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SubjectRe: [PATCH v2] i2c: i801: Register optional lis3lv02d i2c device on Dell machines
On Sat, Jan 27, 2018 at 3:32 PM, Pali Rohár <pali.rohar@gmail.com> wrote:
> Dell platform team told us that some (DMI whitelisted) Dell Latitude
> machines have ST microelectronics accelerometer at i2c address 0x29.
>
> Presence of that ST microelectronics accelerometer is verified by existence
> of SMO88xx ACPI device which represent that accelerometer. Unfortunately
> ACPI device does not specify i2c address.
>
> This patch registers lis3lv02d device for selected Dell Latitude machines
> at i2c address 0x29 after detection. And for Dell Vostro V131 machine at
> i2c address 0x1d which was manually detected.
>
> Finally commit a7ae81952cda ("i2c: i801: Allow ACPI SystemIO OpRegion to
> conflict with PCI BAR") allowed to use i2c-i801 driver on Dell machines so
> lis3lv02d correctly initialize accelerometer.
>
> Tested on Dell Latitude E6440.

> +static acpi_status check_acpi_smo88xx_device(acpi_handle obj_handle,
> + u32 nesting_level,
> + void *context,
> + void **return_value)
> +{
> + struct acpi_device_info *info;
> + acpi_status status;
> + char *hid;
> +
> + status = acpi_get_object_info(obj_handle, &info);
> + if (!ACPI_SUCCESS(status) || !(info->valid & ACPI_VALID_HID))
> + return AE_OK;
> +
> + hid = info->hardware_id.string;
> + if (!hid)
> + return AE_OK;
> +
> + if (strlen(hid) < 7)
> + return AE_OK;
> +
> + if (memcmp(hid, "SMO88", 5) != 0)
> + return AE_OK;
> +
> + *((bool *)return_value) = true;
> + return AE_CTRL_TERMINATE;
> +}
> +
> +static bool is_dell_system_with_lis3lv02d(void)
> +{

> + /*
> + * Check that ACPI device SMO88xx exists and is enabled. That ACPI
> + * device represent our ST microelectronics lis3lv02d accelerometer but
> + * unfortunately without any other information (like i2c address).
> + */

Isn't it simple

return acpi_dev_present("SMO88", NULL, -1);

call?

> + found = false;
> + status = acpi_get_devices(NULL, check_acpi_smo88xx_device, NULL,
> + (void **)&found);
> + if (!ACPI_SUCCESS(status) || !found)
> + return false;
> +
> + return true;
> +}


--
With Best Regards,
Andy Shevchenko

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