[PATCH 1/3] serial: introduce clk_get_enabled_for_console()

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

For all serial drivers that call clk_get_for_console() followed
by clk_enable(), while checking both for errors, switch over to
a new clk_get_enabled_for_console().

This makes code more concise and allows ignoring a specific clk_enable
error code in the next commit.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/serial/serial_lpuart.c   | 12 +++---------
 drivers/serial/serial_lpuart32.c | 12 +++---------
 drivers/serial/serial_ns16550.c  |  9 +++------
 drivers/serial/serial_stm32.c    | 10 ++--------
 include/console.h                | 15 +++++++++++++++
 include/linux/clk.h              | 28 ++++++++++++++++++++++++++++
 6 files changed, 54 insertions(+), 32 deletions(-)

diff --git a/drivers/serial/serial_lpuart.c b/drivers/serial/serial_lpuart.c
index 8bbef08309f9..d9416d538cc5 100644
--- a/drivers/serial/serial_lpuart.c
+++ b/drivers/serial/serial_lpuart.c
@@ -131,16 +131,10 @@ static int lpuart_serial_probe(struct device *dev)
 	}
 	lpuart->base = IOMEM(lpuart->io->start);
 
-	lpuart->clk = clk_get_for_console(dev, NULL);
+	lpuart->clk = clk_get_enabled_for_console(dev, NULL);
 	if (IS_ERR(lpuart->clk)) {
-		ret = PTR_ERR(lpuart->clk);
-		dev_err(dev, "Failed to get UART clock %d\n", ret);
-		goto io_release;
-	}
-
-	ret = clk_enable(lpuart->clk);
-	if (ret) {
-		dev_err(dev, "Failed to enable UART clock %d\n", ret);
+		ret = dev_errp_probe(dev, lpuart->clk,
+				     "Failed to get/enable UART clock\n");
 		goto io_release;
 	}
 
diff --git a/drivers/serial/serial_lpuart32.c b/drivers/serial/serial_lpuart32.c
index 25f0782e026e..e1ba872849ac 100644
--- a/drivers/serial/serial_lpuart32.c
+++ b/drivers/serial/serial_lpuart32.c
@@ -119,16 +119,10 @@ static int lpuart32_serial_probe(struct device *dev)
 	}
 	lpuart32->base = IOMEM(lpuart32->io->start) + devtype->reg_offs;
 
-	lpuart32->clk = clk_get_for_console(dev, NULL);
+	lpuart32->clk = clk_get_enabled_for_console(dev, NULL);
 	if (IS_ERR(lpuart32->clk)) {
-		ret = PTR_ERR(lpuart32->clk);
-		dev_err(dev, "Failed to get UART clock %d\n", ret);
-		goto io_release;
-	}
-
-	ret = clk_enable(lpuart32->clk);
-	if (ret) {
-		dev_err(dev, "Failed to enable UART clock %d\n", ret);
+		ret = dev_errp_probe(dev, lpuart32->clk,
+				     "Failed to get/enable UART clock\n");
 		goto io_release;
 	}
 
diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index 61e294a38c4c..b220982450dd 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -529,15 +529,12 @@ static int ns16550_probe(struct device *dev)
 		priv->plat.clock = devtype->clk_default;
 
 	if (!priv->plat.clock) {
-		priv->clk = clk_get_for_console(dev, NULL);
+		priv->clk = clk_get_enabled_for_console(dev, NULL);
 		if (IS_ERR(priv->clk)) {
-			ret = PTR_ERR(priv->clk);
-			dev_err(dev, "failed to get clk (%d)\n", ret);
+			ret = dev_errp_probe(dev, priv->clk,
+					     "failed to get/enable clk\n");
 			goto release_region;
 		}
-		ret = clk_enable(priv->clk);
-		if (ret)
-			goto clk_put;
 		priv->plat.clock = clk_get_rate(priv->clk);
 	}
 
diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
index f61d04aed440..1cf58be09e2f 100644
--- a/drivers/serial/serial_stm32.c
+++ b/drivers/serial/serial_stm32.c
@@ -165,16 +165,10 @@ static int stm32_serial_probe(struct device *dev)
 	stm32->stm32f4 = info->stm32f4;
 	stm32->uart_enable_bit = info->uart_enable_bit;
 
-	stm32->clk = clk_get_for_console(dev, NULL);
+	stm32->clk = clk_get_enabled_for_console(dev, NULL);
 	if (IS_ERR(stm32->clk)) {
 		ret = dev_err_probe(dev, PTR_ERR(stm32->clk),
-				    "Failed to get UART clock\n");
-		goto io_release;
-	}
-
-	ret = clk_enable(stm32->clk);
-	if (ret) {
-		dev_err_probe(dev, ret, "Failed to enable UART clock\n");
+				    "Failed to get/enable UART clock\n");
 		goto io_release;
 	}
 
diff --git a/include/console.h b/include/console.h
index b163c6684ee1..d5e18bde61c8 100644
--- a/include/console.h
+++ b/include/console.h
@@ -282,4 +282,19 @@ static inline struct clk *clk_get_for_console(struct device *dev, const char *id
 	return clk;
 }
 
+static inline struct clk *clk_get_enabled_for_console(struct device *dev, const char *id)
+{
+	__always_unused unsigned baudrate;
+	struct clk *clk;
+
+	if (!IS_ENABLED(CONFIG_DEBUG_LL) || !of_device_is_stdout_path(dev, &baudrate))
+		return clk_get_enabled(dev, id);
+
+	clk = clk_get_enabled_if_available(dev, id);
+	if (clk == NULL)
+		dev_warn(dev, "couldn't get/enable clock (ignoring)\n");
+
+	return clk;
+}
+
 #endif
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 655e7a52e9b9..1cb8a1898e10 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -1270,4 +1270,32 @@ static inline struct clk *clk_get_if_available(struct device *dev, const char *i
 	return clk;
 }
 
+/**
+ * clk_get_enabled_if_available - get & enable clock, ignoring known unavailable clock controller
+ * @dev: device for clock "consumer"
+ * @id: clock consumer ID
+ *
+ * Return: a struct clk corresponding to the clock producer after enabling it, a
+ * valid IS_ERR() condition containing errno or NULL if it could
+ * be determined that the clock producer will never be probed in
+ * absence of modules.
+ */
+static inline struct clk *clk_get_enabled_if_available(struct device *dev,
+						       const char *id)
+{
+	struct clk *clk = clk_get_if_available(dev, id);
+	int ret;
+
+	if (IS_ERR_OR_NULL(clk))
+		return clk;
+
+	ret = clk_enable(clk);
+	if (ret) {
+		clk_put(clk);
+		return ERR_PTR(ret);
+	}
+
+	return clk;
+}
+
 #endif
-- 
2.47.3