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path: root/include/linux/i2c-smbus.h
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2020-05-29i2c: smbus: Add a way to instantiate SPD EEPROMs automaticallyJean Delvare
In simple cases we can instantiate SPD EEPROMs on the SMBus automatically. Start with just DDR2, DDR3 and DDR4 on x86 for now, and only for systems with no more than 4 memory slots. These limitations may be lifted later. Signed-off-by: Jean Delvare <jdelvare@suse.de> [wsa: minor change for new API] Signed-off-by: Wolfram Sang <wsa@kernel.org>
2020-03-10i2c: smbus: remove outdated references to irq level triggersWolfram Sang
IRQ levels are now handled within the IRQ core. Remove the forgotten references from the documentation. Fixes: 9b9f2b8bc2ac ("i2c: i2c-smbus: Use threaded irq for smbalert") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2020-03-10i2c: convert SMBus alert setup function to return an ERRPTRWolfram Sang
Only few drivers use this call, so drivers and I2C core are converted at once with this patch. By simply using i2c_new_client_device() instead of i2c_new_device(), we easily can return an ERRPTR for this function as well. To make out of tree users aware that something changed, the function is renamed to i2c_new_smbus_alert_device(). Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-05-21treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1Thomas Gleixner
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 51 franklin street fifth floor boston ma 02110 1301 usa this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option [no]_[pad]_[ctrl] any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 51 franklin street fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 176 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190519154040.652910950@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-28i2c: i2c-smbus: add of_i2c_setup_smbus_alertPhil Reid
This commit adds of_i2c_setup_smbus_alert which allows the smbalert driver to be attached to an i2c adapter via the device tree. Signed-off-by: Phil Reid <preid@electromag.com.au> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-10-28i2c: i2c-smbus: Use threaded irq for smbalertPhil Reid
Prior to this commit the smbalert_irq was handling in the hard irq context. This change switch to using a thread irq which avoids the need for the work thread. Using threaded irq also removes the need for the edge_triggered flag as the enabling / disabling of the hard irq for level triggered interrupts will be handled by the irq core. Without this change have an irq connected to something like an i2c gpio resulted in a null ptr deferences. Specifically handle_nested_irq calls the threaded irq handler. There are currently 3 in tree drivers affected by this change. i2c-parport driver calls i2c_handle_smbus_alert in a hard irq context. This driver use edge trigger interrupts which skip the enable / disable calls. But it still need to handle the smbus transaction on a thread. So the work thread is kept for this driver. i2c-parport-light & i2c-thunderx-pcidrv provide the irq number in the setup which will result in the thread irq being used. i2c-parport-light is edge trigger so the enable / disable call was skipped as well. i2c-thunderx-pcidrv is getting the edge / level trigger setting from of data and was setting the flag as required. However the irq core should handle this automatically. Signed-off-by: Phil Reid <preid@electromag.com.au> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-11-24i2c: use an IRQ to report Host Notify events, not alertBenjamin Tissoires
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 <benjamin.tissoires@redhat.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-07-22i2c: i2c-smbus: drop useless stubsJean Delvare
Drivers which use the SMBus extensions select I2C_SMBUS, so the stubs are not needed. Signed-off-by: Jean Delvare <jdelvare@suse.de> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-06-17i2c: smbus: add SMBus Host Notify supportBenjamin Tissoires
SMBus Host Notify allows a slave device to act as a master on a bus to notify the host of an interrupt. On Intel chipsets, the functionality is directly implemented in the firmware. We just need to export a function to call .alert() on the proper device driver. i2c_handle_smbus_host_notify() behaves like i2c_handle_smbus_alert(). When called, it schedules a task that will be able to sleep to go through the list of devices attached to the adapter. The current implementation allows one Host Notification to be scheduled while an other is running. Tested-by: Andrew Duggan <aduggan@synaptics.com> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-01-29Update Jean Delvare's e-mail addressJean Delvare
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2012-03-26i2c: Update the FSF addressJean Delvare
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2010-03-02i2c: Add SMBus alert supportJean Delvare
SMBus alert support. The SMBus alert protocol allows several SMBus slave devices to share a single interrupt pin on the SMBus master, while still allowing the master to know which slave triggered the interrupt. This is based on preliminary work by David Brownell. The key difference between David's implementation and mine is that his was part of i2c-core, while mine is split into a separate, standalone module named i2c-smbus. The i2c-smbus module is meant to include support for all SMBus extensions to the I2C protocol in the future. The benefit of this approach is a zero cost for I2C bus segments which do not need SMBus alert support. Where David's implementation increased the size of struct i2c_adapter by 7% (40 bytes on i386), mine doesn't touch it. Where David's implementation added over 150 lines of code to i2c-core (+10%), mine doesn't touch it. The only change that touches all the users of the i2c subsystem is a new callback in struct i2c_driver (common to both implementations.) I seem to remember Trent was worried about the footprint of David'd implementation, hopefully mine addresses the issue. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Jonathan Cameron <jic23@cam.ac.uk> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Trent Piepho <tpiepho@freescale.com>