On 03/30/2017 10:23 AM, Guochun Mao wrote: > when nor's size larger than 16MByte, nor and controller should > enter 4Byte mode simultaneously. > > Signed-off-by: Guochun Mao <guochun.mao@xxxxxxxxxxxx> > --- > drivers/mtd/spi-nor/mtk-quadspi.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/mtd/spi-nor/mtk-quadspi.c b/drivers/mtd/spi-nor/mtk-quadspi.c > index e661877..05cd8a8 100644 > --- a/drivers/mtd/spi-nor/mtk-quadspi.c > +++ b/drivers/mtd/spi-nor/mtk-quadspi.c > @@ -369,6 +369,13 @@ static int mt8173_nor_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, > /* We only handle 1 byte */ > ret = mt8173_nor_wr_sr(mt8173_nor, *buf); > break; > + case SPINOR_OP_EN4B: > + /* Set nor controller to 4-byte address mode, > + * and simultaneously set nor flash. > + * This case should cooperate with default operation. > + */ > + writeb(readb(mt8173_nor->base + MTK_NOR_DUAL_REG) | 0x10, > + mt8173_nor->base + MTK_NOR_DUAL_REG); And what happens on READ then ? Who clears that bit when protocol changes ? You probably want something like cqspi_set_protocol() instead, which is invoked from {read,write}{,_reg}() and erase(). > default: > ret = mt8173_nor_do_tx_rx(mt8173_nor, opcode, buf, len, NULL, 0); > if (ret) > -- Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html