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Message-ID: <CAPUE2uuEziO=b96ELdsWSQcFfXNweBPYNRPOimNMabYEJmGuYA@mail.gmail.com>
Date: Mon, 13 Apr 2020 12:26:34 -0700
From: Gwendal Grignou <gwendal@...omium.org>
To: Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc: William Breathitt Gray <vilhelm.gray@...il.com>,
Benson Leung <bleung@...omium.org>,
Jonathan Cameron <jic23@...nel.org>,
Guenter Roeck <groeck@...omium.org>,
linux-kernel <linux-kernel@...r.kernel.org>,
linux-iio <linux-iio@...r.kernel.org>
Subject: Re: [PATCH] drivers: counter: Add Cros EC Sync counter
On Mon, Apr 13, 2020 at 8:17 AM Enric Balletbo i Serra
<enric.balletbo@...labora.com> wrote:
>
> Hi Gwendal, William,
>
> Thank you for the patch. Some few comments below.
>
> On 11/4/20 17:00, William Breathitt Gray wrote:
> > On Tue, Apr 07, 2020 at 10:36:55PM -0700, Gwendal Grignou wrote:
> >> When the camera vsync pin is connected to the embedded controller (EC) of
> >> a chromebook, the EC reports a sensor with a counter that increases
> >> at each GPIO rising edge.
> >>
> >> The sensor is presented using the counter subsystem.
> >> In addition, it is also presented via the IIO subsystem with a timestamp,
> >> allowing synchronisation with sensors connected to the same EC, for
> >> image stabilisation or augmented reality applications.
> >>
> >> To enable the counter:
> >> via counter ABI:
> >> echo "rising edge" > counterX/count0/signal_action
> >> via iio ABI
> >> echo 1 > iio:deviceY/en
> >>
> >> To disable the counter:
> >> via counter ABI:
> >> echo "none" > counterX/count0/signal_action
> >> via iio ABI
> >> echo 0 > iio:deviceY/en
> >>
> >> To read the current counter value:
> >> via counter ABI:
> >> cat counterX/count0/count
> >> via iio ABI
> >> cat iio:deviceY/in_count_raw
> >> We can also read the value through the IIO buffer:
> >> echo 1 > iio:deviceY/scan_elements/in_timestamp_en
> >> echo 1 > iio:deviceY/scan_elements/in_count_en
> >> echo 1 > iio:deviceY/buffer/enable
> >>
> >> and each time to counter increase, the following binary blob
> >> will be appended to dev/iio:deviceY:
> >> 000f 0000 0000 0000 dc66 816c 0071 0000
> >> \ <-- padding -> <-- timestamp ---->
> >> count
> >>
> >> Signed-off-by: Gwendal Grignou <gwendal@...omium.org>
> >> ---
> >> An initial version of the driver was presented few month ago at
> >> https://patchwork.kernel.org/patch/11037009/
> >>
> >> drivers/counter/Kconfig | 11 +
> >> drivers/counter/Makefile | 1 +
> >> drivers/counter/cros_ec_sync.c | 342 ++++++++++++++++++
> >> .../cros_ec_sensors/cros_ec_sensors_core.c | 15 +
> >> drivers/platform/chrome/cros_ec_sensorhub.c | 3 +
> >> .../linux/iio/common/cros_ec_sensors_core.h | 4 +-
> >> 6 files changed, 375 insertions(+), 1 deletion(-)
> >> create mode 100644 drivers/counter/cros_ec_sync.c
> >
> > Hi Gwendal,
> >
> > I'm getting some conflicts when I try to merge this patch, so it looks
> > like we're on different bases. Would you be able to rebase on the
> > current testing branch of the IIO tree and resubmit this patch?
> >
>
> I think this patch is based on latest patches from the chrome-platform tree,
> those landed last week and are merged in current 5.7-rc1. I applies cleanly on
> top of current 5.7-rc1 released yesterday.
>
>
> > Thanks,
> >
> > William Breathitt Gray
> >
> >>
> >> diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
> >> index c80fa76bb5311..18fde918ff40b 100644
> >> --- a/drivers/counter/Kconfig
> >> +++ b/drivers/counter/Kconfig
> >> @@ -29,6 +29,17 @@ config 104_QUAD_8
> >> The base port addresses for the devices may be configured via the base
> >> array module parameter.
> >>
> >> +config CROS_EC_SYNC
> >> + tristate "ChromeOS EC Counter driver"
> >> + depends on IIO_CROS_EC_SENSORS_CORE
> >> + help
> >> + Module to handle synchronisation sensor presented by the ChromeOS EC
> >> + Sensor hub.
> >> + Synchronisation sensor sends event to the host when the camera
> >> + take a picture. It allows synchronisation with other MEMS sensor,
> >> + like gyroscope for image statbilization or augmented reality
> >> + application (AR).
> >> +
> >> config STM32_TIMER_CNT
> >> tristate "STM32 Timer encoder counter driver"
> >> depends on MFD_STM32_TIMERS || COMPILE_TEST
> >> diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
> >> index 55142d1f4c436..98378fca50ad6 100644
> >> --- a/drivers/counter/Makefile
> >> +++ b/drivers/counter/Makefile
> >> @@ -6,6 +6,7 @@
> >> obj-$(CONFIG_COUNTER) += counter.o
> >>
> >> obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
> >> +obj-$(CONFIG_CROS_EC_SYNC) += cros_ec_sync.o
> >> obj-$(CONFIG_STM32_TIMER_CNT) += stm32-timer-cnt.o
> >> obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o
> >> obj-$(CONFIG_TI_EQEP) += ti-eqep.o
> >> diff --git a/drivers/counter/cros_ec_sync.c b/drivers/counter/cros_ec_sync.c
> >> new file mode 100644
> >> index 0000000000000..94b3ababab4bd
> >> --- /dev/null
> >> +++ b/drivers/counter/cros_ec_sync.c
> >> @@ -0,0 +1,342 @@
> >> +// SPDX-License-Identifier: GPL-2.0
>
> Following other ChromeOS drivers this should be GPL-2.0-only
>
> >> +/*
> >> + * Driver for synchronisation sensor behind CrOS EC.
> >> + *
> >> + * Copyright 2020 Google, Inc
>
> Copyright 2020 Google LLC.
Fixed in v2.
>
> >> + *
> >> + * This software is licensed under the terms of the GNU General Public
> >> + * License version 2, as published by the Free Software Foundation, and
> >> + * may be copied, distributed, and modified under those terms.
> >> + *
> >> + * This program is distributed in the hope that it will be useful,
> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> >> + * GNU General Public License for more details.
> >> + *
>
> Remove the license boiler plate it is redundand and already specified in the
> SPDX license tag.
Fixed in v2.
>
> >> + * This driver uses the cros-ec interface to communicate with the Chrome OS
> >> + * EC about counter sensors. Counters are presented through
> >> + * iio sysfs.
> >> + */
> >> +
> >> +#include <linux/counter.h>
> >> +#include <linux/device.h>
> >> +#include <linux/iio/buffer.h>
> >> +#include <linux/iio/common/cros_ec_sensors_core.h>
> >> +#include <linux/iio/iio.h>
> >> +#include <linux/kernel.h>
> >> +#include <linux/module.h>
> >> +#include <linux/platform_data/cros_ec_commands.h>
> >> +#include <linux/platform_data/cros_ec_proto.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/slab.h>
> >> +
> >> +/*
> >> + * One channel for counter, the other for timestamp.
> >> + */
> >> +#define MAX_CHANNELS (1 + 1)
> >> +
> >> +/**
> >> + * struct cros_ec_sync_state - device structure
> >> + *
> >> + * @core: common structure for all cros_ec sensor.
> >> + * Must be at the beggining.
> >> + * @channels: presented iio channels(2).
> >> + * @counter: counter data structure.
> >> + */
> >> +struct cros_ec_sync_state {
> >> + struct cros_ec_sensors_core_state core;
> >> + struct iio_chan_spec channels[MAX_CHANNELS];
> >> + struct counter_device counter;
> >> +};
> >> +
> >> +/**
> >> + * cros_ec_sync_get_enable() - Check if the counter is enabled.
> >> + *
> >> + * @st: core cros_ec sensor
> >> + * @val: status: 0: disabled, 1 enabled.
> >> + *
> >> + * Return: 0 on success, -errno on failure.
> >> + */
> >> +static int cros_ec_sync_get_enable(struct cros_ec_sensors_core_state *st,
> >> + int *val)
> >> +{
> >> + int ret;
> >> +
> >> + mutex_lock(&st->cmd_lock);
> >> + st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
> >> + st->param.sensor_odr.data = EC_MOTION_SENSE_NO_VALUE;
> >> +
> >> + ret = cros_ec_motion_send_host_cmd(st, 0);
> >> + mutex_unlock(&st->cmd_lock);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + *val = !!st->resp->sensor_odr.ret;
> >> + return 0;
> >> +}
> >> +
> >> +/**
> >> + * cros_ec_sync_set_enable() - Allow the counter to count.
> >> + *
> >> + * When enable, the counter will increase for each VSYNC rising edge
> >> + * and will produce an event in the iio buffer, if enabled.
> >> + *
> >> + * @st: core cros_ec sensor
> >> + * @val: 0: disable, 1 enable.
> >> + *
> >> + * Return: 0 on success, -errno on failure.
> >> + */
> >> +static int cros_ec_sync_set_enable(struct cros_ec_sensors_core_state *st,
> >> + int val)
> >> +{
> >> + int ret;
> >> +
> >> + mutex_lock(&st->cmd_lock);
> >> + st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
> >> + st->param.sensor_odr.data = val;
> >> + st->param.sensor_odr.roundup = 1;
> >> +
> >> + ret = cros_ec_motion_send_host_cmd(st, 0);
> >> + mutex_unlock(&st->cmd_lock);
> >> + return ret;
> >> +}
> >> +
> >> +static int cros_ec_sync_iio_read(struct iio_dev *indio_dev,
> >> + struct iio_chan_spec const *chan,
> >> + int *val, int *val2, long mask)
> >> +{
> >> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
> >> + u16 data;
> >> + int ret;
> >> + int idx = chan->scan_index;
> >> +
> >> + switch (mask) {
> >> + case IIO_CHAN_INFO_RAW:
> >> + mutex_lock(&st->cmd_lock);
>
> I think you need to review the mutex locking logic.
>
> >> + ret = cros_ec_sensors_read_cmd(indio_dev, 1 << idx, &data);
> >> + mutex_unlock(&st->cmd_lock);
> >> + if (ret < 0)
> >> + break;
> >> + ret = IIO_VAL_INT;
> >> + *val = data;
> >> + break;
> >> + case IIO_CHAN_INFO_ENABLE:
> >> + ret = cros_ec_sync_get_enable(st, val);
> >> + if (ret < 0)
> >> + break;
> >> + ret = IIO_VAL_INT;
> >> + break;
> >> + default:
> >> + ret = -EINVAL;
> >> + break;
> >> + }
> >> + mutex_unlock(&st->cmd_lock);
>
> Where did you lock the mutex?
Fixed in v2. That line is an error.
>
> >> + return ret;
> >> +}
> >> +
> >> +static int cros_ec_sync_iio_write(struct iio_dev *indio_dev,
> >> + struct iio_chan_spec const *chan,
> >> + int val, int val2, long mask)
> >> +{
> >> + struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
> >> +
> >> + switch (mask) {
> >> + case IIO_CHAN_INFO_ENABLE:
> >> + if (val < 0 || val > 1)
> >> + return -EINVAL;
> >> +
> >> + return cros_ec_sync_set_enable(st, val);
> >> +
> >> + default:
> >> + return -EINVAL;
> >> + }
> >> +}
> >> +
> >> +static const struct iio_info cros_ec_sync_info = {
> >> + .read_raw = &cros_ec_sync_iio_read,
> >> + .write_raw = &cros_ec_sync_iio_write,
> >> +};
> >> +
> >> +/* The counter can only increase, so only one function present. */
> >> +static enum counter_count_function cros_ec_sync_functions[] = {
> >> + COUNTER_COUNT_FUNCTION_INCREASE,
> >> +};
> >> +
> >> +/* 2 synapse actions allowed: count for each rising edge, or not. */
> >> +static enum counter_synapse_action cros_ec_sync_synapse_actions[] = {
> >> + COUNTER_SYNAPSE_ACTION_NONE,
> >> + COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> >> +};
> >> +
> >> +static int cros_ec_sync_read_count(struct counter_device *counter,
> >> + struct counter_count *count,
> >> + unsigned long *val)
> >> +{
> >> + struct cros_ec_sensors_core_state *st = counter->priv;
> >> + u16 raw;
> >> + int ret;
> >> +
> >> + mutex_lock(&st->cmd_lock);
> >> + ret = cros_ec_sensors_read_cmd(iio_priv_to_dev(st), 1, &raw);
> >> + mutex_unlock(&st->cmd_lock);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + *val = raw;
> >> + return 0;
> >> +}
> >> +
> >> +static int cros_ec_sync_function_get(struct counter_device *counter,
> >> + struct counter_count *count,
> >> + size_t *function)
> >> +{
> >> + *function = 0;
> >> + return 0;
> >> +}
> >> +
> >> +static int cros_ec_sync_action_get(struct counter_device *counter,
> >> + struct counter_count *count,
> >> + struct counter_synapse *synapse,
> >> + size_t *action)
> >> +{
> >> + struct cros_ec_sensors_core_state *st = counter->priv;
> >> + int ret;
> >> + int raw;
> >> +
> >> + ret = cros_ec_sync_get_enable(st, &raw);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + *action = !!raw;
> >> + return 0;
> >> +}
> >> +
> >> +static int cros_ec_sync_action_set(struct counter_device *counter,
> >> + struct counter_count *count,
> >> + struct counter_synapse *synapse,
> >> + size_t action)
> >> +{
> >> + struct cros_ec_sensors_core_state *st = counter->priv;
> >> +
> >> + return cros_ec_sync_set_enable(st, action);
> >> +}
> >> +
> >> +static const struct counter_ops cros_ec_sync_ops = {
> >> + .count_read = cros_ec_sync_read_count,
> >> + .function_get = cros_ec_sync_function_get,
> >> + .action_get = cros_ec_sync_action_get,
> >> + .action_set = cros_ec_sync_action_set,
> >> +};
> >> +
> >> +static struct counter_signal cros_ec_sync_signals[] = {
> >> + {
> >> + .id = 0,
> >> + .name = "vsync"
> >> + }
> >> +};
> >> +
> >> +static struct counter_synapse cros_ec_sync_synapses[] = {
> >> + {
> >> + .actions_list = cros_ec_sync_synapse_actions,
> >> + .num_actions = ARRAY_SIZE(cros_ec_sync_synapse_actions),
> >> + .signal = cros_ec_sync_signals
> >> + }
> >> +};
> >> +
> >> +static struct counter_count cros_ec_sync_counts[] = {
> >> + {
> >> + .id = 0,
> >> + .name = "vsync",
> >> + .functions_list = cros_ec_sync_functions,
> >> + .num_functions = ARRAY_SIZE(cros_ec_sync_functions),
> >> + .synapses = cros_ec_sync_synapses,
> >> + .num_synapses = ARRAY_SIZE(cros_ec_sync_synapses),
> >> + }
> >> +};
> >> +
> >> +static int cros_ec_sync_probe(struct platform_device *pdev)
> >> +{
> >> + struct device *dev = &pdev->dev;
> >> + struct iio_dev *indio_dev;
> >> + struct cros_ec_sync_state *state;
> >> + struct iio_chan_spec *channel;
> >> + 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,
> >> + cros_ec_sensors_capture,
> >> + cros_ec_sensors_push_data);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + indio_dev->info = &cros_ec_sync_info;
> >> + state = iio_priv(indio_dev);
> >> +
> >> + /* Initialize IIO device */
> >> + channel = state->channels;
> >> +
> >> + /* Counter channel */
> >> + channel->type = IIO_COUNT;
> >> + channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> >> + channel->info_mask_shared_by_all = BIT(IIO_CHAN_INFO_ENABLE);
> >> + channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
> >> + channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
> >> + channel->scan_type.shift = 0;
> >> + channel->scan_index = 0;
> >> + channel->ext_info = cros_ec_sensors_limited_info;
> >> + channel->scan_type.sign = 'u';
> >> +
> >> + /* Timestamp channel */
> >> + channel++;
> >> + 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;
> >> +
> >> + /* Initialize Counter device */
> >> + state->counter.name = dev_name(&pdev->dev);
> >> + state->counter.parent = &pdev->dev;
> >> + state->counter.ops = &cros_ec_sync_ops;
> >> + state->counter.counts = cros_ec_sync_counts;
> >> + state->counter.num_counts = ARRAY_SIZE(cros_ec_sync_counts);
> >> + state->counter.signals = cros_ec_sync_signals;
> >> + state->counter.num_signals = ARRAY_SIZE(cros_ec_sync_signals);
> >> + state->counter.priv = state;
> >> +
> >> + ret = devm_iio_device_register(dev, indio_dev);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + return devm_counter_register(dev, &state->counter);
> >> +}
> >> +
> >> +static const struct platform_device_id cros_ec_sync_ids[] = {
> >> + {
> >> + .name = "cros-ec-sync",
> >> + },
> >> + { /* sentinel */ }
> >> +};
> >> +MODULE_DEVICE_TABLE(platform, cros_ec_sync_ids);
> >> +
> >> +static struct platform_driver cros_ec_sync_platform_driver = {
> >> + .driver = {
> >> + .name = "cros-ec-sync",
> >> + },
> >> + .probe = cros_ec_sync_probe,
> >> + .id_table = cros_ec_sync_ids,
> >> +};
> >> +module_platform_driver(cros_ec_sync_platform_driver);
> >> +
> >> +MODULE_AUTHOR("Gwendal Grignou <gwendal@...omium.org>");
> >> +MODULE_DESCRIPTION("ChromeOS EC synchronisation sensor driver");
> >> +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 c831915ca7e56..3a15094616710 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
> >> @@ -31,6 +31,7 @@
> >> static char *cros_ec_loc[] = {
> >> [MOTIONSENSE_LOC_BASE] = "base",
> >> [MOTIONSENSE_LOC_LID] = "lid",
> >> + [MOTIONSENSE_LOC_CAMERA] = "camera",
> >> [MOTIONSENSE_LOC_MAX] = "unknown",
> >> };
> >>
> >> @@ -467,6 +468,20 @@ const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[] = {
> >> };
> >> EXPORT_SYMBOL_GPL(cros_ec_sensors_ext_info);
> >>
> >> +const struct iio_chan_spec_ext_info cros_ec_sensors_limited_info[] = {
> >> + {
> >> + .name = "id",
> >> + .shared = IIO_SHARED_BY_ALL,
> >> + .read = cros_ec_sensors_id
> >> + },
> >> + {
> >> + .name = "location",
> >> + .shared = IIO_SHARED_BY_ALL,
> >> + .read = cros_ec_sensors_loc
> >> + },
> >> + { },
> >> +};
> >> +EXPORT_SYMBOL_GPL(cros_ec_sensors_limited_info);
> >> /**
> >> * cros_ec_sensors_idx_to_reg - convert index into offset in shared memory
> >> * @st: pointer to state information for device
> >> diff --git a/drivers/platform/chrome/cros_ec_sensorhub.c b/drivers/platform/chrome/cros_ec_sensorhub.c
> >> index b7f2c00db5e1e..e4ae0868d1e06 100644
> >> --- a/drivers/platform/chrome/cros_ec_sensorhub.c
> >> +++ b/drivers/platform/chrome/cros_ec_sensorhub.c
> >> @@ -106,6 +106,9 @@ static int cros_ec_sensorhub_register(struct device *dev,
> >> case MOTIONSENSE_TYPE_ACTIVITY:
> >> name = "cros-ec-activity";
> >> break;
> >> + case MOTIONSENSE_TYPE_SYNC:
> >> + name = "cros-ec-sync";
> >> + break;
> >> default:
> >> dev_warn(dev, "unknown type %d\n",
> >> sensorhub->resp->info.type);
> >> diff --git a/include/linux/iio/common/cros_ec_sensors_core.h b/include/linux/iio/common/cros_ec_sensors_core.h
> >> index 7bc961defa87e..e416b28cf24c7 100644
> >> --- a/include/linux/iio/common/cros_ec_sensors_core.h
> >> +++ b/include/linux/iio/common/cros_ec_sensors_core.h
> >> @@ -114,7 +114,9 @@ int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
> >> struct iio_chan_spec const *chan,
> >> int val, int val2, long mask);
> >>
> >> -/* List of extended channel specification for all sensors */
> >> +/* List of extended channel specification for all sensors. */
> >> +extern const struct iio_chan_spec_ext_info cros_ec_sensors_limited_info[];
> >> +/* Add calibration to set above. */
>
> This change is unrelated to this patch.
It is needed because the sync sensor does not need calibration. It is
used when setting the ext_info of the sync channel.
>
> >> extern const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[];
> >> extern const struct attribute *cros_ec_sensor_fifo_attributes[];
> >>
> >> --
> >> 2.26.0.110.g2183baf09c-goog
> >>
>
> Thanks,
> Enric
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