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serial: 8250-mtk: modify mtk uart power and clock management

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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>
Link: https://lore.kernel.org/r/1582707225-26815-1-git-send-email-changqi.hu@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Changqi Hu 2020-02-26 16:53:45 +08:00 committed by Greg Kroah-Hartman
parent 5a08a4877a
commit e32a83c70c
1 changed files with 32 additions and 18 deletions
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50
drivers/tty/serial/8250/8250_mtk.c
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@ -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;
}