soc: nuvoton: Add SoC info driver for WPCM450

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>
Link: https://lore.kernel.org/r/20221031223926.241641-1-j.neuschaefer@gmx.net
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20230201051717.1005938-1-joel@jms.id.au
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index 81ae4f77974b17c7ab835a286dfb1759e768869c..4e176280113ac9179d7b62355e1544c717b00e3e 100644 (file)
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -16,6 +16,7 @@ source "drivers/soc/litex/Kconfig"
 source "drivers/soc/loongson/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 0447ec7b5552b21859ca86a99d54d763411881eb..3b0f9fb3b5c8420da3f8fb7aa54dcf0317068ce6 100644 (file)
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_LITEX_SOC_CONTROLLER) += litex/
 obj-y                          += loongson/
 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 (file)
index 0000000..df46182
--- /dev/null
+++ b/drivers/soc/nuvoton/Kconfig
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+menuconfig WPCM450_SOC
+       tristate "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 (file)
index 0000000..e30317b
--- /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 (file)
index 0000000..c5e0d11
--- /dev/null
+++ b/drivers/soc/nuvoton/wpcm450-soc.c
@@ -0,0 +1,109 @@
+// 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 struct soc_device_attribute *wpcm450_attr;
+static struct soc_device *wpcm450_soc;
+
+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);
+       }
+
+       wpcm450_soc = soc;
+       wpcm450_attr = attr;
+       return 0;
+}
+module_init(wpcm450_soc_init);
+
+static void __exit wpcm450_soc_exit(void)
+{
+       if (wpcm450_soc) {
+               soc_device_unregister(wpcm450_soc);
+               wpcm450_soc = NULL;
+               kfree(wpcm450_attr);
+       }
+}
+module_exit(wpcm450_soc_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Jonathan Neuschäfer");
+MODULE_DESCRIPTION("Nuvoton WPCM450 SoC Identification driver");