From a9ec81f4ed5c05dbbc671e5fa39de0540eb0495f Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 14 Sep 2015 15:14:23 +0300 Subject: [PATCH] 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: Laurent Pinchart Acked-by: Simon Horman [geert: Handle EPROBE_DEFER, reformat description, break long comment line] Signed-off-by: Geert Uytterhoeven Acked-by: Rob Herring Acked-by: Greg Kroah-Hartman --- .../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 73f825e5e644..2c9e6b8477e9 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 960e50a97558..cc6fa55231ba 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); -- 2.39.5