3 files changed, 28 insertions, 13 deletions

diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c
index 950d354d50e2..47e12cfc2a57 100644
--- a/drivers/w1/masters/mxc_w1.c
+++ b/drivers/w1/masters/mxc_w1.c
@@ -121,9 +121,9 @@ static int mxc_w1_probe(struct platform_device *pdev)
 	mdev->clkdiv = (clk_get_rate(mdev->clk) / 1000000) - 1;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	mdev->regs = devm_request_and_ioremap(&pdev->dev, res);
-	if (!mdev->regs)
-		return -EBUSY;
+	mdev->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mdev->regs))
+		return PTR_ERR(mdev->regs);
 
 	clk_prepare_enable(mdev->clk);
 	__raw_writeb(mdev->clkdiv, mdev->regs + MXC_W1_TIME_DIVIDER);
diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index 762561fbabbf..5e6a3c9e510b 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -22,6 +22,16 @@ config W1_SLAVE_DS2408
 	  Say Y here if you want to use a 1-wire
 	  DS2408 8-Channel Addressable Switch device support
 
+config W1_SLAVE_DS2408_READBACK
+	bool "Read-back values written to DS2408's output register"
+	depends on W1_SLAVE_DS2408
+	default y
+	help
+	  Enabling this will cause the driver to read back the values written
+	  to the chip's output register in order to detect errors.
+
+	  This is slower but useful when debugging chips and/or busses.
+
 config W1_SLAVE_DS2413
 	tristate "Dual Channel Addressable Switch 0x3a family support (DS2413)"
 	help
diff --git a/drivers/w1/slaves/w1_ds2408.c b/drivers/w1/slaves/w1_ds2408.c
index 441ad3a3b586..e45eca1044bd 100644
--- a/drivers/w1/slaves/w1_ds2408.c
+++ b/drivers/w1/slaves/w1_ds2408.c
@@ -178,6 +178,15 @@ static ssize_t w1_f29_write_output(
 		w1_write_block(sl->master, w1_buf, 3);
 
 		readBack = w1_read_8(sl->master);
+
+		if (readBack != W1_F29_SUCCESS_CONFIRM_BYTE) {
+			if (w1_reset_resume_command(sl->master))
+				goto error;
+			/* try again, the slave is ready for a command */
+			continue;
+		}
+
+#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
 		/* here the master could read another byte which
 		   would be the PIO reg (the actual pin logic state)
 		   since in this driver we don't know which pins are
@@ -186,11 +195,6 @@ static ssize_t w1_f29_write_output(
 		if (w1_reset_resume_command(sl->master))
 			goto error;
 
-		if (readBack != 0xAA) {
-			/* try again, the slave is ready for a command */
-			continue;
-		}
-
 		/* go read back the output latches */
 		/* (the direct effect of the write above) */
 		w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
@@ -198,7 +202,9 @@ static ssize_t w1_f29_write_output(
 		w1_buf[2] = 0;
 		w1_write_block(sl->master, w1_buf, 3);
 		/* read the result of the READ_PIO_REGS command */
-		if (w1_read_8(sl->master) == *buf) {
+		if (w1_read_8(sl->master) == *buf)
+#endif
+		{
 			/* success! */
 			mutex_unlock(&sl->master->bus_mutex);
 			dev_dbg(&sl->dev,
@@ -297,8 +303,7 @@ error:
 
 
 
-#define NB_SYSFS_BIN_FILES 6
-static struct bin_attribute w1_f29_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
+static struct bin_attribute w1_f29_sysfs_bin_files[] = {
 	{
 		.attr =	{
 			.name = "state",
@@ -357,7 +362,7 @@ static int w1_f29_add_slave(struct w1_slave *sl)
 	int err = 0;
 	int i;
 
-	for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
+	for (i = 0; i < ARRAY_SIZE(w1_f29_sysfs_bin_files) && !err; ++i)
 		err = sysfs_create_bin_file(
 			&sl->dev.kobj,
 			&(w1_f29_sysfs_bin_files[i]));
@@ -371,7 +376,7 @@ static int w1_f29_add_slave(struct w1_slave *sl)
 static void w1_f29_remove_slave(struct w1_slave *sl)
 {
 	int i;
-	for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
+	for (i = ARRAY_SIZE(w1_f29_sysfs_bin_files) - 1; i >= 0; --i)
 		sysfs_remove_bin_file(&sl->dev.kobj,
 			&(w1_f29_sysfs_bin_files[i]));
 }