diff options
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/rtc-ds1307.c | 60 |
1 files changed, 56 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index 970a236b147a..a65621c42170 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -4,6 +4,7 @@ * Copyright (C) 2005 James Chapman (ds1337 core) * Copyright (C) 2006 David Brownell * Copyright (C) 2009 Matthias Fuchs (rx8025 support) + * Copyright (C) 2012 Bertrand Achard (nvram access fixes) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as @@ -196,7 +197,7 @@ static s32 ds1307_read_block_data_once(const struct i2c_client *client, static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command, u8 length, u8 *values) { - u8 oldvalues[I2C_SMBUS_BLOCK_MAX]; + u8 oldvalues[255]; s32 ret; int tries = 0; @@ -222,7 +223,7 @@ static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command, static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command, u8 length, const u8 *values) { - u8 currvalues[I2C_SMBUS_BLOCK_MAX]; + u8 currvalues[255]; int tries = 0; dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length); @@ -250,6 +251,57 @@ static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command, /*----------------------------------------------------------------------*/ +/* These RTC devices are not designed to be connected to a SMbus adapter. + SMbus limits block operations length to 32 bytes, whereas it's not + limited on I2C buses. As a result, accesses may exceed 32 bytes; + in that case, split them into smaller blocks */ + +static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client, + u8 command, u8 length, const u8 *values) +{ + u8 suboffset = 0; + + if (length <= I2C_SMBUS_BLOCK_MAX) + return i2c_smbus_write_i2c_block_data(client, + command, length, values); + + while (suboffset < length) { + s32 retval = i2c_smbus_write_i2c_block_data(client, + command + suboffset, + min(I2C_SMBUS_BLOCK_MAX, length - suboffset), + values + suboffset); + if (retval < 0) + return retval; + + suboffset += I2C_SMBUS_BLOCK_MAX; + } + return length; +} + +static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client, + u8 command, u8 length, u8 *values) +{ + u8 suboffset = 0; + + if (length <= I2C_SMBUS_BLOCK_MAX) + return i2c_smbus_read_i2c_block_data(client, + command, length, values); + + while (suboffset < length) { + s32 retval = i2c_smbus_read_i2c_block_data(client, + command + suboffset, + min(I2C_SMBUS_BLOCK_MAX, length - suboffset), + values + suboffset); + if (retval < 0) + return retval; + + suboffset += I2C_SMBUS_BLOCK_MAX; + } + return length; +} + +/*----------------------------------------------------------------------*/ + /* * The IRQ logic includes a "real" handler running in IRQ context just * long enough to schedule this workqueue entry. We need a task context @@ -646,8 +698,8 @@ static int ds1307_probe(struct i2c_client *client, buf = ds1307->regs; if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) { - ds1307->read_block_data = i2c_smbus_read_i2c_block_data; - ds1307->write_block_data = i2c_smbus_write_i2c_block_data; + ds1307->read_block_data = ds1307_native_smbus_read_block_data; + ds1307->write_block_data = ds1307_native_smbus_write_block_data; } else { ds1307->read_block_data = ds1307_read_block_data; ds1307->write_block_data = ds1307_write_block_data; |