Commit c50d09a8 authored by Mariusz Bialonczyk's avatar Mariusz Bialonczyk Committed by Greg Kroah-Hartman
Browse files

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: default avatarMariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ae2ee27a

drivers/w1/slaves/w1_ds2413.c

+24 −13
Original line number Diff line number Diff line
@@ -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;



	while (retries--) {

		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)) {

			bytes_read = 1;

			goto out;

		}



	mutex_unlock(&sl->master->bus_mutex);

	dev_dbg(&sl->dev, "mutex unlocked");

		if (w1_reset_resume_command(sl->master))

			goto out; /* unrecoverable error */



	/* check for correct complement */

	if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))

		return -EIO;

	else

		return 1;

		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);