diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0678-w1-ds2413-when-the-slave-is-not-responding-during-re.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0678-w1-ds2413-when-the-slave-is-not-responding-during-re.patch | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0678-w1-ds2413-when-the-slave-is-not-responding-during-re.patch b/target/linux/brcm2708/patches-4.19/950-0678-w1-ds2413-when-the-slave-is-not-responding-during-re.patch new file mode 100644 index 0000000000..c3b0c5d308 --- /dev/null +++ b/target/linux/brcm2708/patches-4.19/950-0678-w1-ds2413-when-the-slave-is-not-responding-during-re.patch @@ -0,0 +1,56 @@ +From 1808665b2b2e06d6f14762eb0ab82d65e3af3e2b Mon Sep 17 00:00:00 2001 +From: Mariusz Bialonczyk <manio@skyboo.net> +Date: Wed, 22 May 2019 12:40:53 +0200 +Subject: [PATCH 678/703] 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)) |