serial: 8250_dw: Enable runtime PM

[cascardo/linux.git] / drivers / tty / serial / 8250 / 8250_dw.c

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index db0e66f..d6aea85 100644 (file)
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -26,6 +26,8 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
 
 #include "8250.h"
 
@@ -55,8 +57,9 @@
 
 
 struct dw8250_data {
-       int     last_lcr;
-       int     line;
+       int             last_lcr;
+       int             line;
+       struct clk      *clk;
 };
 
 static void dw8250_serial_out(struct uart_port *p, int offset, int value)
@@ -113,6 +116,18 @@ static int dw8250_handle_irq(struct uart_port *p)
        return 0;
 }
 
+static void
+dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
+{
+       if (!state)
+               pm_runtime_get_sync(port->dev);
+
+       serial8250_do_pm(port, state, old);
+
+       if (state)
+               pm_runtime_put_sync_suspend(port->dev);
+}
+
 static int dw8250_probe_of(struct uart_port *p)
 {
        struct device_node      *np = p->dev->of_node;
@@ -136,8 +151,13 @@ static int dw8250_probe_of(struct uart_port *p)
        if (!of_property_read_u32(np, "reg-shift", &val))
                p->regshift = val;
 
+       /* clock got configured through clk api, all done */
+       if (p->uartclk)
+               return 0;
+
+       /* try to find out clock frequency from DT as fallback */
        if (of_property_read_u32(np, "clock-frequency", &val)) {
-               dev_err(p->dev, "no clock-frequency property set\n");
+               dev_err(p->dev, "clk or clock-frequency not defined\n");
                return -EINVAL;
        }
        p->uartclk = val;
@@ -286,6 +306,7 @@ static int dw8250_probe(struct platform_device *pdev)
        uart.port.mapbase = regs->start;
        uart.port.irq = irq->start;
        uart.port.handle_irq = dw8250_handle_irq;
+       uart.port.pm = dw8250_do_pm;
        uart.port.type = PORT_8250;
        uart.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
        uart.port.dev = &pdev->dev;
@@ -294,9 +315,20 @@ static int dw8250_probe(struct platform_device *pdev)
        if (!uart.port.membase)
                return -ENOMEM;
 
+       data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+       if (!data)
+               return -ENOMEM;
+
+       data->clk = devm_clk_get(&pdev->dev, NULL);
+       if (!IS_ERR(data->clk)) {
+               clk_prepare_enable(data->clk);
+               uart.port.uartclk = clk_get_rate(data->clk);
+       }
+
        uart.port.iotype = UPIO_MEM;
        uart.port.serial_in = dw8250_serial_in;
        uart.port.serial_out = dw8250_serial_out;
+       uart.port.private_data = data;
 
        dw8250_setup_port(&uart);
 
@@ -312,18 +344,15 @@ static int dw8250_probe(struct platform_device *pdev)
                return -ENODEV;
        }
 
-       data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
-       if (!data)
-               return -ENOMEM;
-
-       uart.port.private_data = data;
-
        data->line = serial8250_register_8250_port(&uart);
        if (data->line < 0)
                return data->line;
 
        platform_set_drvdata(pdev, data);
 
+       pm_runtime_set_active(&pdev->dev);
+       pm_runtime_enable(&pdev->dev);
+
        return 0;
 }
 
@@ -331,34 +360,64 @@ static int dw8250_remove(struct platform_device *pdev)
 {
        struct dw8250_data *data = platform_get_drvdata(pdev);
 
+       pm_runtime_get_sync(&pdev->dev);
+
        serial8250_unregister_port(data->line);
 
+       if (!IS_ERR(data->clk))
+               clk_disable_unprepare(data->clk);
+
+       pm_runtime_disable(&pdev->dev);
+       pm_runtime_put_noidle(&pdev->dev);
+
        return 0;
 }
 
 #ifdef CONFIG_PM
-static int dw8250_suspend(struct platform_device *pdev, pm_message_t state)
+static int dw8250_suspend(struct device *dev)
 {
-       struct dw8250_data *data = platform_get_drvdata(pdev);
+       struct dw8250_data *data = dev_get_drvdata(dev);
 
        serial8250_suspend_port(data->line);
 
        return 0;
 }
 
-static int dw8250_resume(struct platform_device *pdev)
+static int dw8250_resume(struct device *dev)
 {
-       struct dw8250_data *data = platform_get_drvdata(pdev);
+       struct dw8250_data *data = dev_get_drvdata(dev);
 
        serial8250_resume_port(data->line);
 
        return 0;
 }
-#else
-#define dw8250_suspend NULL
-#define dw8250_resume NULL
 #endif /* CONFIG_PM */
 
+#ifdef CONFIG_PM_RUNTIME
+static int dw8250_runtime_suspend(struct device *dev)
+{
+       struct dw8250_data *data = dev_get_drvdata(dev);
+
+       clk_disable_unprepare(data->clk);
+
+       return 0;
+}
+
+static int dw8250_runtime_resume(struct device *dev)
+{
+       struct dw8250_data *data = dev_get_drvdata(dev);
+
+       clk_prepare_enable(data->clk);
+
+       return 0;
+}
+#endif
+
+static const struct dev_pm_ops dw8250_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume)
+       SET_RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL)
+};
+
 static const struct of_device_id dw8250_of_match[] = {
        { .compatible = "snps,dw-apb-uart" },
        { /* Sentinel */ }
@@ -376,13 +435,12 @@ static struct platform_driver dw8250_platform_driver = {
        .driver = {
                .name           = "dw-apb-uart",
                .owner          = THIS_MODULE,
+               .pm             = &dw8250_pm_ops,
                .of_match_table = dw8250_of_match,
                .acpi_match_table = ACPI_PTR(dw8250_acpi_match),
        },
        .probe                  = dw8250_probe,
        .remove                 = dw8250_remove,
-       .suspend                = dw8250_suspend,
-       .resume                 = dw8250_resume,
 };
 
 module_platform_driver(dw8250_platform_driver);