iio: proximity: as3935: noise detection + threshold changes

Most applications are too noisy to allow the default noise and
watchdog settings, and thus need to be configurable via DT
properties.

Also default settings to POR defaults on a reset, and register
distuber interrupts as noise since it prevents proper usage.

Cc: devicetree@vger.kernel.org
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-proximity-as3935 b/Documentation/ABI/testing/sysfs-bus-iio-proximity-as3935
index 33e96f74063925fb253b7ac16c73f43b76c334c8..147d4e8a140393ce06a1076183b5a4a62432c7da 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-iio-proximity-as3935
+++ b/Documentation/ABI/testing/sysfs-bus-iio-proximity-as3935
@@ -14,3 +14,11 @@ Description:
                Show or set the gain boost of the amp, from 0-31 range.
                18 = indoors (default)
                14 = outdoors
+
+What           /sys/bus/iio/devices/iio:deviceX/noise_level_tripped
+Date:          May 2017
+KernelVersion: 4.13
+Contact:       Matt Ranostay <matt.ranostay@konsulko.com>
+Description:
+               When 1 the noise level is over the trip level and not reporting
+               valid data

diff --git a/Documentation/devicetree/bindings/iio/proximity/as3935.txt b/Documentation/devicetree/bindings/iio/proximity/as3935.txt
index 38d74314b7abe5c52999d77f36489a0486f222f7..b6c1afa6f02d3663fd547cb3f34b1d70d2d63049 100644 (file)
--- a/Documentation/devicetree/bindings/iio/proximity/as3935.txt
+++ b/Documentation/devicetree/bindings/iio/proximity/as3935.txt
@@ -16,6 +16,10 @@ Optional properties:
        - ams,tuning-capacitor-pf: Calibration tuning capacitor stepping
          value 0 - 120pF. This will require using the calibration data from
          the manufacturer.
+       - ams,nflwdth: Set the noise and watchdog threshold register on
+         startup. This will need to set according to the noise from the
+         MCU board, and possibly the local environment. Refer to the
+         datasheet for the threshold settings.
 
 Example:
 
@@ -27,4 +31,5 @@ as3935@0 {
        interrupt-parent = <&gpio1>;
        interrupts = <16 1>;
        ams,tuning-capacitor-pf = <80>;
+       ams,nflwdth = <0x44>;
 };

diff --git a/drivers/iio/proximity/as3935.c b/drivers/iio/proximity/as3935.c
index 0eeff29b61bed8cc2f678c05a22f1fa51562794b..4a48b7ba3a1c1753c6c3f7d847131ca0ba61b4ac 100644 (file)
--- a/drivers/iio/proximity/as3935.c
+++ b/drivers/iio/proximity/as3935.c
@@ -39,8 +39,12 @@
 #define AS3935_AFE_GAIN_MAX    0x1F
 #define AS3935_AFE_PWR_BIT     BIT(0)
 
+#define AS3935_NFLWDTH         0x01
+#define AS3935_NFLWDTH_MASK    0x7f
+
 #define AS3935_INT             0x03
 #define AS3935_INT_MASK                0x0f
+#define AS3935_DISTURB_INT     BIT(2)
 #define AS3935_EVENT_INT       BIT(3)
 #define AS3935_NOISE_INT       BIT(0)
 
@@ -48,6 +52,7 @@
 #define AS3935_DATA_MASK       0x3F
 
 #define AS3935_TUNE_CAP                0x08
+#define AS3935_DEFAULTS                0x3C
 #define AS3935_CALIBRATE       0x3D
 
 #define AS3935_READ_DATA       BIT(14)
@@ -62,7 +67,9 @@ struct as3935_state {
        struct mutex lock;
        struct delayed_work work;
 
+       unsigned long noise_tripped;
        u32 tune_cap;
+       u32 nflwdth_reg;
        u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
        u8 buf[2] ____cacheline_aligned;
 };
@@ -145,12 +152,29 @@ static ssize_t as3935_sensor_sensitivity_store(struct device *dev,
        return len;
 }
 
+static ssize_t as3935_noise_level_tripped_show(struct device *dev,
+                                       struct device_attribute *attr,
+                                       char *buf)
+{
+       struct as3935_state *st = iio_priv(dev_to_iio_dev(dev));
+       int ret;
+
+       mutex_lock(&st->lock);
+       ret = sprintf(buf, "%d\n", !time_after(jiffies, st->noise_tripped + HZ));
+       mutex_unlock(&st->lock);
+
+       return ret;
+}
+
 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
        as3935_sensor_sensitivity_show, as3935_sensor_sensitivity_store, 0);
 
+static IIO_DEVICE_ATTR(noise_level_tripped, S_IRUGO,
+       as3935_noise_level_tripped_show, NULL, 0);
 
 static struct attribute *as3935_attributes[] = {
        &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
+       &iio_dev_attr_noise_level_tripped.dev_attr.attr,
        NULL,
 };
 
@@ -246,7 +270,11 @@ static void as3935_event_work(struct work_struct *work)
        case AS3935_EVENT_INT:
                iio_trigger_poll_chained(st->trig);
                break;
+       case AS3935_DISTURB_INT:
        case AS3935_NOISE_INT:
+               mutex_lock(&st->lock);
+               st->noise_tripped = jiffies;
+               mutex_unlock(&st->lock);
                dev_warn(&st->spi->dev, "noise level is too high\n");
                break;
        }
@@ -269,15 +297,14 @@ static irqreturn_t as3935_interrupt_handler(int irq, void *private)
 
 static void calibrate_as3935(struct as3935_state *st)
 {
-       /* mask disturber interrupt bit */
-       as3935_write(st, AS3935_INT, BIT(5));
-
+       as3935_write(st, AS3935_DEFAULTS, 0x96);
        as3935_write(st, AS3935_CALIBRATE, 0x96);
        as3935_write(st, AS3935_TUNE_CAP,
                BIT(5) | (st->tune_cap / TUNE_CAP_DIV));
 
        mdelay(2);
        as3935_write(st, AS3935_TUNE_CAP, (st->tune_cap / TUNE_CAP_DIV));
+       as3935_write(st, AS3935_NFLWDTH, st->nflwdth_reg);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -370,6 +397,15 @@ static int as3935_probe(struct spi_device *spi)
                return -EINVAL;
        }
 
+       ret = of_property_read_u32(np,
+                       "ams,nflwdth", &st->nflwdth_reg);
+       if (!ret && st->nflwdth_reg > AS3935_NFLWDTH_MASK) {
+               dev_err(&spi->dev,
+                       "invalid nflwdth setting of %d\n",
+                       st->nflwdth_reg);
+               return -EINVAL;
+       }
+
        indio_dev->dev.parent = &spi->dev;
        indio_dev->name = spi_get_device_id(spi)->name;
        indio_dev->channels = as3935_channels;
@@ -384,6 +420,7 @@ static int as3935_probe(struct spi_device *spi)
                return -ENOMEM;
 
        st->trig = trig;
+       st->noise_tripped = jiffies - HZ;
        trig->dev.parent = indio_dev->dev.parent;
        iio_trigger_set_drvdata(trig, indio_dev);
        trig->ops = &iio_interrupt_trigger_ops;