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path: root/drivers/misc/eeprom/ee1004.c
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Diffstat (limited to 'drivers/misc/eeprom/ee1004.c')
-rw-r--r--drivers/misc/eeprom/ee1004.c43
1 files changed, 32 insertions, 11 deletions
diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c
index be3263df278a..6f00c33cfe22 100644
--- a/drivers/misc/eeprom/ee1004.c
+++ b/drivers/misc/eeprom/ee1004.c
@@ -2,7 +2,7 @@
/*
* 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
@@ -53,6 +53,24 @@ MODULE_DEVICE_TABLE(i2c, ee1004_ids);
/*-------------------------------------------------------------------------*/
+static int ee1004_get_current_page(void)
+{
+ int err;
+
+ err = i2c_smbus_read_byte(ee1004_set_page[0]);
+ if (err == -ENXIO) {
+ /* Nack means page 1 is selected */
+ return 1;
+ }
+ if (err < 0) {
+ /* Anything else is a real error, bail out */
+ return err;
+ }
+
+ /* Ack means page 0 is selected, returned value meaningless */
+ return 0;
+}
+
static ssize_t ee1004_eeprom_read(struct i2c_client *client, char *buf,
unsigned int offset, size_t count)
{
@@ -102,6 +120,16 @@ 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);
@@ -186,17 +214,10 @@ static int ee1004_probe(struct i2c_client *client,
}
/* Remember current page to avoid unneeded page select */
- err = i2c_smbus_read_byte(ee1004_set_page[0]);
- if (err == -ENXIO) {
- /* Nack means page 1 is selected */
- ee1004_current_page = 1;
- } else if (err < 0) {
- /* Anything else is a real error, bail out */
+ err = ee1004_get_current_page();
+ if (err < 0)
goto err_clients;
- } else {
- /* Ack means page 0 is selected, returned value meaningless */
- ee1004_current_page = 0;
- }
+ ee1004_current_page = err;
dev_dbg(&client->dev, "Currently selected page: %d\n",
ee1004_current_page);
mutex_unlock(&ee1004_bus_lock);