diff options
| author | Andy Shevchenko <andriy.shevchenko@linux.intel.com> | 2022-03-01 00:39:30 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-03-03 20:34:44 +0100 |
| commit | b625fe694626992c1d640b37c691cfcfc58d6006 (patch) | |
| tree | f0519fffa2e979125b72d5a0cca49ae3cfd8e79b /Documentation/firmware-guide | |
| parent | 7e57714cd0ad2d5bb90e50b5096a0e671dec1ef3 (diff) | |
| download | linux-b625fe694626992c1d640b37c691cfcfc58d6006.tar.gz | |
ACPI: docs: enumeration: Discourage to use custom _DSM methods
Since we have _DSD established and specified (ACPI v5.1+) there is no
need to use custom _DSM methods. Rewrite documentation to use _DSD.
Fixes: f60e7074902a ("misc: at25: Make use of device property API")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/firmware-guide')
| -rw-r--r-- | Documentation/firmware-guide/acpi/enumeration.rst | 48 |
1 files changed, 21 insertions, 27 deletions
diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst index 74b830b2fd59e..cda41e4255ebf 100644 --- a/Documentation/firmware-guide/acpi/enumeration.rst +++ b/Documentation/firmware-guide/acpi/enumeration.rst @@ -188,43 +188,37 @@ to at25 SPI eeprom driver (this is meant for the above ACPI snippet):: }; Note that this driver actually needs more information like page size of the -eeprom etc. but at the time writing this there is no standard way of -passing those. One idea is to return this in _DSM method like:: +eeprom, etc. This information can be passed via _DSD method like:: Device (EEP0) { ... - Method (_DSM, 4, NotSerialized) + Name (_DSD, Package () { - Store (Package (6) + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), + Package () { - "byte-len", 1024, - "addr-mode", 2, - "page-size, 32 - }, Local0) - - // Check UUIDs etc. - - Return (Local0) - } - -Then the at25 SPI driver can get this configuration by calling _DSM on its -ACPI handle like:: - - struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; - struct acpi_object_list input; - acpi_status status; + Package () { "size", 1024 }, + Package () { "pagesize", 32 }, + Package () { "address-width", 16 }, + } + }) + } - /* Fill in the input buffer */ +Then the at25 SPI driver can get this configuration by calling device property +APIs during ->probe() phase like:: - status = acpi_evaluate_object(ACPI_HANDLE(&spi->dev), "_DSM", - &input, &output); - if (ACPI_FAILURE(status)) - /* Handle the error */ + err = device_property_read_u32(dev, "size", &size); + if (err) + ...error handling... - /* Extract the data here */ + err = device_property_read_u32(dev, "pagesize", &page_size); + if (err) + ...error handling... - kfree(output.pointer); + err = device_property_read_u32(dev, "address-width", &addr_width); + if (err) + ...error handling... I2C serial bus support ====================== |