From: Rafał Miłecki <rafal@xxxxxxxxxx>
With nvmem layouts in place we should now work on plain content access
NVMEM drivers (e.g. IO one). Actual NVMEM content handling should go to
layout drivers.
Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
---
drivers/nvmem/Kconfig | 7 ++++
drivers/nvmem/Makefile | 2 ++
drivers/nvmem/io.c | 79 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 88 insertions(+)
create mode 100644 drivers/nvmem/io.c
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 789729ff7e50..e77bfe6eb52e 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -90,6 +90,13 @@ config NVMEM_IMX_OCOTP_SCU
This is a driver for the SCU On-Chip OTP Controller (OCOTP)
available on i.MX8 SoCs.
+config NVMEM_IO
+ tristate "IO access based NVMEM support"
+ depends on HAS_IOMEM
+ help
+ This driver provides support for NVMEM devices that can be accessed
+ using I/O mapping.
+
config NVMEM_JZ4780_EFUSE
tristate "JZ4780 EFUSE Memory Support"
depends on MACH_INGENIC || COMPILE_TEST
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 442f9a4876a5..82db0a89c4d6 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -20,6 +20,8 @@ obj-$(CONFIG_NVMEM_IMX_OCOTP) += nvmem-imx-ocotp.o
nvmem-imx-ocotp-y := imx-ocotp.o
obj-$(CONFIG_NVMEM_IMX_OCOTP_SCU) += nvmem-imx-ocotp-scu.o
nvmem-imx-ocotp-scu-y := imx-ocotp-scu.o
+obj-$(CONFIG_NVMEM_IO) += nvmem-io.o
+nvmem-io-y := io.o
obj-$(CONFIG_NVMEM_JZ4780_EFUSE) += nvmem_jz4780_efuse.o
nvmem_jz4780_efuse-y := jz4780-efuse.o
obj-$(CONFIG_NVMEM_LAN9662_OTPC) += nvmem-lan9662-otpc.o
diff --git a/drivers/nvmem/io.c b/drivers/nvmem/io.c
new file mode 100644
index 000000000000..307526fda036
--- /dev/null
+++ b/drivers/nvmem/io.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 Rafał Miłecki <rafal@xxxxxxxxxx>
+ */
+
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+struct io_nvmem {
+ void __iomem *base;
+};
+
+static int io_nvmem_read(void *context, unsigned int offset, void *val, size_t bytes)
+{
+ struct io_nvmem *priv = context;
+ u8 *dst = val;
+
+ while (bytes--)
+ *dst++ = readb(priv->base + offset++);
+
+ return 0;
+}
+
+static int io_nvmem_probe(struct platform_device *pdev)
+{
+ struct nvmem_config config = {
+ .name = "io-nvmem",
+ .reg_read = io_nvmem_read,
+ };
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct io_nvmem *priv;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ config.dev = dev;
+ config.priv = priv;
+ config.size = resource_size(res);
+
+ if (!device_property_present(dev, "read-only"))
+ dev_warn(dev, "Writing is not supported yet");
+
+ return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
+}
+
+static const struct of_device_id io_nvmem_of_match_table[] = {
+ { .compatible = "io-nvmem", },
+ {},
+};
+
+static struct platform_driver io_nvmem_driver = {
+ .probe = io_nvmem_probe,
+ .driver = {
+ .name = "io_nvmem",
+ .of_match_table = io_nvmem_of_match_table,
+ },
+};
+
+static int __init io_nvmem_init(void)
+{
+ return platform_driver_register(&io_nvmem_driver);
+}
+
+subsys_initcall_sync(io_nvmem_init);
+
+MODULE_AUTHOR("Rafał Miłecki");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(of, io_nvmem_of_match_table);
--
2.34.1
