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linux/drivers/i2c/i2c-core.h

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 Based on 3 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 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 [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] 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 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 [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-27 06:55:06 +00:00
/* SPDX-License-Identifier: GPL-2.0-or-later */
i2c: Add i2c_board_info and i2c_new_device() This provides partial support for new-style I2C driver binding. It builds on "struct i2c_board_info" declarations that identify I2C devices on a given board. This is needed on systems with I2C devices that can't be fully probed and/or autoconfigured, such as many embedded Linux configurations where the way a given I2C device is wired may affect how it must be used. There are two models for declaring such devices: * LATE -- using a public function i2c_new_device(). This lets modules declare I2C devices found *AFTER* a given I2C adapter becomes available. For example, a PCI card could create adapters giving access to utility chips on that card, and this would be used to associate those chips with those adapters. * EARLY -- from arch_initcall() level code, using a non-exported function i2c_register_board_info(). This copies the declarations *BEFORE* such an i2c_adapter becomes available, arranging that i2c_new_device() will be called later when i2c-core registers the relevant i2c_adapter. For example, arch/.../.../board-*.c files would declare the I2C devices along with their platform data, and I2C devices would behave much like PNPACPI devices. (That is, both enumerate from board-specific tables.) To match the exported i2c_new_device(), the previously-private function i2c_unregister_device() is now exported. Pending later patches using these new APIs, this is effectively a NOP. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 21:26:31 +00:00
/*
* i2c-core.h - interfaces internal to the I2C framework
*/
i2c: Use rwsem instead of mutex for board info By using rwsem we can easily manage recursive calls of i2c_scan_static_board_info() function without breaking the locking. Signed-off-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Jean Delvare <khali@linux-fr.org>
2009-06-19 14:58:20 +00:00
#include <linux/rwsem.h>
i2c: Add i2c_board_info and i2c_new_device() This provides partial support for new-style I2C driver binding. It builds on "struct i2c_board_info" declarations that identify I2C devices on a given board. This is needed on systems with I2C devices that can't be fully probed and/or autoconfigured, such as many embedded Linux configurations where the way a given I2C device is wired may affect how it must be used. There are two models for declaring such devices: * LATE -- using a public function i2c_new_device(). This lets modules declare I2C devices found *AFTER* a given I2C adapter becomes available. For example, a PCI card could create adapters giving access to utility chips on that card, and this would be used to associate those chips with those adapters. * EARLY -- from arch_initcall() level code, using a non-exported function i2c_register_board_info(). This copies the declarations *BEFORE* such an i2c_adapter becomes available, arranging that i2c_new_device() will be called later when i2c-core registers the relevant i2c_adapter. For example, arch/.../.../board-*.c files would declare the I2C devices along with their platform data, and I2C devices would behave much like PNPACPI devices. (That is, both enumerate from board-specific tables.) To match the exported i2c_new_device(), the previously-private function i2c_unregister_device() is now exported. Pending later patches using these new APIs, this is effectively a NOP. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 21:26:31 +00:00
struct i2c_devinfo {
struct list_head list;
int busnum;
struct i2c_board_info board_info;
};
/* board_lock protects board_list and first_dynamic_bus_num.
* only i2c core components are allowed to use these symbols.
*/
i2c: Use rwsem instead of mutex for board info By using rwsem we can easily manage recursive calls of i2c_scan_static_board_info() function without breaking the locking. Signed-off-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Jean Delvare <khali@linux-fr.org>
2009-06-19 14:58:20 +00:00
extern struct rw_semaphore __i2c_board_lock;
i2c: Add i2c_board_info and i2c_new_device() This provides partial support for new-style I2C driver binding. It builds on "struct i2c_board_info" declarations that identify I2C devices on a given board. This is needed on systems with I2C devices that can't be fully probed and/or autoconfigured, such as many embedded Linux configurations where the way a given I2C device is wired may affect how it must be used. There are two models for declaring such devices: * LATE -- using a public function i2c_new_device(). This lets modules declare I2C devices found *AFTER* a given I2C adapter becomes available. For example, a PCI card could create adapters giving access to utility chips on that card, and this would be used to associate those chips with those adapters. * EARLY -- from arch_initcall() level code, using a non-exported function i2c_register_board_info(). This copies the declarations *BEFORE* such an i2c_adapter becomes available, arranging that i2c_new_device() will be called later when i2c-core registers the relevant i2c_adapter. For example, arch/.../.../board-*.c files would declare the I2C devices along with their platform data, and I2C devices would behave much like PNPACPI devices. (That is, both enumerate from board-specific tables.) To match the exported i2c_new_device(), the previously-private function i2c_unregister_device() is now exported. Pending later patches using these new APIs, this is effectively a NOP. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 21:26:31 +00:00
extern struct list_head __i2c_board_list;
extern int __i2c_first_dynamic_bus_num;
i2c: break out slave support into separate file Also removes some ifdeffery. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-05-23 09:14:17 +00:00
int i2c_check_7bit_addr_validity_strict(unsigned short addr);
i2c: core: Allow whole core to use i2c_dev_irq_from_resources Remove the static from i2c_dev_irq_from _resources so that other parts of the core code can use this helper function. Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-06-27 09:24:06 +00:00
int i2c_dev_irq_from_resources(const struct resource *resources,
unsigned int num_resources);
i2c: break out OF support into separate file Also removes some ifdeffery. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-05-23 09:50:58 +00:00
i2c: core: remove use of in_atomic() Commit cea443a81c9c ("i2c: Support i2c_transfer in atomic contexts") added in_atomic() to the I2C core. However, the use of in_atomic() outside of core kernel code is discouraged and was already[1] when this code was added in early 2008. The above commit was a preparation for commit b7a3670131c7 ("i2c-pxa: Add polling transfer"). Its commit message says explicitly it was added "for cases where I2C transactions have to occur at times interrup[t]s are disabled". So, the intention was 'disabled interrupts'. This matches the use cases for atomic I2C transfers I have seen so far: very late communication (mostly to a PMIC) to powerdown or reboot the system. For those cases, interrupts are disabled then. It doesn't seem that in_atomic() adds value. After a discussion with Peter Zijlstra[2], we came up with a better set of conditionals to match the use case. The I2C core will soon gain an extra callback into bus drivers especially for atomic transfers to make them more generic. The code deciding which transfer to use (atomic/non-atomic) should mimic the behaviour which locking to use (trylock/lock). This is why we add a helper for it. [1] https://lwn.net/Articles/274695/ [2] http://patchwork.ozlabs.org/patch/1067437/ Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Stefan Lengfeld <contact@stefanchrist.eu> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:08 +00:00
/*
i2c: reword explanation about atomic transfers Atomic transfers are not only about sending messages like the original wording suggested. Speak of 'accessing' now like in i2c.h. Reported-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Wolfram Sang <wsa@kernel.org>
2020-05-05 16:01:01 +00:00
* We only allow atomic transfers for very late communication, e.g. to access a
* PMIC when powering down. Atomic transfers are a corner case and not for
* generic use!
i2c: core: remove use of in_atomic() Commit cea443a81c9c ("i2c: Support i2c_transfer in atomic contexts") added in_atomic() to the I2C core. However, the use of in_atomic() outside of core kernel code is discouraged and was already[1] when this code was added in early 2008. The above commit was a preparation for commit b7a3670131c7 ("i2c-pxa: Add polling transfer"). Its commit message says explicitly it was added "for cases where I2C transactions have to occur at times interrup[t]s are disabled". So, the intention was 'disabled interrupts'. This matches the use cases for atomic I2C transfers I have seen so far: very late communication (mostly to a PMIC) to powerdown or reboot the system. For those cases, interrupts are disabled then. It doesn't seem that in_atomic() adds value. After a discussion with Peter Zijlstra[2], we came up with a better set of conditionals to match the use case. The I2C core will soon gain an extra callback into bus drivers especially for atomic transfers to make them more generic. The code deciding which transfer to use (atomic/non-atomic) should mimic the behaviour which locking to use (trylock/lock). This is why we add a helper for it. [1] https://lwn.net/Articles/274695/ [2] http://patchwork.ozlabs.org/patch/1067437/ Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Stefan Lengfeld <contact@stefanchrist.eu> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:08 +00:00
*/
static inline bool i2c_in_atomic_xfer_mode(void)
{
return system_state > SYSTEM_RUNNING && irqs_disabled();
}
i2c: core: use I2C locking behaviour also for SMBUS If I2C transfers are executed in atomic contexts, trylock is used instead of lock. This behaviour was missing for SMBUS, although a lot of transfers are of SMBUS type, either emulated or direct. So, factor out the locking routine into a helper and use it for I2C and SMBUS. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:09 +00:00
static inline int __i2c_lock_bus_helper(struct i2c_adapter *adap)
{
int ret = 0;
i2c: core: introduce callbacks for atomic transfers We had the request to access devices very late when interrupts are not available anymore multiple times now. Mostly to prepare shutdown or reboot. Allow adapters to specify a specific callback for this case. Note that we fall back to the generic {master|smbus}_xfer callback if this new atomic one is not present. This is intentional to preserve the previous behaviour and avoid regressions. Because there are drivers not using interrupts or because it might have worked "accidently" before. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Stefan Lengfeld <contact@stefanchrist.eu> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:10 +00:00
if (i2c_in_atomic_xfer_mode()) {
WARN(!adap->algo->master_xfer_atomic && !adap->algo->smbus_xfer_atomic,
"No atomic I2C transfer handler for '%s'\n", dev_name(&adap->dev));
i2c: core: use I2C locking behaviour also for SMBUS If I2C transfers are executed in atomic contexts, trylock is used instead of lock. This behaviour was missing for SMBUS, although a lot of transfers are of SMBUS type, either emulated or direct. So, factor out the locking routine into a helper and use it for I2C and SMBUS. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:09 +00:00
ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT) ? 0 : -EAGAIN;
i2c: core: introduce callbacks for atomic transfers We had the request to access devices very late when interrupts are not available anymore multiple times now. Mostly to prepare shutdown or reboot. Allow adapters to specify a specific callback for this case. Note that we fall back to the generic {master|smbus}_xfer callback if this new atomic one is not present. This is intentional to preserve the previous behaviour and avoid regressions. Because there are drivers not using interrupts or because it might have worked "accidently" before. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Stefan Lengfeld <contact@stefanchrist.eu> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:10 +00:00
} else {
i2c: core: use I2C locking behaviour also for SMBUS If I2C transfers are executed in atomic contexts, trylock is used instead of lock. This behaviour was missing for SMBUS, although a lot of transfers are of SMBUS type, either emulated or direct. So, factor out the locking routine into a helper and use it for I2C and SMBUS. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:09 +00:00
i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
i2c: core: introduce callbacks for atomic transfers We had the request to access devices very late when interrupts are not available anymore multiple times now. Mostly to prepare shutdown or reboot. Allow adapters to specify a specific callback for this case. Note that we fall back to the generic {master|smbus}_xfer callback if this new atomic one is not present. This is intentional to preserve the previous behaviour and avoid regressions. Because there are drivers not using interrupts or because it might have worked "accidently" before. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Stefan Lengfeld <contact@stefanchrist.eu> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:10 +00:00
}
i2c: core: use I2C locking behaviour also for SMBUS If I2C transfers are executed in atomic contexts, trylock is used instead of lock. This behaviour was missing for SMBUS, although a lot of transfers are of SMBUS type, either emulated or direct. So, factor out the locking routine into a helper and use it for I2C and SMBUS. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-03 12:40:09 +00:00
return ret;
}
i2c: core: apply 'is_suspended' check for SMBus, too We checked I2C calls, but not SMBus. Refactor the helper to an inline function and use it for both, I2C and SMBus. Fixes: 9ac6cb5fbb17 ("i2c: add suspended flag and accessors for i2c adapters") Reported-by: Peter Rosin <peda@axentia.se> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-04-25 14:19:48 +00:00
static inline int __i2c_check_suspended(struct i2c_adapter *adap)
{
if (test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)) {
if (!test_and_set_bit(I2C_ALF_SUSPEND_REPORTED, &adap->locked_flags))
dev_WARN(&adap->dev, "Transfer while suspended\n");
return -ESHUTDOWN;
}
return 0;
}
i2c: break out ACPI support into separate file Removes some ifdeffery. Also add the new file to the relevant MAINTAINERS section. Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-05-23 14:22:23 +00:00
#ifdef CONFIG_ACPI
void i2c_acpi_register_devices(struct i2c_adapter *adap);
i2c: core: Move ACPI IRQ handling to probe time Bring the ACPI path in sync with the device tree path and handle all the IRQ fetching at probe time. This leaves the only IRQ handling at device registration time being that which is passed directly through the board info as either a resource or an actual IRQ number. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-06-27 09:24:09 +00:00
int i2c_acpi_get_irq(struct i2c_client *client);
i2c: break out ACPI support into separate file Removes some ifdeffery. Also add the new file to the relevant MAINTAINERS section. Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-05-23 14:22:23 +00:00
#else /* CONFIG_ACPI */
static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
i2c: core: Move ACPI IRQ handling to probe time Bring the ACPI path in sync with the device tree path and handle all the IRQ fetching at probe time. This leaves the only IRQ handling at device registration time being that which is passed directly through the board info as either a resource or an actual IRQ number. Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2019-06-27 09:24:09 +00:00
static inline int i2c_acpi_get_irq(struct i2c_client *client)
{
return 0;
}
i2c: break out ACPI support into separate file Removes some ifdeffery. Also add the new file to the relevant MAINTAINERS section. Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-05-23 14:22:23 +00:00
#endif /* CONFIG_ACPI */
extern struct notifier_block i2c_acpi_notifier;
#ifdef CONFIG_ACPI_I2C_OPREGION
int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
#else /* CONFIG_ACPI_I2C_OPREGION */
static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
#endif /* CONFIG_ACPI_I2C_OPREGION */
i2c: break out OF support into separate file Also removes some ifdeffery. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2017-05-23 09:50:58 +00:00
#ifdef CONFIG_OF
void of_i2c_register_devices(struct i2c_adapter *adap);
#else
static inline void of_i2c_register_devices(struct i2c_adapter *adap) { }
#endif
extern struct notifier_block i2c_of_notifier;
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