On 04/06/2021 19:27, Stephan Gerhold wrote: > The Samsung Galaxy A3/A5 both have a Samsung S3FWRN5 NFC chip that > works quite well with the s3fwrn5 driver in the Linux NFC subsystem. > > The clock setup for the NFC chip is a bit special (although this > seems to be a common approach used for Qualcomm devices with NFC): > > The NFC chip has an output GPIO that is asserted whenever the clock > is needed to function properly. On the A3/A5 this is wired up to > PM8916 GPIO2, which is then configured with a special function > (NFC_CLK_REQ or BB_CLK2_REQ). > > Enabling the rpmcc RPM_SMD_BB_CLK2_PIN clock will then instruct > PM8916 to automatically enable the clock whenever the NFC chip > requests it. The advantage is that the clock is only enabled when > needed and we don't need to manage it ourselves from the NFC driver. > > Note that for some reason Samsung decided to connect the I2C pins > to GPIOs where no hardware I2C bus is available, so we need to > fall back to software bit-banging with i2c-gpio. > > Cc: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx> > Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx> > --- > .../qcom/msm8916-samsung-a2015-common.dtsi | 64 +++++++++++++++++++ > 1 file changed, 64 insertions(+) > Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx> Best regards, Krzysztof
