target/linux/generic/backport-5.4/827-v5.16-spi-add-power-control-when-set_cs.patch

drivers: spi: backport PM improvement for SPI framework

Fix PM improvement for SPI framework.
As to set_cs takes effect immediately, power spi
is needed when setup spi.

(cherry picked from commit d948e6ca189985495a21cd622c31e30e72b6b688)
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/spi/spi.c?h=v5.16-rc4&id=d948e6ca189985495a21cd622c31e30e72b6b688
(cherry picked from commit 57a9460705f105e1d79d1410c5cfe285beda8986)
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/spi/spi.c?h=v5.16-rc4&id=57a9460705f105e1d79d1410c5cfe285beda8986

--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3170,7 +3170,29 @@ 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;
+		}
+
+		/*
+		 * We do not want to return positive value from pm_runtime_get,
+		 * there are many instances of devices calling spi_setup() and
+		 * checking for a non-zero return value instead of a negative
+		 * return value.
+		 */
+		status = 0;
+
+		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;
-- 
2.18.0