Support parsing the header used by capes compatible with Nextthing's
C.H.I.P.

Signed-off-by: Antoine Tenart <antoine.ten...@free-electrons.com>
---
 drivers/of/overlay-manager/Kconfig       | 13 ++++++
 drivers/of/overlay-manager/Makefile      |  1 +
 drivers/of/overlay-manager/format-chip.c | 72 ++++++++++++++++++++++++++++++++
 include/linux/overlay-manager.h          | 13 ++++++
 4 files changed, 99 insertions(+)
 create mode 100644 drivers/of/overlay-manager/format-chip.c

diff --git a/drivers/of/overlay-manager/Kconfig 
b/drivers/of/overlay-manager/Kconfig
index eeb76054dcb8..1a36613c0c53 100644
--- a/drivers/of/overlay-manager/Kconfig
+++ b/drivers/of/overlay-manager/Kconfig
@@ -4,3 +4,16 @@ config OF_OVERLAY_MGR
        help
          Enable the overlay manager to handle automatic overlay loading when
          devices are detected.
+
+if OF_OVERLAY_MGR
+
+menu "Dips header formats"
+
+config OF_OVERLAY_MGR_FORMAT_CHIP
+       bool "Nextthing's C.H.I.P. dip header format"
+       help
+         Enable Nextthing's C.H.I.P. dip header format support.
+
+endmenu
+
+endif
diff --git a/drivers/of/overlay-manager/Makefile 
b/drivers/of/overlay-manager/Makefile
index 86d2b53950e7..637cc7ba20c2 100644
--- a/drivers/of/overlay-manager/Makefile
+++ b/drivers/of/overlay-manager/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_OF_OVERLAY_MGR)                   += overlay-manager.o
+obj-$(CONFIG_OF_OVERLAY_MGR_FORMAT_CHIP)       += format-chip.o
diff --git a/drivers/of/overlay-manager/format-chip.c 
b/drivers/of/overlay-manager/format-chip.c
new file mode 100644
index 000000000000..3a3d315dcb5c
--- /dev/null
+++ b/drivers/of/overlay-manager/format-chip.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2016 - Antoine Tenart <antoine.ten...@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/device.h>
+#include <linux/overlay-manager.h>
+#include <linux/slab.h>
+
+#define CAPE_CHIP_MAGIC                0x43484950
+#define CAPE_CHIP_VERSION      1
+#define CAPE_CHIP_CANDIDATES   2
+
+static int cape_chip_parse(struct device *dev, void *data, char ***candidates,
+                          unsigned *n)
+{
+       struct chip_header *header = (struct chip_header *)data;
+       char **tmp;
+       int err;
+
+       if (dip_convert(header->magic) != CAPE_CHIP_MAGIC)
+               return -EINVAL;
+
+       if (dip_convert(header->version) > CAPE_CHIP_VERSION)
+               return -EINVAL;
+
+       tmp = devm_kzalloc(dev, CAPE_CHIP_CANDIDATES * sizeof(char *), 
GFP_KERNEL);
+       if (!tmp)
+               return -ENOMEM;
+
+       tmp[0] = devm_kasprintf(dev, GFP_KERNEL, "%x-%x-%x",
+                               dip_convert(header->vendor_id),
+                               dip_convert(header->product_id),
+                               dip_convert(header->product_version));
+       if (!tmp[0]) {
+               err = -ENOMEM;
+               goto err_free_list;
+       }
+
+       tmp[1] = devm_kasprintf(dev, GFP_KERNEL, "%x-%x",
+                               dip_convert(header->vendor_id),
+                               dip_convert(header->product_id));
+       if (!tmp[1]) {
+               err = -ENOMEM;
+               goto err_free_0;
+       }
+
+       *candidates = tmp;
+       *n = CAPE_CHIP_CANDIDATES;
+
+       return 0;
+
+err_free_0:
+       devm_kfree(dev, tmp[0]);
+err_free_list:
+       devm_kfree(dev, tmp);
+       return err;
+}
+
+static struct overlay_mgr_format format_chip = {
+       .name   = "Nextthing C.H.I.P. dip header format",
+       .parse  = &cape_chip_parse,
+};
+
+static int __init cape_chip_init(void)
+{
+       return overlay_mgr_register_format(&format_chip);
+}
+device_initcall(cape_chip_init);
diff --git a/include/linux/overlay-manager.h b/include/linux/overlay-manager.h
index 8adcc4f5ddf6..d76c3c9fd863 100644
--- a/include/linux/overlay-manager.h
+++ b/include/linux/overlay-manager.h
@@ -35,4 +35,17 @@ int overlay_mgr_apply(struct device *dev, char **candidates, 
unsigned n);
                 -1                                              \
         )
 
+/* Nextthing's C.H.I.P. dip header */
+struct chip_header {
+        u32     magic;                  /* rsvd */
+        u8      version;                /* spec version */
+        u32     vendor_id;
+        u16     product_id;
+        u8      product_version;
+        char    vendor_name[32];
+        char    product_name[32];
+        u8      rsvd[36];               /* rsvd for futre spec versions */
+        u8      data[16];               /* user data, per-cape specific */
+} __packed;
+
 #endif /* __OVERLAY_MGR_H__ */
-- 
2.10.1

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