Lis3 accelerometer sensors have quite long power on delay (up to 125

ms). This patch adds necessary delay to power on sequence for currently
supported lis3 chips.
Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Tested-by: ric Piel <eric.piel@tremplin-utc.net>
Acked-by: ric Piel <eric.piel@tremplin-utc.net>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/hwmon/lis3lv02d.c

@@ -50,6 +50,9 @@
  * joystick.
  */
 
+#define LIS3_PWRON_DELAY_WAI_12B	(5000)
+#define LIS3_PWRON_DELAY_WAI_8B		(3000)
+
 struct lis3lv02d lis3_dev = {
 	.misc_wait   = __WAIT_QUEUE_HEAD_INITIALIZER(lis3_dev.misc_wait),
 };
@@ -112,6 +115,24 @@ static void lis3lv02d_get_xyz(struct lis3lv02d *lis3, int *x, int *y, int *z)
 	*z = lis3lv02d_get_axis(lis3->ac.z, position);
 }
 
+/* conversion btw sampling rate and the register values */
+static int lis3_12_rates[4] = {40, 160, 640, 2560};
+static int lis3_8_rates[2] = {100, 400};
+
+static int lis3lv02d_get_odr(void)
+{
+	u8 ctrl;
+	int val;
+
+	lis3_dev.read(&lis3_dev, CTRL_REG1, &ctrl);
+
+	if (lis3_dev.whoami == WAI_12B)
+		val = lis3_12_rates[(ctrl & (CTRL1_DF0 | CTRL1_DF1)) >> 4];
+	else
+		val = lis3_8_rates[(ctrl & CTRL1_DR) >> 7];
+	return val;
+}
+
 void lis3lv02d_poweroff(struct lis3lv02d *lis3)
 {
 	/* disable X,Y,Z axis and power down */
@@ -125,6 +146,9 @@ void lis3lv02d_poweron(struct lis3lv02d *lis3)
 
 	lis3->init(lis3);
 
+	/* LIS3 power on delay is quite long */
+	msleep(lis3->pwron_delay / lis3lv02d_get_odr());
+
 	/*
 	 * Common configuration
 	 * BDU: (12 bits sensors only) LSB and MSB values are not updated until
@@ -364,23 +388,10 @@ static ssize_t lis3lv02d_calibrate_store(struct device *dev,
 	return count;
 }
 
-/* conversion btw sampling rate and the register values */
-static int lis3_12_rates[4] = {40, 160, 640, 2560};
-static int lis3_8_rates[2] = {100, 400};
 static ssize_t lis3lv02d_rate_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
-	u8 ctrl;
-	int val;
-
-	lis3_dev.read(&lis3_dev, CTRL_REG1, &ctrl);
-
-	if (lis3_dev.whoami == WAI_12B)
-		val = lis3_12_rates[(ctrl & (CTRL1_DF0 | CTRL1_DF1)) >> 4];
-	else
-		val = lis3_8_rates[(ctrl & CTRL1_DR) >> 7];
-
-	return sprintf(buf, "%d\n", val);
+	return sprintf(buf, "%d\n", lis3lv02d_get_odr());
 }
 
 static DEVICE_ATTR(position, S_IRUGO, lis3lv02d_position_show, NULL);
@@ -430,11 +441,13 @@ int lis3lv02d_init_device(struct lis3lv02d *dev)
 		printk(KERN_INFO DRIVER_NAME ": 12 bits sensor found\n");
 		dev->read_data = lis3lv02d_read_12;
 		dev->mdps_max_val = 2048;
+		dev->pwron_delay = LIS3_PWRON_DELAY_WAI_12B;
 		break;
 	case WAI_8B:
 		printk(KERN_INFO DRIVER_NAME ": 8 bits sensor found\n");
 		dev->read_data = lis3lv02d_read_8;
 		dev->mdps_max_val = 128;
+		dev->pwron_delay = LIS3_PWRON_DELAY_WAI_8B;
 		break;
 	default:
 		printk(KERN_ERR DRIVER_NAME

drivers/hwmon/lis3lv02d.h

@@ -202,6 +202,7 @@ struct lis3lv02d {
 	u8			whoami;    /* indicates measurement precision */
 	s16 (*read_data) (struct lis3lv02d *lis3, int reg);
 	int			mdps_max_val;
+	int			pwron_delay;
 
 	struct input_polled_dev	*idev;     /* input device */
 	struct platform_device	*pdev;     /* platform device */