drivers/leds/leds-lp5521.c: support led pattern data

The lp5521 has autonomous operation mode without external control.
Using lp5521_platform_data, various led patterns can be configurable.
For supporting this feature, new functions and device attribute are
added.

Structure of lp5521_led_pattern: 3 channels are supported - red, green
and blue. Pattern(s) of each channel and numbers of pattern(s) are
defined in the pla= tform data. Pattern data are hexa codes which
include pattern commands such like set pwm, wait, ramp up/down, branch
and so on.

Pattern mode functions:
* lp5521_clear_program_memory
Before running new led pattern, program memory should be cleared.
* lp5521_write_program_memory
Pattern data updated in the program memory via the i2c.
* lp5521_get_pattern
Get pattern from predefined in the platform data.
* lp5521_run_led_pattern
Stop current pattern or run new pattern.
Transition time is required between different operation mode.

Device attribute - 'led_pattern': To load specific led pattern, new device
attribute is added.

When the lp5521 driver is unloaded, stop current led pattern mode.

Documentation updated : description about how to define the led patterns
and example.

[[e-mail]: checkpatch fixes]
Signed-off-by: Milo(Woogyom) Kim <[e-mail]>
Acked-by: Linus Walleij <[e-mail]>
Cc: Arun MURTHY <[e-mail]>
Cc: Srinidhi Kasagar <[e-mail]>
Cc: Richard Purdie <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

Documentation/leds/leds-lp5521.txt

···
 	.clock_mode = LP5521_CLOCK_INT,
 	.update_config = LP5521_CONFIGS,
 };
+
+LED patterns : LP5521 has autonomous operation without external control.
+Pattern data can be defined in the platform data.
+
+example of led pattern data :
+
+/* RGB(50,5,0) 500ms on, 500ms off, infinite loop */
+static u8 pattern_red[] = {
+		0x40, 0x32, 0x60, 0x00,	0x40, 0x00, 0x60, 0x00,
+		};
+
+static u8 pattern_green[] = {
+		0x40, 0x05, 0x60, 0x00, 0x40, 0x00, 0x60, 0x00,
+		};
+
+static struct lp5521_led_pattern board_led_patterns[] = {
+	{
+		.r = pattern_red,
+		.g = pattern_green,
+		.size_r = ARRAY_SIZE(pattern_red),
+		.size_g = ARRAY_SIZE(pattern_green),
+	},
+};
+
+static struct lp5521_platform_data lp5521_platform_data = {
+        .led_config     = lp5521_led_config,
+        .num_channels   = ARRAY_SIZE(lp5521_led_config),
+        .clock_mode     = LP5521_CLOCK_EXT,
+	.patterns = board_led_patterns,
+	.num_patterns = ARRAY_SIZE(board_led_patterns),
+};
+
+Then predefined led pattern(s) can be executed via the sysfs.
+To start the pattern #1,
+# echo 1 > /sys/bus/i2c/devices/xxxx/led_pattern
+(xxxx : i2c bus & slave address)
+To end the pattern,
+# echo 0 > /sys/bus/i2c/devices/xxxx/led_pattern

drivers/leds/leds-lp5521.c

···
 /* default R channel current register value */
 #define LP5521_REG_R_CURR_DEFAULT	0xAF
 
+/* Pattern Mode */
+#define PATTERN_OFF	0
+
 struct lp5521_engine {
 	int		id;
 	u8		mode;
···
 	ssize_t ret;
 	unsigned long curr;
 
-	if (strict_strtoul(buf, 0, &curr))
+	if (kstrtoul(buf, 0, &curr))
 		return -EINVAL;
 
 	if (curr > led->max_current)
···
 	return sprintf(buf, "%s\n", ret ? "FAIL" : "OK");
 }
 
+static void lp5521_clear_program_memory(struct i2c_client *cl)
+{
+	int i;
+	u8 rgb_mem[] = {
+		LP5521_REG_R_PROG_MEM,
+		LP5521_REG_G_PROG_MEM,
+		LP5521_REG_B_PROG_MEM,
+	};
+
+	for (i = 0; i < ARRAY_SIZE(rgb_mem); i++) {
+		lp5521_write(cl, rgb_mem[i], 0);
+		lp5521_write(cl, rgb_mem[i] + 1, 0);
+	}
+}
+
+static void lp5521_write_program_memory(struct i2c_client *cl,
+				u8 base, u8 *rgb, int size)
+{
+	int i;
+
+	if (!rgb || size <= 0)
+		return;
+
+	for (i = 0; i < size; i++)
+		lp5521_write(cl, base + i, *(rgb + i));
+
+	lp5521_write(cl, base + i, 0);
+	lp5521_write(cl, base + i + 1, 0);
+}
+
+static inline struct lp5521_led_pattern *lp5521_get_pattern
+					(struct lp5521_chip *chip, u8 offset)
+{
+	struct lp5521_led_pattern *ptn;
+	ptn = chip->pdata->patterns + (offset - 1);
+	return ptn;
+}
+
+static void lp5521_run_led_pattern(int mode, struct lp5521_chip *chip)
+{
+	struct lp5521_led_pattern *ptn;
+	struct i2c_client *cl = chip->client;
+	int num_patterns = chip->pdata->num_patterns;
+
+	if (mode > num_patterns || !(chip->pdata->patterns))
+		return;
+
+	if (mode == PATTERN_OFF) {
+		lp5521_write(cl, LP5521_REG_ENABLE,
+			LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM);
+		usleep_range(1000, 2000);
+		lp5521_write(cl, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
+	} else {
+		ptn = lp5521_get_pattern(chip, mode);
+		if (!ptn)
+			return;
+
+		lp5521_write(cl, LP5521_REG_OP_MODE, LP5521_CMD_LOAD);
+		usleep_range(1000, 2000);
+
+		lp5521_clear_program_memory(cl);
+
+		lp5521_write_program_memory(cl, LP5521_REG_R_PROG_MEM,
+					ptn->r, ptn->size_r);
+		lp5521_write_program_memory(cl, LP5521_REG_G_PROG_MEM,
+					ptn->g, ptn->size_g);
+		lp5521_write_program_memory(cl, LP5521_REG_B_PROG_MEM,
+					ptn->b, ptn->size_b);
+
+		lp5521_write(cl, LP5521_REG_OP_MODE, LP5521_CMD_RUN);
+		usleep_range(1000, 2000);
+		lp5521_write(cl, LP5521_REG_ENABLE,
+			LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM |
+			LP5521_EXEC_RUN);
+	}
+}
+
+static ssize_t store_led_pattern(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t len)
+{
+	struct lp5521_chip *chip = i2c_get_clientdata(to_i2c_client(dev));
+	unsigned long val;
+	int ret;
+
+	ret = strict_strtoul(buf, 16, &val);
+	if (ret)
+		return ret;
+
+	lp5521_run_led_pattern(val, chip);
+
+	return len;
+}
+
 /* led class device attributes */
 static DEVICE_ATTR(led_current, S_IRUGO | S_IWUSR, show_current, store_current);
 static DEVICE_ATTR(max_current, S_IRUGO , show_max_current, NULL);
···
 static DEVICE_ATTR(engine2_load, S_IWUSR, NULL, store_engine2_load);
 static DEVICE_ATTR(engine3_load, S_IWUSR, NULL, store_engine3_load);
 static DEVICE_ATTR(selftest, S_IRUGO, lp5521_selftest, NULL);
+static DEVICE_ATTR(led_pattern, S_IWUSR, NULL, store_led_pattern);
 
 static struct attribute *lp5521_attributes[] = {
 	&dev_attr_engine1_mode.attr,
···
 	&dev_attr_engine1_load.attr,
 	&dev_attr_engine2_load.attr,
 	&dev_attr_engine3_load.attr,
+	&dev_attr_led_pattern.attr,
 	NULL
 };
 
···
 	struct lp5521_chip *chip = i2c_get_clientdata(client);
 	int i;
 
+	lp5521_run_led_pattern(PATTERN_OFF, chip);
 	lp5521_unregister_sysfs(client);
 
 	for (i = 0; i < chip->num_leds; i++) {

include/linux/leds-lp5521.h

···
 	u8		max_current;
 };
 
+struct lp5521_led_pattern {
+	u8 *r;
+	u8 *g;
+	u8 *b;
+	u8 size_r;
+	u8 size_g;
+	u8 size_b;
+};
+
 #define LP5521_CLOCK_AUTO	0
 #define LP5521_CLOCK_INT	1
 #define LP5521_CLOCK_EXT	2
···
 	void	(*enable)(bool state);
 	const char *label;
 	u8	update_config;
+	struct lp5521_led_pattern *patterns;
+	int num_patterns;
 };
 
 #endif /* __LINUX_LP5521_H */