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Date: Tue, 01 Dec 2009 09:53:10 +0100
From: Éric Piel <Eric.Piel@...mplin-utc.net>
To: Samu Onkalo <samu.p.onkalo@...ia.com>
Cc: linux-kernel@...r.kernel.org, lm-sensors@...sensors.org
Subject: Re: [PATCH v4 1/5] lis3: Selftest support
Op 01-12-09 09:33, Samu Onkalo schreef:
> Implement selftest feature as specified by chip manufacturer.
> Control: read selftest sysfs entry
> Response: "OK x y z" or "FAIL x y z"
> where x, y, and z are difference between selftest mode and normal mode.
> Test is passed when values are within acceptance limit values.
>
> Acceptance limits are provided via platform data. See chip spesifications
> for acceptance limits. If limits are not properly set, OK / FAIL decision is
> meaningless. However, userspace application can still make decision based on
> the numeric x, y, z values.
>
> Selftest is meant for HW diagnostic purposes. It is not meant to be called
> during normal use of the chip. It may cause false interrupt events.
> Selftest mode delays polling of the normal results but it doesn't cause
> wrong values. Chip must be in static state during selftest.
> Any acceration during the test causes most probably failure.
>
> Signed-off-by: Samu Onkalo<samu.p.onkalo@...ia.com>
Signed-off-by: Éric Piel <eric.piel@...mplin-utc.net>
> ---
> drivers/hwmon/lis3lv02d.c | 67 ++++++++++++++++++++++++++++++++++++++++++++-
> drivers/hwmon/lis3lv02d.h | 14 ++++++++-
> include/linux/lis3lv02d.h | 3 ++
> 3 files changed, 81 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hwmon/lis3lv02d.c b/drivers/hwmon/lis3lv02d.c
> index 39b9ac8..55ec883 100644
> --- a/drivers/hwmon/lis3lv02d.c
> +++ b/drivers/hwmon/lis3lv02d.c
> @@ -106,9 +106,11 @@ static void lis3lv02d_get_xyz(struct lis3lv02d *lis3, int *x, int *y, int *z)
> {
> int position[3];
>
> + mutex_lock(&lis3->mutex);
> position[0] = lis3->read_data(lis3, OUTX);
> position[1] = lis3->read_data(lis3, OUTY);
> position[2] = lis3->read_data(lis3, OUTZ);
> + mutex_unlock(&lis3->mutex);
>
> *x = lis3lv02d_get_axis(lis3->ac.x, position);
> *y = lis3lv02d_get_axis(lis3->ac.y, position);
> @@ -133,6 +135,55 @@ 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;
> + int ret;
> +
> + mutex_lock(&lis3->mutex);
> + if (lis3_dev.whoami == WAI_12B)
> + selftest = CTRL1_ST;
> + else
> + selftest = CTRL1_STP;
> +
> + lis3->read(lis3, CTRL_REG1,®);
> + 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);
> +
> + ret = 0;
> + if (lis3->pdata) {
> + int i;
> + for (i = 0; i< 3; i++) {
> + /* Check against selftest acceptance limits */
> + if ((results[i]< lis3->pdata->st_min_limits[i]) ||
> + (results[i]> lis3->pdata->st_max_limits[i])) {
> + ret = -EIO;
> + goto fail;
> + }
> + }
> + }
> +
> + /* test passed */
> +fail:
> + mutex_unlock(&lis3->mutex);
> + return ret;
> +}
> +
> void lis3lv02d_poweroff(struct lis3lv02d *lis3)
> {
> /* disable X,Y,Z axis and power down */
> @@ -365,6 +416,17 @@ 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 +456,14 @@ static ssize_t lis3lv02d_rate_show(struct device *dev,
> return sprintf(buf, "%d\n", lis3lv02d_get_odr());
> }
>
> +static DEVICE_ATTR(selftest, S_IRUSR, 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,
> @@ -455,6 +519,8 @@ int lis3lv02d_init_device(struct lis3lv02d *dev)
> return -EINVAL;
> }
>
> + mutex_init(&dev->mutex);
> +
> lis3lv02d_add_fs(dev);
> lis3lv02d_poweron(dev);
>
> @@ -507,4 +573,3 @@ 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..166794c 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,
> @@ -218,6 +227,7 @@ struct lis3lv02d {
> unsigned long misc_opened; /* bit0: whether the device is open */
>
> struct lis3lv02d_platform_data *pdata; /* for passing board config */
> + struct mutex mutex; /* Serialize poll and selftest */
> };
>
> int lis3lv02d_init_device(struct lis3lv02d *lis3);
> diff --git a/include/linux/lis3lv02d.h b/include/linux/lis3lv02d.h
> index 8970135..f1ca0dc 100644
> --- a/include/linux/lis3lv02d.h
> +++ b/include/linux/lis3lv02d.h
> @@ -55,6 +55,9 @@ struct lis3lv02d_platform_data {
> s8 axis_z;
> int (*setup_resources)(void);
> int (*release_resources)(void);
> + /* Limits for selftest are specified in chip data sheet */
> + s16 st_min_limits[3]; /* min pass limit x, y, z */
> + s16 st_max_limits[3]; /* max pass limit x, y, z */
> };
>
> #endif /* __LIS3LV02D_H_ */
--
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