From 4d5538f5882a6b67eefbab0f0a3a67ce811621aa Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 13 Oct 2016 14:10:40 +0200 Subject: i2c: use an IRQ to report Host Notify events, not alert The current SMBus Host Notify implementation relies on .alert() to relay its notifications. However, the use cases where SMBus Host Notify is needed currently is to signal data ready on touchpads. This is closer to an IRQ than a custom API through .alert(). Given that the 2 touchpad manufacturers (Synaptics and Elan) that use SMBus Host Notify don't put any data in the SMBus payload, the concept actually matches one to one. Benefits are multiple: - simpler code and API: the client will just have an IRQ, and nothing needs to be added in the adapter beside internally enabling it. - no more specific workqueue, the threading is handled by IRQ core directly (when required) - no more races when removing the device (the drivers are already required to disable irq on remove) - simpler handling for drivers: use plain regular IRQs - no more dependency on i2c-smbus for i2c-i801 (and any other adapter) - the IRQ domain is created automatically when the adapter exports the Host Notify capability - the IRQ are assign only if ACPI, OF and the caller did not assign one already - the domain is automatically destroyed on remove - fewer lines of code (minus 20, yeah!) Signed-off-by: Benjamin Tissoires Signed-off-by: Wolfram Sang --- drivers/i2c/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/i2c/Kconfig') diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index d223650a97e4..de305f89a659 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -7,6 +7,7 @@ menu "I2C support" config I2C tristate "I2C support" select RT_MUTEXES + select IRQ_DOMAIN ---help--- I2C (pronounce: I-squared-C) is a slow serial bus protocol used in many micro controller applications and developed by Philips. SMBus, -- cgit v1.2.3