spi: mediatek: fix spi cs polarity error

Mediatek spi HW can't set cs inactive(keep cs high) directly.
Instead, it supplies pause mode to do it indirectly. If driver
unsets SPI_CMD_PAUSE_MODE in CMD_REG, it also needs to reset
internal state machine to let cs inactive at once.

Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 5f6315c47920efcb42dc52b5c93c26ce60cb7de4..b6073bbff8d94c95c7938241c1ce33572e0fe5aa 100644 (file)
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -173,22 +173,6 @@ static void mtk_spi_config(struct mtk_spi *mdata,
                writel(mdata->pad_sel, mdata->base + SPI_PAD_SEL_REG);
 }
 
-static int mtk_spi_prepare_hardware(struct spi_master *master)
-{
-       struct spi_transfer *trans;
-       struct mtk_spi *mdata = spi_master_get_devdata(master);
-       struct spi_message *msg = master->cur_msg;
-
-       trans = list_first_entry(&msg->transfers, struct spi_transfer,
-                                transfer_list);
-       if (!trans->cs_change) {
-               mdata->state = MTK_SPI_IDLE;
-               mtk_spi_reset(mdata);
-       }
-
-       return 0;
-}
-
 static int mtk_spi_prepare_message(struct spi_master *master,
                                   struct spi_message *msg)
 {
@@ -228,11 +212,15 @@ static void mtk_spi_set_cs(struct spi_device *spi, bool enable)
        struct mtk_spi *mdata = spi_master_get_devdata(spi->master);
 
        reg_val = readl(mdata->base + SPI_CMD_REG);
-       if (!enable)
+       if (!enable) {
                reg_val |= SPI_CMD_PAUSE_EN;
-       else
+               writel(reg_val, mdata->base + SPI_CMD_REG);
+       } else {
                reg_val &= ~SPI_CMD_PAUSE_EN;
-       writel(reg_val, mdata->base + SPI_CMD_REG);
+               writel(reg_val, mdata->base + SPI_CMD_REG);
+               mdata->state = MTK_SPI_IDLE;
+               mtk_spi_reset(mdata);
+       }
 }
 
 static void mtk_spi_prepare_transfer(struct spi_master *master,
@@ -509,7 +497,6 @@ static int mtk_spi_probe(struct platform_device *pdev)
        master->mode_bits = SPI_CPOL | SPI_CPHA;
 
        master->set_cs = mtk_spi_set_cs;
-       master->prepare_transfer_hardware = mtk_spi_prepare_hardware;
        master->prepare_message = mtk_spi_prepare_message;
        master->transfer_one = mtk_spi_transfer_one;
        master->can_dma = mtk_spi_can_dma;