brcm2708: update to latest patches from RPi Foundation

[openwrt/staging/dedeckeh.git] / target / linux / brcm2708 / patches-4.19 / 950-0592-w1-ds2413-when-the-slave-is-not-responding-during-re.patch

diff --git a/target/linux/brcm2708/patches-4.19/950-0592-w1-ds2413-when-the-slave-is-not-responding-during-re.patch b/target/linux/brcm2708/patches-4.19/950-0592-w1-ds2413-when-the-slave-is-not-responding-during-re.patch
new file mode 100644 (file)
index 0000000..9d7a941
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.19/950-0592-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))