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Commit 3c6d89ea authored by Doug Anderson's avatar Doug Anderson Committed by Chris Ball
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mmc: dw_mmc: Add the ability to set the ciu clock frequency 



As of now we rely on code outside of the driver to set the ciu clock
frequency.  There's no reason to do that.  Add support for setting up
the clock in the driver during probe.

Signed-off-by: default avatarDoug Anderson <dianders@chromium.org>
Acked-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 870556a3

Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt

+16 −0
Original line number Diff line number Diff line
@@ -39,6 +39,19 @@ Required Properties: 


Optional properties:



* clocks: from common clock binding: handle to biu and ciu clocks for the

  bus interface unit clock and the card interface unit clock.



* clock-names: from common clock binding: Shall be "biu" and "ciu".

  If the biu clock is missing we'll simply skip enabling it.  If the

  ciu clock is missing we'll just assume that the clock is running at

  clock-frequency.  It is an error to omit both the ciu clock and the

  clock-frequency.



* clock-frequency: should be the frequency (in Hz) of the ciu clock.  If this

  is specified and the ciu clock is specified then we'll try to set the ciu

  clock to this at probe time.



* num-slots: specifies the number of slots supported by the controller.

  The number of physical slots actually used could be equal or less than the

  value specified by num-slots. If this property is not specified, the value
@@ -70,6 +83,8 @@ board specific portions as listed below. 


	dwmmc0@12200000 {

		compatible = "snps,dw-mshc";

		clocks = <&clock 351>, <&clock 132>;

		clock-names = "biu", "ciu";

		reg = <0x12200000 0x1000>;

		interrupts = <0 75 0>;

		#address-cells = <1>;
@@ -77,6 +92,7 @@ board specific portions as listed below. 
	};



	dwmmc0@12200000 {

		clock-frequency = <400000000>;

		num-slots = <1>;

		supports-highspeed;

		broken-cd;

drivers/mmc/host/dw_mmc.c

+13 −4
Original line number Diff line number Diff line
@@ -2117,6 +2117,7 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host) 
	struct device_node *np = dev->of_node;

	const struct dw_mci_drv_data *drv_data = host->drv_data;

	int idx, ret;

	u32 clock_frequency;



	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);

	if (!pdata) {
@@ -2143,6 +2144,9 @@ static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host) 


	of_property_read_u32(np, "card-detect-delay", &pdata->detect_delay_ms);



	if (!of_property_read_u32(np, "clock-frequency", &clock_frequency))

		pdata->bus_hz = clock_frequency;



	if (drv_data && drv_data->parse_dt) {

		ret = drv_data->parse_dt(host);

		if (ret)
@@ -2200,18 +2204,23 @@ int dw_mci_probe(struct dw_mci *host) 
	host->ciu_clk = devm_clk_get(host->dev, "ciu");

	if (IS_ERR(host->ciu_clk)) {

		dev_dbg(host->dev, "ciu clock not available\n");

		host->bus_hz = host->pdata->bus_hz;

	} else {

		ret = clk_prepare_enable(host->ciu_clk);

		if (ret) {

			dev_err(host->dev, "failed to enable ciu clock\n");

			goto err_clk_biu;

		}

	}



	if (IS_ERR(host->ciu_clk))

		host->bus_hz = host->pdata->bus_hz;

	else

		if (host->pdata->bus_hz) {

			ret = clk_set_rate(host->ciu_clk, host->pdata->bus_hz);

			if (ret)

				dev_warn(host->dev,

					 "Unable to set bus rate to %ul\n",

					 host->pdata->bus_hz);

		}

		host->bus_hz = clk_get_rate(host->ciu_clk);

	}



	if (drv_data && drv_data->setup_clock) {

		ret = drv_data->setup_clock(host);