Re: [PATCH v4 3/6] rtc: goldfish: Support platform data for non-DT probing

Heinrich Schuchardt
2026-01-02T08:28:07Z

On 1/1/26 18:54, Kuan-Wei Chiu 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@gmail.com>

Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

> ---
> Changes in v4:
> - Fix sandbox build warning by removing incorrect pointer casting.
> - Assign plat->base directly to priv->base instead of using
> map_sysmem() for platform data.
>
> 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
>
> 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@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_ */