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

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;
}