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path: root/drivers/counter/stm32-timer-cnt.c
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2021-10-17counter: Internalize sysfs interface codeWilliam Breathitt Gray
This is a reimplementation of the Generic Counter driver interface. There are no modifications to the Counter subsystem userspace interface, so existing userspace applications should continue to run seamlessly. The purpose of this patch is to internalize the sysfs interface code among the various counter drivers into a shared module. Counter drivers pass and take data natively (i.e. u8, u64, etc.) and the shared counter module handles the translation between the sysfs interface and the device drivers. This guarantees a standard userspace interface for all counter drivers, and helps generalize the Generic Counter driver ABI in order to support the Generic Counter chrdev interface (introduced in a subsequent patch) without significant changes to the existing counter drivers. Note, Counter device registration is the same as before: drivers populate a struct counter_device with components and callbacks, then pass the structure to the devm_counter_register function. However, what's different now is how the Counter subsystem code handles this registration internally. Whereas before callbacks would interact directly with sysfs data, this interaction is now abstracted and instead callbacks interact with native C data types. The counter_comp structure forms the basis for Counter extensions. The counter-sysfs.c file contains the code to parse through the counter_device structure and register the requested components and extensions. Attributes are created and populated based on type, with respective translation functions to handle the mapping between sysfs and the counter driver callbacks. The translation performed for each attribute is straightforward: the attribute type and data is parsed from the counter_attribute structure, the respective counter driver read/write callback is called, and sysfs I/O is handled before or after the driver read/write function is called. Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com> Cc: Patrick Havelange <patrick.havelange@essensium.com> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com> Reviewed-by: David Lechner <david@lechnology.com> Tested-by: David Lechner <david@lechnology.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> # for stm32 Link: https://lore.kernel.org/r/c68b4a1ffb195c1a2f65e8dd5ad7b7c14e79c6ef.1630031207.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-10-17counter: stm32-timer-cnt: Provide defines for slave mode selectionWilliam Breathitt Gray
The STM32 timer permits configuration of the counter encoder mode via the slave mode control register (SMCR) slave mode selection (SMS) bits. This patch provides preprocessor defines for the supported encoder modes. Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Link: https://lore.kernel.org/r/ad3d9cd7af580d586316d368f74964cbc394f981.1630031207.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-08-09counter: Rename counter_count_function to counter_functionWilliam Breathitt Gray
The phrase "Counter Count function" is verbose and unintentionally implies that function is a Count extension. This patch adjusts the Counter subsystem code to use the more direct "Counter function" phrase to make the intent of this code clearer. Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com> Cc: Patrick Havelange <patrick.havelange@essensium.com> Cc: Oleksij Rempel <o.rempel@pengutronix.de> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: David Lechner <david@lechnology.com> Acked-by: Syed Nayyar Waris <syednwaris@gmail.com> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Link: https://lore.kernel.org/r/8268c54d6f42075a19bb08151a37831e22652499.1627990337.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-06-09counter: stm32-timer-cnt: Add const qualifier for actions_list arrayWilliam Breathitt Gray
The struct counter_synapse actions_list member expects a const enum counter_synapse_action array. This patch adds the const qualifier to the stm32_synapse_actions to match actions_list. Cc: Benjamin Gaignard <benjamin.gaignard@st.com> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Link: https://lore.kernel.org/r/9675edda958ee2ca371d271f46445d3e1934ba82.1623201081.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-06-09counter: stm32-timer-cnt: Add const qualifier for functions_list arrayWilliam Breathitt Gray
The struct counter_count functions_list member expects a const enum counter_count_function array. This patch adds the const qualifier to the stm32_count_functions to match functions_list. Cc: Benjamin Gaignard <benjamin.gaignard@st.com> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Link: https://lore.kernel.org/r/46a1e7096dd9280d8f241894186b3c903956a55f.1623201081.git.vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-03-06counter: stm32-timer-cnt: fix ceiling miss-alignment with reload registerFabrice Gasnier
Ceiling value may be miss-aligned with what's actually configured into the ARR register. This is seen after probe as currently the ARR value is zero, whereas ceiling value is set to the maximum. So: - reading ceiling reports zero - in case the counter gets enabled without any prior configuration, it won't count. - in case the function gets set by the user 1st, (priv->ceiling) is used. Fix it by getting rid of the cached "priv->ceiling" variable. Rather use the ARR register value directly by using regmap read or write when needed. There should be no drawback on performance as priv->ceiling isn't used in performance critical path. There's also no point in writing ARR while setting function (sms), so it can be safely removed. Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder") Suggested-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Cc: <Stable@vger.kernel.org> Link: https://lore.kernel.org/r/1614793789-10346-1-git-send-email-fabrice.gasnier@foss.st.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-03-06counter: stm32-timer-cnt: fix ceiling write max valueFabrice Gasnier
The ceiling value isn't checked before writing it into registers. The user could write a value higher than the counter resolution (e.g. 16 or 32 bits indicated by max_arr). This makes most significant bits to be truncated. Fix it by checking the max_arr to report a range error [1] to the user. [1] https://lkml.org/lkml/2021/2/12/358 Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder") Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Cc: <Stable@vger.kernel.org> Link: https://lore.kernel.org/r/1614696235-24088-1-git-send-email-fabrice.gasnier@foss.st.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2021-02-27counter: stm32-timer-cnt: Report count function when SLAVE_MODE_DISABLEDWilliam Breathitt Gray
When in SLAVE_MODE_DISABLED mode, the count still increases if the counter is enabled because an internal clock is used. This patch fixes the stm32_count_function_get() and stm32_count_function_set() functions to properly handle this behavior. Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder") Cc: Fabrice Gasnier <fabrice.gasnier@st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Link: https://lore.kernel.org/r/20210226012931.161429-1-vilhelm.gray@gmail.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2020-02-21counter: stm32-timer-cnt: remove iio headersFabrice Gasnier
The stm32-timer-cnt driver doesn't use the iio interface. The iio headers aren't relevant and can be removed as reported by William in [1]. With this change, mod_devicetable.h needs to be added to define the 'of_device_id' struct. [1] https://lkml.org/lkml/2020/2/10/1516 Reported-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2020-02-21counter: stm32-timer-cnt: add power management supportFabrice Gasnier
Add suspend/resume PM sleep ops. When going to low power, enforce the counter isn't active. Gracefully restore its state upon resume in case it's been left enabled prior to suspend. Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-10-18counter: Simplify the count_read and count_write callbacksWilliam Breathitt Gray
The count_read and count_write callbacks are simplified to pass val as unsigned long rather than as an opaque data structure. The opaque counter_count_read_value and counter_count_write_value structures, counter_count_value_type enum, and relevant counter_count_read_value_set and counter_count_write_value_get functions, are removed as they are no longer used. Cc: Patrick Havelange <patrick.havelange@essensium.com> Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com> Acked-by: David Lechner <david@lechnology.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-10-07counter: stm32: clean up indentation issueColin Ian King
There is an if statement that is indented one level too deeply, remove the extraneous tabs. Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-10-05counter: stm32-timer-cnt: fix a kernel-doc warningFabrice Gasnier
Fix the following warning when documentation is built: drivers/counter/stm32-timer-cnt.c:37: warning: cannot understand function prototype: 'enum stm32_count_function' Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> Fixes: ad29937e206f ("counter: Add STM32 Timer quadrature encoder") Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2019-04-25counter: Add STM32 Timer quadrature encoderBenjamin Gaignard
Implement counter part of the STM32 timer hardware block by using counter API. Hardware only supports X2 and X4 quadrature modes. A ceiling value can be set to define the maximum value reachable by the counter. Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com> Co-authored-by: Fabrice Gasnier <fabrice.gasnier@st.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>