Re: [PATCH v2 1/4] HID: hid-sensor-custom: Add custom sensor iio support

Ye, Xiang
2020-11-24T10:28:11Z

On Sat, Nov 21, 2020 at 05:21:27PM +0000, Jonathan Cameron wrote:
> On Thu, 19 Nov 2020 18:03:28 +0800
> Ye Xiang <xiang.ye@intel.com> wrote:
>
> > Currently custom sensors properties are not decoded and it is up to
> > user space to interpret.
> >
> > Some manufacturers already standardized the meaning of some custom sensors.
> > They can be presented as a proper IIO sensor. We can identify these sensors
> > based on manufacturer and serial number property in the report.
> >
> > This change is identifying hinge sensor when the manufacturer is "INTEL".
> > This creates a platform device so that a sensor driver can be loaded to
> > process these sensors.
> >
> > Signed-off-by: Ye Xiang <xiang.ye@intel.com>
>
> Hi Ye Xiang,
>
> Various comments inline.
>
> Thanks,
>
> Jonathan
Thanks for review and comments

Xiang
>
> > ---
> > drivers/hid/hid-sensor-custom.c | 170 ++++++++++++++++++++++++++++++++
> > include/linux/hid-sensor-ids.h | 39 ++++++++
> > 2 files changed, 209 insertions(+)
> >
> > diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
> > index 4d25577a8573..bb96d9c09daf 100644
> > --- a/drivers/hid/hid-sensor-custom.c
> > +++ b/drivers/hid/hid-sensor-custom.c
> > @@ -4,6 +4,7 @@
> > * Copyright (c) 2015, Intel Corporation.
> > */
> >
> > +#include <linux/ctype.h>
> > #include <linux/kernel.h>
> > #include <linux/module.h>
> > #include <linux/init.h>
> > @@ -21,6 +22,7 @@
> > #define HID_CUSTOM_TOTAL_ATTRS (HID_CUSTOM_MAX_CORE_ATTRS + 1)
> > #define HID_CUSTOM_FIFO_SIZE 4096
> > #define HID_CUSTOM_MAX_FEATURE_BYTES 64
> > +#define HID_SENSOR_USAGE_LENGTH (4 + 1)
> >
> > struct hid_sensor_custom_field {
> > int report_id;
> > @@ -50,6 +52,8 @@ struct hid_sensor_custom {
> > struct kfifo data_fifo;
> > unsigned long misc_opened;
> > wait_queue_head_t wait;
> > + struct platform_device *custom_pdev;
> > + bool custom_pdev_exposed;
> > };
> >
> > /* Header for each sample to user space via dev interface */
> > @@ -746,11 +750,159 @@ static void hid_sensor_custom_dev_if_remove(struct hid_sensor_custom
> >
> > }
> >
> > +/*
> > + * use sensors luid which is defined in FW, such as ISH,
> > + * to identify sensor.
> > + */
>
> const?
yes, it shoud be const.
>
> > +static char *known_sensor_luid[] = { "020B000000000000" };
> > +
> > +static int get_luid_table_index(unsigned char *usage_str)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < ARRAY_SIZE(known_sensor_luid); i++) {
> > + if (!strncmp(usage_str, known_sensor_luid[i],
> > + strlen(known_sensor_luid[i])))
> > + return i;
> > + }
> > +
> > + return -1;
> > +}
> > +
> > +static int get_known_custom_sensor_index(struct hid_sensor_hub_device *hsdev)
> > +{
> > + struct hid_sensor_hub_attribute_info sensor_manufacturer = { 0 };
> > + struct hid_sensor_hub_attribute_info sensor_luid_info = { 0 };
> > + int report_size;
> > + int ret;
> > + u16 *w_buf;
> > + int w_buf_len;
> > + char *buf;
> > + int buf_len;
> > + int i;
> > + int index;
> > +
> > + w_buf_len = sizeof(u16) * HID_CUSTOM_MAX_FEATURE_BYTES;
> > + buf_len = sizeof(char) * HID_CUSTOM_MAX_FEATURE_BYTES;
> Given these are compile time values, these two could just go
> directly above with no loss of readability.
>
> int w_buf_len = siezof(u16)...
got it
>
> > + w_buf = kzalloc(w_buf_len, GFP_KERNEL);
> > + if (!w_buf)
> > + return -1;
>
> Better to return meaningful error values and if the error
> isn't just 'didn't find it' - probably -ENODEV and we should check that
> was the cause of the problem at the call site for this function.
> If it was a memory allocation error we should quit out instead of trying
> something else.
agree, will use -ENODEV, when "didn't find it"; use -ENOMEM when alloc failed.
>
> > +
> > + buf = kzalloc(buf_len, GFP_KERNEL);
> > + if (!buf) {
> > + kfree(w_buf);
> Given we have error handling for this below, better to be consistent
> and use a goto + an additional error label for htis case.
ok, will add additional error label to make it consistent.
>
> > + return -1;
> > + }
> > +
> > + /* get manufacturer info */
> > + ret = sensor_hub_input_get_attribute_info(
> > + hsdev, HID_FEATURE_REPORT, hsdev->usage,
> > + HID_USAGE_SENSOR_PROP_MANUFACTURER, &sensor_manufacturer);
> > + if (ret < 0)
>
> From HID point of view, is that allowed to fail? Probably best to add
> a comment to say if it is or isn't.
> I'd like to be able to read this code and know which of these error paths
> just means we don't have a matching sensor.
This is error checking of sensor_hub_input_get_attribute_info. If error, will
return the return value of sensor_hub_input_get_attribute_info in next version
patch.

>
> > + goto err_out;
> > +
> > + report_size =
> > + sensor_hub_get_feature(hsdev, sensor_manufacturer.report_id,
> > + sensor_manufacturer.index, w_buf_len,
> > + w_buf);
> > + if (report_size <= 0) {
> > + hid_err(hsdev->hdev,
> > + "Failed to get sensor manufacturer info %d\n",
> > + report_size);
> > + goto err_out;
> > + }
> > +
> > + /* convert from wide char to char */
> > + for (i = 0; i < buf_len - 1 && w_buf[i]; i++)
> > + buf[i] = (char)w_buf[i];
> > +
> > + /* ensure it's ISH sensor */
> > + if (strncmp(buf, "INTEL", strlen("INTEL")))
> > + goto err_out;
> > +
> > + memset(w_buf, 0, w_buf_len);
> > + memset(buf, 0, buf_len);
> > +
> > + /* get real usage id */
> > + ret = sensor_hub_input_get_attribute_info(
> > + hsdev, HID_FEATURE_REPORT, hsdev->usage,
> > + HID_USAGE_SENSOR_PROP_SERIAL_NUM, &sensor_luid_info);
> > + if (ret < 0)
> > + goto err_out;
> > +
> > + report_size = sensor_hub_get_feature(hsdev, sensor_luid_info.report_id,
> > + sensor_luid_info.index, w_buf_len,
> > + w_buf);
> > + if (report_size <= 0) {
> > + hid_err(hsdev->hdev, "Failed to get real usage info %d\n",
> > + report_size);
> > + goto err_out;
> > + }
> > +
> > + /* convert from wide char to char */
> > + for (i = 0; i < buf_len - 1 && w_buf[i]; i++)
> > + buf[i] = (char)w_buf[i];
> > +
> > + if (strlen(buf) != strlen(known_sensor_luid[0]) + 5) {
> > + hid_err(hsdev->hdev,
> > + "%s luid length not match %zu != (%zu + 5)\n", __func__,
> > + strlen(buf), strlen(known_sensor_luid[0]));
> > + goto err_out;
> > + }
> > +
> > + /* get table index with luid (not matching 'LUID: ' in luid) */
> > + index = get_luid_table_index(&buf[5]);
>
> Nicer to share the code block here with the error / unwind path below.
> Particular as index might be -1 and hence an error.
ok, will try to share it with error out.
>
> > + kfree(w_buf);
> > + kfree(buf);
> > + return index;
> > +
> > +err_out:
> > + kfree(w_buf);
> > + kfree(buf);
> > + return -1;
> > +}
> > +
> > +static struct platform_device *
> > +register_platform_device(struct platform_device *pdev,
>
> Function needs a prefix as that sounds very generic.
> When I saw it below, I assumed it was a generic call not
> one in this file.
got it.
>
> > + struct hid_sensor_hub_device *hsdev, int index)
> > +{
> > + char real_usage[HID_SENSOR_USAGE_LENGTH] = { 0 };
> > + struct platform_device *custom_pdev;
> > + const char *dev_name;
> > + char *c;
> > + int ret;
> > +
> > + /* copy real usage id */
> > + memcpy(real_usage, known_sensor_luid[index], 4);
> > +
> > + /* usage id are all lowcase */
> > + for (c = real_usage; *c != '\0'; c++)
> > + *c = tolower(*c);
> > +
> > + /* HID-SENSOR-INT-REAL_USAGE_ID */
> > + dev_name = kasprintf(GFP_KERNEL, "HID-SENSOR-INT-%s", real_usage);
> > + if (!dev_name)
> > + return NULL;
> > +
> > + custom_pdev = platform_device_register_data(pdev->dev.parent, dev_name,
> > + PLATFORM_DEVID_NONE, hsdev,
> > + sizeof(*hsdev));
> > + kfree(dev_name);
> > + ret = PTR_ERR_OR_ZERO(custom_pdev);
> > + if (ret) {
> > + dev_err(&pdev->dev, "platform_device_register_data failed ret:%d\n", ret);
> > + return NULL;
> > + }
> > +
> > + return custom_pdev;
> > +}
> > +
> > static int hid_sensor_custom_probe(struct platform_device *pdev)
> > {
> > struct hid_sensor_custom *sensor_inst;
> > struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
> > int ret;
> > + int index;
> >
> > sensor_inst = devm_kzalloc(&pdev->dev, sizeof(*sensor_inst),
> > GFP_KERNEL);
> > @@ -764,6 +916,19 @@ static int hid_sensor_custom_probe(struct platform_device *pdev)
> > sensor_inst->pdev = pdev;
> > mutex_init(&sensor_inst->mutex);
> > platform_set_drvdata(pdev, sensor_inst);
> > +
> > + index = get_known_custom_sensor_index(hsdev);
> > + if (index >= 0) {
> > + sensor_inst->custom_pdev =
> > + register_platform_device(pdev, hsdev, index);
> > + if (sensor_inst->custom_pdev) {
> > + sensor_inst->custom_pdev_exposed = true;
> > + return 0;
> > + }
> > +
> > + dev_err(&pdev->dev, "register_platform_device failed\n");
>
> This feels like somewhat odd logic. We aren't looking at a fallback for
> something that is expected to fail so it doesn't make sense to carry
> on.
agree, will change to: if register platform failed, then return error code.
>
>
> > + }
> > +
> > ret = sensor_hub_register_callback(hsdev, hsdev->usage,
> > &sensor_inst->callbacks);
> > if (ret < 0) {
> > @@ -802,6 +967,11 @@ static int hid_sensor_custom_remove(struct platform_device *pdev)
> > struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
> > struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
> >
> > + if (sensor_inst->custom_pdev_exposed) {
> > + platform_device_unregister(sensor_inst->custom_pdev);
> > + return 0;
> > + }
> > +
> > hid_sensor_custom_dev_if_remove(sensor_inst);
> > hid_sensor_custom_remove_attributes(sensor_inst);
> > sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
> > diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
> > index 530c09f3e64a..46db3056f04b 100644
> > --- a/include/linux/hid-sensor-ids.h
> > +++ b/include/linux/hid-sensor-ids.h
> > @@ -128,6 +128,10 @@
> > #define HID_USAGE_SENSOR_UNITS_DEGREES_PER_SECOND 0x15
> >
> > /* Common selectors */
> > +#define HID_USAGE_SENSOR_PROP_DESC 0x200300
> > +#define HID_USAGE_SENSOR_PROP_FRIENDLY_NAME 0x200301
> > +#define HID_USAGE_SENSOR_PROP_SERIAL_NUM 0x200307
> > +#define HID_USAGE_SENSOR_PROP_MANUFACTURER 0x200305
> > #define HID_USAGE_SENSOR_PROP_REPORT_INTERVAL 0x20030E
> > #define HID_USAGE_SENSOR_PROP_SENSITIVITY_ABS 0x20030F
> > #define HID_USAGE_SENSOR_PROP_SENSITIVITY_RANGE_PCT 0x200310
> > @@ -159,4 +163,39 @@
> > #define HID_USAGE_SENSOR_PROP_REPORTING_STATE_NO_EVENTS_ENUM 0x200840
> > #define HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM 0x200841
> >
> > +/* Custom Sensor (2000e1) */
> > +#define HID_USAGE_SENSOR_HINGE 0x20020B
> > +#define HID_USAGE_SENSOR_DATA_FIELD_LOCATION 0x200400
> > +#define HID_USAGE_SENSOR_DATA_FIELE_TIME_SINCE_SYS_BOOT 0x20052B
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_USAGE 0x200541
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE 0x200543
> Given these are all defined in a block could we use a macro?
> HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(x) 0x200543 + (x)
>
> perhaps?
>
> I'm not sure what the preferred convention is in this file.
If using HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(x), we should give a range to x, like (1<x<28).
How to ensure the x is in the range? It can be an issue when someone using x out of the range.

Thanks
Xiang
>
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_1 0x200544
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_2 0x200545
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_3 0x200546
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_4 0x200547
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_5 0x200548
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_6 0x200549
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_7 0x20054A
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_8 0x20054B
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_9 0x20054C
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_10 0x20054D
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_11 0x20054E
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_12 0x20054F
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_13 0x200550
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_14 0x200551
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_15 0x200552
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_16 0x200553
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_17 0x200554
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_18 0x200555
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_19 0x200556
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_20 0x200557
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_21 0x200558
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_22 0x200559
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_23 0x20055A
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_24 0x20055B
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_25 0x20055C
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_26 0x20055D
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_27 0x20055E
> > +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_28 0x20055F
> > +
> > #endif
>