@@ -32,6 +32,7 @@
#define MTK_UART_RXTRI_AD 0x14 /* RX Trigger address */
#define MTK_UART_FRACDIV_L 0x15 /* Fractional divider LSB address */
#define MTK_UART_FRACDIV_M 0x16 /* Fractional divider MSB address */
+#define MTK_UART_DEBUG0 0x18
#define MTK_UART_IER_XOFFI 0x20 /* Enable XOFF character interrupt */
#define MTK_UART_IER_RTSI 0x40 /* Enable RTS Modem status interrupt */
#define MTK_UART_IER_CTSI 0x80 /* Enable CTS Modem status interrupt */
@@ -388,9 +389,18 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
static int __maybe_unused mtk8250_runtime_suspend(struct device *dev)
{
struct mtk8250_data *data = dev_get_drvdata(dev);
+ struct uart_8250_port *up = serial8250_get_port(data->line);
- clk_disable_unprepare(data->uart_clk);
- clk_disable_unprepare(data->bus_clk);
+ /* wait until UART in idle status */
+ while
+ (serial_in(up, MTK_UART_DEBUG0));
+
+ if (data->clk_count == 0U) {
+ dev_dbg(dev, "%s clock count is 0\n", __func__);
+ } else {
+ clk_disable_unprepare(data->bus_clk);
+ data->clk_count--;
+ }
return 0;
}
@@ -400,16 +410,16 @@ static int __maybe_unused mtk8250_runtime_resume(struct device *dev)
struct mtk8250_data *data = dev_get_drvdata(dev);
int err;
- err = clk_prepare_enable(data->uart_clk);
- if (err) {
- dev_warn(dev, "Can't enable clock\n");
- return err;
- }
-
- err = clk_prepare_enable(data->bus_clk);
- if (err) {
- dev_warn(dev, "Can't enable bus clock\n");
- return err;
+ if (data->clk_count > 0U) {
+ dev_dbg(dev, "%s clock count is %d\n", __func__,
+ data->clk_count);
+ } else {
+ err = clk_prepare_enable(data->bus_clk);
+ if (err) {
+ dev_warn(dev, "Can't enable bus clock\n");
+ return err;
+ }
+ data->clk_count++;
}
return 0;
@@ -419,12 +429,14 @@ static void
mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
{
if (!state)
- pm_runtime_get_sync(port->dev);
+ if (!mtk8250_runtime_resume(port->dev))
+ pm_runtime_get_sync(port->dev);
serial8250_do_pm(port, state, old);
if (state)
- pm_runtime_put_sync_suspend(port->dev);
+ if (!pm_runtime_put_sync_suspend(port->dev))
+ mtk8250_runtime_suspend(port->dev);
}
#ifdef CONFIG_SERIAL_8250_DMA
@@ -501,6 +513,8 @@ static int mtk8250_probe(struct platform_device *pdev)
if (!data)
return -ENOMEM;
+ data->clk_count = 0;
+
if (pdev->dev.of_node) {
err = mtk8250_probe_of(pdev, &uart.port, data);
if (err)
@@ -533,6 +547,7 @@ static int mtk8250_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, data);
+ pm_runtime_enable(&pdev->dev);
err = mtk8250_runtime_resume(&pdev->dev);
if (err)
return err;
@@ -541,9 +556,6 @@ static int mtk8250_probe(struct platform_device *pdev)
if (data->line < 0)
return data->line;
- pm_runtime_set_active(&pdev->dev);
- pm_runtime_enable(&pdev->dev);
-
data->rx_wakeup_irq = platform_get_irq_optional(pdev, 1);
return 0;
@@ -556,11 +568,13 @@ static int mtk8250_remove(struct platform_device *pdev)
pm_runtime_get_sync(&pdev->dev);
serial8250_unregister_port(data->line);
- mtk8250_runtime_suspend(&pdev->dev);
pm_runtime_disable(&pdev->dev);
pm_runtime_put_noidle(&pdev->dev);
+ if (!pm_runtime_status_suspended(&pdev->dev))
+ mtk8250_runtime_suspend(&pdev->dev);
+
return 0;
}
MTK uart design no need to control uart clock, so we just control bus clock in runtime function. Add uart clock used count to avoid repeatedly switching the clock. Signed-off-by: Changqi Hu <changqi.hu@mediatek.com> --- Changes in v4: Modify commit-message Changes in v3: Merge patch v1 and v2 together. Changes in v2: Enable uart bus clock when probe and resume base on v1 patch, but miss v1 patch itself. drivers/tty/serial/8250/8250_mtk.c | 50 ++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 18 deletions(-) -- 2.6.4