diff options
Diffstat (limited to 'drivers/misc/eeprom')
| -rw-r--r-- | drivers/misc/eeprom/ee1004.c | 43 |
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); |