linux-kernel - [PATCH V2] spi: add power control when set

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Date:   Wed, 30 Oct 2019 17:03:54 +0800
From:   Luhua Xu <luhua.xu@...iatek.com>
To:     Mark Brown <broonie@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     <linux-spi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <wsd_upstream@...iatek.com>,
        Luhua Xu <luhua.xu@...iatek.com>
Subject: [PATCH V2] spi: add power control when set_cs

From: "Luhua Xu" <luhua.xu@...iatek.com>

As to set_cs takes effect immediately, power spi
is needed when setup spi.

Cc: Mark Brown <broonie@...nel.org>
Signed-off-by: Luhua Xu <luhua.xu@...iatek.com>
---
V2:
- move set_cs PM control from .set_cs callback in
  vendor driver to spi_setup in spi framework.


 drivers/spi/spi.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index f9502db..19007e0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3091,7 +3091,20 @@ int spi_setup(struct spi_device *spi)
 	if (spi->controller->setup)
 		status = spi->controller->setup(spi);
 
-	spi_set_cs(spi, false);
+	if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
+		status = pm_runtime_get_sync(spi->controller->dev.parent);
+		if (status < 0) {
+			pm_runtime_put_noidle(spi->controller->dev.parent);
+			dev_err(&spi->controller->dev, "Failed to power device: %d\n",
+				status);
+			return status;
+		}
+		spi_set_cs(spi, false);
+		pm_runtime_mark_last_busy(spi->controller->dev.parent);
+		pm_runtime_put_autosuspend(spi->controller->dev.parent);
+	} else {
+		spi_set_cs(spi, false);
+	}
 
 	if (spi->rt && !spi->controller->rt) {
 		spi->controller->rt = true;
-- 
2.6.4