The ACCES 104-QUAD-8 series provides status information about the
connection state of the differential encoder cable inputs. This patch
implements support to expose such information from these devices.
Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
---
Changes in v3:
- Split cable_status attribute into cable_fault and cable_fault_enable;
both under each Signal so we can control each channel independently
- Initialize to a default state of disabled for all channels
.../ABI/testing/sysfs-bus-counter-104-quad-8 | 18 +++++
drivers/counter/104-quad-8.c | 75 +++++++++++++++++++
2 files changed, 93 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8 b/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
index 3c905d3cf5d7..eac32180c40d 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
+++ b/Documentation/ABI/testing/sysfs-bus-counter-104-quad-8
@@ -1,3 +1,21 @@
+What: /sys/bus/counter/devices/counterX/signalY/cable_fault
+KernelVersion: 5.7
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Read-only attribute that indicates whether a differential
+ encoder cable fault (not connected or loose wires) is detected
+ for the respective channel of Signal Y. Valid attribute values
+ are boolean. Detection must first be enabled via the
+ corresponding cable_fault_enable attribute.
+
+What: /sys/bus/counter/devices/counterX/signalY/cable_fault_enable
+KernelVersion: 5.7
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Whether detection of differential encoder cable faults for the
+ respective channel of Signal Y is enabled. Valid attribute
+ values are boolean.
+
What: /sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler
KernelVersion: 5.7
Contact: linux-iio@xxxxxxxxxxxxxxx
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index 0cfc813ee2cb..9dab190c49b0 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -31,6 +31,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
/**
* struct quad8_iio - IIO device private data structure
* @counter: instance of the counter_device
+ * @fck_prescaler: array of filter clock prescaler configurations
* @preset: array of preset values
* @count_mode: array of count mode configurations
* @quadrature_mode: array of quadrature mode configurations
@@ -39,6 +40,7 @@ MODULE_PARM_DESC(base, "ACCES 104-QUAD-8 base addresses");
* @preset_enable: array of set_to_preset_on_index attribute configurations
* @synchronous_mode: array of index function synchronous mode configurations
* @index_polarity: array of index function polarity configurations
+ * @cable_fault_enable: differential encoder cable status enable configurations
* @base: base port address of the IIO device
*/
struct quad8_iio {
@@ -52,11 +54,13 @@ struct quad8_iio {
unsigned int preset_enable[QUAD8_NUM_COUNTERS];
unsigned int synchronous_mode[QUAD8_NUM_COUNTERS];
unsigned int index_polarity[QUAD8_NUM_COUNTERS];
+ unsigned int cable_fault_enable;
unsigned int base;
};
#define QUAD8_REG_CHAN_OP 0x11
#define QUAD8_REG_INDEX_INPUT_LEVELS 0x16
+#define QUAD8_DIFF_ENCODER_CABLE_STATUS 0x17
/* Borrow Toggle flip-flop */
#define QUAD8_FLAG_BT BIT(0)
/* Carry Toggle flip-flop */
@@ -1143,6 +1147,66 @@ static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
return len;
}
+static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter,
+ struct counter_signal *signal,
+ void *private, char *buf)
+{
+ const struct quad8_iio *const priv = counter->priv;
+ const size_t channel_id = signal->id / 2;
+ const bool disabled = !(priv->cable_fault_enable & BIT(channel_id));
+ unsigned int status;
+ unsigned int fault;
+
+ if (disabled)
+ return -EINVAL;
+
+ /* Logic 0 = cable fault */
+ status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
+
+ /* Mask respective channel and invert logic */
+ fault = !(status & BIT(channel_id));
+
+ return sprintf(buf, "%u\n", fault);
+}
+
+static ssize_t quad8_signal_cable_fault_enable_read(
+ struct counter_device *counter, struct counter_signal *signal,
+ void *private, char *buf)
+{
+ const struct quad8_iio *const priv = counter->priv;
+ const size_t channel_id = signal->id / 2;
+ const unsigned int enb = !!(priv->cable_fault_enable & BIT(channel_id));
+
+ return sprintf(buf, "%u\n", enb);
+}
+
+static ssize_t quad8_signal_cable_fault_enable_write(
+ struct counter_device *counter, struct counter_signal *signal,
+ void *private, const char *buf, size_t len)
+{
+ struct quad8_iio *const priv = counter->priv;
+ const size_t channel_id = signal->id / 2;
+ bool enable;
+ int ret;
+ unsigned int cable_fault_enable;
+
+ ret = kstrtobool(buf, &enable);
+ if (ret)
+ return ret;
+
+ if (enable)
+ priv->cable_fault_enable |= BIT(channel_id);
+ else
+ priv->cable_fault_enable &= ~BIT(channel_id);
+
+ /* Enable is active low in Differential Encoder Cable Status register */
+ cable_fault_enable = ~priv->cable_fault_enable;
+
+ outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
+
+ return len;
+}
+
static ssize_t quad8_signal_fck_prescaler_read(struct counter_device *counter,
struct counter_signal *signal, void *private, char *buf)
{
@@ -1180,6 +1244,15 @@ static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
}
static const struct counter_signal_ext quad8_signal_ext[] = {
+ {
+ .name = "cable_fault",
+ .read = quad8_signal_cable_fault_read
+ },
+ {
+ .name = "cable_fault_enable",
+ .read = quad8_signal_cable_fault_enable_read,
+ .write = quad8_signal_cable_fault_enable_write
+ },
{
.name = "filter_clock_prescaler",
.read = quad8_signal_fck_prescaler_read,
@@ -1383,6 +1456,8 @@ static int quad8_probe(struct device *dev, unsigned int id)
/* Disable index function; negative index polarity */
outb(QUAD8_CTR_IDR, base_offset + 1);
}
+ /* Disable Differential Encoder Cable Status for all channels */
+ outb(0xFF, base[id] + QUAD8_DIFF_ENCODER_CABLE_STATUS);
/* Enable all counters */
outb(QUAD8_CHAN_OP_ENABLE_COUNTERS, base[id] + QUAD8_REG_CHAN_OP);
--
2.24.1
