Messages in this thread | | | Date | Mon, 18 Mar 2024 11:16:05 +0100 | Subject | Re: [PATCH v2] spi: mt7621: allow GPIO chip select lines | From | AngeloGioacchino Del Regno <> |
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Il 16/03/24 02:03, Justin Swartz ha scritto: > Extract a magic number, from mt7621_spi_probe(), used to > declare the number of chip select lines (which co-incides > with the native chip select count of 2) to a macro. > > Use the newly defined MT7621_NATIVE_CS_COUNT macro to > instead populate both the spi_controller's max_native_cs > and num_chipselect members. > > Declare that the spi_controller should use_gpio_descriptors > if present in the device properties (such as those declared > in the cs-gpio property of a "ralink,mt7621-spi" compatible > device-tree node) so that the SPI core will recalculcate > num_chipselect to account for the GPIO descriptors that > it should have populated in the cs_gpiod array member. > > Remove the assignment of mt7621_spi_transfer_one_message() > to the spi_controller's transfer_one_message hook. > > Refactor the mt7621_spi_transfer_one_message() logic into > mt7621_spi_prepare_message() and mt7621_spi_transfer_one() > and assign both to the spi_controller's prepare_message > and transfer_one hooks respectively. > > Migrate the call mt7621_spi_transfer_one_message() made to > mt7621_spi_flush() just before chip select deactivation, > to the end of mt7621_spi_write_half_duplex() to ensure > that any pending data is shifted out of MOSI before the SPI > core deactivates the chip select line. > > As chip select activation is now taken care of by the SPI > core, due to the use of the transfer_one hook instead of > transfer_one_message, the calls to mt7621_spi_set_cs() > from mt7621_spi_transfer_one_message() have fallen away. > > And although the SPI core will handle activation for GPIO > chip select lines behind the scenes, it requires a callback > to allow the driver to perform controller-specific > operations to control its native chip select lines. > > Rename mt7621_spi_set_cs() to mt7621_spi_set_native_cs() > and make sure that it takes into account the activation > polarity of the chip select line it's acting upon, as the > passed enable parameter represents the desired line level > and not the desired activation state, and then assign > mt7621_set_cs() to the spi_controller's set_cs hook. > > Signed-off-by: Justin Swartz <justin.swartz@risingedge.co.za>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
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