diff options
author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-03-18 17:59:53 +0100 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-03-18 17:59:53 +0100 |
commit | 1bde8bddb5db59e5bcd090b227c74d48965cedef (patch) | |
tree | 48ff735d237d8135cdf68801c9349537ec947e85 | |
parent | 8a9bd50a9d68ba68c88cb5e8f64413a8520c33fe (diff) | |
parent | 830751d54b4abb2d4d9e5e8072dffdd8ce195f1f (diff) |
Merge branch 'acpi-docs'
Make ACPI documentation updates for 5.18-rc1:
- Update the ACPI device enumeration documentation and unify the ASL
style in GPIO-related examples (Andy Shevchenko).
* acpi-docs:
ACPI: docs: gpio-properties: Unify ASL style for GPIO examples
ACPI: docs: enumeration: Unify Package () for properties
ACPI: docs: enumeration: Drop comma for terminator entry
ACPI: docs: enumeration: Drop ugly ifdeffery from the examples
ACPI: docs: enumeration: Amend PWM enumeration ASL example
ACPI: docs: enumeration: Remove redundant .owner assignment
ACPI: docs: enumeration: Update UART serial bus resource documentation
ACPI: docs: enumeration: Discourage to use custom _DSM methods
-rw-r--r-- | Documentation/driver-api/gpio/board.rst | 21 | ||||
-rw-r--r-- | Documentation/firmware-guide/acpi/enumeration.rst | 111 | ||||
-rw-r--r-- | Documentation/firmware-guide/acpi/gpio-properties.rst | 26 |
3 files changed, 67 insertions, 91 deletions
diff --git a/Documentation/driver-api/gpio/board.rst b/Documentation/driver-api/gpio/board.rst index 191fa867826a..4e3adf31c8d1 100644 --- a/Documentation/driver-api/gpio/board.rst +++ b/Documentation/driver-api/gpio/board.rst @@ -71,14 +71,14 @@ with the help of _DSD (Device Specific Data), introduced in ACPI 5.1:: Device (FOO) { Name (_CRS, ResourceTemplate () { - GpioIo (Exclusive, ..., IoRestrictionOutputOnly, - "\\_SB.GPI0") {15} // red - GpioIo (Exclusive, ..., IoRestrictionOutputOnly, - "\\_SB.GPI0") {16} // green - GpioIo (Exclusive, ..., IoRestrictionOutputOnly, - "\\_SB.GPI0") {17} // blue - GpioIo (Exclusive, ..., IoRestrictionOutputOnly, - "\\_SB.GPI0") {1} // power + GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionOutputOnly, + "\\_SB.GPI0", 0, ResourceConsumer) { 15 } // red + GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionOutputOnly, + "\\_SB.GPI0", 0, ResourceConsumer) { 16 } // green + GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionOutputOnly, + "\\_SB.GPI0", 0, ResourceConsumer) { 17 } // blue + GpioIo (Exclusive, PullNone, 0, 0, IoRestrictionOutputOnly, + "\\_SB.GPI0", 0, ResourceConsumer) { 1 } // power }) Name (_DSD, Package () { @@ -92,10 +92,7 @@ with the help of _DSD (Device Specific Data), introduced in ACPI 5.1:: ^FOO, 2, 0, 1, } }, - Package () { - "power-gpios", - Package () {^FOO, 3, 0, 0}, - }, + Package () { "power-gpios", Package () { ^FOO, 3, 0, 0 } }, } }) } diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst index 74b830b2fd59..c414646a1bb4 100644 --- a/Documentation/firmware-guide/acpi/enumeration.rst +++ b/Documentation/firmware-guide/acpi/enumeration.rst @@ -19,16 +19,17 @@ possible we decided to do following: platform devices. - Devices behind real busses where there is a connector resource - are represented as struct spi_device or struct i2c_device - (standard UARTs are not busses so there is no struct uart_device). + are represented as struct spi_device or struct i2c_device. Note + that standard UARTs are not busses so there is no struct uart_device, + although some of them may be represented by sturct serdev_device. As both ACPI and Device Tree represent a tree of devices (and their resources) this implementation follows the Device Tree way as much as possible. -The ACPI implementation enumerates devices behind busses (platform, SPI and -I2C), creates the physical devices and binds them to their ACPI handle in -the ACPI namespace. +The ACPI implementation enumerates devices behind busses (platform, SPI, +I2C, and in some cases UART), creates the physical devices and binds them +to their ACPI handle in the ACPI namespace. This means that when ACPI_HANDLE(dev) returns non-NULL the device was enumerated from ACPI namespace. This handle can be used to extract other @@ -46,18 +47,16 @@ some minor changes. Adding ACPI support for an existing driver should be pretty straightforward. Here is the simplest example:: - #ifdef CONFIG_ACPI static const struct acpi_device_id mydrv_acpi_match[] = { /* ACPI IDs here */ { } }; MODULE_DEVICE_TABLE(acpi, mydrv_acpi_match); - #endif static struct platform_driver my_driver = { ... .driver = { - .acpi_match_table = ACPI_PTR(mydrv_acpi_match), + .acpi_match_table = mydrv_acpi_match, }, }; @@ -155,7 +154,7 @@ Here is what the ACPI namespace for a SPI slave might look like:: Device (EEP0) { Name (_ADR, 1) - Name (_CID, Package() { + Name (_CID, Package () { "ATML0025", "AT25", }) @@ -172,59 +171,51 @@ The SPI device drivers only need to add ACPI IDs in a similar way than with the platform device drivers. Below is an example where we add ACPI support to at25 SPI eeprom driver (this is meant for the above ACPI snippet):: - #ifdef CONFIG_ACPI static const struct acpi_device_id at25_acpi_match[] = { { "AT25", 0 }, - { }, + { } }; MODULE_DEVICE_TABLE(acpi, at25_acpi_match); - #endif static struct spi_driver at25_driver = { .driver = { ... - .acpi_match_table = ACPI_PTR(at25_acpi_match), + .acpi_match_table = at25_acpi_match, }, }; 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 ====================== @@ -237,26 +228,24 @@ registered. Below is an example of how to add ACPI support to the existing mpu3050 input driver:: - #ifdef CONFIG_ACPI static const struct acpi_device_id mpu3050_acpi_match[] = { { "MPU3050", 0 }, - { }, + { } }; MODULE_DEVICE_TABLE(acpi, mpu3050_acpi_match); - #endif static struct i2c_driver mpu3050_i2c_driver = { .driver = { .name = "mpu3050", - .owner = THIS_MODULE, .pm = &mpu3050_pm, .of_match_table = mpu3050_of_match, - .acpi_match_table = ACPI_PTR(mpu3050_acpi_match), + .acpi_match_table = mpu3050_acpi_match, }, .probe = mpu3050_probe, .remove = mpu3050_remove, .id_table = mpu3050_ids, }; + module_i2c_driver(mpu3050_i2c_driver); Reference to PWM device ======================= @@ -282,9 +271,9 @@ introduced, i.e.:: } } } - }) ... + } In the above example the PWM-based LED driver references to the PWM channel 0 of \_SB.PCI0.PWM device with initial period setting equal to 600 ms (note that @@ -306,26 +295,13 @@ For example:: { Name (SBUF, ResourceTemplate() { - ... // Used to power on/off the device - GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, - IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0", - 0x00, ResourceConsumer,,) - { - // Pin List - 0x0055 - } + GpioIo (Exclusive, PullNone, 0, 0, IoRestrictionOutputOnly, + "\\_SB.PCI0.GPI0", 0, ResourceConsumer) { 85 } // Interrupt for the device - GpioInt (Edge, ActiveHigh, ExclusiveAndWake, PullNone, - 0x0000, "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer,,) - { - // Pin list - 0x0058 - } - - ... - + GpioInt (Edge, ActiveHigh, ExclusiveAndWake, PullNone, 0, + "\\_SB.PCI0.GPI0", 0, ResourceConsumer) { 88 } } Return (SBUF) @@ -337,11 +313,12 @@ For example:: ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { - Package () {"power-gpios", Package() {^DEV, 0, 0, 0 }}, - Package () {"irq-gpios", Package() {^DEV, 1, 0, 0 }}, + Package () { "power-gpios", Package () { ^DEV, 0, 0, 0 } }, + Package () { "irq-gpios", Package () { ^DEV, 1, 0, 0 } }, } }) ... + } These GPIO numbers are controller relative and path "\\_SB.PCI0.GPI0" specifies the path to the controller. In order to use these GPIOs in Linux @@ -460,10 +437,10 @@ namespace link:: Device (TMP0) { Name (_HID, "PRP0001") - Name (_DSD, Package() { + Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { - Package (2) { "compatible", "ti,tmp75" }, + Package () { "compatible", "ti,tmp75" }, } }) Method (_CRS, 0, Serialized) diff --git a/Documentation/firmware-guide/acpi/gpio-properties.rst b/Documentation/firmware-guide/acpi/gpio-properties.rst index df4b711053ee..eaec732cc77c 100644 --- a/Documentation/firmware-guide/acpi/gpio-properties.rst +++ b/Documentation/firmware-guide/acpi/gpio-properties.rst @@ -21,18 +21,18 @@ index, like the ASL example below shows:: Name (_CRS, ResourceTemplate () { GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionOutputOnly, - "\\_SB.GPO0", 0, ResourceConsumer) {15} + "\\_SB.GPO0", 0, ResourceConsumer) { 15 } GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionOutputOnly, - "\\_SB.GPO0", 0, ResourceConsumer) {27, 31} + "\\_SB.GPO0", 0, ResourceConsumer) { 27, 31 } }) Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () - { - Package () {"reset-gpios", Package() {^BTH, 1, 1, 0 }}, - Package () {"shutdown-gpios", Package() {^BTH, 0, 0, 0 }}, + { + Package () { "reset-gpios", Package () { ^BTH, 1, 1, 0 } }, + Package () { "shutdown-gpios", Package () { ^BTH, 0, 0, 0 } }, } }) } @@ -123,17 +123,17 @@ Example:: // _DSD Hierarchical Properties Extension UUID ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"), Package () { - Package () {"hog-gpio8", "G8PU"} + Package () { "hog-gpio8", "G8PU" } } }) Name (G8PU, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { - Package () {"gpio-hog", 1}, - Package () {"gpios", Package () {8, 0}}, - Package () {"output-high", 1}, - Package () {"line-name", "gpio8-pullup"}, + Package () { "gpio-hog", 1 }, + Package () { "gpios", Package () { 8, 0 } }, + Package () { "output-high", 1 }, + Package () { "line-name", "gpio8-pullup" }, } }) @@ -266,15 +266,17 @@ have a device like below:: Name (_CRS, ResourceTemplate () { GpioIo (Exclusive, PullNone, 0, 0, IoRestrictionNone, - "\\_SB.GPO0", 0, ResourceConsumer) {15} + "\\_SB.GPO0", 0, ResourceConsumer) { 15 } GpioIo (Exclusive, PullNone, 0, 0, IoRestrictionNone, - "\\_SB.GPO0", 0, ResourceConsumer) {27} + "\\_SB.GPO0", 0, ResourceConsumer) { 27 } }) } The driver might expect to get the right GPIO when it does:: desc = gpiod_get(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(desc)) + ...error handling... but since there is no way to know the mapping between "reset" and the GpioIo() in _CRS desc will hold ERR_PTR(-ENOENT). |