Re: [PATCH v4 02/17] platform: cros_ec: Add cros_ec_sensor_hub driver

Enric Balletbo i Serra
2019-11-11T09:24:08Z

Hi,

On 10/11/19 13:10, Jonathan Cameron wrote:
> On Tue, 5 Nov 2019 14:26:37 -0800
> Gwendal Grignou <gwendal@chromium.org> wrote:
>
>> Similar to HID sensor stack, the new driver sits between cros_ec_dev
>> and the iio device drivers:
>>
>> EC based iio device topology would be:
>> iio:device1 ->
>> ...0/0000:00:1f.0/PNP0C09:00/GOOG0004:00/cros-ec-dev.6.auto/
>> cros-ec-sensorhub.7.auto/
>> cros-ec-accel.15.auto/
>> iio:device1
>>
>> It will be expanded to control EC sensor FIFO.
>>
>> Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
>
> Random suggestion for a possible cleanup...
>
> Would a devm_platform_device_register_data make sense? Drops a
> fair bit of boilerplate in here. If its not a common enough
> pattern, could use the devm_add_action_or_reset route
> to do the same thing.
>

I don't think devm_platform_device_register exists, exist?

After solving the changes pointed by Jonathan the patch looks good to me.

> I would suggest this as a possible future element, but you
> have some other issues around that area that this would cleanup
> nicely for you. See inline.
>
>
> Thanks,
>
> Jonathan
>
>
>
>> ---
>> Changes in v4:
>> - Use platform_device_register_data in children registration.
>> - Free registered pdev children at remove time.
>> - Remove useless includes
>> - Check patch with --strict option
>> Use sizeof(*obj) instead of sizeof(struct ...obj)
>> Alignement
>> - Describe cros_ec_sensorhub in kernel-doc format.
>> Changes in v3:
>> - Fix doxygen comments
>> - Fix use of ret |=
>> - Remove unncessary goto.
>> Changes in v2:
>> - Remove unerelated changes.
>> - Fix spelling.
>> - Use !x instead of x == NULL
>> - Use platform_ API directly to register IIO sensors from
>> cros_ec_sensorhub.
>>
>> drivers/iio/common/cros_ec_sensors/Kconfig | 2 +-
>> drivers/platform/chrome/Kconfig | 12 +
>> drivers/platform/chrome/Makefile | 1 +
>> drivers/platform/chrome/cros_ec_sensorhub.c | 223 ++++++++++++++++++
>> .../linux/platform_data/cros_ec_sensorhub.h | 33 +++
>> 5 files changed, 270 insertions(+), 1 deletion(-)
>> create mode 100644 drivers/platform/chrome/cros_ec_sensorhub.c
>> create mode 100644 include/linux/platform_data/cros_ec_sensorhub.h
>>
>> diff --git a/drivers/iio/common/cros_ec_sensors/Kconfig b/drivers/iio/common/cros_ec_sensors/Kconfig
>> index cdbb29cfb907..fefad9572790 100644
>> --- a/drivers/iio/common/cros_ec_sensors/Kconfig
>> +++ b/drivers/iio/common/cros_ec_sensors/Kconfig
>> @@ -4,7 +4,7 @@
>> #
>> config IIO_CROS_EC_SENSORS_CORE
>> tristate "ChromeOS EC Sensors Core"
>> - depends on SYSFS && CROS_EC
>> + depends on SYSFS && CROS_EC_SENSORHUB
>> select IIO_BUFFER
>> select IIO_TRIGGERED_BUFFER
>> help
>> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
>> index ee5f08ea57b6..56a25317a6be 100644
>> --- a/drivers/platform/chrome/Kconfig
>> +++ b/drivers/platform/chrome/Kconfig
>> @@ -190,6 +190,18 @@ config CROS_EC_DEBUGFS
>> To compile this driver as a module, choose M here: the
>> module will be called cros_ec_debugfs.
>>
>> +config CROS_EC_SENSORHUB
>> + tristate "ChromeOS EC MEMS Sensor Hub"
>> + depends on CROS_EC && IIO
>
> Could relax the IIO dependency I think... Get you more build coverage.
>
>> + help
>> + Allow loading IIO sensors. This driver is loaded by MFD and will in
>> + turn query the EC and register the sensors.
>> + It also spreads the sensor data coming from the EC to the IIO sensor
>> + object.
>> +
>> + To compile this driver as a module, choose M here: the
>> + module will be called cros_ec_sensorhub.
>> +
>> config CROS_EC_SYSFS
>> tristate "ChromeOS EC control and information through sysfs"
>> depends on MFD_CROS_EC_DEV && SYSFS
>> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
>> index 477ec3d1d1c9..a164c40dc099 100644
>> --- a/drivers/platform/chrome/Makefile
>> +++ b/drivers/platform/chrome/Makefile
>> @@ -17,6 +17,7 @@ obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o cros_ec_trace.o
>> obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
>> obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_chardev.o
>> obj-$(CONFIG_CROS_EC_LIGHTBAR) += cros_ec_lightbar.o
>> +obj-$(CONFIG_CROS_EC_SENSORHUB) += cros_ec_sensorhub.o
>> obj-$(CONFIG_CROS_EC_VBC) += cros_ec_vbc.o
>> obj-$(CONFIG_CROS_EC_DEBUGFS) += cros_ec_debugfs.o
>> obj-$(CONFIG_CROS_EC_SYSFS) += cros_ec_sysfs.o
>> diff --git a/drivers/platform/chrome/cros_ec_sensorhub.c b/drivers/platform/chrome/cros_ec_sensorhub.c
>> new file mode 100644
>> index 000000000000..6a0aa84cf092
>> --- /dev/null
>> +++ b/drivers/platform/chrome/cros_ec_sensorhub.c
>> @@ -0,0 +1,223 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * SensorHub: driver that discover sensors behind
>> + * a ChromeOS Embedded controller.
>> + *
>> + * Copyright 2019 Google LLC
>> + */
>> +
>> +#include <linux/init.h>
>> +#include <linux/device.h>
>> +#include <linux/module.h>
>> +#include <linux/mfd/cros_ec.h>
>> +#include <linux/platform_data/cros_ec_commands.h>
>> +#include <linux/platform_data/cros_ec_proto.h>
>> +#include <linux/platform_data/cros_ec_sensorhub.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/slab.h>
>> +
>> +#define DRV_NAME "cros-ec-sensorhub"
>> +
>> +static struct platform_device *cros_ec_sensorhub_allocate_single_sensor(
>> + struct device *parent,
>> + char *sensor_name,
>> + int sensor_num)
>> +{
>> + struct cros_ec_sensor_platform sensor_platforms = {
>> + .sensor_num = sensor_num,
>> + };
>> +
>> + return platform_device_register_data(parent, sensor_name,
>> + PLATFORM_DEVID_AUTO,
>> + &sensor_platforms,
>> + sizeof(sensor_platforms));
>> +}
>> +
>> +static int cros_ec_sensorhub_register(struct device *dev,
>> + struct cros_ec_sensorhub *sensorhub)
>
> As noted below, I'd be happier if this function did it's own cleanup on
> error rather than leaving that for the caller.
>
>> +{
>> + int ret, i, id, sensor_num;
>> + struct cros_ec_dev *ec = sensorhub->ec;
>> + int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
>> + struct ec_params_motion_sense *params;
>> + struct ec_response_motion_sense *resp;
>> + struct cros_ec_command *msg;
>> + struct platform_device *pdev;
>> + char *name;
>> +
>> + sensor_num = cros_ec_get_sensor_count(ec);
>> + if (sensor_num < 0) {
>> + dev_err(dev,
>> + "Unable to retrieve sensor information (err:%d)\n",
>> + sensor_num);
>> + return sensor_num;
>> + }
>> +
>> + if (sensor_num == 0) {
>> + dev_err(dev, "Zero sensors reported.\n");
>> + return -EINVAL;
>> + }
>> +
>> + /* Prepare a message to send INFO command to each sensor. */
>> + msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*resp)),
>> + GFP_KERNEL);
>> + if (!msg)
>> + return -ENOMEM;
>> +
>> + msg->version = 1;
>> + msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
>> + msg->outsize = sizeof(*params);
>> + msg->insize = sizeof(*resp);
>> + params = (struct ec_params_motion_sense *)msg->data;
>> + resp = (struct ec_response_motion_sense *)msg->data;
>> +
>> + id = 0;
>> + for (i = 0; i < sensor_num; i++) {
>> + params->cmd = MOTIONSENSE_CMD_INFO;
>> + params->info.sensor_num = i;
>> + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
>> + if (ret < 0) {
>> + dev_warn(dev, "no info for EC sensor %d : %d/%d\n",
>> + i, ret, msg->result);
>> + continue;
>> + }
>> + switch (resp->info.type) {
>> + case MOTIONSENSE_TYPE_ACCEL:
>> + name = "cros-ec-accel";
>> + break;
>> + case MOTIONSENSE_TYPE_BARO:
>> + name = "cros-ec-baro";
>> + break;
>> + case MOTIONSENSE_TYPE_GYRO:
>> + name = "cros-ec-gyro";
>> + break;
>> + case MOTIONSENSE_TYPE_MAG:
>> + name = "cros-ec-mag";
>> + break;
>> + case MOTIONSENSE_TYPE_PROX:
>> + name = "cros-ec-prox";
>> + break;
>> + case MOTIONSENSE_TYPE_LIGHT:
>> + name = "cros-ec-light";
>> + break;
>> + case MOTIONSENSE_TYPE_ACTIVITY:
>> + name = "cros-ec-activity";
>> + break;
>> + default:
>> + dev_warn(dev, "unknown type %d\n", resp->info.type);
>> + continue;
>> + }
>> + pdev = cros_ec_sensorhub_allocate_single_sensor(dev, name, i);
>> + if (IS_ERR(pdev)) {
>> + ret = IS_ERR(pdev);
>> + goto error;
>> + }
>> + sensorhub->sensor_pdev[id++] = pdev;
>> + sensor_type[resp->info.type]++;
>> + }
>> +
>> + if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
>> + ec->has_kb_wake_angle = true;
>> +
>> + if (cros_ec_check_features(ec,
>> + EC_FEATURE_REFINED_TABLET_MODE_HYSTERESIS)) {
>> + pdev = cros_ec_sensorhub_allocate_single_sensor(dev,
>> + "cros-ec-lid-angle", 0);
>> + if (IS_ERR(pdev)) {
>> + ret = IS_ERR(pdev);
>> + goto error;
>> + }
>> + sensorhub->sensor_pdev[id++] = pdev;
>> + }
>> +
>> +error:
>> + kfree(msg);
>> + return ret;
>> +}
>> +
>> +static int cros_ec_sensorhub_probe(struct platform_device *sensorhub_pdev)
>> +{
>> + struct device *dev = &sensorhub_pdev->dev;
>> + struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
>> + int ret, i;
>> + struct platform_device *pdev;
>> + struct cros_ec_sensorhub *data =
>> + kzalloc(sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
>
> Do we free this anywhere? Could just use devm_kzalloc to do it
> automatically.
>
>> +
>> + if (!data)
>> + return -ENOMEM;
>> +
>> + data->ec = ec;
>> + dev_set_drvdata(dev, data);
>> +
>> + /* Check whether this EC is a sensor hub. */
>> + if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE)) {
>> + ret = cros_ec_sensorhub_register(dev, data);
>> + if (ret) {
>> + dev_err(dev, "Register failed %d\n", ret);
>> + goto unregister_sensors;
>
> From a code structure point of view, cros_ec_sensorhub_register
> should have done any cleanup necessary if it returns an error. Hence
> we should be fine doing a direct return here (other than the memory
> not being freed comment above.
>
> This may seem an overly restrictive request, but that sort of rule
> makes code a lot easier to review as we don't have to go look
> to see where the error handling occurs and check for multiple paths
> etc. Note that if you use managed functions then there is no
> cleanup to do anyway ;)
>
>> + }
>> + } else {
>> + /*
>> + * If the device has sensors but does not claim to
>> + * be a sensor hub, we are in legacy mode.
>> + */
>> + for (i = 0; i < 2; i++) {
>> + pdev = cros_ec_sensorhub_allocate_single_sensor(dev,
>> + "cros-ec-accel-legacy", i);
>> + if (IS_ERR(pdev)) {
>> + ret = IS_ERR(pdev);
>> + dev_err(dev, "Legacy %d failed %d\n", i, ret);
>> + goto unregister_sensors;
>> + } else {
>> + data->sensor_pdev[i] = pdev;
>> + }
>> + }
>> + }
>> +
>> + return 0;
>> +
>> +unregister_sensors:
>> + /*
>> + * Given the probe has failed, we need to unregister all the sensors,
>> + * not jutst the one that did not work: this device will be
>> + * de-allocated.
>> + */
>> + for (i = 0; i < CROS_EC_SENSOR_PDEV_MAX; i++) {
>> + pdev = data->sensor_pdev[i];
>> + if (pdev)
>> + platform_device_unregister(pdev);
>> + }
>> + return ret;
>> +}
>> +
>> +static int cros_ec_sensorhub_remove(struct platform_device *sensorhub_pdev)
>> +{
>> + struct cros_ec_sensorhub *sensorhub =
>> + platform_get_drvdata(sensorhub_pdev);
>> + struct platform_device *pdev;
>> + int i;
>> +
>> + for (i = 0; i < CROS_EC_SENSOR_PDEV_MAX; i++) {
>> + pdev = sensorhub->sensor_pdev[i];
>> + if (pdev)
>> + platform_device_unregister(pdev);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static struct platform_driver cros_ec_sensorhub_driver = {
>> + .driver = {
>> + .name = DRV_NAME,
>> + },
>> + .probe = cros_ec_sensorhub_probe,
>> + .remove = cros_ec_sensorhub_remove,
>> +};
>> +
>> +module_platform_driver(cros_ec_sensorhub_driver);
>> +
>> +MODULE_ALIAS("platform:" DRV_NAME);
>> +MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
>> +MODULE_DESCRIPTION("ChromeOS EC MEMS Sensor Hub Driver");
>> +MODULE_LICENSE("GPL");
>> diff --git a/include/linux/platform_data/cros_ec_sensorhub.h b/include/linux/platform_data/cros_ec_sensorhub.h
>> new file mode 100644
>> index 000000000000..da0ba1d201e4
>> --- /dev/null
>> +++ b/include/linux/platform_data/cros_ec_sensorhub.h
>> @@ -0,0 +1,33 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * cros_ec_sensorhub- Chrome OS EC MEMS Sensor Hub driver.
>> + *
>> + * Copyright (C) 2019 Google, Inc
>> + */
>> +
>> +#ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
>> +#define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
>> +
>> +#include <linux/platform_data/cros_ec_commands.h>
>> +
>> +/* Maximal number of sensors supported by the EC. */
>> +#define CROS_EC_SENSOR_MAX 16
>> +
>> +/*
>> + * Maximal number of sensors supported by the hub:
>> + * We add one for the lid angle inclinometer sensor.
>> + */
>> +#define CROS_EC_SENSOR_PDEV_MAX (CROS_EC_SENSOR_MAX + 1)
>> +
>> +/**
>> + * struct cros_ec_sensorhub - Sensor Hub device data.
>> + *
>> + * @ec: Embedded Controller where the hub is located.
>> + * @sensor_pdev: Array of platform_device, one per sensor.
>> + */
>> +struct cros_ec_sensorhub {
>> + struct cros_ec_dev *ec;
>> + struct platform_device *sensor_pdev[CROS_EC_SENSOR_PDEV_MAX];
>> +};
>> +
>> +#endif /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */
>