On Thu, Nov 19, 2015 at 07:35:58PM +0100, Geert Uytterhoeven wrote:
> From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
>
> 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 deprecated "sci_ick").
>
> Cc: devicetree@xxxxxxxxxxxxxxx
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> Acked-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
> [geert: Handle EPROBE_DEFER, reformat description, break long comment line]
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
This could break users that care about the clock name. A new dtb with
old kernel would be one example. I guess you are okay with that, so:
Acked-by: Rob Herring <robh@xxxxxxxxxx>
> ---
> v2:
> - Add Acked-by,
> - Amendment by geert.
> ---
> .../bindings/serial/renesas,sci-serial.txt | 4 +-
> drivers/tty/serial/sh-sci.c | 64 ++++++++++++++--------
> 2 files changed, 43 insertions(+), 25 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
> index 73f825e5e6448815..2c9e6b8477e92792 100644
> --- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
> +++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
> @@ -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";
> };
> diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
> index 51c7507b0444957b..3c908804cab1c88c 100644
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -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);
> --
> 1.9.1
>
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