[RFC PATCH 06/10] LIS3LV02D: Selftest support

[Samu Onkalo <samu.p.onkalo@xxxxxxxxx>]

Selftest as specified by chip manufacturer.
Controlled via sysfs. Response is OK / FAIL with measurement data for
each axes. test acceptance limits are set using platform data.

Signed-off-by: Samu Onkalo <samu.p.onkalo@xxxxxxxxx>
---
 drivers/hwmon/lis3lv02d.c |   59 ++++++++++++++++++++++++++++++++++++++++++++-
 drivers/hwmon/lis3lv02d.h |   13 ++++++++-
 include/linux/lis3lv02d.h |    2 +
 3 files changed, 71 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/lis3lv02d.c b/drivers/hwmon/lis3lv02d.c
index 39b9ac8..0335b36 100644
--- a/drivers/hwmon/lis3lv02d.c
+++ b/drivers/hwmon/lis3lv02d.c
@@ -133,6 +133,51 @@ static int lis3lv02d_get_odr(void)
 	return val;
 }
 
+static int lis3lv02d_selftest(struct lis3lv02d *lis3, s16 results[3])
+{
+	u8 reg;
+	s16 x, y, z;
+	u8 selftest;
+
+	if (lis3_dev.whoami == WAI_12B)
+		selftest = CTRL1_ST;
+	else
+		selftest = CTRL1_STP;
+
+	lis3->read(lis3, CTRL_REG1, &reg);
+	lis3->write(lis3, CTRL_REG1, (reg | selftest));
+	msleep(lis3->pwron_delay / lis3lv02d_get_odr());
+
+	/* Read directly to avoid axis remap */
+	x = lis3->read_data(lis3, OUTX);
+	y = lis3->read_data(lis3, OUTY);
+	z = lis3->read_data(lis3, OUTZ);
+
+	/* back to normal settings */
+	lis3->write(lis3, CTRL_REG1, reg);
+	msleep(lis3->pwron_delay / lis3lv02d_get_odr());
+
+	results[0] = x - lis3->read_data(lis3, OUTX);
+	results[1] = y - lis3->read_data(lis3, OUTY);
+	results[2] = z - lis3->read_data(lis3, OUTZ);
+
+	if (lis3->pdata) {
+		int i;
+		for (i = 0; i < 3; i++) {
+			/* Check minimum acceptance limits */
+			if (results[i] < lis3->pdata->selftest_min_limits[i])
+				return -1;
+
+			/* Check maximum acceptance limits */
+			if (results[i] > lis3->pdata->selftest_max_limits[i])
+				return -1;
+		}
+	}
+
+	/* test passed */
+	return 0;
+}
+
 void lis3lv02d_poweroff(struct lis3lv02d *lis3)
 {
 	/* disable X,Y,Z axis and power down */
@@ -365,6 +410,17 @@ void lis3lv02d_joystick_disable(void)
 EXPORT_SYMBOL_GPL(lis3lv02d_joystick_disable);
 
 /* Sysfs stuff */
+static ssize_t lis3lv02d_selftest_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	int result;
+	s16 values[3];
+
+	result = lis3lv02d_selftest(&lis3_dev, values);
+	return sprintf(buf, "%s %d %d %d\n", result == 0 ? "OK" : "FAIL",
+		values[0], values[1], values[2]);
+}
+
 static ssize_t lis3lv02d_position_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
@@ -394,12 +450,14 @@ static ssize_t lis3lv02d_rate_show(struct device *dev,
 	return sprintf(buf, "%d\n", lis3lv02d_get_odr());
 }
 
+static DEVICE_ATTR(selftest, S_IRUGO, lis3lv02d_selftest_show, NULL);
 static DEVICE_ATTR(position, S_IRUGO, lis3lv02d_position_show, NULL);
 static DEVICE_ATTR(calibrate, S_IRUGO|S_IWUSR, lis3lv02d_calibrate_show,
 	lis3lv02d_calibrate_store);
 static DEVICE_ATTR(rate, S_IRUGO, lis3lv02d_rate_show, NULL);
 
 static struct attribute *lis3lv02d_attributes[] = {
+	&dev_attr_selftest.attr,
 	&dev_attr_position.attr,
 	&dev_attr_calibrate.attr,
 	&dev_attr_rate.attr,
@@ -507,4 +565,3 @@ EXPORT_SYMBOL_GPL(lis3lv02d_init_device);
 MODULE_DESCRIPTION("ST LIS3LV02Dx three-axis digital accelerometer driver");
 MODULE_AUTHOR("Yan Burman, Eric Piel, Pavel Machek");
 MODULE_LICENSE("GPL");
-
diff --git a/drivers/hwmon/lis3lv02d.h b/drivers/hwmon/lis3lv02d.h
index c57f21f..655875e 100644
--- a/drivers/hwmon/lis3lv02d.h
+++ b/drivers/hwmon/lis3lv02d.h
@@ -98,7 +98,7 @@ enum lis3_who_am_i {
 	WAI_6B		= 0x52, /* 6 bits: LIS331DLF - not supported */
 };
 
-enum lis3lv02d_ctrl1 {
+enum lis3lv02d_ctrl1_12b {
 	CTRL1_Xen	= 0x01,
 	CTRL1_Yen	= 0x02,
 	CTRL1_Zen	= 0x04,
@@ -107,8 +107,17 @@ enum lis3lv02d_ctrl1 {
 	CTRL1_DF1	= 0x20,
 	CTRL1_PD0	= 0x40,
 	CTRL1_PD1	= 0x80,
-	CTRL1_DR	= 0x80, /* Data rate on 8 bits */
 };
+
+/* Delta to ctrl1_12b version */
+enum lis3lv02d_ctrl1_8b {
+	CTRL1_STM	= 0x08,
+	CTRL1_STP	= 0x10,
+	CTRL1_FS	= 0x20,
+	CTRL1_PD	= 0x40,
+	CTRL1_DR	= 0x80,
+};
+
 enum lis3lv02d_ctrl2 {
 	CTRL2_DAS	= 0x01,
 	CTRL2_SIM	= 0x02,
diff --git a/include/linux/lis3lv02d.h b/include/linux/lis3lv02d.h
index 8970135..32d278d 100644
--- a/include/linux/lis3lv02d.h
+++ b/include/linux/lis3lv02d.h
@@ -55,6 +55,8 @@ struct lis3lv02d_platform_data {
 	s8 axis_z;
 	int (*setup_resources)(void);
 	int (*release_resources)(void);
+	s16 selftest_min_limits[3]; /* x, y, z */
+	s16 selftest_max_limits[3]; /* x, y, z */
 };
 
 #endif /* __LIS3LV02D_H_ */
-- 
1.5.6.3


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