spi: mediatek: add no_need_unprepare support

This patch add no_need_unprepare support for spi, if spi src clk is
MAIN PLL, it can keep the clk_prepare and will not cause low power
issue. So we no need do clk_prepare/clk_unprepare in runtime pm,
and it will get better performance, because clk_prepare has called
mutex lock.
In the same way,
clk_get_rate also has called mutex lock, so we moved it to spi_probe.

Signed-off-by: Mason Zhang <Mason.Zhang@mediatek.com>
Link: https://lore.kernel.org/r/20210629100814.21402-1-mason.zhang@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 976f73b9e2998334df86fc3c22f87bee56301f28..097625d7915e94e5edb9e06b822b0097e7504f26 100644 (file)
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -90,6 +90,8 @@ struct mtk_spi_compatible {
        bool enhance_timing;
        /* some IC support DMA addr extension */
        bool dma_ext;
+       /* some IC no need unprepare SPI clk */
+       bool no_need_unprepare;
 };
 
 struct mtk_spi {
@@ -104,6 +106,7 @@ struct mtk_spi {
        struct scatterlist *tx_sgl, *rx_sgl;
        u32 tx_sgl_len, rx_sgl_len;
        const struct mtk_spi_compatible *dev_comp;
+       u32 spi_clk_hz;
 };
 
 static const struct mtk_spi_compatible mtk_common_compat;
@@ -135,6 +138,14 @@ static const struct mtk_spi_compatible mt8183_compat = {
        .enhance_timing = true,
 };
 
+static const struct mtk_spi_compatible mt6893_compat = {
+       .need_pad_sel = true,
+       .must_tx = true,
+       .enhance_timing = true,
+       .dma_ext = true,
+       .no_need_unprepare = true,
+};
+
 /*
  * A piece of default chip info unless the platform
  * supplies it.
@@ -174,6 +185,9 @@ static const struct of_device_id mtk_spi_of_match[] = {
        { .compatible = "mediatek,mt8192-spi",
                .data = (void *)&mt6765_compat,
        },
+       { .compatible = "mediatek,mt6893-spi",
+               .data = (void *)&mt6893_compat,
+       },
        {}
 };
 MODULE_DEVICE_TABLE(of, mtk_spi_of_match);
@@ -287,12 +301,11 @@ static void mtk_spi_set_cs(struct spi_device *spi, bool enable)
 static void mtk_spi_prepare_transfer(struct spi_master *master,
                                     struct spi_transfer *xfer)
 {
-       u32 spi_clk_hz, div, sck_time, reg_val;
+       u32 div, sck_time, reg_val;
        struct mtk_spi *mdata = spi_master_get_devdata(master);
 
-       spi_clk_hz = clk_get_rate(mdata->spi_clk);
-       if (xfer->speed_hz < spi_clk_hz / 2)
-               div = DIV_ROUND_UP(spi_clk_hz, xfer->speed_hz);
+       if (xfer->speed_hz < mdata->spi_clk_hz / 2)
+               div = DIV_ROUND_UP(mdata->spi_clk_hz, xfer->speed_hz);
        else
                div = 1;
 
@@ -789,7 +802,12 @@ static int mtk_spi_probe(struct platform_device *pdev)
                goto err_put_master;
        }
 
-       clk_disable_unprepare(mdata->spi_clk);
+       mdata->spi_clk_hz = clk_get_rate(mdata->spi_clk);
+
+       if (mdata->dev_comp->no_need_unprepare)
+               clk_disable(mdata->spi_clk);
+       else
+               clk_disable_unprepare(mdata->spi_clk);
 
        pm_runtime_enable(&pdev->dev);
 
@@ -857,6 +875,9 @@ static int mtk_spi_remove(struct platform_device *pdev)
 
        mtk_spi_reset(mdata);
 
+       if (mdata->dev_comp->no_need_unprepare)
+               clk_unprepare(mdata->spi_clk);
+
        return 0;
 }
 
@@ -905,7 +926,10 @@ static int mtk_spi_runtime_suspend(struct device *dev)
        struct spi_master *master = dev_get_drvdata(dev);
        struct mtk_spi *mdata = spi_master_get_devdata(master);
 
-       clk_disable_unprepare(mdata->spi_clk);
+       if (mdata->dev_comp->no_need_unprepare)
+               clk_disable(mdata->spi_clk);
+       else
+               clk_disable_unprepare(mdata->spi_clk);
 
        return 0;
 }
@@ -916,7 +940,10 @@ static int mtk_spi_runtime_resume(struct device *dev)
        struct mtk_spi *mdata = spi_master_get_devdata(master);
        int ret;
 
-       ret = clk_prepare_enable(mdata->spi_clk);
+       if (mdata->dev_comp->no_need_unprepare)
+               ret = clk_enable(mdata->spi_clk);
+       else
+               ret = clk_prepare_enable(mdata->spi_clk);
        if (ret < 0) {
                dev_err(dev, "failed to enable spi_clk (%d)\n", ret);
                return ret;