Provide a driver which should act as nvmem consumer
for board serial number information.
To make use of this driver, DTS should contain a serial
node with compatibe "barebox,serial" and nvmem-cell-names
"serial-number":
...
chosen {
serial {
compatible = "barebox,serial";
nvmem-cell-names = "serial-number";
nvmem-cells = &some_provider;
};
};
...
The driver will read nvmem cell on probe and register
a fixup for the kernel devicetree.
This fixup will create a "/serial-number" property, which is
used by current kernel:
https://elixir.bootlin.com/linux/v5.7/source/arch/arm/kernel/setup.c#L941
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
drivers/of/Makefile | 2 +-
drivers/of/barebox_serial.c | 111 ++++++++++++++++++++++++++++++++++++
2 files changed, 112 insertions(+), 1 deletion(-)
create mode 100644 drivers/of/barebox_serial.c
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index b6847752d2..b4a4c36b2a 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -5,5 +5,5 @@ obj-$(CONFIG_OF_PCI) += of_pci.o
obj-y += partition.o
obj-y += of_net.o
obj-$(CONFIG_MTD) += of_mtd.o
-obj-$(CONFIG_OF_BAREBOX_DRIVERS) += barebox.o
+obj-$(CONFIG_OF_BAREBOX_DRIVERS) += barebox.o barebox_serial.o
obj-$(CONFIG_OF_OVERLAY) += overlay.o resolver.o of_firmware.o
diff --git a/drivers/of/barebox_serial.c b/drivers/of/barebox_serial.c
new file mode 100644
index 0000000000..40efb731d3
--- /dev/null
+++ b/drivers/of/barebox_serial.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2020 Pengutronix, Oleksij Rempel <kernel@xxxxxxxxxxxxxx>
+
+#include <common.h>
+#include <init.h>
+#include <linux/nvmem-consumer.h>
+
+struct bb_ser_priv {
+ struct device_d *dev;
+ char *ser;
+};
+
+static int bb_ser_fixup(struct device_node *root, void *data)
+{
+ struct bb_ser_priv *priv = data;
+ int ret;
+
+ ret = of_property_write_string(root, "serial-number", priv->ser);
+ if (ret)
+ dev_err(priv->dev, "Failed to set /serial-number\n");
+
+ return ret;
+}
+
+static int bb_ser_of_get_nvmem(struct bb_ser_priv *priv)
+{
+ struct nvmem_cell *cell;
+ size_t len;
+ char *ser;
+
+ cell = nvmem_cell_get(priv->dev, "serial-number");
+ if (IS_ERR(cell))
+ return PTR_ERR(cell);
+
+ ser = nvmem_cell_read(cell, &len);
+ nvmem_cell_put(cell);
+
+ if (IS_ERR(ser))
+ return PTR_ERR(ser);
+
+ /* check if serial number is zero terminated */
+ if (ser[len - 1] != 0x0) {
+ char *tmp;
+
+ tmp = kzalloc(len + 1, GFP_KERNEL);
+ if (!tmp) {
+ kfree(ser);
+ return -ENOMEM;
+ }
+
+ memcpy(tmp, ser, len);
+ tmp[len] = 0x0;
+ kfree(ser);
+ ser = tmp;
+ }
+
+ priv->ser = ser;
+
+ return 0;
+}
+
+static int bb_ser_probe(struct device_d *dev)
+{
+ struct bb_ser_priv *priv;
+ struct param_d *p;
+ int ret;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = dev;
+
+ ret = bb_ser_of_get_nvmem(priv);
+ if (ret) {
+ dev_err(priv->dev, "Failed to read nvmem\n");
+ goto free_priv;
+ }
+
+ p = dev_add_param_string_fixed(dev, "serial-number", priv->ser);
+ if (IS_ERR(p)) {
+ dev_err(priv->dev, "Failed to set param_string\n");
+ ret = PTR_ERR(p);
+ goto free_ser;
+ }
+
+ ret = of_register_fixup(bb_ser_fixup, priv);
+ if (ret) {
+ dev_err(priv->dev, "Failed to register fixup\n");
+ goto free_ser;
+ }
+
+ return 0;
+free_ser:
+ kfree(priv->ser);
+free_priv:
+ kfree(priv);
+ return ret;
+}
+
+static const struct of_device_id bb_ser_of_match[] = {
+ { .compatible = "barebox,serial", },
+ { /* sentinel */ },
+};
+
+static struct driver_d bb_ser_driver = {
+ .name = "barebox-serial",
+ .probe = bb_ser_probe,
+ .of_compatible = DRV_OF_COMPAT(bb_ser_of_match),
+};
+device_platform_driver(bb_ser_driver);
--
2.27.0
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