[PATCH v3 2/2] serial: fsl_linflexuart: add clock support

[Ciprian Costea <ciprianmarian.costea@xxxxxxxxxxx>]

From: Ciprian Marian Costea <ciprianmarian.costea@xxxxxxxxxxx>

Add clocking support to the NXP LINFlexD UART driver.
It is used by S32G2 and S32G3 SoCs.
Clocking support is added as optional in order to not break
existing support for S32V234 SoC.

Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@xxxxxxxxxxx>
---
 drivers/tty/serial/fsl_linflexuart.c | 67 +++++++++++++++++++++-------
 1 file changed, 51 insertions(+), 16 deletions(-)

diff --git a/drivers/tty/serial/fsl_linflexuart.c b/drivers/tty/serial/fsl_linflexuart.c
index e972df4b188d..23aed3bbff6c 100644
--- a/drivers/tty/serial/fsl_linflexuart.c
+++ b/drivers/tty/serial/fsl_linflexuart.c
@@ -3,9 +3,10 @@
  * Freescale LINFlexD UART serial port driver
  *
  * Copyright 2012-2016 Freescale Semiconductor, Inc.
- * Copyright 2017-2019 NXP
+ * Copyright 2017-2019, 2024 NXP
  */
 
+#include <linux/clk.h>
 #include <linux/console.h>
 #include <linux/io.h>
 #include <linux/irq.h>
@@ -120,6 +121,12 @@
 
 #define PREINIT_DELAY			2000 /* us */
 
+struct linflex_port {
+	struct uart_port port;
+	struct clk *clk_lin;
+	struct clk *clk_ipg;
+};
+
 static const struct of_device_id linflex_dt_ids[] = {
 	{
 		.compatible = "fsl,s32v234-linflexuart",
@@ -807,12 +814,13 @@ static struct uart_driver linflex_reg = {
 static int linflex_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
+	struct linflex_port *lfport;
 	struct uart_port *sport;
 	struct resource *res;
 	int ret;
 
-	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
-	if (!sport)
+	lfport = devm_kzalloc(&pdev->dev, sizeof(*lfport), GFP_KERNEL);
+	if (!lfport)
 		return -ENOMEM;
 
 	ret = of_alias_get_id(np, "serial");
@@ -826,6 +834,7 @@ static int linflex_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
+	sport = &lfport->port;
 	sport->line = ret;
 
 	sport->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
@@ -844,39 +853,65 @@ static int linflex_probe(struct platform_device *pdev)
 	sport->flags = UPF_BOOT_AUTOCONF;
 	sport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE);
 
-	linflex_ports[sport->line] = sport;
+	lfport->clk_lin = devm_clk_get_optional_enabled(&pdev->dev, "lin");
+	if (IS_ERR(lfport->clk_lin))
+		return dev_err_probe(&pdev->dev, PTR_ERR(lfport->clk_lin),
+				"Failed to get linflexuart clk\n");
 
-	platform_set_drvdata(pdev, sport);
+	lfport->clk_ipg = devm_clk_get_optional_enabled(&pdev->dev, "ipg");
+	if (IS_ERR(lfport->clk_ipg))
+		return dev_err_probe(&pdev->dev, PTR_ERR(lfport->clk_ipg),
+				"Failed to get linflexuart ipg clk\n");
+
+	linflex_ports[sport->line] = sport;
+	platform_set_drvdata(pdev, lfport);
 
 	return uart_add_one_port(&linflex_reg, sport);
 }
 
 static void linflex_remove(struct platform_device *pdev)
 {
-	struct uart_port *sport = platform_get_drvdata(pdev);
+	struct linflex_port *lfport = platform_get_drvdata(pdev);
 
-	uart_remove_one_port(&linflex_reg, sport);
+	uart_remove_one_port(&linflex_reg, &lfport->port);
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int linflex_suspend(struct device *dev)
+static int __maybe_unused linflex_suspend(struct device *dev)
 {
-	struct uart_port *sport = dev_get_drvdata(dev);
+	struct linflex_port *lfport = dev_get_drvdata(dev);
+
+	uart_suspend_port(&linflex_reg, &lfport->port);
 
-	uart_suspend_port(&linflex_reg, sport);
+	clk_disable_unprepare(lfport->clk_lin);
+	clk_disable_unprepare(lfport->clk_ipg);
 
 	return 0;
 }
 
-static int linflex_resume(struct device *dev)
+static int __maybe_unused linflex_resume(struct device *dev)
 {
-	struct uart_port *sport = dev_get_drvdata(dev);
+	struct linflex_port *lfport = dev_get_drvdata(dev);
+	int ret;
 
-	uart_resume_port(&linflex_reg, sport);
+	if (lfport->clk_lin) {
+		ret = clk_prepare_enable(lfport->clk_lin);
+		if (ret) {
+			dev_err(dev, "Failed to enable linflexuart clk: %d\n", ret);
+			return ret;
+		}
+	}
 
-	return 0;
+	if (lfport->clk_ipg) {
+		ret = clk_prepare_enable(lfport->clk_ipg);
+		if (ret) {
+			dev_err(dev, "Failed to enable linflexuart ipg clk: %d\n", ret);
+			clk_disable_unprepare(lfport->clk_lin);
+			return ret;
+		}
+	}
+
+	return uart_resume_port(&linflex_reg, &lfport->port);
 }
-#endif
 
 static SIMPLE_DEV_PM_OPS(linflex_pm_ops, linflex_suspend, linflex_resume);
 
-- 
2.45.2