mtd: spi-nor: simplify write loop

	size_t *retlen, const u_char *buf)

{

	struct spi_nor *nor = mtd_to_spi_nor(mtd);

	u32 page_offset, page_size, i;

	int ret;

	size_t page_offset, page_remain, i;

	ssize_t ret;

	dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);

	if (ret)

		return ret;

	write_enable(nor);

	page_offset = to & (nor->page_size - 1);

	for (i = 0; i < len; ) {

		ssize_t written;

	/* do all the bytes fit onto one page? */

	if (page_offset + len <= nor->page_size) {

		ret = nor->write(nor, to, len, buf);

		if (ret < 0)

			goto write_err;

		*retlen += ret;

	} else {

		page_offset = (to + i) & (nor->page_size - 1);

		WARN_ONCE(page_offset,

			  "Writing at offset %zu into a NOR page. Writing partial pages may decrease reliability and increase wear of NOR flash.",

			  page_offset);

		/* the size of data remaining on the first page */

		page_size = nor->page_size - page_offset;

		ret = nor->write(nor, to, page_size, buf);

		page_remain = min_t(size_t,

				    nor->page_size - page_offset, len - i);

		write_enable(nor);

		ret = nor->write(nor, to + i, page_remain, buf + i);

		if (ret < 0)

			goto write_err;

		*retlen += ret;

		/* write everything in nor->page_size chunks */

		for (i = ret; i < len; ) {

			page_size = len - i;

			if (page_size > nor->page_size)

				page_size = nor->page_size;

		written = ret;

		ret = spi_nor_wait_till_ready(nor);

		if (ret)

			goto write_err;

			write_enable(nor);

			ret = nor->write(nor, to + i, page_size, buf + i);

			if (ret < 0)

		*retlen += written;

		i += written;

		if (written != page_remain) {

			dev_err(nor->dev,

				"While writing %zu bytes written %zd bytes\n",

				page_remain, written);

			ret = -EIO;

			goto write_err;

			*retlen += ret;

			i += ret;

		}

	}

	ret = spi_nor_wait_till_ready(nor);

write_err:

	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);

	return ret;