@@ -5,3 +5,14 @@ config AT91_SOC_ID
default ARCH_AT91
help
Include support for the SoC bus on the Atmel ARM SoCs.
+
+config AT91_SOC_SFR
+ tristate "Special Function Registers support"
+ depends on ARCH_AT91 || COMPILE_TEST
+ help
+ This is a driver for the Special Function Registers available on
+ Atmel SAMA5Dx SoCs, providing access to specific aspects of the
+ integrated memory, bridge implementations, proccessor etc.
+
+ This driver can also be built as a module. If so, the module
+ will be called sfr.
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_AT91_SOC_ID) += soc.o
+obj-$(CONFIG_AT91_SOC_SFR) += atmel-sfr.o
new file mode 100644
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sfr.c - driver for special function registers
+ *
+ * Copyright (C) 2019 Bootlin.
+ *
+ */
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define SFR_SN0 0x4c
+#define SFR_NREGS 0x8
+
+struct sfr_priv {
+ struct device *dev;
+ struct regmap *regmap;
+ struct nvmem_config *config;
+ struct atmel_sfr_drvdata *drvdata;
+};
+
+static int atmel_sfr_read(void *context, unsigned int offset,
+ void *buf, size_t bytes)
+{
+ struct sfr_priv *priv = context;
+ struct atmel_sfr_drvdata *drvdata = priv->drvdata;
+
+ return regmap_bulk_read(priv->regmap, SFR_SN0 + offset,
+ buf, bytes / 4);
+}
+
+static struct nvmem_config atmel_sfr_nvmem_config = {
+ .name = "atmel-sfr",
+ .read_only = true,
+ .word_size = 4,
+ .stride = 4,
+ .reg_read = atmel_sfr_read,
+};
+
+static int atmel_sfr_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct sfr_priv *priv;
+ struct nvmem_device *nvmem;
+ const struct atmel_sfr_drvdata *drvdata;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ drvdata = of_device_get_match_data(dev);
+ if (!drvdata)
+ return -EINVAL;
+
+ priv->regmap = syscon_node_to_regmap(np);
+ if (IS_ERR(priv->regmap)) {
+ dev_err(dev, "cannot get parent's regmap\n");
+ return PTR_ERR(priv->regmap);
+ }
+
+ priv->drvdata = drvdata;
+
+ atmel_sfr_nvmem_config.size = drvdata->nregs;
+ atmel_sfr_nvmem_config.dev = dev;
+ atmel_sfr_nvmem_config.priv = priv;
+
+ priv->config = &atmel_sfr_nvmem_config;
+
+ nvmem = devm_nvmem_register(dev, &atmel_sfr_nvmem_config);
+ if (IS_ERR(nvmem)) {
+ dev_err(dev, "error registering nvmem config\n");
+ return PTR_ERR(nvmem);
+ }
+
+ return 0;
+}
+
+static const struct of_device_id atmel_sfr_dt_ids[] = {
+ {
+ .compatible = "atmel,sama5d2-sfr",
+ .data = &sama5d2_sama5d4_drvdata,
+ }, {
+ .compatible = "atmel,sama5d4-sfr",
+ .data = &sama5d2_sama5d4_drvdata,
+ }, {
+ /* sentinel */
+ },
+};
+MODULE_DEVICE_TABLE(of, atmel_sfr_dt_ids);
+
+static struct platform_driver atmel_sfr_driver = {
+ .probe = atmel_sfr_probe,
+ .driver = {
+ .name = "atmel-sfr",
+ .of_match_table = atmel_sfr_dt_ids,
+ },
+};
+module_platform_driver(atmel_sfr_driver);
+
+MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
+MODULE_DESCRIPTION("Atmel SFR SN driver for SAMA5D2/4 SoC family");
+MODULE_LICENSE("GPL v2");
+
Add support to read SFR's read-only registers providing the SoC Serial Numbers (SN0+SN1) to userspace. ~ # hexdump -n 8 -e'"%d\n"' /sys/bus/nvmem/devices/atmel-sfr0/nvmem 959527243 371539274 Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com> --- drivers/soc/atmel/Kconfig | 11 ++++ drivers/soc/atmel/Makefile | 1 + drivers/soc/atmel/sfr.c | 108 +++++++++++++++++++++++++++++++++++++ 3 files changed, 120 insertions(+) create mode 100644 drivers/soc/atmel/sfr.c