[PATCH 2/2] rtc: ds1305: use generic nvmem

From: Alexandre Belloni
Date: Thu Oct 12 2017 - 18:03:40 EST


Instead of adding a binary sysfs attribute from the driver (which suffers
from a race condition as the attribute appears after the device), use the
core to register an nvmem device.

Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
---
drivers/rtc/rtc-ds1305.c | 59 +++++++++++++++++-------------------------------
1 file changed, 21 insertions(+), 38 deletions(-)

diff --git a/drivers/rtc/rtc-ds1305.c b/drivers/rtc/rtc-ds1305.c
index c3232c818e65..d8df2e9e14ad 100644
--- a/drivers/rtc/rtc-ds1305.c
+++ b/drivers/rtc/rtc-ds1305.c
@@ -514,56 +514,43 @@ static void msg_init(struct spi_message *m, struct spi_transfer *x,
spi_message_add_tail(x, m);
}

-static ssize_t
-ds1305_nvram_read(struct file *filp, struct kobject *kobj,
- struct bin_attribute *attr,
- char *buf, loff_t off, size_t count)
+static int ds1305_nvram_read(void *priv, unsigned int off, void *buf,
+ size_t count)
{
- struct spi_device *spi;
+ struct ds1305 *ds1305 = priv;
+ struct spi_device *spi = ds1305->spi;
u8 addr;
struct spi_message m;
struct spi_transfer x[2];
- int status;
-
- spi = to_spi_device(kobj_to_dev(kobj));

addr = DS1305_NVRAM + off;
msg_init(&m, x, &addr, count, NULL, buf);

- status = spi_sync(spi, &m);
- if (status < 0)
- dev_err(&spi->dev, "nvram %s error %d\n", "read", status);
- return (status < 0) ? status : count;
+ return spi_sync(spi, &m);
}

-static ssize_t
-ds1305_nvram_write(struct file *filp, struct kobject *kobj,
- struct bin_attribute *attr,
- char *buf, loff_t off, size_t count)
+static int ds1305_nvram_write(void *priv, unsigned int off, void *buf,
+ size_t count)
{
- struct spi_device *spi;
+ struct ds1305 *ds1305 = priv;
+ struct spi_device *spi = ds1305->spi;
u8 addr;
struct spi_message m;
struct spi_transfer x[2];
- int status;
-
- spi = to_spi_device(kobj_to_dev(kobj));

addr = (DS1305_WRITE | DS1305_NVRAM) + off;
msg_init(&m, x, &addr, count, buf, NULL);

- status = spi_sync(spi, &m);
- if (status < 0)
- dev_err(&spi->dev, "nvram %s error %d\n", "write", status);
- return (status < 0) ? status : count;
+ return spi_sync(spi, &m);
}

-static struct bin_attribute nvram = {
- .attr.name = "nvram",
- .attr.mode = S_IRUGO | S_IWUSR,
- .read = ds1305_nvram_read,
- .write = ds1305_nvram_write,
- .size = DS1305_NVRAM_LEN,
+static struct nvmem_config ds1305_nvmem_cfg = {
+ .name = "ds1305_nvram",
+ .word_size = 1,
+ .stride = 1,
+ .size = DS1305_NVRAM_LEN,
+ .reg_read = ds1305_nvram_read,
+ .reg_write = ds1305_nvram_write,
};

/*----------------------------------------------------------------------*/
@@ -715,6 +702,10 @@ static int ds1305_probe(struct spi_device *spi)

ds1305->rtc->ops = &ds1305_ops;

+ ds1305_nvmem_cfg.priv = ds1305;
+ ds1305->rtc->nvmem_config = &ds1305_nvmem_cfg;
+ ds1305->rtc->nvram_old_abi = true;
+
status = rtc_register_device(ds1305->rtc);
if (status) {
dev_dbg(&spi->dev, "register rtc --> %d\n", status);
@@ -739,12 +730,6 @@ static int ds1305_probe(struct spi_device *spi)
}
}

- /* export NVRAM */
- status = sysfs_create_bin_file(&spi->dev.kobj, &nvram);
- if (status < 0) {
- dev_err(&spi->dev, "register nvram --> %d\n", status);
- }
-
return 0;
}

@@ -752,8 +737,6 @@ static int ds1305_remove(struct spi_device *spi)
{
struct ds1305 *ds1305 = spi_get_drvdata(spi);

- sysfs_remove_bin_file(&spi->dev.kobj, &nvram);
-
/* carefully shut down irq and workqueue, if present */
if (spi->irq) {
set_bit(FLAG_EXITING, &ds1305->flags);
--
2.14.2