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

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Mon, 11 Nov 2019 10:24:01 +0100
Enric Balletbo i Serra <enric.balletbo@collabora.com> wrote:

> 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?

It doesn't.  I was rather unclear :(  Suggestion was that we might want
to think about adding one if this pattern is reasonably common.

In meantime devm_add_action_or_reset will give us much the same
with changes only in the driver.

Jonathan

> 
> 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 */  
> >