[PATCH v5 3/7] rtc: goldfish: Support platform data for non-DT probing

[Simon Glass]

Hi Kuan-Wei,

On Mon, 5 Jan 2026 at 11:20, Kuan-Wei Chiu <visitorckw at gmail.com> wrote:
>
> Currently, the Goldfish RTC driver exclusively relies on device tree
> to retrieve the base address, failing immediately if dev_read_addr()
> returns FDT_ADDR_T_NONE. This restriction prevents the driver from
> being used on platforms that instantiate devices via U_BOOT_DRVINFO()
> instead of device tree, such as the QEMU m68k virt machine.
>
> Add support for platform data to address this limitation. Update the
> probe function to fall back to retrieving the base address from
> struct goldfish_rtc_plat if the device tree address is unavailable.
> Introduce a new header file include/goldfish_rtc.h to define the
> platform data structure.
>
> Signed-off-by: Kuan-Wei Chiu <visitorckw at gmail.com>
> Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
> Changes in v5:
> - Rebase on u-boot/next branch.
>
>  drivers/rtc/goldfish_rtc.c | 13 ++++++++++---
>  include/goldfish_rtc.h     | 15 +++++++++++++++
>  2 files changed, 25 insertions(+), 3 deletions(-)
>  create mode 100644 include/goldfish_rtc.h
>

You can package your own devicetree in the U-Boot source, to handle
what you need.

> diff --git a/drivers/rtc/goldfish_rtc.c b/drivers/rtc/goldfish_rtc.c
> index e63a2766c76..f6316896595 100644
> --- a/drivers/rtc/goldfish_rtc.c
> +++ b/drivers/rtc/goldfish_rtc.c
> @@ -9,6 +9,7 @@
>
>  #include <div64.h>
>  #include <dm.h>
> +#include <goldfish_rtc.h>
>  #include <mapmem.h>
>  #include <rtc.h>
>  #include <linux/io.h>
> @@ -77,12 +78,18 @@ static int goldfish_rtc_set(struct udevice *dev, const struct rtc_time *time)
>  static int goldfish_rtc_probe(struct udevice *dev)
>  {
>         struct goldfish_rtc *priv = dev_get_priv(dev);
> +       struct goldfish_rtc_plat *plat;
>         fdt_addr_t addr;
>
>         addr = dev_read_addr(dev);
> -       if (addr == FDT_ADDR_T_NONE)
> -               return -EINVAL;
> -       priv->base = map_sysmem(addr, 0x20);
> +       if (addr != FDT_ADDR_T_NONE) {
> +               priv->base = map_sysmem(addr, 0x20);
> +       } else {
> +               plat = dev_get_plat(dev);
> +               if (!plat)
> +                       return -EINVAL;
> +               priv->base = plat->base;
> +       }
>
>         return 0;
>  }
> diff --git a/include/goldfish_rtc.h b/include/goldfish_rtc.h
> new file mode 100644
> index 00000000000..bb113a0bd79
> --- /dev/null
> +++ b/include/goldfish_rtc.h
> @@ -0,0 +1,15 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2025, Kuan-Wei Chiu <visitorckw at gmail.com>
> + */
> +
> +#ifndef _GOLDFISH_RTC_H_
> +#define _GOLDFISH_RTC_H_
> +
> +#include <linux/types.h>
> +
> +struct goldfish_rtc_plat {
> +       void __iomem *base;
> +};
> +
> +#endif /* _GOLDFISH_RTC_H_ */
> --
> 2.52.0.358.g0dd7633a29-goog
>

Regards,
Simon