[PATCH 2/2] riscv: dts: unmatched: Add gpio card detect to mmc-spi-slot

[Ron Economos]

> From: Bin Meng <bin.meng at windriver.com  <http://lists.infradead.org/mailman/listinfo/linux-riscv>>
>
> Per HiFive Unmatched schematics, the card detect signal of the
> micro SD card is connected to gpio pin #15, which should be
> reflected in the DT via the <gpios> property, as described in
> Documentation/devicetree/bindings/mmc/mmc-spi-slot.txt.
>
> [1]https://sifive.cdn.prismic.io/sifive/6a06d6c0-6e66-49b5-8e9e-e68ce76f4192_hifive-unmatched-schematics-v3.pdf  <https://sifive.cdn.prismic.io/sifive/6a06d6c0-6e66-49b5-8e9e-e68ce76f4192_hifive-unmatched-schematics-v3.pdf>
>
> Signed-off-by: Bin Meng <bin.meng at windriver.com  <http://lists.infradead.org/mailman/listinfo/linux-riscv>>
> ---
>
>   arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts b/arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts
> index b1c3c596578f..214794363c6a 100644
> --- a/arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts
> +++ b/arch/riscv/boot/dts/sifive/hifive-unmatched-a00.dts
> @@ -2,6 +2,7 @@
>   /* Copyright (c) 2020 SiFive, Inc */
>   
>   #include "fu740-c000.dtsi"
> +#include <dt-bindings/gpio/gpio.h>
>   #include <dt-bindings/interrupt-controller/irq.h>
>   
>   /* Clock frequency (in Hz) of the PCB crystal for rtcclk */
> @@ -228,6 +229,7 @@mmc at 0  <http://lists.infradead.org/mailman/listinfo/linux-riscv>  {
>   		spi-max-frequency = <20000000>;
>   		voltage-ranges = <3300 3300>;
>   		disable-wp;
> +		gpios = <&gpio 15 GPIO_ACTIVE_LOW>;
>   	};
>   };
>   
> -- 
> 2.25.1

This is a very useful patch. When running the HiFive Unmatched board 
without an SD card inserted, /var/log/syslog and dmesg gets spammed 
every four seconds with:

|[Thu Aug 26 06:03:54 2021] mmc_spi spi1.0: no support for card's volts 
[Thu Aug 26 06:03:54 2021] mmc0: error -22 whilst initialising SDIO card 
This patch prevents that. Tested on HiFive Unmatched with Ubuntu 21.04 
and v5.14.1 kernel. |