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commit 50352c5b757dcc8cf8f9bb5ba4de429109e6fc46 Author: Eren Terzioglu <[email protected]> AuthorDate: Wed May 13 14:35:41 2026 +0200 Docs/platforms/risc-v: Add Analog Comparator docs for esp32[-h2|-p4] Add Analog Comparator docs for esp32h2 and esp32p4 Signed-off-by: Eren Terzioglu <[email protected]> --- .../risc-v/esp32h2/boards/esp32h2-devkit/index.rst | 32 ++++++++++++++++++++ Documentation/platforms/risc-v/esp32h2/index.rst | 1 + .../boards/esp32p4-function-ev-board/index.rst | 34 ++++++++++++++++++++++ Documentation/platforms/risc-v/esp32p4/index.rst | 1 + 4 files changed, 68 insertions(+) diff --git a/Documentation/platforms/risc-v/esp32h2/boards/esp32h2-devkit/index.rst b/Documentation/platforms/risc-v/esp32h2/boards/esp32h2-devkit/index.rst index 8e47c46925f..5703429f07c 100644 --- a/Documentation/platforms/risc-v/esp32h2/boards/esp32h2-devkit/index.rst +++ b/Documentation/platforms/risc-v/esp32h2/boards/esp32h2-devkit/index.rst @@ -108,6 +108,38 @@ show in units of mV):: 3: channel: 2 value: 1 4: channel: 3 value: 0 +analog_cmpr +----------- + +Enables the analog comparator driver. Driver unit is registered as ``/dev/anacmpr0`` +for analog comparator unit0. For each unit, the reference is either internal, +comparing the source input against a fraction of VDD in 10% steps from 0% to 70% +(for example, 50% VDD triggers when the source crosses half the supply voltage), or +external, comparing the source GPIO against the voltage on the external reference +pin. Reference source and debounce timeout for each unit can be adjusted in +``Analog Comparator Configuration``. + +Comparator GPIOs are fixed by hardware and cannot be remapped. Following table demonstrates +which pins are dedicated for comparator: + +======== ================================================================================= +Pin Role +======== ================================================================================= +GPIO11 Input source for unit0 +GPIO10 External reference input (if external reference source is selected for unit0) +======== ================================================================================= + +The following snippet demonstrates how to read the comparator result: + +.. code-block:: C + + int fd; + int ret; + int res; + + fd = open("/dev/anacmpr0", O_RDONLY); + ret = read(fd, &res, sizeof(res)); + autopm ------ diff --git a/Documentation/platforms/risc-v/esp32h2/index.rst b/Documentation/platforms/risc-v/esp32h2/index.rst index 9c24bbd465c..e14db7bba66 100644 --- a/Documentation/platforms/risc-v/esp32h2/index.rst +++ b/Documentation/platforms/risc-v/esp32h2/index.rst @@ -437,6 +437,7 @@ USB Serial Yes Watchdog Yes Wifi No XTS No +Analog Comp Yes ============== ======= ==================== Analog-to-digital converter (ADC) diff --git a/Documentation/platforms/risc-v/esp32p4/boards/esp32p4-function-ev-board/index.rst b/Documentation/platforms/risc-v/esp32p4/boards/esp32p4-function-ev-board/index.rst index 7d9e2ca11b5..1a76190ad9a 100644 --- a/Documentation/platforms/risc-v/esp32p4/boards/esp32p4-function-ev-board/index.rst +++ b/Documentation/platforms/risc-v/esp32p4/boards/esp32p4-function-ev-board/index.rst @@ -179,6 +179,40 @@ adc Enables the ADC driver. ADC unit(s) are registered (``/dev/adc0`` as ADC1). Attenuation, mode, and channel set can be adjusted in ``ADC Configuration``. +analog_cmpr +----------- + +Enables the analog comparator driver. Driver unit is registered as ``/dev/anacmpr0`` +for analog comparator unit0. For each unit, the reference is either internal, +comparing the source input against a fraction of VDD in 10% steps from 0% to 70% +(for example, 50% VDD triggers when the source crosses half the supply voltage), or +external, comparing the source GPIO against the voltage on the external reference +pin. Reference source and debounce timeout for each unit can be adjusted in +``Analog Comparator Configuration``. + +Comparator GPIOs are fixed by hardware and cannot be remapped. Following table demonstrates +which pins are dedicated for comparator: + +======== ================================================================================= +Pin Role +======== ================================================================================= +GPIO52 Input source for unit0 +GPIO51 External reference input (if external reference source is selected for unit0) +GPIO54 Input source for unit1 +GPIO53 External reference input (if external reference source is selected for unit1) +======== ================================================================================= + +The following snippet demonstrates how to read the comparator result: + +.. code-block:: C + + int fd; + int ret; + int res; + + fd = open("/dev/anacmpr0", O_RDONLY); + ret = read(fd, &res, sizeof(res)); + autopm ------ diff --git a/Documentation/platforms/risc-v/esp32p4/index.rst b/Documentation/platforms/risc-v/esp32p4/index.rst index 550bab2974e..30764106a66 100644 --- a/Documentation/platforms/risc-v/esp32p4/index.rst +++ b/Documentation/platforms/risc-v/esp32p4/index.rst @@ -363,6 +363,7 @@ Watchdog Yes MWDT0/1 and RWDT Ethernet Yes Brownout No Debug Probe No +Analog Comp Yes COMP0/1 ================= ======= ================================== LP Peripherals
