[PATCH v2 1/1] counter: cros_ec: Add synchronization sensor

Fabien Lahoudere
2019-08-23T12:42:46Z

From: Gwendal Grignou <gwendal@chromium.org>

EC returns a counter when there is an event on camera vsync.
This patch comes from chromeos kernel 4.4

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>

CROS EC sync sensor was originally designed as an IIO device.
Now that the counter subsystem will replace IIO_COUNTER, we
have to implement a new way to get sync count.

Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>
---
Documentation/driver-api/generic-counter.rst | 3 +
MAINTAINERS | 7 +
drivers/counter/Kconfig | 9 +
drivers/counter/Makefile | 1 +
drivers/counter/counter.c | 2 +
drivers/counter/cros_ec_sensors_sync.c | 208 ++++++++++++++++++
.../cros_ec_sensors/cros_ec_sensors_core.c | 1 +
drivers/mfd/cros_ec_dev.c | 3 +
include/linux/counter.h | 1 +
9 files changed, 235 insertions(+)
create mode 100644 drivers/counter/cros_ec_sensors_sync.c

diff --git a/Documentation/driver-api/generic-counter.rst b/Documentation/driver-api/generic-counter.rst
index 8382f01a53e3..beb80714ac8b 100644
--- a/Documentation/driver-api/generic-counter.rst
+++ b/Documentation/driver-api/generic-counter.rst
@@ -44,6 +44,9 @@ Counter interface provides the following available count data types:
* COUNT_POSITION:
Unsigned integer value representing position.

+* COUNT_TALLY:
+ Unsigned integer value representing tally.
+
A Count has a count function mode which represents the update behavior
for the count data. The Generic Counter interface provides the following
available count function modes:
diff --git a/MAINTAINERS b/MAINTAINERS
index e60f5c361969..83bd291d103e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3902,6 +3902,13 @@ R: Guenter Roeck <groeck@chromium.org>
F: Documentation/devicetree/bindings/sound/google,cros-ec-codec.txt
F: sound/soc/codecs/cros_ec_codec.*

+CHROMEOS EC COUNTER DRIVER
+M: Fabien Lahoudere <fabien.lahoudere@collabora.com>
+M: William Breathitt Gray <vilhelm.gray@gmail.com>
+L: linux-iio@vger.kernel.org
+S: Maintained
+F: drivers/counter/cros_ec_sensors_sync.c
+
CIRRUS LOGIC AUDIO CODEC DRIVERS
M: Brian Austin <brian.austin@cirrus.com>
M: Paul Handrigan <Paul.Handrigan@cirrus.com>
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index 2967d0a9ff91..22287f5715e5 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -59,4 +59,13 @@ config FTM_QUADDEC
To compile this driver as a module, choose M here: the
module will be called ftm-quaddec.

+config IIO_CROS_EC_SENSORS_SYNC
+ tristate "ChromeOS EC Counter Sensors"
+ depends on IIO_CROS_EC_SENSORS_CORE && IIO
+ help
+ Module to handle synchronisation sensors presented by the ChromeOS EC
+ Sensor hub.
+ Synchronisation sensors are counter sensors triggered when events
+ occurs from other subsystems.
+
endif # COUNTER
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 40d35522937d..6fe4c98a446f 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
obj-$(CONFIG_STM32_TIMER_CNT) += stm32-timer-cnt.o
obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o
obj-$(CONFIG_FTM_QUADDEC) += ftm-quaddec.o
+obj-$(CONFIG_IIO_CROS_EC_SENSORS_SYNC) += cros_ec_sensors_sync.o
diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
index 106bc7180cd8..53525b109094 100644
--- a/drivers/counter/counter.c
+++ b/drivers/counter/counter.c
@@ -261,6 +261,7 @@ void counter_count_read_value_set(struct counter_count_read_value *const val,
{
switch (type) {
case COUNTER_COUNT_POSITION:
+ case COUNTER_COUNT_TALLY:
val->len = sprintf(val->buf, "%lu\n", *(unsigned long *)data);
break;
default:
@@ -290,6 +291,7 @@ int counter_count_write_value_get(void *const data,

switch (type) {
case COUNTER_COUNT_POSITION:
+ case COUNTER_COUNT_TALLY:
err = kstrtoul(val->buf, 0, data);
if (err)
return err;
diff --git a/drivers/counter/cros_ec_sensors_sync.c b/drivers/counter/cros_ec_sensors_sync.c
new file mode 100644
index 000000000000..b6f5e2c6da9f
--- /dev/null
+++ b/drivers/counter/cros_ec_sensors_sync.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver of counter incremented after events on interrupt line in EC.
+ *
+ * Copyright 2018 Google, Inc
+ */
+
+#include <linux/device.h>
+#include <linux/counter.h>
+#include <linux/iio/common/cros_ec_sensors_core.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/kernel.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define DRV_NAME "cros-ec-sync"
+
+/*
+ * One channel for counter, the other for timestamp.
+ */
+#define MAX_CHANNELS (1)
+
+/* State data for ec_sensors iio driver. */
+struct cros_ec_sensors_sync_state {
+ /* Shared by all sensors */
+ struct cros_ec_sensors_core_state core;
+ struct counter_device counter;
+ struct iio_chan_spec channels[MAX_CHANNELS];
+};
+
+static int cros_ec_sensors_sync_read(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct cros_ec_sensors_sync_state *st = iio_priv(indio_dev);
+ u16 data;
+ int ret;
+
+ mutex_lock(&st->core.cmd_lock);
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = cros_ec_sensors_read_cmd(indio_dev, BIT(0), &data);
+ if (ret < 0)
+ break;
+ ret = IIO_VAL_INT;
+ *val = data;
+ break;
+ default:
+ ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
+ mask);
+ break;
+ }
+ mutex_unlock(&st->core.cmd_lock);
+ return ret;
+}
+
+static struct iio_info cros_ec_sensors_sync_info = {
+ .read_raw = &cros_ec_sensors_sync_read,
+ .read_avail = &cros_ec_sensors_core_read_avail,
+};
+
+static struct counter_count cros_ec_sync_counts = {
+ .id = 0,
+ .name = "Cros EC sync counter",
+};
+
+static int cros_ec_sync_cnt_read(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_count_read_value *val)
+{
+ s16 cnt;
+ int ret;
+ struct iio_dev *indio_dev = counter->priv;
+ struct cros_ec_sensors_sync_state *const st = iio_priv(indio_dev);
+ unsigned long data;
+
+ mutex_lock(&st->core.cmd_lock);
+ ret = cros_ec_sensors_read_cmd(indio_dev, BIT(0), &cnt);
+ mutex_unlock(&st->core.cmd_lock);
+ if (ret != 0) {
+ dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
+ return ret;
+ }
+
+ data = (unsigned long) cnt;
+ counter_count_read_value_set(val, COUNTER_COUNT_TALLY, &data);
+
+ return 0;
+}
+
+static const struct counter_ops cros_ec_sync_cnt_ops = {
+ .count_read = cros_ec_sync_cnt_read,
+};
+
+static char *cros_ec_loc[] = {
+ [MOTIONSENSE_LOC_BASE] = "base",
+ [MOTIONSENSE_LOC_LID] = "lid",
+ [MOTIONSENSE_LOC_CAMERA] = "camera",
+ [MOTIONSENSE_LOC_MAX] = "unknown",
+};
+
+static ssize_t cros_ec_sync_id(struct counter_device *counter,
+ void *private, char *buf)
+{
+ struct iio_dev *indio_dev = counter->priv;
+ struct cros_ec_sensors_sync_state *const st = iio_priv(indio_dev);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", st->core.param.info.sensor_num);
+}
+
+static ssize_t cros_ec_sync_loc(struct counter_device *counter,
+ void *private, char *buf)
+{
+ struct iio_dev *indio_dev = counter->priv;
+ struct cros_ec_sensors_sync_state *const st = iio_priv(indio_dev);
+
+ return snprintf(buf, PAGE_SIZE, "%s\n", cros_ec_loc[st->core.loc]);
+}
+
+static struct counter_device_ext cros_ec_sync_cnt_ext[] = {
+ {
+ .name = "id",
+ .read = cros_ec_sync_id
+ },
+ {
+ .name = "location",
+ .read = cros_ec_sync_loc
+ },
+};
+
+static int cros_ec_sensors_sync_probe(struct platform_device *pdev)
+{
+ struct cros_ec_sensors_sync_state *state;
+ struct device *dev = &pdev->dev;
+ struct iio_chan_spec *channel;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
+ if (ret)
+ return ret;
+
+ indio_dev->info = &cros_ec_sensors_sync_info;
+ state = iio_priv(indio_dev);
+
+ if (state->core.type != MOTIONSENSE_TYPE_SYNC)
+ return -EINVAL;
+
+ /* Initialize IIO device */
+ channel = state->channels;
+ channel->type = IIO_TIMESTAMP;
+ channel->channel = -1;
+ channel->scan_index = 1;
+ channel->scan_type.sign = 's';
+ channel->scan_type.realbits = 64;
+ channel->scan_type.storagebits = 64;
+
+ indio_dev->channels = state->channels;
+ indio_dev->num_channels = MAX_CHANNELS;
+
+ state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
+
+ ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+ cros_ec_sensors_capture, NULL);
+ if (ret)
+ return ret;
+
+ ret = devm_iio_device_register(dev, indio_dev);
+ if (ret)
+ return ret;
+
+ /* Initialize counter device */
+ state->counter.name = dev_name(&pdev->dev);
+ state->counter.parent = &pdev->dev;
+ state->counter.counts = &cros_ec_sync_counts;
+ state->counter.num_counts = 1;
+ state->counter.priv = indio_dev;
+ state->counter.ops = &cros_ec_sync_cnt_ops;
+ state->counter.ext = cros_ec_sync_cnt_ext;
+ state->counter.num_ext = ARRAY_SIZE(cros_ec_sync_cnt_ext);
+
+ return devm_counter_register(&pdev->dev, &state->counter);
+}
+
+static const struct platform_device_id cros_ec_sensors_sync_ids[] = {
+ { .name = DRV_NAME, },
+ { }
+};
+MODULE_DEVICE_TABLE(platform, cros_ec_sensors_sync_ids);
+
+static struct platform_driver cros_ec_sensors_sync_platform_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ .pm = &cros_ec_sensors_pm_ops,
+ },
+ .probe = cros_ec_sensors_sync_probe,
+ .id_table = cros_ec_sensors_sync_ids,
+};
+module_platform_driver(cros_ec_sensors_sync_platform_driver);
+
+MODULE_DESCRIPTION("ChromeOS EC synchronisation sensor driver");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
index 805652250960..2bf183425eaf 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
@@ -22,6 +22,7 @@
static char *cros_ec_loc[] = {
[MOTIONSENSE_LOC_BASE] = "base",
[MOTIONSENSE_LOC_LID] = "lid",
+ [MOTIONSENSE_LOC_CAMERA] = "camera",
[MOTIONSENSE_LOC_MAX] = "unknown",
};

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 41dccced5026..1c5c2c38af88 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -332,6 +332,9 @@ static void cros_ec_sensors_register(struct cros_ec_dev *ec)
case MOTIONSENSE_TYPE_ACTIVITY:
sensor_cells[id].name = "cros-ec-activity";
break;
+ case MOTIONSENSE_TYPE_SYNC:
+ sensor_cells[id].name = "cros-ec-sync";
+ break;
default:
dev_warn(ec->dev, "unknown type %d\n", resp->info.type);
continue;
diff --git a/include/linux/counter.h b/include/linux/counter.h
index a061cdcdef7c..1198e675306f 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -488,6 +488,7 @@ enum counter_signal_value_type {

enum counter_count_value_type {
COUNTER_COUNT_POSITION = 0,
+ COUNTER_COUNT_TALLY
};

void counter_signal_read_value_set(struct counter_signal_read_value *const val,
--
2.20.1