Re: [PATCH-v3] Support M95040 SPI EEPROM

From: Chris Wright
Date: Tue Apr 03 2012 - 12:53:45 EST


* Ivo Sieben (meltedpianoman@xxxxxxxxx) wrote:
> + instr = AT25_READ;
> + if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR)
> + if (offset >= (1U << (at25->addrlen * 8)))
> + instr |= AT25_INSTR_BIT3;
> + *cp++ = instr;
<snip>
> + /*
> + * 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

Is there some guarantee that this chip flag will always have this
meaning?

thanks,
-chris
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