[RFC/RFT 3/6] serial: msm: convert driver to use runtime PM apis

[Rajendra Nayak <rnayak@codeaurora.org>]

With platform support now in place to manage clocks from within runtime PM
callbacks, get rid of all clock handling from the driver and convert the
driver to use runtime PM apis.

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Cc: <linux-serial@vger.kernel.org>
---
 drivers/tty/serial/msm_serial.c | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index b73889c..eb66502 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -33,6 +33,7 @@
 #include <linux/serial.h>
 #include <linux/clk.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/delay.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -50,11 +51,11 @@ struct msm_port {
 	struct uart_port	uart;
 	char			name[16];
 	struct clk		*clk;
-	struct clk		*pclk;
 	unsigned int		imr;
 	int			is_uartdm;
 	unsigned int		old_snap_state;
 	bool			break_detected;
+	struct device		*dev;
 };
 
 static inline void wait_for_xmitr(struct uart_port *port)
@@ -464,12 +465,11 @@ static int msm_set_baud_rate(struct uart_port *port, unsigned int baud)
 	return baud;
 }
 
-static void msm_init_clock(struct uart_port *port)
+static void msm_init(struct uart_port *port)
 {
 	struct msm_port *msm_port = UART_TO_MSM(port);
 
-	clk_prepare_enable(msm_port->clk);
-	clk_prepare_enable(msm_port->pclk);
+	pm_runtime_get_sync(msm_port->dev);
 	msm_serial_set_mnd_regs(port);
 }
 
@@ -487,7 +487,7 @@ static int msm_startup(struct uart_port *port)
 	if (unlikely(ret))
 		return ret;
 
-	msm_init_clock(port);
+	msm_init(port);
 
 	if (likely(port->fifosize > 12))
 		rfr_level = port->fifosize - 12;
@@ -511,7 +511,7 @@ static void msm_shutdown(struct uart_port *port)
 	msm_port->imr = 0;
 	msm_write(port, 0, UART_IMR); /* disable interrupts */
 
-	clk_disable_unprepare(msm_port->clk);
+	pm_runtime_put_sync(msm_port->dev);
 
 	free_irq(port->irq, port);
 }
@@ -669,12 +669,10 @@ static void msm_power(struct uart_port *port, unsigned int state,
 
 	switch (state) {
 	case 0:
-		clk_prepare_enable(msm_port->clk);
-		clk_prepare_enable(msm_port->pclk);
+		pm_runtime_get_sync(msm_port->dev);
 		break;
 	case 3:
-		clk_disable_unprepare(msm_port->clk);
-		clk_disable_unprepare(msm_port->pclk);
+		pm_runtime_put_sync(msm_port->dev);
 		break;
 	default:
 		pr_err("msm_serial: Unknown PM state %d\n", state);
@@ -933,7 +931,7 @@ static int __init msm_console_setup(struct console *co, char *options)
 	if (unlikely(!port->membase))
 		return -ENXIO;
 
-	msm_init_clock(port);
+	msm_init(port);
 
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
@@ -1057,13 +1055,10 @@ static int msm_serial_probe(struct platform_device *pdev)
 	if (IS_ERR(msm_port->clk))
 		return PTR_ERR(msm_port->clk);
 
-	if (msm_port->is_uartdm) {
-		msm_port->pclk = devm_clk_get(&pdev->dev, "iface");
-		if (IS_ERR(msm_port->pclk))
-			return PTR_ERR(msm_port->pclk);
-
+	if (msm_port->is_uartdm)
 		clk_set_rate(msm_port->clk, 1843200);
-	}
+
+	msm_port->dev = &pdev->dev;
 
 	port->uartclk = clk_get_rate(msm_port->clk);
 	dev_info(&pdev->dev, "uartclk = %d\n", port->uartclk);
@@ -1080,13 +1075,17 @@ static int msm_serial_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, port);
 
+	pm_runtime_enable(&pdev->dev);
+
 	return uart_add_one_port(&msm_uart_driver, port);
 }
 
 static int msm_serial_remove(struct platform_device *pdev)
 {
 	struct uart_port *port = platform_get_drvdata(pdev);
+	struct msm_port *msm_port = UART_TO_MSM(port);
 
+	pm_runtime_disable(msm_port->dev);
 	uart_remove_one_port(&msm_uart_driver, port);
 
 	return 0;
-- 
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