tty: xuartps: disable clocks when not used

Currently the clocks are enabled at probe and disabled
at remove. Instead enable the clocks when used.

Signed-off-by: Shubhrajyoti Datta <shubhraj@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index cd46e64c4255559580ce7adf279300902f504975..9ca1a4d1b66a1e02186a438af498a4ac2ec5ea29 100644 (file)
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -976,6 +976,23 @@ static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c)
 }
 #endif
 
+static void cdns_uart_pm(struct uart_port *port, unsigned int state,
+                  unsigned int oldstate)
+{
+       struct cdns_uart *cdns_uart = port->private_data;
+
+       switch (state) {
+       case UART_PM_STATE_OFF:
+               clk_disable(cdns_uart->uartclk);
+               clk_disable(cdns_uart->pclk);
+               break;
+       default:
+               clk_enable(cdns_uart->pclk);
+               clk_enable(cdns_uart->uartclk);
+               break;
+       }
+}
+
 static struct uart_ops cdns_uart_ops = {
        .set_mctrl      = cdns_uart_set_mctrl,
        .get_mctrl      = cdns_uart_get_mctrl,
@@ -987,6 +1004,7 @@ static struct uart_ops cdns_uart_ops = {
        .set_termios    = cdns_uart_set_termios,
        .startup        = cdns_uart_startup,
        .shutdown       = cdns_uart_shutdown,
+       .pm             = cdns_uart_pm,
        .type           = cdns_uart_type,
        .verify_port    = cdns_uart_verify_port,
        .request_port   = cdns_uart_request_port,
@@ -1350,12 +1368,12 @@ static int cdns_uart_probe(struct platform_device *pdev)
                return PTR_ERR(cdns_uart_data->uartclk);
        }
 
-       rc = clk_prepare_enable(cdns_uart_data->pclk);
+       rc = clk_prepare(cdns_uart_data->pclk);
        if (rc) {
                dev_err(&pdev->dev, "Unable to enable pclk clock.\n");
                return rc;
        }
-       rc = clk_prepare_enable(cdns_uart_data->uartclk);
+       rc = clk_prepare(cdns_uart_data->uartclk);
        if (rc) {
                dev_err(&pdev->dev, "Unable to enable device clock.\n");
                goto err_out_clk_dis_pclk;
@@ -1422,9 +1440,9 @@ err_out_notif_unreg:
                        &cdns_uart_data->clk_rate_change_nb);
 #endif
 err_out_clk_disable:
-       clk_disable_unprepare(cdns_uart_data->uartclk);
+       clk_unprepare(cdns_uart_data->uartclk);
 err_out_clk_dis_pclk:
-       clk_disable_unprepare(cdns_uart_data->pclk);
+       clk_unprepare(cdns_uart_data->pclk);
 
        return rc;
 }
@@ -1448,8 +1466,8 @@ static int cdns_uart_remove(struct platform_device *pdev)
 #endif
        rc = uart_remove_one_port(&cdns_uart_uart_driver, port);
        port->mapbase = 0;
-       clk_disable_unprepare(cdns_uart_data->uartclk);
-       clk_disable_unprepare(cdns_uart_data->pclk);
+       clk_unprepare(cdns_uart_data->uartclk);
+       clk_unprepare(cdns_uart_data->pclk);
        return rc;
 }