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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>
This commit is contained in:
Leilk Liu 2015-09-07 19:37:57 +08:00 committed by Mark Brown
parent c5992f610f
commit 6583d2032d
1 changed files with 7 additions and 20 deletions
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27
drivers/spi/spi-mt65xx.c
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@ -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;