RE: [PATCH linux-next v4 5/5] mtd: atmel-quadspi: add driver for Atmel QSPI controller

Bean Huo 霍斌斌 (beanhuo)
2015-08-25T01:46:41Z

>+ nor->read_reg = atmel_qspi_read_reg;
>+ nor->write_reg = atmel_qspi_write_reg;
>+ nor->read = atmel_qspi_read;
>+ nor->write = atmel_qspi_write;
>+ nor->erase = atmel_qspi_erase;
>+ nor->set_protocol = atmel_qspi_set_protocol;

This is very good, the structure of spi_nor should add a hook function to notify spi controller
That spi nor transfer protocol already changed.

>+
>+ if (of_modalias_node(child, modalias, sizeof(modalias)) < 0) {
>+ err = -ENODEV;
>+ goto release_channel;
>+ }
>+
>+ err = of_property_read_u32(child, "spi-max-frequency", &aq->clk_rate);
>+ if (err < 0)
>+ goto release_channel;
>+
>+ err = atmel_qspi_init(aq);
>+ if (err)
>+ goto release_channel;
>+
>+ nor->dev->of_node = child;
>+ err = spi_nor_scan(nor, modalias, SPI_NOR_QUAD);
> goto release_channel;
>+

.......

>static inline struct spi_nor *mtd_to_spi_nor(struct mtd_info *mtd) {
return mtd->priv;
>@@ -944,6 +960,11 @@ static int micron_quad_enable(struct spi_nor *nor)
> return ret;
> }
>
>+ /* switch protocol to Quad CMD 4-4-4 */
>+ ret = spi_nor_set_protocol(nor, SPI_PROTO_4_4_4);
>+ if (ret)
>+ return ret;
>+

This make sense,from spi nor side,once its protocol being changed,
Mtd layer must notify this status to spi nor controller immediately,
And spi nor controller also should re-adjust its protocol.
Otherwise, following reading SR operation will fail.

>
> ret = spi_nor_wait_till_ready(nor);
> if (ret)
> return ret;

If my ack has any value in here, feel free to add it.

Acked-by: Bean Huo <beanhuo@micron.com>