, struct pca955x_led, led_cdev);
+	pca955x = pca955x_led->pca955x;
+
+	chip_ls = pca955x_led->led_num / 4;
+	ls_led = pca955x_led->led_num % 4;
+
+	ret = pca955x_read_ls(pca955x->client, chip_ls, &ls);
+	if (ret)
+		return;
+
+	switch (value) {
+	case LED_FULL:
+		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_ON);
+		break;
+	case LED_OFF:
+		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_LED_OFF);
+		break;
+	case LED_HALF:
+		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK0);
+		break;
+	default:
+		/*
+		 * Use PWM1 for all other values.  This has the unwanted
+		 * side effect of making all LEDs on the chip share the
+		 * same brightness level if set to a value other than
+		 * OFF, HALF, or FULL.  But, this is probably better than
+		 * just turning off for all other values.
+		 */
+		ret = pca955x_write_pwm(pca955x->client, 1, 255 - value);
+		if (ret)
+			return;
+		ls = pca955x_ledsel(ls, ls_led, PCA955X_LS_BLINK1);
+		break;
+	}
+
+	pca955x_write_ls(pca955x->client, chip_ls, ls);
+}
+
+static struct pca955x_platform_data *
+led_pca955x_pdata_of_init(struct device_node *np, struct pca955x *pca955x)
+{
+	struct device_node *child;
+	struct pca955x_chipdef *chip = pca955x->chipdef;
+	struct pca955x_platform_data *pdata;
+	int count, err;
+
+	count = of_get_child_count(np);
+	if (!count || count > chip->bits)
+		return ERR_PTR(-ENODEV);
+
+	pdata = xzalloc(sizeof(*pdata));
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	pdata->leds = xzalloc(chip->bits * sizeof(struct pca955x_led));
+	if (!pdata->leds)
+		return ERR_PTR(-ENOMEM);
+
+	for_each_child_of_node(np, child) {
+		struct pca955x_led *pca955x_led;
+		const char *name;
+		u32 reg;
+		int res;
+
+		res = of_property_read_u32(child, "reg", &reg);
+		if ((res != 0) || (reg >= chip->bits))
+			continue;
+
+		pca955x_led = &pdata->leds[reg];
+		pca955x_led->led_num = reg;
+		pca955x_led->pca955x = pca955x;
+
+		if (of_property_read_string(child, "label", &name))
+			name = child->name;
+
+		snprintf(pca955x_led->name, sizeof(pca955x_led->name),
+								"%s", name);
+
+		pca955x_led->led_cdev.name = pca955x_led->name;
+		pca955x_led->led_cdev.set = pca955x_led_set;
+		pca955x_led->led_cdev.num = pca955x_led->led_num;
+		pca955x_led->led_cdev.max_value = 255;
+
+		err = led_register(&pca955x_led->led_cdev);
+		if (err)
+			return ERR_PTR(err);
+
+		/* Turn off LED */
+		pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
+
+		led_of_parse_trigger(&pca955x_led->led_cdev, child);
+	}
+
+	pdata->num_leds = count;
+
+	return pdata;
+}
+
+static const struct of_device_id of_pca955x_match[] = {
+	{ .compatible = "nxp,pca9550", .data = (void *)pca9550 },
+	{ .compatible = "nxp,pca9551", .data = (void *)pca9551 },
+	{ .compatible = "nxp,pca9552", .data = (void *)pca9552 },
+	{ .compatible = "nxp,pca9553", .data = (void *)pca9553 },
+	{},
+};
+
+static int led_pca955x_probe(struct device_d *dev)
+{
+	struct pca955x *pca955x;
+	struct pca955x_led *pca955x_led;
+	struct pca955x_chipdef *chip;
+	struct i2c_client *client;
+	int err;
+	struct pca955x_platform_data *pdata;
+
+	chip = &pca955x_chipdefs[dev->id_entry->driver_data];
+	client = to_i2c_client(dev);
+
+	/* Make sure the slave address / chip type combo given is possible */
+	if ((client->addr & ~((1 << chip->slv_addr_shift) - 1)) !=
+	    chip->slv_addr) {
+		dev_err(dev, "invalid slave address %02x\n", client->addr);
+		return -ENODEV;
+	}
+
+	dev_info(dev, "leds-pca955x: Using %s %d-bit LED driver at "
+			"slave address 0x%02x\n",
+			client->dev.name, chip->bits, client->addr);
+
+	pca955x = xzalloc(sizeof(*pca955x));
+	if (!pca955x)
+		return -ENOMEM;
+
+	pca955x->leds = xzalloc(chip->bits * sizeof(*pca955x_led));
+	if (!pca955x->leds)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, pca955x);
+
+	pca955x->client = client;
+	pca955x->chipdef = chip;
+
+	pdata =	led_pca955x_pdata_of_init(dev->device_node, pca955x);
+	if (IS_ERR(pdata))
+		return PTR_ERR(pdata);
+
+	if (pdata->num_leds != chip->bits)
+		dev_warn(dev, "board info claims %d LEDs on a %d-bit chip\n",
+			pdata->num_leds, chip->bits);
+
+	/* PWM0 is used for half brightness or 50% duty cycle */
+	err = pca955x_write_pwm(client, 0, 255 - LED_HALF);
+	if (err)
+		return err;
+
+	/* PWM1 is used for variable brightness, default to OFF */
+	err = pca955x_write_pwm(client, 1, 0);
+	if (err)
+		return err;
+
+	/* Set to fast frequency so we do not see flashing */
+	err = pca955x_write_psc(client, 0, 0);
+	if (err)
+		return err;
+	err = pca955x_write_psc(client, 1, 0);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static struct driver_d led_pca955x_driver = {
+	.name	= "led-pca955x",
+	.probe	= led_pca955x_probe,
+	.id_table = led_pca955x_id,
+	.of_compatible = DRV_OF_COMPAT(of_pca955x_match),
+};
+
+static int __init led_pca955x_init(void)
+{
+	return i2c_driver_register(&led_pca955x_driver);
+}
+device_initcall(led_pca955x_init);
-- 
2.7.4



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