diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-devfreq | 44 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-power | 31 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-sun | 14 | ||||
| -rw-r--r-- | Documentation/acpi/enumeration.txt | 227 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/cpufreq/cpufreq-spear.txt | 42 | ||||
| -rw-r--r-- | Documentation/power/pm_qos_interface.txt | 2 |
6 files changed, 351 insertions, 9 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq index 23d78b5aab11..0ba6ea2f89d9 100644 --- a/Documentation/ABI/testing/sysfs-class-devfreq +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -11,7 +11,7 @@ What: /sys/class/devfreq/.../governor Date: September 2011 Contact: MyungJoo Ham <myungjoo.ham@samsung.com> Description: - The /sys/class/devfreq/.../governor shows the name of the + The /sys/class/devfreq/.../governor show or set the name of the governor used by the corresponding devfreq object. What: /sys/class/devfreq/.../cur_freq @@ -19,15 +19,16 @@ Date: September 2011 Contact: MyungJoo Ham <myungjoo.ham@samsung.com> Description: The /sys/class/devfreq/.../cur_freq shows the current - frequency of the corresponding devfreq object. + frequency of the corresponding devfreq object. Same as + target_freq when get_cur_freq() is not implemented by + devfreq driver. -What: /sys/class/devfreq/.../central_polling -Date: September 2011 -Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +What: /sys/class/devfreq/.../target_freq +Date: September 2012 +Contact: Rajagopal Venkat <rajagopal.venkat@linaro.org> Description: - The /sys/class/devfreq/.../central_polling shows whether - the devfreq ojbect is using devfreq-provided central - polling mechanism or not. + The /sys/class/devfreq/.../target_freq shows the next governor + predicted target frequency of the corresponding devfreq object. What: /sys/class/devfreq/.../polling_interval Date: September 2011 @@ -43,6 +44,17 @@ Description: (/sys/class/devfreq/.../central_polling is 0), this value may be useless. +What: /sys/class/devfreq/.../trans_stat +Date: October 2012 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Descrtiption: + This ABI shows the statistics of devfreq behavior on a + specific device. It shows the time spent in each state and + the number of transitions between states. + In order to activate this ABI, the devfreq target device + driver should provide the list of available frequencies + with its profile. + What: /sys/class/devfreq/.../userspace/set_freq Date: September 2011 Contact: MyungJoo Ham <myungjoo.ham@samsung.com> @@ -50,3 +62,19 @@ Description: The /sys/class/devfreq/.../userspace/set_freq shows and sets the requested frequency for the devfreq object if userspace governor is in effect. + +What: /sys/class/devfreq/.../available_frequencies +Date: October 2012 +Contact: Nishanth Menon <nm@ti.com> +Description: + The /sys/class/devfreq/.../available_frequencies shows + the available frequencies of the corresponding devfreq object. + This is a snapshot of available frequencies and not limited + by the min/max frequency restrictions. + +What: /sys/class/devfreq/.../available_governors +Date: October 2012 +Contact: Nishanth Menon <nm@ti.com> +Description: + The /sys/class/devfreq/.../available_governors shows + currently available governors in the system. diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power index 45000f0db4d4..7fc2997b23a6 100644 --- a/Documentation/ABI/testing/sysfs-devices-power +++ b/Documentation/ABI/testing/sysfs-devices-power @@ -204,3 +204,34 @@ Description: This attribute has no effect on system-wide suspend/resume and hibernation. + +What: /sys/devices/.../power/pm_qos_no_power_off +Date: September 2012 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/devices/.../power/pm_qos_no_power_off attribute + is used for manipulating the PM QoS "no power off" flag. If + set, this flag indicates to the kernel that power should not + be removed entirely from the device. + + Not all drivers support this attribute. If it isn't supported, + it is not present. + + This attribute has no effect on system-wide suspend/resume and + hibernation. + +What: /sys/devices/.../power/pm_qos_remote_wakeup +Date: September 2012 +Contact: Rafael J. Wysocki <rjw@sisk.pl> +Description: + The /sys/devices/.../power/pm_qos_remote_wakeup attribute + is used for manipulating the PM QoS "remote wakeup required" + flag. If set, this flag indicates to the kernel that the + device is a source of user events that have to be signaled from + its low-power states. + + Not all drivers support this attribute. If it isn't supported, + it is not present. + + This attribute has no effect on system-wide suspend/resume and + hibernation. diff --git a/Documentation/ABI/testing/sysfs-devices-sun b/Documentation/ABI/testing/sysfs-devices-sun new file mode 100644 index 000000000000..86be9848a77e --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-sun @@ -0,0 +1,14 @@ +Whatt: /sys/devices/.../sun +Date: October 2012 +Contact: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> +Description: + The file contains a Slot-unique ID which provided by the _SUN + method in the ACPI namespace. The value is written in Advanced + Configuration and Power Interface Specification as follows: + + "The _SUN value is required to be unique among the slots of + the same type. It is also recommended that this number match + the slot number printed on the physical slot whenever possible." + + So reading the sysfs file, we can identify a physical position + of the slot in the system. diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt new file mode 100644 index 000000000000..4f27785ca0c8 --- /dev/null +++ b/Documentation/acpi/enumeration.txt @@ -0,0 +1,227 @@ +ACPI based device enumeration +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +ACPI 5 introduced a set of new resources (UartTSerialBus, I2cSerialBus, +SpiSerialBus, GpioIo and GpioInt) which can be used in enumerating slave +devices behind serial bus controllers. + +In addition we are starting to see peripherals integrated in the +SoC/Chipset to appear only in ACPI namespace. These are typically devices +that are accessed through memory-mapped registers. + +In order to support this and re-use the existing drivers as much as +possible we decided to do following: + + o Devices that have no bus connector resource are represented as + platform devices. + + o 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). + +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. + +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 +device-specific configuration. There is an example of this below. + +Platform bus support +~~~~~~~~~~~~~~~~~~~~ +Since we are using platform devices to represent devices that are not +connected to any physical bus we only need to implement a platform driver +for the device and add supported ACPI IDs. If this same IP-block is used on +some other non-ACPI platform, the driver might work out of the box or needs +some minor changes. + +Adding ACPI support for an existing driver should be pretty +straightforward. Here is the simplest example: + + #ifdef CONFIG_ACPI + static 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), + }, + }; + +If the driver needs to perform more complex initialization like getting and +configuring GPIOs it can get its ACPI handle and extract this information +from ACPI tables. + +Currently the kernel is not able to automatically determine from which ACPI +device it should make the corresponding platform device so we need to add +the ACPI device explicitly to acpi_platform_device_ids list defined in +drivers/acpi/scan.c. This limitation is only for the platform devices, SPI +and I2C devices are created automatically as described below. + +SPI serial bus support +~~~~~~~~~~~~~~~~~~~~~~ +Slave devices behind SPI bus have SpiSerialBus resource attached to them. +This is extracted automatically by the SPI core and the slave devices are +enumerated once spi_register_master() is called by the bus driver. + +Here is what the ACPI namespace for a SPI slave might look like: + + Device (EEP0) + { + Name (_ADR, 1) + Name (_CID, Package() { + "ATML0025", + "AT25", + }) + ... + Method (_CRS, 0, NotSerialized) + { + SPISerialBus(1, PolarityLow, FourWireMode, 8, + ControllerInitiated, 1000000, ClockPolarityLow, + ClockPhaseFirst, "\\_SB.PCI0.SPI1",) + } + ... + +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 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), + }, + }; + +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: + + Device (EEP0) + { + ... + Method (_DSM, 4, NotSerialized) + { + Store (Package (6) + { + "byte-len", 1024, + "addr-mode", 2, + "page-size, 32 + }, Local0) + + // Check UUIDs etc. + + Return (Local0) + } + +Then the at25 SPI driver can get this configation by calling _DSM on its +ACPI handle like: + + struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; + struct acpi_object_list input; + acpi_status status; + + /* Fill in the input buffer */ + + status = acpi_evaluate_object(ACPI_HANDLE(&spi->dev), "_DSM", + &input, &output); + if (ACPI_FAILURE(status)) + /* Handle the error */ + + /* Extract the data here */ + + kfree(output.pointer); + +I2C serial bus support +~~~~~~~~~~~~~~~~~~~~~~ +The slaves behind I2C bus controller only need to add the ACPI IDs like +with the platform and SPI drivers. However the I2C bus controller driver +needs to call acpi_i2c_register_devices() after it has added the adapter. + +An I2C bus (controller) driver does: + + ... + ret = i2c_add_numbered_adapter(adapter); + if (ret) + /* handle error */ + + of_i2c_register_devices(adapter); + /* Enumerate the slave devices behind this bus via ACPI */ + acpi_i2c_register_devices(adapter); + +Below is an example of how to add ACPI support to the existing mpu3050 +input driver: + + #ifdef CONFIG_ACPI + static 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), + }, + .probe = mpu3050_probe, + .remove = __devexit_p(mpu3050_remove), + .id_table = mpu3050_ids, + }; + +GPIO support +~~~~~~~~~~~~ +ACPI 5 introduced two new resources to describe GPIO connections: GpioIo +and GpioInt. These resources are used be used to pass GPIO numbers used by +the device to the driver. For example: + + Method (_CRS, 0, NotSerialized) + { + Name (SBUF, ResourceTemplate() + { + GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, + IoRestrictionOutputOnly, "\\_SB.PCI0.GPI0", + 0x00, ResourceConsumer,,) + { + // Pin List + 0x0055 + } + ... + + Return (SBUF) + } + } + +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 +we need to translate them to the Linux GPIO numbers. + +The driver can do this by including <linux/acpi_gpio.h> and then calling +acpi_get_gpio(path, gpio). This will return the Linux GPIO number or +negative errno if there was no translation found. + +Other GpioIo parameters must be converted first by the driver to be +suitable to the gpiolib before passing them. + +In case of GpioInt resource an additional call to gpio_to_irq() must be +done before calling request_irq(). diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-spear.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-spear.txt new file mode 100644 index 000000000000..f3d44984d91c --- /dev/null +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-spear.txt @@ -0,0 +1,42 @@ +SPEAr cpufreq driver +------------------- + +SPEAr SoC cpufreq driver for CPU frequency scaling. +It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) systems +which share clock across all CPUs. + +Required properties: +- cpufreq_tbl: Table of frequencies CPU could be transitioned into, in the + increasing order. + +Optional properties: +- clock-latency: Specify the possible maximum transition latency for clock, in + unit of nanoseconds. + +Both required and optional properties listed above must be defined under node +/cpus/cpu@0. + +Examples: +-------- +cpus { + + <...> + + cpu@0 { + compatible = "arm,cortex-a9"; + reg = <0>; + + <...> + + cpufreq_tbl = < 166000 + 200000 + 250000 + 300000 + 400000 + 500000 + 600000 >; + }; + + <...> + +}; diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt index 17e130a80347..79a2a58425ee 100644 --- a/Documentation/power/pm_qos_interface.txt +++ b/Documentation/power/pm_qos_interface.txt @@ -99,7 +99,7 @@ reading the aggregated value does not require any locking mechanism. From kernel mode the use of this interface is the following: -int dev_pm_qos_add_request(device, handle, value): +int dev_pm_qos_add_request(device, handle, type, value): Will insert an element into the list for that identified device with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. |