misc: i2c_eeprom: consider pagesize when writing to eeprom

Calculate the maximum length of the buffer when writing
across the page boundary. If the buffer length (len)
exceeds the page boundary (pagesize), split it. Use this
length instead of comparing the length with the pagesize,
because if the write start address (offset) is not at the
beginning of a page and the page_offset + len is greater
than the page boundary (pagesize), the write operation
would overflow the current page and the behaviour can be
undefined (e.g. at24).

Signed-off-by: Alex Michel <alex.michel@wiedemann-group.com>

diff --git a/drivers/misc/i2c_eeprom.c b/drivers/misc/i2c_eeprom.c
index e1d0b8f918a29929abc397352c040275cf2368f4..9111bd724cbbfb097460e4bae87343254d60143a 100644 (file)
--- a/drivers/misc/i2c_eeprom.c
+++ b/drivers/misc/i2c_eeprom.c
@@ -60,6 +60,17 @@ static int i2c_eeprom_std_read(struct udevice *dev, int offset, uint8_t *buf,
        return dm_i2c_read(dev, offset, buf, size);
 }
 
+static int i2c_eeprom_len(int offset, int len, int pagesize)
+{
+       int page_offset = offset & (pagesize - 1);
+       int maxlen = pagesize - page_offset;
+
+       if (len > maxlen)
+               len = maxlen;
+
+       return len;
+}
+
 static int i2c_eeprom_std_write(struct udevice *dev, int offset,
                                const uint8_t *buf, int size)
 {
@@ -67,7 +78,7 @@ static int i2c_eeprom_std_write(struct udevice *dev, int offset,
        int ret;
 
        while (size > 0) {
-               int write_size = min_t(int, size, priv->pagesize);
+               int write_size = i2c_eeprom_len(offset, size, priv->pagesize);
 
                ret = dm_i2c_write(dev, offset, buf, write_size);
                if (ret)