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authorJean Delvare <jdelvare@suse.de>2019-05-06 15:16:56 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-05-24 20:42:50 +0200
commit31641e34e8a3da5735d3cc901fb986bf6df28b6f (patch)
tree4318a4207e2407a7223936d054ed6ac61f2ed91a /drivers/misc/eeprom
parent5d458751749abda241b7d0a16136c3d49080cf07 (diff)
downloadlinux-31641e34e8a3da5735d3cc901fb986bf6df28b6f.tar.bz2
eeprom: ee1004: Deal with nack on page selection
Some EE1004 implementations will not properly ack page selection commands. They still set the page correctly, so there is no actual error. Deal with this case gracefully by checking the currently selected page after we receive a nack. If the page is set right then we can continue. Signed-off-by: Jean Delvare <jdelvare@suse.de> Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc/eeprom')
-rw-r--r--drivers/misc/eeprom/ee1004.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c
index 6c6348f816cc..89abfa78aa15 100644
--- a/drivers/misc/eeprom/ee1004.c
+++ b/drivers/misc/eeprom/ee1004.c
@@ -1,7 +1,7 @@
/*
* ee1004 - driver for DDR4 SPD EEPROMs
*
- * Copyright (C) 2017 Jean Delvare
+ * Copyright (C) 2017-2019 Jean Delvare
*
* Based on the at24 driver:
* Copyright (C) 2005-2007 David Brownell
@@ -124,6 +124,16 @@ static ssize_t ee1004_read(struct file *filp, struct kobject *kobj,
/* Data is ignored */
status = i2c_smbus_write_byte(ee1004_set_page[page],
0x00);
+ if (status == -ENXIO) {
+ /*
+ * Don't give up just yet. Some memory
+ * modules will select the page but not
+ * ack the command. Check which page is
+ * selected now.
+ */
+ if (ee1004_get_current_page() == page)
+ status = 0;
+ }
if (status < 0) {
dev_err(dev, "Failed to select page %d (%d)\n",
page, status);