[PATCH 4/4] board: rockchip: Add early ADC button detect for RGxx3

[Kever Yang]

On 2024/2/6 02:58, Chris Morgan wrote:
> From: Chris Morgan <macromorgan at hotmail.com>
>
> Add ADC button detect for early SPL stage for RGxx3 device. This is
> important because on at least the RG353P and RG353V a clk pin is not
> exposed that would allow us to take the eMMC out of the boot path.
>
> Signed-off-by: Chris Morgan <macromorgan at hotmail.com>
Reviewed-by: Kever Yang <kever.yang at rock-chips.com>

Thanks,
- Kever
> ---
>   board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c | 64 ++++++++++++++++++++++
>   1 file changed, 64 insertions(+)
>
> diff --git a/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c b/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c
> index 5c57b902d1..099eea60c3 100644
> --- a/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c
> +++ b/board/anbernic/rgxx3_rk3566/rgxx3-rk3566.c
> @@ -6,12 +6,14 @@
>   #include <abuf.h>
>   #include <adc.h>
>   #include <asm/io.h>
> +#include <command.h>
>   #include <display.h>
>   #include <dm.h>
>   #include <dm/lists.h>
>   #include <env.h>
>   #include <fdt_support.h>
>   #include <linux/delay.h>
> +#include <linux/iopoll.h>
>   #include <mipi_dsi.h>
>   #include <mmc.h>
>   #include <panel.h>
> @@ -19,6 +21,8 @@
>   #include <stdlib.h>
>   #include <video_bridge.h>
>   
> +#define BOOT_BROM_DOWNLOAD	0xef08a53c
> +
>   #define GPIO0_BASE		0xfdd60000
>   #define GPIO4_BASE		0xfe770000
>   #define GPIO_SWPORT_DR_L	0x0000
> @@ -32,6 +36,14 @@
>   
>   #define GPIO_WRITEMASK(bits)	((bits) << 16)
>   
> +#define SARADC_BASE		0xfe720000
> +#define SARADC_DATA		0x0000
> +#define SARADC_STAS		0x0004
> +#define SARADC_ADC_STATUS	BIT(0)
> +#define SARADC_CTRL		0x0008
> +#define SARADC_INPUT_SRC_MSK	0x7
> +#define SARADC_POWER_CTRL	BIT(3)
> +
>   #define DTB_DIR			"rockchip/"
>   
>   struct rg3xx_model {
> @@ -157,12 +169,64 @@ static const struct rg353_panel rg353_panel_details[] = {
>   	},
>   };
>   
> +/*
> + * The device has internal eMMC, and while some devices have an exposed
> + * clk pin you can ground to force a bypass not all devices do. As a
> + * result it may be possible for some devices to become a perma-brick
> + * if a corrupted TPL or SPL stage with a valid header is flashed to
> + * the internal eMMC. Add functionality to read ADC channel 0 (the func
> + * button) as early as possible in the boot process to provide some
> + * protection against this. If we ever get an open TPL stage, we should
> + * consider moving this function there.
> + */
> +void read_func_button(void)
> +{
> +	int ret;
> +	u32 reg;
> +
> +	/* Turn off SARADC to reset it. */
> +	writel(0, (SARADC_BASE + SARADC_CTRL));
> +
> +	/* Enable channel 0 and power on SARADC. */
> +	writel(((0 & SARADC_INPUT_SRC_MSK) | SARADC_POWER_CTRL),
> +	       (SARADC_BASE + SARADC_CTRL));
> +
> +	/*
> +	 * Wait for data to be ready. Use timeout of 20000us from
> +	 * rockchip_saradc driver.
> +	 */
> +	ret = readl_poll_timeout((SARADC_BASE + SARADC_STAS), reg,
> +				 !(reg & SARADC_ADC_STATUS), 20000);
> +	if (ret) {
> +		printf("ADC Timeout");
> +		return;
> +	}
> +
> +	/* Read the data from the SARADC. */
> +	reg = readl((SARADC_BASE + SARADC_DATA));
> +
> +	/* Turn the SARADC back off so it's ready to be used again. */
> +	writel(0, (SARADC_BASE + SARADC_CTRL));
> +
> +	/*
> +	 * If the value is less than 30 the button is being pressed.
> +	 * Reset the device back into Rockchip download mode.
> +	 */
> +	if (reg <= 30) {
> +		printf("download key pressed, entering download mode...");
> +		writel(BOOT_BROM_DOWNLOAD, CONFIG_ROCKCHIP_BOOT_MODE_REG);
> +		do_reset(NULL, 0, 0, NULL);
> +	}
> +};
> +
>   /*
>    * Start LED very early so user knows device is on. Set color
>    * to red.
>    */
>   void spl_board_init(void)
>   {
> +	read_func_button();
> +
>   	/* Set GPIO0_C5, GPIO0_C6, and GPIO0_C7 to output. */
>   	writel(GPIO_WRITEMASK(GPIO_C7 | GPIO_C6 | GPIO_C5) | \
>   	       (GPIO_C7 | GPIO_C6 | GPIO_C5),