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-rw-r--r--drivers/soc/atmel/sfr.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/drivers/soc/atmel/sfr.c b/drivers/soc/atmel/sfr.c
new file mode 100644
index 000000000..0525eef49
--- /dev/null
+++ b/drivers/soc/atmel/sfr.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sfr.c - driver for special function registers
+ *
+ * Copyright (C) 2019 Bootlin.
+ *
+ */
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/random.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_SN_SIZE 8
+
+struct atmel_sfr_priv {
+ struct regmap *regmap;
+};
+
+static int atmel_sfr_read(void *context, unsigned int offset,
+ void *buf, size_t bytes)
+{
+ struct atmel_sfr_priv *priv = context;
+
+ 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,
+ .size = SFR_SN_SIZE,
+ .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 nvmem_device *nvmem;
+ struct atmel_sfr_priv *priv;
+ u8 sn[SFR_SN_SIZE];
+ int ret;
+
+ priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ 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);
+ }
+
+ atmel_sfr_nvmem_config.dev = dev;
+ atmel_sfr_nvmem_config.priv = priv;
+
+ 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);
+ }
+
+ ret = atmel_sfr_read(priv, 0, sn, SFR_SN_SIZE);
+ if (ret == 0)
+ add_device_randomness(sn, SFR_SN_SIZE);
+
+ return ret;
+}
+
+static const struct of_device_id atmel_sfr_dt_ids[] = {
+ {
+ .compatible = "atmel,sama5d2-sfr",
+ }, {
+ .compatible = "atmel,sama5d4-sfr",
+ }, {
+ /* 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");