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Subject[PATCH v2 2/4] spi: qup: Parse OPP table for DVFS support
Parse the OPP table from the device tree and use dev_pm_opp_set_rate()
instead of clk_set_rate() to allow making performance state for power
domains specified in the OPP table.

This is needed to guarantee correct behavior of the clock, especially
with the higher clock/SPI bus frequencies.

Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
---
drivers/spi/spi-qup.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index 4b6f6b25219b..bf043be3a2a9 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/dmaengine.h>
@@ -667,7 +668,7 @@ static int spi_qup_io_prep(struct spi_device *spi, struct spi_transfer *xfer)
return -EIO;
}

- ret = clk_set_rate(controller->cclk, xfer->speed_hz);
+ ret = dev_pm_opp_set_rate(controller->dev, xfer->speed_hz);
if (ret) {
dev_err(controller->dev, "fail to set frequency %d",
xfer->speed_hz);
@@ -1027,6 +1028,15 @@ static int spi_qup_probe(struct platform_device *pdev)
return -ENXIO;
}

+ ret = devm_pm_opp_set_clkname(dev, "core");
+ if (ret)
+ return ret;
+
+ /* OPP table is optional */
+ ret = devm_pm_opp_of_add_table(dev);
+ if (ret && ret != -ENODEV)
+ return dev_err_probe(dev, ret, "invalid OPP table\n");
+
host = spi_alloc_host(dev, sizeof(struct spi_qup));
if (!host) {
dev_err(dev, "cannot allocate host\n");
--
2.39.2

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