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 <rna...@codeaurora.org>
Cc: Mark Brown <broo...@kernel.org>
Cc: Alok Chauhan <al...@codeaurora.org>
Cc: Akash Asthana <akash...@codeaurora.org>
Cc: linux-...@vger.kernel.org
---
 drivers/spi/spi-qcom-qspi.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-qcom-qspi.c b/drivers/spi/spi-qcom-qspi.c
index 3c4f83b..eb53c00 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);
@@ -498,6 +518,11 @@ 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);
+
+       if (ctrl->has_opp_table)
+               dev_pm_opp_of_remove_table(&pdev->dev);
+       dev_pm_opp_put_clkname(ctrl->opp_table);
 
        /* Unregister _before_ disabling pm_runtime() so we stop transfers */
        spi_unregister_master(master);
@@ -512,6 +537,8 @@ 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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of Code Aurora Forum, hosted by The Linux Foundation

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