[PATCH v8 22/34] spi: tegra20-slink: Add OPP support

[Dmitry Osipenko <digetx@xxxxxxxxx>]

The SPI on Tegra belongs to the core power domain and we're going to
enable GENPD support for the core domain. Now SPI driver must use OPP
API for driving the controller's clock rate because OPP API takes care
of reconfiguring the domain's performance state in accordance to the
rate. Add OPP support to the driver.

Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/spi/spi-tegra20-slink.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-tegra20-slink.c b/drivers/spi/spi-tegra20-slink.c
index deff16ba6d58..37cb15dc59f7 100644
--- a/drivers/spi/spi-tegra20-slink.c
+++ b/drivers/spi/spi-tegra20-slink.c
@@ -18,12 +18,15 @@
 #include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pm_opp.h>
 #include <linux/pm_runtime.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/reset.h>
 #include <linux/spi/spi.h>
 
+#include <soc/tegra/common.h>
+
 #define SLINK_COMMAND			0x000
 #define SLINK_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
 #define SLINK_WORD_SIZE(x)		(((x) & 0x1f) << 5)
@@ -683,7 +686,7 @@ static int tegra_slink_start_transfer_one(struct spi_device *spi,
 	bits_per_word = t->bits_per_word;
 	speed = t->speed_hz;
 	if (speed != tspi->cur_speed) {
-		clk_set_rate(tspi->clk, speed * 4);
+		dev_pm_opp_set_rate(tspi->dev, speed * 4);
 		tspi->cur_speed = speed;
 	}
 
@@ -1054,6 +1057,10 @@ static int tegra_slink_probe(struct platform_device *pdev)
 		goto exit_free_master;
 	}
 
+	ret = devm_tegra_core_dev_init_opp_table_simple(&pdev->dev);
+	if (ret)
+		return ret;
+
 	/* disabled clock may cause interrupt storm upon request */
 	tspi->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(tspi->clk)) {
@@ -1205,6 +1212,12 @@ static int tegra_slink_runtime_resume(struct device *dev)
 	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
 	int ret;
 
+	ret = dev_pm_opp_sync(dev);
+	if (ret) {
+		dev_err(dev, "failed to sync OPP: %d\n", ret);
+		return ret;
+	}
+
 	ret = clk_prepare_enable(tspi->clk);
 	if (ret < 0) {
 		dev_err(tspi->dev, "clk_prepare failed: %d\n", ret);
-- 
2.32.0