X-Git-Url: http://git.openwrt.org/?a=blobdiff_plain;f=target%2Flinux%2Fbrcm2708%2Fpatches-4.19%2F950-0590-w1-ds2413-when-the-slave-is-not-responding-during-re.patch;fp=target%2Flinux%2Fbrcm2708%2Fpatches-4.19%2F950-0590-w1-ds2413-when-the-slave-is-not-responding-during-re.patch;h=9d7a94159ec1a25654d0dbb9dd701119f5a27e27;hb=84d555aa74434392b682fd9eb0fa701c89a046d6;hp=0000000000000000000000000000000000000000;hpb=953973c2991e8640549a55df7a0574a1abac8644;p=openwrt%2Fstaging%2Fchunkeey.git

diff --git a/target/linux/brcm2708/patches-4.19/950-0590-w1-ds2413-when-the-slave-is-not-responding-during-re.patch b/target/linux/brcm2708/patches-4.19/950-0590-w1-ds2413-when-the-slave-is-not-responding-during-re.patch
new file mode 100644
index 0000000000..9d7a94159e
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0590-w1-ds2413-when-the-slave-is-not-responding-during-re.patch
@@ -0,0 +1,56 @@
+From c84676e57896fedb47a69739fb82bb9941f624c4 Mon Sep 17 00:00:00 2001
+From: Mariusz Bialonczyk <manio@skyboo.net>
+Date: Wed, 22 May 2019 12:40:53 +0200
+Subject: [PATCH] w1: ds2413: when the slave is not responding during
+ read, select it again
+
+commit 3856032a0628e6b94badb9131a706dda185e071d upstream.
+
+The protocol is not allowing to obtain a byte of 0xff for PIO_ACCESS_READ
+call. It is very likely that the slave was not addressed properly and
+it is just not respoding (leaving the bus in logic high state) during
+the read of sampled PIO value.
+We cannot just call w1_reset_resume_command() because the problem will
+persist, instead try selecting (addressing) the slave again.
+
+Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/w1/slaves/w1_ds2413.c | 9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+--- a/drivers/w1/slaves/w1_ds2413.c
++++ b/drivers/w1/slaves/w1_ds2413.c
+@@ -24,6 +24,7 @@
+ #define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
+ #define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
+ #define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
++#define W1_F3A_INVALID_PIO_STATE           0xFF
+ 
+ static ssize_t state_read(struct file *filp, struct kobject *kobj,
+ 			  struct bin_attribute *bin_attr, char *buf, loff_t off,
+@@ -45,6 +46,7 @@ static ssize_t state_read(struct file *f
+ 	mutex_lock(&sl->master->bus_mutex);
+ 	dev_dbg(&sl->dev, "mutex locked");
+ 
++next:
+ 	if (w1_reset_select_slave(sl))
+ 		goto out;
+ 
+@@ -52,10 +54,15 @@ static ssize_t state_read(struct file *f
+ 		w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
+ 
+ 		*buf = w1_read_8(sl->master);
+-		/* check for correct complement */
+ 		if ((*buf & 0x0F) == ((~*buf >> 4) & 0x0F)) {
++			/* complement is correct */
+ 			bytes_read = 1;
+ 			goto out;
++		} else if (*buf == W1_F3A_INVALID_PIO_STATE) {
++			/* slave didn't respond, try to select it again */
++			dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \
++					    "reselecting, retries left: %d\n", retries);
++			goto next;
+ 		}
+ 
+ 		if (w1_reset_resume_command(sl->master))