[PATCH v4] soc: nuvoton: Add SoC info driver for WPCM450

[PATCH v4] soc: nuvoton: Add SoC info driver for WPCM450

[Jonathan Neuschäfer]

Add a SoC information driver for Nuvoton WPCM450 SoCs. It provides
information such as the SoC revision.

Usage example:

  # grep . /sys/devices/soc0/*
  /sys/devices/soc0/family:Nuvoton NPCM
  /sys/devices/soc0/revision:A3
  /sys/devices/soc0/soc_id:WPCM450

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
---
v4:
- rebase on 5.19-rc1

v3:
- Declare revisions array as static
- Change get_revision parameter to `unsigned int`
- Add Paul's R-b tag
- Add usage example
- Sort includes

v2:
- https://lore.kernel.org/lkml/20220409173319.2491196-1-j.neuschaefer@gmx.net/
- Add R-b tag
- rebase on 5.18-rc1

v1:
- https://lore.kernel.org/lkml/20220129143316.2321460-1-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 86ccf5970bc1b..cca3dfa5c6aea 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -14,6 +14,7 @@ source "drivers/soc/ixp4xx/Kconfig"
 source "drivers/soc/litex/Kconfig"
 source "drivers/soc/mediatek/Kconfig"
 source "drivers/soc/microchip/Kconfig"
+source "drivers/soc/nuvoton/Kconfig"
 source "drivers/soc/pxa/Kconfig"
 source "drivers/soc/qcom/Kconfig"
 source "drivers/soc/renesas/Kconfig"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index 919716e0e7001..b9eb3c75e551a 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_SOC_XWAY)		+= lantiq/
 obj-$(CONFIG_LITEX_SOC_CONTROLLER) += litex/
 obj-y				+= mediatek/
 obj-y				+= microchip/
+obj-y				+= nuvoton/
 obj-y				+= pxa/
 obj-y				+= amlogic/
 obj-y				+= qcom/
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..9ff876ea71361
--- /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) 2022 Jonathan Neuschäfer
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/sys_soc.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;
+};
+
+static const struct revision revisions[] __initconst = {
+	{ 0x00, "Z1" },
+	{ 0x03, "Z2" },
+	{ 0x04, "Z21" },
+	{ 0x08, "A1" },
+	{ 0x09, "A2" },
+	{ 0x0a, "A3" },
+	{}
+};
+
+static const char * __init get_revision(unsigned int 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);
--
2.35.1

Re: [PATCH v4] soc: nuvoton: Add SoC info driver for WPCM450

[Arnd Bergmann]

On Thu, Jun 9, 2022 at 11:35 PM Jonathan Neuschäfer
<j.neuschaefer@gmx.net> wrote:
>
> Add a SoC information driver for Nuvoton WPCM450 SoCs. It provides
> information such as the SoC revision.
>
> Usage example:
>
>   # grep . /sys/devices/soc0/*
>   /sys/devices/soc0/family:Nuvoton NPCM
>   /sys/devices/soc0/revision:A3
>   /sys/devices/soc0/soc_id:WPCM450
>
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> Reviewed-by: Joel Stanley <joel@jms.id.au>
> Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>

Looks good overall.

> +menuconfig WPCM450_SOC
> +       bool "Nuvoton WPCM450 SoC driver"
> +       default y if ARCH_WPCM450

It would be nice to make this a tristate option, as we generally
like to keep optional drivers out of the allmodconfig vmlinux file,
even if this is a tiny one.

Just add the trivial cleanup function and MODULE_LICENSE() etc tags.

        Arnd

Re: [PATCH v4] soc: nuvoton: Add SoC info driver for WPCM450

[Jonathan Neuschäfer]

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On Wed, Jun 15, 2022 at 04:00:17PM +0200, Arnd Bergmann wrote:
> On Thu, Jun 9, 2022 at 11:35 PM Jonathan Neuschäfer
> <j.neuschaefer@gmx.net> wrote:
> >
> > Add a SoC information driver for Nuvoton WPCM450 SoCs. It provides
> > information such as the SoC revision.
> >
> > Usage example:
> >
> >   # grep . /sys/devices/soc0/*
> >   /sys/devices/soc0/family:Nuvoton NPCM
> >   /sys/devices/soc0/revision:A3
> >   /sys/devices/soc0/soc_id:WPCM450
> >
> > Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> > Reviewed-by: Joel Stanley <joel@jms.id.au>
> > Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
> 
> Looks good overall.
> 
> > +menuconfig WPCM450_SOC
> > +       bool "Nuvoton WPCM450 SoC driver"
> > +       default y if ARCH_WPCM450
> 
> It would be nice to make this a tristate option, as we generally
> like to keep optional drivers out of the allmodconfig vmlinux file,
> even if this is a tiny one.

Ok.

> Just add the trivial cleanup function and MODULE_LICENSE() etc tags.

The right thing to do seems to be to unregister the SoC device in the
cleanup function. Is that what you mean?


Jonathan

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Re: [PATCH v4] soc: nuvoton: Add SoC info driver for WPCM450

[Arnd Bergmann]

On Fri, Jun 17, 2022 at 11:28 AM Jonathan Neuschäfer
<j.neuschaefer@gmx.net> wrote:
> > Just add the trivial cleanup function and MODULE_LICENSE() etc tags.
>
> The right thing to do seems to be to unregister the SoC device in the
> cleanup function. Is that what you mean?

Yes, plus kfree() the soc_device_attribute, or make it statically allocated.

     Arnd