Unverified Commit da6de6d3 authored by Mark Brown's avatar Mark Brown
Browse files

spi: qup: Allow scaling power domains and 

Merge series from Stephan Gerhold <stephan.gerhold@kernkonzept.com>:

Make it possible to scale performance states of the power domain and
interconnect of the SPI QUP controller in relation to the selected SPI
speed / core clock. This is done separately by:

  - Parsing the OPP table from the device tree for performance state
    votes of the power domain
  - Voting for the necessary bandwidth on the interconnect path to DRAM
parents 8a771075 ecdaa947

Documentation/devicetree/bindings/spi/qcom,spi-qup.yaml

+13 −0
Original line number Diff line number Diff line
@@ -44,9 +44,17 @@ properties: 
      - const: tx

      - const: rx



  interconnects:

    maxItems: 1



  interrupts:

    maxItems: 1



  operating-points-v2: true



  power-domains:

    maxItems: 1



  reg:

    maxItems: 1
@@ -62,7 +70,9 @@ unevaluatedProperties: false 
examples:

  - |

    #include <dt-bindings/clock/qcom,gcc-msm8996.h>

    #include <dt-bindings/interconnect/qcom,msm8996.h>

    #include <dt-bindings/interrupt-controller/arm-gic.h>

    #include <dt-bindings/power/qcom-rpmpd.h>



    spi@7575000 {

        compatible = "qcom,spi-qup-v2.2.1";
@@ -76,6 +86,9 @@ examples: 
        pinctrl-1 = <&blsp1_spi1_sleep>;

        dmas = <&blsp1_dma 12>, <&blsp1_dma 13>;

        dma-names = "tx", "rx";

        power-domains = <&rpmpd MSM8996_VDDCX>;

        operating-points-v2 = <&spi_opp_table>;

        interconnects = <&pnoc MASTER_BLSP_1 &bimc SLAVE_EBI_CH0>;

        #address-cells = <1>;

        #size-cells = <0>;

    };

drivers/spi/spi-qup.c

+49 −1
Original line number Diff line number Diff line
@@ -6,12 +6,14 @@ 
#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/interconnect.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/list.h>

#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>
@@ -121,11 +123,14 @@ 
#define SPI_DELAY_THRESHOLD		1

#define SPI_DELAY_RETRY			10



#define SPI_BUS_WIDTH			8



struct spi_qup {

	void __iomem		*base;

	struct device		*dev;

	struct clk		*cclk;	/* core clock */

	struct clk		*iclk;	/* interface clock */

	struct icc_path		*icc_path; /* interconnect to RAM */

	int			irq;

	spinlock_t		lock;
@@ -148,6 +153,8 @@ struct spi_qup { 
	int			mode;

	struct dma_slave_config	rx_conf;

	struct dma_slave_config	tx_conf;



	u32			bw_speed_hz;

};



static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer);
@@ -180,6 +187,23 @@ static inline bool spi_qup_is_valid_state(struct spi_qup *controller) 
	return opstate & QUP_STATE_VALID;

}



static int spi_qup_vote_bw(struct spi_qup *controller, u32 speed_hz)

{

	u32 needed_peak_bw;

	int ret;



	if (controller->bw_speed_hz == speed_hz)

		return 0;



	needed_peak_bw = Bps_to_icc(speed_hz * SPI_BUS_WIDTH);

	ret = icc_set_bw(controller->icc_path, 0, needed_peak_bw);

	if (ret)

		return ret;



	controller->bw_speed_hz = speed_hz;

	return 0;

}



static int spi_qup_set_state(struct spi_qup *controller, u32 state)

{

	unsigned long loop;
@@ -450,6 +474,12 @@ static int spi_qup_do_dma(struct spi_device *spi, struct spi_transfer *xfer, 
	struct scatterlist *tx_sgl, *rx_sgl;

	int ret;



	ret = spi_qup_vote_bw(qup, xfer->speed_hz);

	if (ret) {

		dev_err(qup->dev, "fail to vote for ICC bandwidth: %d\n", ret);

		return -EIO;

	}



	if (xfer->rx_buf)

		rx_done = spi_qup_dma_done;

	else if (xfer->tx_buf)
@@ -667,7 +697,7 @@ 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);
@@ -993,6 +1023,7 @@ static void spi_qup_set_cs(struct spi_device *spi, bool val) 
static int spi_qup_probe(struct platform_device *pdev)

{

	struct spi_controller *host;

	struct icc_path *icc_path;

	struct clk *iclk, *cclk;

	struct spi_qup *controller;

	struct resource *res;
@@ -1018,6 +1049,11 @@ static int spi_qup_probe(struct platform_device *pdev) 
	if (IS_ERR(iclk))

		return PTR_ERR(iclk);



	icc_path = devm_of_icc_get(dev, NULL);

	if (IS_ERR(icc_path))

		return dev_err_probe(dev, PTR_ERR(icc_path),

				     "failed to get interconnect path\n");



	/* This is optional parameter */

	if (of_property_read_u32(dev->of_node, "spi-max-frequency", &max_freq))

		max_freq = SPI_MAX_RATE;
@@ -1027,6 +1063,15 @@ 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");
@@ -1060,6 +1105,7 @@ static int spi_qup_probe(struct platform_device *pdev) 
	controller->base = base;

	controller->iclk = iclk;

	controller->cclk = cclk;

	controller->icc_path = icc_path;

	controller->irq = irq;



	ret = spi_qup_init_dma(host, res->start);
@@ -1180,6 +1226,7 @@ static int spi_qup_pm_suspend_runtime(struct device *device) 
	writel_relaxed(config, controller->base + QUP_CONFIG);



	clk_disable_unprepare(controller->cclk);

	spi_qup_vote_bw(controller, 0);

	clk_disable_unprepare(controller->iclk);



	return 0;
@@ -1231,6 +1278,7 @@ static int spi_qup_suspend(struct device *device) 
		return ret;



	clk_disable_unprepare(controller->cclk);

	spi_qup_vote_bw(controller, 0);

	clk_disable_unprepare(controller->iclk);

	return 0;

}