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authorMariusz Bialonczyk <manio@skyboo.net>2019-05-20 09:05:56 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-24 20:21:43 +0200
commitc50d09a86172073f55ebac0b92ad5a75907d64e7 (patch)
tree189a69b66881d9e208565777a07f50a8eee763ac
parentae2ee27aa985232f66421d7cd1c7f4b87c7dba7d (diff)
downloadlinux-c50d09a86172073f55ebac0b92ad5a75907d64e7.tar.bz2
w1: ds2413: add retry support to state_read()
The state_read() was calling PIO_ACCESS_READ once and bail out if it failed for this first time. This commit is improving this to trying more times before it give up, similarly as the write call is currently doing. Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/w1/slaves/w1_ds2413.c37
1 files changed, 24 insertions, 13 deletions
diff --git a/drivers/w1/slaves/w1_ds2413.c b/drivers/w1/slaves/w1_ds2413.c
index cd3763df69ac..d63778c70568 100644
--- a/drivers/w1/slaves/w1_ds2413.c
+++ b/drivers/w1/slaves/w1_ds2413.c
@@ -30,6 +30,9 @@ static ssize_t state_read(struct file *filp, struct kobject *kobj,
size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ unsigned int retries = W1_F3A_RETRIES;
+ ssize_t bytes_read = -EIO;
+
dev_dbg(&sl->dev,
"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
@@ -42,22 +45,30 @@ static ssize_t state_read(struct file *filp, struct kobject *kobj,
mutex_lock(&sl->master->bus_mutex);
dev_dbg(&sl->dev, "mutex locked");
- if (w1_reset_select_slave(sl)) {
- mutex_unlock(&sl->master->bus_mutex);
- return -EIO;
- }
+ if (w1_reset_select_slave(sl))
+ goto out;
- w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
- *buf = w1_read_8(sl->master);
+ while (retries--) {
+ w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
- mutex_unlock(&sl->master->bus_mutex);
- dev_dbg(&sl->dev, "mutex unlocked");
+ *buf = w1_read_8(sl->master);
+ /* check for correct complement */
+ if ((*buf & 0x0F) == ((~*buf >> 4) & 0x0F)) {
+ bytes_read = 1;
+ goto out;
+ }
- /* check for correct complement */
- if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
- return -EIO;
- else
- return 1;
+ if (w1_reset_resume_command(sl->master))
+ goto out; /* unrecoverable error */
+
+ dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
+ }
+
+out:
+ mutex_unlock(&sl->master->bus_mutex);
+ dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
+ (bytes_read > 0) ? "succeeded" : "error", retries);
+ return bytes_read;
}
static BIN_ATTR_RO(state, 1);