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Subject[PATCH v9 4/5] nvmem: eeprom: at25: export FRAM serial num
Date
This exports serial number of FRAM in sysfs file named "sernum".
Formatted in hex, each byte separated by space.
Example:
$ cat /sys/class/spi_master/spi0/spi0.0/sernum
ef cd ab 89 67 45 23 01

Signed-off-by: Jiri Prchal <jiri.prchal@aksignal.cz>
---
v2: no change here
v3: resend and added more recipients
v4: resend
v5: reworked up on Greg comments: no spaces in string, sysfs done correctly
v6: no change here
v7: moved FM25_SN_LEN, static array, used sysfs_emit, DEVICE_ATTR_RO
v8: clarify sysfs_emit format
v9: sizeof parentheses, export with spaces MSB first
---
drivers/misc/eeprom/at25.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)

diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index e59b6852816d..19280e9f118d 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -31,6 +31,7 @@
* AT25M02, AT25128B
*/

+#define FM25_SN_LEN 8 /* serial number length */
struct at25_data {
struct spi_device *spi;
struct mutex lock;
@@ -38,6 +39,7 @@ struct at25_data {
unsigned addrlen;
struct nvmem_config nvmem_config;
struct nvmem_device *nvmem;
+ u8 sernum[FM25_SN_LEN];
};

#define AT25_WREN 0x06 /* latch the write enable */
@@ -171,6 +173,21 @@ static int fm25_aux_read(struct at25_data *at25, u8 *buf, uint8_t command,
return status;
}

+static ssize_t sernum_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct at25_data *at25;
+
+ at25 = dev_get_drvdata(dev);
+ return sysfs_emit(buf, "%*ph\n", sizeof(at25->sernum), at25->sernum);
+}
+static DEVICE_ATTR_RO(sernum);
+
+static struct attribute *sernum_attrs[] = {
+ &dev_attr_sernum.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(sernum);
+
static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count)
{
struct at25_data *at25 = priv;
@@ -359,6 +376,8 @@ static int at25_probe(struct spi_device *spi)
int err;
int sr;
u8 id[FM25_ID_LEN];
+ u8 sernum[FM25_SN_LEN];
+ int i;
const struct of_device_id *match;
int is_fram = 0;

@@ -415,6 +434,13 @@ static int at25_probe(struct spi_device *spi)
else
at25->chip.flags |= EE_ADDR2;

+ if (id[8]) {
+ fm25_aux_read(at25, sernum, FM25_RDSN, FM25_SN_LEN);
+ /* swap byte order */
+ for (i = 0; i < FM25_SN_LEN; i++)
+ at25->sernum[i] = sernum[FM25_SN_LEN - 1 - i];
+ }
+
at25->chip.page_size = PAGE_SIZE;
strncpy(at25->chip.name, "fm25", sizeof(at25->chip.name));
}
@@ -465,6 +491,7 @@ static struct spi_driver at25_driver = {
.driver = {
.name = "at25",
.of_match_table = at25_of_match,
+ .dev_groups = sernum_groups,
},
.probe = at25_probe,
};
--
2.25.1
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