[PATCH] soc: nuvoton: Add SoC info driver for WPCM450

[Joel Stanley]

On Sat, 29 Jan 2022 at 14:34, Jonathan Neuschäfer <j.neuschaefer at gmx.net> wrote:
>
> Add a SoC information driver for Nuvoton WPCM450 SoCs. It provides
> information such as the SoC revision.
>
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer at gmx.net>

Reviewed-by: Joel Stanley <joel at jms.id.au>

> ---
>
> The "nuvoton,wpcm450-gcr" compatible string is defined in:
>
>   [PATCH v5 1/9] dt-bindings: arm/npcm: Add binding for global control registers (GCR)
>   https://lore.kernel.org/lkml/20220129115228.2257310-2-j.neuschaefer@gmx.net/
> ---
>  drivers/soc/Kconfig               |  1 +
>  drivers/soc/Makefile              |  1 +
>  drivers/soc/nuvoton/Kconfig       | 11 ++++
>  drivers/soc/nuvoton/Makefile      |  2 +
>  drivers/soc/nuvoton/wpcm450-soc.c | 90 +++++++++++++++++++++++++++++++
>  5 files changed, 105 insertions(+)
>  create mode 100644 drivers/soc/nuvoton/Kconfig
>  create mode 100644 drivers/soc/nuvoton/Makefile
>  create mode 100644 drivers/soc/nuvoton/wpcm450-soc.c
>
> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
> index a8562678c4370..310c7e3a17723 100644
> --- a/drivers/soc/Kconfig
> +++ b/drivers/soc/Kconfig
> @@ -13,6 +13,7 @@ source "drivers/soc/imx/Kconfig"
>  source "drivers/soc/ixp4xx/Kconfig"
>  source "drivers/soc/litex/Kconfig"
>  source "drivers/soc/mediatek/Kconfig"
> +source "drivers/soc/nuvoton/Kconfig"
>  source "drivers/soc/qcom/Kconfig"
>  source "drivers/soc/renesas/Kconfig"
>  source "drivers/soc/rockchip/Kconfig"
> diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
> index adb30c2d4feaa..f02c9b091a513 100644
> --- a/drivers/soc/Makefile
> +++ b/drivers/soc/Makefile
> @@ -18,6 +18,7 @@ obj-y                         += ixp4xx/
>  obj-$(CONFIG_SOC_XWAY)         += lantiq/
>  obj-$(CONFIG_LITEX_SOC_CONTROLLER) += litex/
>  obj-y                          += mediatek/
> +obj-y                          += nuvoton/
>  obj-y                          += amlogic/
>  obj-y                          += qcom/
>  obj-y                          += renesas/
> diff --git a/drivers/soc/nuvoton/Kconfig b/drivers/soc/nuvoton/Kconfig
> new file mode 100644
> index 0000000000000..50166f37096b7
> --- /dev/null
> +++ b/drivers/soc/nuvoton/Kconfig
> @@ -0,0 +1,11 @@
> +# SPDX-License-Identifier: GPL-2.0
> +menuconfig WPCM450_SOC
> +       bool "Nuvoton WPCM450 SoC driver"
> +       default y if ARCH_WPCM450
> +       select SOC_BUS
> +       help
> +         Say Y here to compile the SoC information driver for Nuvoton
> +         WPCM450 SoCs.
> +
> +         This driver provides information such as the SoC model and
> +         revision.
> diff --git a/drivers/soc/nuvoton/Makefile b/drivers/soc/nuvoton/Makefile
> new file mode 100644
> index 0000000000000..e30317b4e8290
> --- /dev/null
> +++ b/drivers/soc/nuvoton/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_WPCM450_SOC)      += wpcm450-soc.o
> diff --git a/drivers/soc/nuvoton/wpcm450-soc.c b/drivers/soc/nuvoton/wpcm450-soc.c
> new file mode 100644
> index 0000000000000..e5723d6c933bc
> --- /dev/null
> +++ b/drivers/soc/nuvoton/wpcm450-soc.c
> @@ -0,0 +1,90 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Nuvoton WPCM450 SoC Identification
> + *
> + * Copyright (C) 2021 Jonathan Neuschäfer
> + */
> +
> +#include <linux/mfd/syscon.h>
> +#include <linux/of.h>
> +#include <linux/regmap.h>
> +#include <linux/sys_soc.h>
> +#include <linux/slab.h>
> +
> +#define GCR_PDID       0
> +#define PDID_CHIP(x)   ((x) & 0x00ffffff)
> +#define CHIP_WPCM450   0x926450
> +#define PDID_REV(x)    ((x) >> 24)
> +
> +struct revision {
> +       u8 number;
> +       const char *name;
> +};
> +
> +const struct revision revisions[] __initconst = {
> +       { 0x00, "Z1" },
> +       { 0x03, "Z2" },
> +       { 0x04, "Z21" },
> +       { 0x08, "A1" },
> +       { 0x09, "A2" },
> +       { 0x0a, "A3" },
> +       {}
> +};
> +
> +static const char * __init get_revision(u8 rev)
> +{
> +       int i;
> +
> +       for (i = 0; revisions[i].name; i++)
> +               if (revisions[i].number == rev)
> +                       return revisions[i].name;
> +       return NULL;
> +}
> +
> +static int __init wpcm450_soc_init(void)
> +{
> +       struct soc_device_attribute *attr;
> +       struct soc_device *soc;
> +       const char *revision;
> +       struct regmap *gcr;
> +       u32 pdid;
> +       int ret;
> +
> +       if (!of_machine_is_compatible("nuvoton,wpcm450"))
> +               return 0;
> +
> +       gcr = syscon_regmap_lookup_by_compatible("nuvoton,wpcm450-gcr");
> +       if (IS_ERR(gcr))
> +               return PTR_ERR(gcr);
> +       ret = regmap_read(gcr, GCR_PDID, &pdid);
> +       if (ret)
> +               return ret;
> +
> +       if (PDID_CHIP(pdid) != CHIP_WPCM450) {
> +               pr_warn("Unknown chip ID in GCR.PDID: 0x%06x\n", PDID_CHIP(pdid));
> +               return -ENODEV;
> +       }
> +
> +       revision = get_revision(PDID_REV(pdid));
> +       if (!revision) {
> +               pr_warn("Unknown chip revision in GCR.PDID: 0x%02x\n", PDID_REV(pdid));
> +               return -ENODEV;
> +       }
> +
> +       attr = kzalloc(sizeof(*attr), GFP_KERNEL);
> +       if (!attr)
> +               return -ENOMEM;
> +
> +       attr->family = "Nuvoton NPCM";
> +       attr->soc_id = "WPCM450";
> +       attr->revision = revision;
> +       soc = soc_device_register(attr);
> +       if (IS_ERR(soc)) {
> +               kfree(attr);
> +               pr_warn("Could not register SoC device\n");
> +               return PTR_ERR(soc);
> +       }
> +
> +       return 0;
> +}
> +device_initcall(wpcm450_soc_init);
> --
> 2.34.1
>