iio: cros_ec: Expose hwfifo_timeout

Expose EC minimal interrupt period through buffer/hwfifo_timeout:
- Maximal timeout is limited to 65s.
- When timeout for all sensors is set to 0, EC will not send events,
  even if the sensor sampling rate is greater than 0.

Rename frequency to sampling_frequency to match IIO ABI.
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c

@@ -236,6 +236,8 @@ static int cros_ec_sensors_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	iio_buffer_set_attrs(indio_dev->buffer, cros_ec_sensor_fifo_attributes);
+
 	indio_dev->info = &ec_sensors_info;
 	state = iio_priv(indio_dev);
 	for (channel = state->channels, i = CROS_EC_SENSOR_X;
@@ -247,7 +249,6 @@ static int cros_ec_sensors_probe(struct platform_device *pdev)
 			BIT(IIO_CHAN_INFO_CALIBSCALE);
 		channel->info_mask_shared_by_all =
 			BIT(IIO_CHAN_INFO_SCALE) |
-			BIT(IIO_CHAN_INFO_FREQUENCY) |
 			BIT(IIO_CHAN_INFO_SAMP_FREQ);
 		channel->info_mask_shared_by_all_available =
 			BIT(IIO_CHAN_INFO_SAMP_FREQ);

drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c

@@ -11,6 +11,7 @@
 #include <linux/iio/common/cros_ec_sensors_core.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/kfifo_buf.h>
+#include <linux/iio/sysfs.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/kernel.h>
@@ -83,6 +84,77 @@ static void get_default_min_max_freq(enum motionsensor_type type,
 	}
 }
 
+static int cros_ec_sensor_set_ec_rate(struct cros_ec_sensors_core_state *st,
+				      int rate)
+{
+	int ret;
+
+	if (rate > U16_MAX)
+		rate = U16_MAX;
+
+	mutex_lock(&st->cmd_lock);
+	st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
+	st->param.ec_rate.data = rate;
+	ret = cros_ec_motion_send_host_cmd(st, 0);
+	mutex_unlock(&st->cmd_lock);
+	return ret;
+}
+
+static ssize_t cros_ec_sensor_set_report_latency(struct device *dev,
+						 struct device_attribute *attr,
+						 const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	int integer, fract, ret;
+	int latency;
+
+	ret = iio_str_to_fixpoint(buf, 100000, &integer, &fract);
+	if (ret)
+		return ret;
+
+	/* EC rate is in ms. */
+	latency = integer * 1000 + fract / 1000;
+	ret = cros_ec_sensor_set_ec_rate(st, latency);
+	if (ret < 0)
+		return ret;
+
+	return len;
+}
+
+static ssize_t cros_ec_sensor_get_report_latency(struct device *dev,
+						 struct device_attribute *attr,
+						 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	int latency, ret;
+
+	mutex_lock(&st->cmd_lock);
+	st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
+	st->param.ec_rate.data = EC_MOTION_SENSE_NO_VALUE;
+
+	ret = cros_ec_motion_send_host_cmd(st, 0);
+	latency = st->resp->ec_rate.ret;
+	mutex_unlock(&st->cmd_lock);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d.%06u\n",
+		       latency / 1000,
+		       (latency % 1000) * 1000);
+}
+
+static IIO_DEVICE_ATTR(hwfifo_timeout, 0644,
+		       cros_ec_sensor_get_report_latency,
+		       cros_ec_sensor_set_report_latency, 0);
+
+const struct attribute *cros_ec_sensor_fifo_attributes[] = {
+	&iio_dev_attr_hwfifo_timeout.dev_attr.attr,
+	NULL,
+};
+EXPORT_SYMBOL_GPL(cros_ec_sensor_fifo_attributes);
+
 int cros_ec_sensors_push_data(struct iio_dev *indio_dev,
 			      s16 *data,
 			      s64 timestamp)
@@ -631,18 +703,6 @@ int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
-		st->param.ec_rate.data =
-			EC_MOTION_SENSE_NO_VALUE;
-
-		ret = cros_ec_motion_send_host_cmd(st, 0);
-		if (ret)
-			break;
-
-		*val = st->resp->ec_rate.ret;
-		ret = IIO_VAL_INT;
-		break;
-	case IIO_CHAN_INFO_FREQUENCY:
 		st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
 		st->param.sensor_odr.data =
 			EC_MOTION_SENSE_NO_VALUE;
@@ -712,7 +772,7 @@ int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
 	int ret;
 
 	switch (mask) {
-	case IIO_CHAN_INFO_FREQUENCY:
+	case IIO_CHAN_INFO_SAMP_FREQ:
 		st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
 		st->param.sensor_odr.data = val;
 
@@ -721,15 +781,6 @@ int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
 
 		ret = cros_ec_motion_send_host_cmd(st, 0);
 		break;
-	case IIO_CHAN_INFO_SAMP_FREQ:
-		st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
-		st->param.ec_rate.data = val;
-
-		ret = cros_ec_motion_send_host_cmd(st, 0);
-		if (ret)
-			break;
-		st->curr_sampl_freq = val;
-		break;
 	default:
 		ret = -EINVAL;
 		break;

drivers/iio/light/cros_ec_light_prox.c

@@ -183,6 +183,8 @@ static int cros_ec_light_prox_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	iio_buffer_set_attrs(indio_dev->buffer, cros_ec_sensor_fifo_attributes);
+
 	indio_dev->info = &cros_ec_light_prox_info;
 	state = iio_priv(indio_dev);
 	state->core.type = state->core.resp->info.type;
@@ -191,8 +193,7 @@ static int cros_ec_light_prox_probe(struct platform_device *pdev)
 
 	/* Common part */
 	channel->info_mask_shared_by_all =
-		BIT(IIO_CHAN_INFO_SAMP_FREQ) |
-		BIT(IIO_CHAN_INFO_FREQUENCY);
+		BIT(IIO_CHAN_INFO_SAMP_FREQ);
 	channel->info_mask_shared_by_all_available =
 		BIT(IIO_CHAN_INFO_SAMP_FREQ);
 	channel->scan_type.realbits = CROS_EC_SENSOR_BITS;

drivers/iio/pressure/cros_ec_baro.c

@@ -140,6 +140,8 @@ static int cros_ec_baro_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	iio_buffer_set_attrs(indio_dev->buffer, cros_ec_sensor_fifo_attributes);
+
 	indio_dev->info = &cros_ec_baro_info;
 	state = iio_priv(indio_dev);
 	state->core.type = state->core.resp->info.type;
@@ -149,8 +151,7 @@ static int cros_ec_baro_probe(struct platform_device *pdev)
 	channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 	channel->info_mask_shared_by_all =
 		BIT(IIO_CHAN_INFO_SCALE) |
-		BIT(IIO_CHAN_INFO_SAMP_FREQ) |
-		BIT(IIO_CHAN_INFO_FREQUENCY);
+		BIT(IIO_CHAN_INFO_SAMP_FREQ);
 	channel->info_mask_shared_by_all_available =
 		BIT(IIO_CHAN_INFO_SAMP_FREQ);
 	channel->scan_type.realbits = CROS_EC_SENSOR_BITS;

include/linux/iio/common/cros_ec_sensors_core.h

@@ -50,7 +50,6 @@ typedef irqreturn_t (*cros_ec_sensors_capture_t)(int irq, void *p);
  *				the timestamp. The timestamp is always last and
  *				is always 8-byte aligned.
  * @read_ec_sensors_data:	function used for accessing sensors values
- * @cuur_sampl_freq:		current sampling period
  */
 struct cros_ec_sensors_core_state {
 	struct cros_ec_device *ec;
@@ -73,8 +72,6 @@ struct cros_ec_sensors_core_state {
 	int (*read_ec_sensors_data)(struct iio_dev *indio_dev,
 				    unsigned long scan_mask, s16 *data);
 
-	int curr_sampl_freq;
-
 	/* Table of known available frequencies : 0, Min and Max in mHz */
 	int frequencies[3];
 };
@@ -116,5 +113,6 @@ int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
 
 /* List of extended channel specification for all sensors */
 extern const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[];
+extern const struct attribute *cros_ec_sensor_fifo_attributes[];
 
 #endif  /* __CROS_EC_SENSORS_CORE_H */