[PATCH v6 6/6] spi: spi-qcom-qspi: Use OPP API to set clk/perf state

Rajendra Nayak
2020-06-15T12:04:11Z

QSPI needs to vote on a performance state of a power domain depending on
the clock rate. Add support for it by specifying the perf state/clock rate
as an OPP table in device tree.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Mark Brown <broonie@kernel.org>
Cc: Alok Chauhan <alokc@codeaurora.org>
Cc: Akash Asthana <akashast@codeaurora.org>
Cc: linux-spi@vger.kernel.org
---
No functional change in v6, rebased over 5.8-rc1

drivers/spi/spi-qcom-qspi.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-qcom-qspi.c b/drivers/spi/spi-qcom-qspi.c
index 3c4f83b..ef51982 100644
--- a/drivers/spi/spi-qcom-qspi.c
+++ b/drivers/spi/spi-qcom-qspi.c
@@ -8,6 +8,7 @@
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/pm_runtime.h>
+#include <linux/pm_opp.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>

@@ -139,6 +140,8 @@ struct qcom_qspi {
struct device *dev;
struct clk_bulk_data *clks;
struct qspi_xfer xfer;
+ struct opp_table *opp_table;
+ bool has_opp_table;
/* Lock to protect xfer and IRQ accessed registers */
spinlock_t lock;
};
@@ -235,7 +238,7 @@ static int qcom_qspi_transfer_one(struct spi_master *master,
speed_hz = xfer->speed_hz;

/* In regular operation (SBL_EN=1) core must be 4x transfer clock */
- ret = clk_set_rate(ctrl->clks[QSPI_CLK_CORE].clk, speed_hz * 4);
+ ret = dev_pm_opp_set_rate(ctrl->dev, speed_hz * 4);
if (ret) {
dev_err(ctrl->dev, "Failed to set core clk %d\n", ret);
return ret;
@@ -481,6 +484,20 @@ static int qcom_qspi_probe(struct platform_device *pdev)
master->handle_err = qcom_qspi_handle_err;
master->auto_runtime_pm = true;

+ ctrl->opp_table = dev_pm_opp_set_clkname(&pdev->dev, "core");
+ if (IS_ERR(ctrl->opp_table)) {
+ ret = PTR_ERR(ctrl->opp_table);
+ goto exit_probe_master_put;
+ }
+ /* OPP table is optional */
+ ret = dev_pm_opp_of_add_table(&pdev->dev);
+ if (!ret) {
+ ctrl->has_opp_table = true;
+ } else if (ret != -ENODEV) {
+ dev_err(&pdev->dev, "invalid OPP table in device tree\n");
+ goto exit_probe_master_put;
+ }
+
pm_runtime_enable(dev);

ret = spi_register_master(master);
@@ -488,6 +505,9 @@ static int qcom_qspi_probe(struct platform_device *pdev)
return 0;

pm_runtime_disable(dev);
+ if (ctrl->has_opp_table)
+ dev_pm_opp_of_remove_table(&pdev->dev);
+ dev_pm_opp_put_clkname(ctrl->opp_table);

exit_probe_master_put:
spi_master_put(master);
@@ -498,11 +518,15 @@ static int qcom_qspi_probe(struct platform_device *pdev)
static int qcom_qspi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
+ struct qcom_qspi *ctrl = spi_master_get_devdata(master);

/* Unregister _before_ disabling pm_runtime() so we stop transfers */
spi_unregister_master(master);

pm_runtime_disable(&pdev->dev);
+ if (ctrl->has_opp_table)
+ dev_pm_opp_of_remove_table(&pdev->dev);
+ dev_pm_opp_put_clkname(ctrl->opp_table);

return 0;
}
@@ -512,6 +536,8 @@ static int __maybe_unused qcom_qspi_runtime_suspend(struct device *dev)
struct spi_master *master = dev_get_drvdata(dev);
struct qcom_qspi *ctrl = spi_master_get_devdata(master);

+ /* Drop the performance state vote */
+ dev_pm_opp_set_rate(dev, 0);
clk_bulk_disable_unprepare(QSPI_NUM_CLKS, ctrl->clks);

return 0;
--
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