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Peijie Shao authored
The failure paths in tpm_tis_spi_transfer() do not deactivate chip select. Send an empty message (cs_select == 0) to overcome this. The patch is tested by two ways. One way needs to touch hardware: 1. force pull MISO pin down to GND, it emulates a forever 'WAIT' timing. 2. probe cs pin by an oscilloscope. 3. load tpm_tis_spi.ko. After loading, dmesg prints: "probe of spi0.0 failed with error -110" and oscilloscope shows cs pin goes high(deactivated) after the failure. Before the patch, cs pin keeps low. Second way is by writing a fake spi controller. 1. implement .transfer_one method, fill all rx buf with 0. 2. implement .set_cs method, print the state of cs pin. we can see cs goes high after the failure. Signed-off-by: Peijie Shao <shaopeijie@cestc.cn> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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