diff options
| -rw-r--r-- | drivers/misc/eeprom/at25.c | 19 | ||||
| -rw-r--r-- | include/linux/spi/eeprom.h | 10 |
2 files changed, 26 insertions, 3 deletions
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c index 01ab3c9b4cf..0842c2994ee 100644 --- a/drivers/misc/eeprom/at25.c +++ b/drivers/misc/eeprom/at25.c @@ -50,6 +50,7 @@ struct at25_data { #define AT25_SR_BP1 0x08 #define AT25_SR_WPEN 0x80 /* writeprotect enable */ +#define AT25_INSTR_BIT3 0x08 /* Additional address bit in instr */ #define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */ @@ -75,6 +76,7 @@ at25_ee_read( ssize_t status; struct spi_transfer t[2]; struct spi_message m; + u8 instr; if (unlikely(offset >= at25->bin.size)) return 0; @@ -84,7 +86,12 @@ at25_ee_read( return count; cp = command; - *cp++ = AT25_READ; + + instr = AT25_READ; + if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR) + if (offset >= (1U << (at25->addrlen * 8))) + instr |= AT25_INSTR_BIT3; + *cp++ = instr; /* 8/16/24-bit address is written MSB first */ switch (at25->addrlen) { @@ -167,14 +174,14 @@ at25_ee_write(struct at25_data *at25, const char *buf, loff_t off, /* For write, rollover is within the page ... so we write at * most one page, then manually roll over to the next page. */ - bounce[0] = AT25_WRITE; mutex_lock(&at25->lock); do { unsigned long timeout, retries; unsigned segment; unsigned offset = (unsigned) off; - u8 *cp = bounce + 1; + u8 *cp = bounce; int sr; + u8 instr; *cp = AT25_WREN; status = spi_write(at25->spi, cp, 1); @@ -184,6 +191,12 @@ at25_ee_write(struct at25_data *at25, const char *buf, loff_t off, break; } + instr = AT25_WRITE; + if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR) + if (offset >= (1U << (at25->addrlen * 8))) + instr |= AT25_INSTR_BIT3; + *cp++ = instr; + /* 8/16/24-bit address is written MSB first */ switch (at25->addrlen) { default: /* case 3 */ diff --git a/include/linux/spi/eeprom.h b/include/linux/spi/eeprom.h index 306e7b1c69e..403e007aef6 100644 --- a/include/linux/spi/eeprom.h +++ b/include/linux/spi/eeprom.h @@ -20,6 +20,16 @@ struct spi_eeprom { #define EE_ADDR3 0x0004 /* 24 bit addrs */ #define EE_READONLY 0x0008 /* disallow writes */ + /* + * Certain EEPROMS have a size that is larger than the number of address + * bytes would allow (e.g. like M95040 from ST that has 512 Byte size + * but uses only one address byte (A0 to A7) for addressing.) For + * the extra address bit (A8, A16 or A24) bit 3 of the instruction byte + * is used. This instruction bit is normally defined as don't care for + * other AT25 like chips. + */ +#define EE_INSTR_BIT3_IS_ADDR 0x0010 + /* for exporting this chip's data to other kernel code */ void (*setup)(struct memory_accessor *mem, void *context); void *context; |