[1/3] spi: spi-qcom-qspi: Use OPP API to set clk/perf state

Commit Message

Rajendra Nayak July 3, 2020, 9:41 a.m. UTC

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 <[e-mail]>
Reviewed-by: Matthias Kaehlcke <[e-mail]>
Acked-by: Mark Brown <[e-mail]>
Cc: Alok Chauhan <[e-mail]>
Cc: Akash Asthana <[e-mail]>
Cc: [e-mail]
---
 drivers/spi/spi-qcom-qspi.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

Comments

Mark Brown July 3, 2020, 5:01 p.m. UTC | #1

On Fri, Jul 03, 2020 at 03:11:31PM +0530, Rajendra Nayak wrote:
> 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.

This doesn't apply against current code, please check and resend.

Rajendra Nayak July 7, 2020, 4:27 a.m. UTC | #2

On 7/3/2020 10:31 PM, Mark Brown wrote:
> On Fri, Jul 03, 2020 at 03:11:31PM +0530, Rajendra Nayak wrote:
>> 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.
> 
> This doesn't apply against current code, please check and resend.

Hey Mark, as mentioned in the cover letter I wanted this to land via the
qcom tree, since Bjorn already has a patch in his tree which would otherwise
conflict with this change, if you were to pull this.
Hence I had this rebased on qcom for-next and requested Bjorn to pull it in,
with your ACK. Hope thats fine with you.

thanks,
Rajendra

Patch

diff --git a/drivers/spi/spi-qcom-qspi.c b/drivers/spi/spi-qcom-qspi.c
index b5b4cf6..18a59aa 100644
--- a/drivers/spi/spi-qcom-qspi.c
+++ b/drivers/spi/spi-qcom-qspi.c
@@ -9,6 +9,7 @@ 
 #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>
 
@@ -141,6 +142,8 @@  struct qcom_qspi {
 	struct clk_bulk_data *clks;
 	struct qspi_xfer xfer;
 	struct icc_path *icc_path_cpu_to_qspi;
+	struct opp_table *opp_table;
+	bool has_opp_table;
 	/* Lock to protect data accessed by IRQs */
 	spinlock_t lock;
 };
@@ -238,7 +241,7 @@  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;
@@ -519,6 +522,20 @@  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);
@@ -526,6 +543,9 @@  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);
@@ -536,11 +556,15 @@  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;
 }
@@ -551,6 +575,8 @@  static int __maybe_unused qcom_qspi_runtime_suspend(struct device *dev)
 	struct qcom_qspi *ctrl = spi_master_get_devdata(master);
 	int ret;
 
+	/* Drop the performance state vote */
+	dev_pm_opp_set_rate(dev, 0);
 	clk_bulk_disable_unprepare(QSPI_NUM_CLKS, ctrl->clks);
 
 	ret = icc_disable(ctrl->icc_path_cpu_to_qspi);