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authorDavid Brownell <dbrownell@users.sourceforge.net>2009-04-02 16:56:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-02 19:04:50 -0700
commit14dd1ff0f9e75dd4ae2f1ff8e48becb76d14f4ab (patch)
treea9e208f0c35c8e24ed0edb8a1bc5ca9a4dc9b585 /drivers/misc
parent7274ec8bd71e99018642f474528ea7de4bb3ae25 (diff)
memory_accessor: implement the new memory_accessor interfaces for SPI EEPROMs
- Define new setup() hook to export the accessor - Implement accessor methods Moves some error checking out of the sysfs interface code into the layer below it, which is now shared by both sysfs and memory access code. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/eeprom/at25.c58
1 files changed, 44 insertions, 14 deletions
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index 290dbe99647..6bc0dac5c1e 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -30,6 +30,7 @@
struct at25_data {
struct spi_device *spi;
+ struct memory_accessor mem;
struct mutex lock;
struct spi_eeprom chip;
struct bin_attribute bin;
@@ -75,6 +76,13 @@ at25_ee_read(
struct spi_transfer t[2];
struct spi_message m;
+ if (unlikely(offset >= at25->bin.size))
+ return 0;
+ if ((offset + count) > at25->bin.size)
+ count = at25->bin.size - offset;
+ if (unlikely(!count))
+ return count;
+
cp = command;
*cp++ = AT25_READ;
@@ -127,13 +135,6 @@ at25_bin_read(struct kobject *kobj, struct bin_attribute *bin_attr,
dev = container_of(kobj, struct device, kobj);
at25 = dev_get_drvdata(dev);
- if (unlikely(off >= at25->bin.size))
- return 0;
- if ((off + count) > at25->bin.size)
- count = at25->bin.size - off;
- if (unlikely(!count))
- return count;
-
return at25_ee_read(at25, buf, off, count);
}
@@ -146,6 +147,13 @@ at25_ee_write(struct at25_data *at25, char *buf, loff_t off, size_t count)
unsigned buf_size;
u8 *bounce;
+ if (unlikely(off >= at25->bin.size))
+ return -EFBIG;
+ if ((off + count) > at25->bin.size)
+ count = at25->bin.size - off;
+ if (unlikely(!count))
+ return count;
+
/* Temp buffer starts with command and address */
buf_size = at25->chip.page_size;
if (buf_size > io_limit)
@@ -253,18 +261,31 @@ at25_bin_write(struct kobject *kobj, struct bin_attribute *bin_attr,
dev = container_of(kobj, struct device, kobj);
at25 = dev_get_drvdata(dev);
- if (unlikely(off >= at25->bin.size))
- return -EFBIG;
- if ((off + count) > at25->bin.size)
- count = at25->bin.size - off;
- if (unlikely(!count))
- return count;
-
return at25_ee_write(at25, buf, off, count);
}
/*-------------------------------------------------------------------------*/
+/* Let in-kernel code access the eeprom data. */
+
+static ssize_t at25_mem_read(struct memory_accessor *mem, char *buf,
+ off_t offset, size_t count)
+{
+ struct at25_data *at25 = container_of(mem, struct at25_data, mem);
+
+ return at25_ee_read(at25, buf, offset, count);
+}
+
+static ssize_t at25_mem_write(struct memory_accessor *mem, char *buf,
+ off_t offset, size_t count)
+{
+ struct at25_data *at25 = container_of(mem, struct at25_data, mem);
+
+ return at25_ee_write(at25, buf, offset, count);
+}
+
+/*-------------------------------------------------------------------------*/
+
static int at25_probe(struct spi_device *spi)
{
struct at25_data *at25 = NULL;
@@ -317,6 +338,10 @@ static int at25_probe(struct spi_device *spi)
at25->addrlen = addrlen;
/* Export the EEPROM bytes through sysfs, since that's convenient.
+ * And maybe to other kernel code; it might hold a board's Ethernet
+ * address, or board-specific calibration data generated on the
+ * manufacturing floor.
+ *
* Default to root-only access to the data; EEPROMs often hold data
* that's sensitive for read and/or write, like ethernet addresses,
* security codes, board-specific manufacturing calibrations, etc.
@@ -324,17 +349,22 @@ static int at25_probe(struct spi_device *spi)
at25->bin.attr.name = "eeprom";
at25->bin.attr.mode = S_IRUSR;
at25->bin.read = at25_bin_read;
+ at25->mem.read = at25_mem_read;
at25->bin.size = at25->chip.byte_len;
if (!(chip->flags & EE_READONLY)) {
at25->bin.write = at25_bin_write;
at25->bin.attr.mode |= S_IWUSR;
+ at25->mem.write = at25_mem_write;
}
err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin);
if (err)
goto fail;
+ if (chip->setup)
+ chip->setup(&at25->mem, chip->context);
+
dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",
(at25->bin.size < 1024)
? at25->bin.size