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Date: Mon, 22 Feb 2016 11:52:10 -0800
From: Andrey Smirnov <andrew.smirnov@...il.com>
To: linux-kernel@...r.kernel.org
Cc: srinivas.kandagatla@...aro.org, maxime.ripard@...e-electrons.com,
s.hauer@...gutronix.de, Andrey Smirnov <andrew.smirnov@...il.com>
Subject: [RFC 2/3] nvmem: Add 'nvmem-blob' driver
Add 'nvmem-blob' driver, which allows to access device tree embedded
data via NVMEM subsystem API.
Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
---
Documentation/devicetree/bindings/nvmem/blob.txt | 35 ++++++
drivers/nvmem/Makefile | 1 +
drivers/nvmem/blob.c | 132 +++++++++++++++++++++++
3 files changed, 168 insertions(+)
create mode 100644 Documentation/devicetree/bindings/nvmem/blob.txt
create mode 100644 drivers/nvmem/blob.c
diff --git a/Documentation/devicetree/bindings/nvmem/blob.txt b/Documentation/devicetree/bindings/nvmem/blob.txt
new file mode 100644
index 0000000..b299576
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/blob.txt
@@ -0,0 +1,35 @@
+= Deviece Tree Embedded Blob As NVMEM Device =
+
+This binding is designed to provide a way for a developer to reference
+data, built-in into device tree blob file, as NVMEM provider and acccess
+certain portions of that data as NVMEM cells using NVMEM consumer API.
+
+Required properties:
+- compatible: should be "nvmem-blob"
+- data: specifies data contained in nvmem device
+
+= Data cells =
+Are child nodes of nvmem-composite, bindings of which as described in
+bindings/nvmem/nvmem.txt
+
+Example:
+
+ a-blob {
+ compatible = "nvmem-blob";
+ data = [aa bb cc dd ee];
+
+ cell1: cell@0 {
+ reg = <0 5>;
+ };
+ };
+
+= Data consumers =
+Are device nodes which consume nvmem data cells.
+
+Example:
+
+ a-node {
+ ...
+ nvmem-cells = <&cell1>;
+ nvmem-cell-names = "some-data";
+ };
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 95dde3f..1a1adba 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o
nvmem_sunxi_sid-y := sunxi_sid.o
obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o
nvmem-vf610-ocotp-y := vf610-ocotp.o
+obj-y += blob.o
diff --git a/drivers/nvmem/blob.c b/drivers/nvmem/blob.c
new file mode 100644
index 0000000..3f2296b
--- /dev/null
+++ b/drivers/nvmem/blob.c
@@ -0,0 +1,132 @@
+#define DEBUG 1
+
+#include <linux/device.h>
+#include <linux/io.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>
+#include <linux/slab.h>
+
+struct nvmem_blob {
+ const u8 *data;
+ size_t data_size;
+};
+
+static int nvmem_blob_write(void *context, const void *data,
+ size_t count)
+{
+ return -ENOTSUPP;
+}
+
+static int nvmem_blob_read(void *context,
+ const void *reg, size_t reg_size,
+ void *val, size_t val_size)
+{
+ struct nvmem_blob *nblob = context;
+ const unsigned int offset = *(u32 *)reg;
+
+ memcpy(val, nblob->data + offset,
+ min(val_size, nblob->data_size - offset));
+ return 0;
+}
+
+static const struct regmap_bus nvmem_blob_regmap_bus = {
+ .write = nvmem_blob_write,
+ .read = nvmem_blob_read,
+};
+
+
+static int nvmem_blob_validate_dt(struct device_node *np)
+{
+ return 0;
+}
+
+static int nvmem_blob_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct regmap *map;
+ struct nvmem_device *nvmem;
+ struct nvmem_blob *nblob;
+ struct property *pp;
+ struct nvmem_config nv_cnf = {0};
+ struct regmap_config rm_cnf = {0};
+
+ ret = nvmem_blob_validate_dt(np);
+ if (ret < 0) {
+ dev_dbg(dev, "Device tree validation failed\n");
+ return ret;
+ }
+
+ nblob = devm_kzalloc(dev, sizeof(*nblob), GFP_KERNEL);
+ if (!nblob) {
+ dev_dbg(dev, "Not enough memory to allocate a blob\n");
+ return -ENOMEM;
+ }
+
+ pp = of_find_property(np, "data", NULL);
+ BUG_ON(!pp);
+
+ nblob->data = pp->value;
+ nblob->data_size = pp->length;
+
+ rm_cnf.reg_bits = 32;
+ rm_cnf.val_bits = 8;
+ rm_cnf.reg_stride = 1;
+ rm_cnf.name = "nvmem-blob";
+ rm_cnf.max_register = nblob->data_size - 1;
+
+ map = devm_regmap_init(dev,
+ &nvmem_blob_regmap_bus,
+ nblob,
+ &rm_cnf);
+ if (IS_ERR(map)) {
+ dev_dbg(dev, "Failed to initilize regmap\n");
+ return PTR_ERR(map);
+ }
+
+ nv_cnf.name = "nvmem-blob";
+ nv_cnf.read_only = true;
+ nv_cnf.dev = dev;
+ nv_cnf.owner = THIS_MODULE;
+
+ nvmem = nvmem_register(&nv_cnf);
+ if (IS_ERR(nvmem)) {
+ dev_dbg(dev, "Filed to register nvmem device\n");
+ return PTR_ERR(nvmem);
+ }
+
+ platform_set_drvdata(pdev, nblob);
+ return 0;
+}
+
+static int nvmem_blob_remove(struct platform_device *pdev)
+{
+ struct nvmem_device *nvmem = platform_get_drvdata(pdev);
+
+ return nvmem_unregister(nvmem);
+}
+
+static const struct of_device_id nvmem_blob_dt_ids[] = {
+ { .compatible = "nvmem-blob", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, nvmem_blob_dt_ids);
+
+static struct platform_driver nvmem_blob_driver = {
+ .probe = nvmem_blob_probe,
+ .remove = nvmem_blob_remove,
+ .driver = {
+ .name = "nvmem-blob",
+ .of_match_table = nvmem_blob_dt_ids,
+ },
+};
+module_platform_driver(nvmem_blob_driver);
+
+MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@...il.com>");
+MODULE_DESCRIPTION("FIXME");
+MODULE_LICENSE("GPL v2");
--
2.5.0
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