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Commit a9ec81f4 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Geert Uytterhoeven

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

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

Signed-off-by: default avatarLaurent Pinchart <>
Acked-by: default avatarSimon Horman <>
[geert: Handle EPROBE_DEFER, reformat description, break long comment line]
Signed-off-by: default avatarGeert Uytterhoeven <>
Acked-by: default avatarRob Herring <>
Acked-by: default avatarGreg Kroah-Hartman <>
parent 8005c49d
......@@ -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";
......@@ -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)
sci_port->port.uartclk = clk_get_rate(sci_port->iclk);
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;
......@@ -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 = {
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)
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)
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)
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