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Commit a9ec81f4 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Geert Uytterhoeven
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serial: sh-sci: Drop the interface clock 



As no platform defines an interface clock the SCI driver always falls
back to a clock named "peripheral_clk".
  - On SH platforms that clock is the base clock for the SCI functional
    clock and has the same frequency,
  - On ARM platforms that clock doesn't exist, and clk_get() will return
    the default clock for the device.
We can thus make the functional clock mandatory and drop the interface
clock.

EPROBE_DEFER is handled for clocks that may be referenced from DT (i.e.
"fck", and the deprecated "sci_ick").

Cc: devicetree@vger.kernel.org
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: default avatarSimon Horman <horms+renesas@verge.net.au>
[geert: Handle EPROBE_DEFER, reformat description, break long comment line]
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: default avatarRob Herring <robh@kernel.org>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8005c49d

Documentation/devicetree/bindings/serial/renesas,sci-serial.txt

+2 −2
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ Required properties: 


  - clocks: Must contain a phandle and clock-specifier pair for each entry

    in clock-names.

  - clock-names: Must contain "sci_ick" for the SCIx UART interface clock.

  - clock-names: Must contain "fck" for the SCIx UART functional clock.



Note: Each enabled SCIx UART should have an alias correctly numbered in the

"aliases" node.
@@ -63,7 +63,7 @@ Example: 
		interrupt-parent = <&gic>;

		interrupts = <0 144 IRQ_TYPE_LEVEL_HIGH>;

		clocks = <&mstp2_clks R8A7790_CLK_SCIFA0>;

		clock-names = "sci_ick";

		clock-names = "fck";

		dmas = <&dmac0 0x21>, <&dmac0 0x22>;

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

	};

drivers/tty/serial/sh-sci.c

+41 −23
Original line number Diff line number Diff line
@@ -92,8 +92,6 @@ struct sci_port { 
	struct timer_list	break_timer;

	int			break_flag;



	/* Interface clock */

	struct clk		*iclk;

	/* Function clock */

	struct clk		*fclk;
@@ -457,9 +455,8 @@ static void sci_port_enable(struct sci_port *sci_port) 


	pm_runtime_get_sync(sci_port->port.dev);



	clk_prepare_enable(sci_port->iclk);

	sci_port->port.uartclk = clk_get_rate(sci_port->iclk);

	clk_prepare_enable(sci_port->fclk);

	sci_port->port.uartclk = clk_get_rate(sci_port->fclk);

}



static void sci_port_disable(struct sci_port *sci_port)
@@ -476,7 +473,6 @@ static void sci_port_disable(struct sci_port *sci_port) 
	sci_port->break_flag = 0;



	clk_disable_unprepare(sci_port->fclk);

	clk_disable_unprepare(sci_port->iclk);



	pm_runtime_put_sync(sci_port->port.dev);

}
@@ -1622,7 +1618,7 @@ static int sci_notifier(struct notifier_block *self, 
		struct uart_port *port = &sci_port->port;



		spin_lock_irqsave(&port->lock, flags);

		port->uartclk = clk_get_rate(sci_port->iclk);

		port->uartclk = clk_get_rate(sci_port->fclk);

		spin_unlock_irqrestore(&port->lock, flags);

	}
@@ -2241,6 +2237,42 @@ static struct uart_ops sci_uart_ops = { 
#endif

};



static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)

{

	/* Get the SCI functional clock. It's called "fck" on ARM. */

	sci_port->fclk = clk_get(dev, "fck");

	if (PTR_ERR(sci_port->fclk) == -EPROBE_DEFER)

		return -EPROBE_DEFER;

	if (!IS_ERR(sci_port->fclk))

		return 0;



	/*

	 * But it used to be called "sci_ick", and we need to maintain DT

	 * backward compatibility.

	 */

	sci_port->fclk = clk_get(dev, "sci_ick");

	if (PTR_ERR(sci_port->fclk) == -EPROBE_DEFER)

		return -EPROBE_DEFER;

	if (!IS_ERR(sci_port->fclk))

		return 0;



	/* SH has historically named the clock "sci_fck". */

	sci_port->fclk = clk_get(dev, "sci_fck");

	if (!IS_ERR(sci_port->fclk))

		return 0;



	/*

	 * Not all SH platforms declare a clock lookup entry for SCI devices,

	 * in which case we need to get the global "peripheral_clk" clock.

	 */

	sci_port->fclk = clk_get(dev, "peripheral_clk");

	if (!IS_ERR(sci_port->fclk))

		return 0;



	dev_err(dev, "failed to get functional clock\n");

	return PTR_ERR(sci_port->fclk);

}



static int sci_init_single(struct platform_device *dev,

			   struct sci_port *sci_port, unsigned int index,

			   struct plat_sci_port *p, bool early)
@@ -2333,22 +2365,9 @@ static int sci_init_single(struct platform_device *dev, 
		sci_port->sampling_rate = p->sampling_rate;



	if (!early) {

		sci_port->iclk = clk_get(&dev->dev, "sci_ick");

		if (IS_ERR(sci_port->iclk)) {

			sci_port->iclk = clk_get(&dev->dev, "peripheral_clk");

			if (IS_ERR(sci_port->iclk)) {

				dev_err(&dev->dev, "can't get iclk\n");

				return PTR_ERR(sci_port->iclk);

			}

		}



		/*

		 * The function clock is optional, ignore it if we can't

		 * find it.

		 */

		sci_port->fclk = clk_get(&dev->dev, "sci_fck");

		if (IS_ERR(sci_port->fclk))

			sci_port->fclk = NULL;

		ret = sci_init_clocks(sci_port, &dev->dev);

		if (ret < 0)

			return ret;



		port->dev = &dev->dev;
@@ -2405,7 +2424,6 @@ static int sci_init_single(struct platform_device *dev, 


static void sci_cleanup_single(struct sci_port *port)

{

	clk_put(port->iclk);

	clk_put(port->fclk);



	pm_runtime_disable(port->port.dev);