[PATCH 15/27] mtd: nand: update the documentation to reflect framework changes

Boris Brezillon
2015-11-16T13:43:58Z

The MTD device is now directly embedded in the nand_chip struct. Update the
mtdnand documentation to mention this aspect and fix the different
examples.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
Documentation/DocBook/mtdnand.tmpl | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/Documentation/DocBook/mtdnand.tmpl b/Documentation/DocBook/mtdnand.tmpl
index 403a7ab..b442921 100644
--- a/Documentation/DocBook/mtdnand.tmpl
+++ b/Documentation/DocBook/mtdnand.tmpl
@@ -162,12 +162,15 @@
<sect1 id="Basic_defines">
Basic defines

- At least you have to provide a mtd structure and
- a storage for the ioremap'ed chip address.
- You can allocate the mtd structure using kmalloc
- or you can allocate it statically.
- In case of static allocation you have to allocate
- a nand_chip structure too.
+ At least you have to provide a nand_chip structure
+ and a storage for the ioremap'ed chip address.
+ You can allocate the nand_chip structure using
+ kmalloc or you can allocate it statically.
+ The NAND chip structure embeds an mtd structure
+ which will be registered to the MTD subsystem.
+ You can extract a pointer to the mtd structure
+ from a nand_chip pointer using the nand_to_mtd()
+ helper.


Kmalloc based example
@@ -180,7 +183,6 @@ static void __iomem *baseaddr;
Static example

<programlisting>
-static struct mtd_info board_mtd;
static struct nand_chip board_chip;
static void __iomem *baseaddr;
</programlisting>
@@ -274,13 +276,15 @@ static int __init board_init (void)
int err = 0;

/* Allocate memory for MTD device structure and private data */
- board_mtd = kzalloc(sizeof(struct mtd_info) + sizeof(struct nand_chip), GFP_KERNEL);
- if (!board_mtd) {
+ this = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);
+ if (!this) {
printk ("Unable to allocate NAND MTD device structure.\n");
err = -ENOMEM;
goto out;
}

+ board_mtd = nand_to_mtd(this);
+
/* map physical address */
baseaddr = ioremap(CHIP_PHYSICAL_ADDRESS, 1024);
if (!baseaddr) {
@@ -289,11 +293,6 @@ static int __init board_init (void)
goto out_mtd;
}

- /* Get pointer to private data */
- this = (struct nand_chip *) ();
- /* Link the private data with the MTD structure */
- board_mtd->priv = this;
-
/* Set address of NAND IO lines */
this->IO_ADDR_R = baseaddr;
this->IO_ADDR_W = baseaddr;
@@ -317,7 +316,7 @@ static int __init board_init (void)
out_ior:
iounmap(baseaddr);
out_mtd:
- kfree (board_mtd);
+ kfree (this);
out:
return err;
}
@@ -343,7 +342,7 @@ static void __exit board_cleanup (void)
iounmap(baseaddr);

/* Free the MTD device structure */
- kfree (board_mtd);
+ kfree (mtd_to_nand(board_mtd));
}
module_exit(board_cleanup);
#endif
--
2.1.4