forked from Minki/linux
3fffd12839
Instead of having each i2c driver individually parse device tree data in case it or platform supports separate wakeup interrupt, and handle enabling and disabling wakeup interrupts in their power management routines, let's have i2c core do that for us. Platforms wishing to specify separate wakeup interrupt for the device should use named interrupt syntax in their DTSes: interrupt-parent = <&intc1>; interrupts = <5 0>, <6 0>; interrupt-names = "irq", "wakeup"; This patch is inspired by work done by Vignesh R <vigneshr@ti.com> for pixcir_i2c_ts driver. Note that the original code tried to preserve any existing wakeup settings from userspace but was not quite right in that regard: it would preserve wakeup flag set by userspace upon driver rebinding; but it would re-arm the wakeup flag if it was disabled by userspace. We think that resetting the flag upon re-binding the driver is proper behavior as the driver is responsible for setting up and handling wakeups. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Tested-by: Vignesh R <vigneshr@ti.com> [wsa: updated the commit message] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
46 lines
1.9 KiB
Plaintext
46 lines
1.9 KiB
Plaintext
Generic device tree bindings for I2C busses
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===========================================
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This document describes generic bindings which can be used to describe I2C
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busses in a device tree.
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Required properties
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-------------------
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- #address-cells - should be <1>. Read more about addresses below.
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- #size-cells - should be <0>.
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- compatible - name of I2C bus controller following generic names
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recommended practice.
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For other required properties e.g. to describe register sets,
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clocks, etc. check the binding documentation of the specific driver.
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The cells properties above define that an address of children of an I2C bus
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are described by a single value. This is usually a 7 bit address. However,
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flags can be attached to the address. I2C_TEN_BIT_ADDRESS is used to mark a 10
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bit address. It is needed to avoid the ambiguity between e.g. a 7 bit address
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of 0x50 and a 10 bit address of 0x050 which, in theory, can be on the same bus.
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Another flag is I2C_OWN_SLAVE_ADDRESS to mark addresses on which we listen to
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be devices ourselves.
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Optional properties
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-------------------
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These properties may not be supported by all drivers. However, if a driver
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wants to support one of the below features, it should adapt the bindings below.
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- clock-frequency - frequency of bus clock in Hz.
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- wakeup-source - device can be used as a wakeup source.
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- interrupts - interrupts used by the device.
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- interrupt-names - "irq" and "wakeup" names are recognized by I2C core,
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other names are left to individual drivers.
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Binding may contain optional "interrupts" property, describing interrupts
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used by the device. I2C core will assign "irq" interrupt (or the very first
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interrupt if not using interrupt names) as primary interrupt for the slave.
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Also, if device is marked as a wakeup source, I2C core will set up "wakeup"
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interrupt for the device. If "wakeup" interrupt name is not present in the
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binding, then primary interrupt will be used as wakeup interrupt.
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