Messages in this thread | | | Date | Wed, 19 Feb 2020 11:11:30 -0800 (PST) | Subject | Re: [PATCH v1] nfc: pn544: Fix occasional HW initialization failure | From | David Miller <> |
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From: Dmitry Osipenko <digetx@gmail.com> Date: Wed, 19 Feb 2020 18:01:22 +0300
> The PN544 driver checks the "enable" polarity during of driver's probe and > it's doing that by turning ON and OFF NFC with different polarities until > enabling succeeds. It takes some time for the hardware to power-down, and > thus, to deassert the IRQ that is raised by turning ON the hardware. > Since the delay after last power-down of the polarity-checking process is > missed in the code, the interrupt may trigger immediately after installing > the IRQ handler (right after the checking is done), which results in IRQ > handler trying to touch the disabled HW and ends with marking NFC as > 'DEAD' during of the driver's probe: > > pn544_hci_i2c 1-002a: NFC: nfc_en polarity : active high > pn544_hci_i2c 1-002a: NFC: invalid len byte > shdlc: llc_shdlc_recv_frame: NULL Frame -> link is dead > > This patch fixes the occasional NFC initialization failure on Nexus 7 > device. > > Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Applied and queued up for -stable, thanks.
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