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75 lines
2.3 KiB
Diff
75 lines
2.3 KiB
Diff
From 91e443597cdd8f89d2b68ea5bf0f0823d1853ab7 Mon Sep 17 00:00:00 2001
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From: Mariusz Bialonczyk <manio@skyboo.net>
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Date: Mon, 20 May 2019 09:05:56 +0200
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Subject: [PATCH] w1: ds2413: add retry support to state_read()
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commit c50d09a86172073f55ebac0b92ad5a75907d64e7 upstream.
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The state_read() was calling PIO_ACCESS_READ once and bail out if it
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failed for this first time.
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This commit is improving this to trying more times before it give up,
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similarly as the write call is currently doing.
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Signed-off-by: Mariusz Bialonczyk <manio@skyboo.net>
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Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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---
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drivers/w1/slaves/w1_ds2413.c | 37 +++++++++++++++++++++++------------
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1 file changed, 24 insertions(+), 13 deletions(-)
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--- a/drivers/w1/slaves/w1_ds2413.c
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+++ b/drivers/w1/slaves/w1_ds2413.c
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@@ -30,6 +30,9 @@ static ssize_t state_read(struct file *f
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size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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+ unsigned int retries = W1_F3A_RETRIES;
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+ ssize_t bytes_read = -EIO;
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+
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dev_dbg(&sl->dev,
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"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
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bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
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@@ -42,22 +45,30 @@ static ssize_t state_read(struct file *f
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mutex_lock(&sl->master->bus_mutex);
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dev_dbg(&sl->dev, "mutex locked");
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- if (w1_reset_select_slave(sl)) {
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- mutex_unlock(&sl->master->bus_mutex);
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- return -EIO;
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- }
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+ if (w1_reset_select_slave(sl))
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+ goto out;
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- w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
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- *buf = w1_read_8(sl->master);
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+ while (retries--) {
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+ w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
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- mutex_unlock(&sl->master->bus_mutex);
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- dev_dbg(&sl->dev, "mutex unlocked");
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+ *buf = w1_read_8(sl->master);
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+ /* check for correct complement */
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+ if ((*buf & 0x0F) == ((~*buf >> 4) & 0x0F)) {
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+ bytes_read = 1;
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+ goto out;
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+ }
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+
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+ if (w1_reset_resume_command(sl->master))
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+ goto out; /* unrecoverable error */
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- /* check for correct complement */
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- if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
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- return -EIO;
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- else
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- return 1;
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+ dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
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+ }
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+
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+out:
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+ mutex_unlock(&sl->master->bus_mutex);
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+ dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
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+ (bytes_read > 0) ? "succeeded" : "error", retries);
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+ return bytes_read;
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}
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static BIN_ATTR_RO(state, 1);
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