Re: [PATCH 1/1] spi: mediatek: add power control when set_cs

[Mark Brown]

On Wed, Oct 23, 2019 at 08:38:42AM -0400, Luhua Xu wrote:
> From: "luhua.xu" 

> Use runtime PM to power spi when set_cs
> As set_cs may be called from interrupt context,
> set runtime PM IRQ safe for spi.

Why might we be trying to set the chip select state while the device is
runtime idle?  It seems like whatever is trying to set the chip select
should be dealing with this, not the chip select operation itself since
that's unlikely to be happening in isolation.


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[PATCH 1/1] spi: mediatek: add power control when set_cs

[Luhua Xu]

From: "luhua.xu" 

Use runtime PM to power spi when set_cs
As set_cs may be called from interrupt context,
set runtime PM IRQ safe for spi.

Signed-off-by: luhua.xu 
---
 drivers/spi/spi-mt65xx.c | 12 
 1 file changed, 12 insertions(+)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 6888a4d..039b67d 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -262,8 +262,16 @@ static int mtk_spi_prepare_message(struct spi_master 
*master,
 static void mtk_spi_set_cs(struct spi_device *spi, bool enable)
 {
u32 reg_val;
+   int ret;
struct mtk_spi *mdata = spi_master_get_devdata(spi->master);
 
+   ret = pm_runtime_get_sync(spi->master->dev.parent);
+   if (ret < 0) {
+   pm_runtime_put_noidle(spi->master->dev.parent);
+   dev_err(&spi->dev, "failed to power device(%d)\n", ret);
+   return;
+   }
+
reg_val = readl(mdata->base + SPI_CMD_REG);
if (!enable) {
reg_val |= SPI_CMD_PAUSE_EN;
@@ -274,6 +282,9 @@ static void mtk_spi_set_cs(struct spi_device *spi, bool 
enable)
mdata->state = MTK_SPI_IDLE;
mtk_spi_reset(mdata);
}
+
+   pm_runtime_mark_last_busy(spi->master->dev.parent);
+   pm_runtime_put_autosuspend(spi->master->dev.parent);
 }
 
 static void mtk_spi_prepare_transfer(struct spi_master *master,
@@ -749,6 +760,7 @@ static int mtk_spi_probe(struct platform_device *pdev)
clk_disable_unprepare(mdata->spi_clk);
 
pm_runtime_enable(&pdev->dev);
+   pm_runtime_irq_safe(&pdev->dev);
 
ret = devm_spi_register_master(&pdev->dev, master);
if (ret) {
-- 
2.6.4