[PATCH] serial: ns16550: Add devicetree support

[PATCH] serial: ns16550: Add devicetree support

[Sascha Hauer]

This adds the necessary preparations to make the ns16550 driver devicetree
aware and finally adds devicetree support to the driver.

----------------------------------------------------------------
Sascha Hauer (6):
      clk: provide static inline wrappers
      serial: ns16550: reorder functions to avoid forward declaration
      serial: ns16550: introduce private struct
      serial: ns16550: remove f_caps from platform_data
      serial: ns16550: Add clk support and make platform_data optional
      serial: ns16550: Add devicetree probe support

 arch/arm/Kconfig                |   3 +
 drivers/clk/Kconfig             |   3 +
 drivers/serial/serial_ns16550.c | 134 ++++++++++++++++++++++++++++------------
 include/linux/clk.h             |  39 +++++++++++-
 include/ns16550.h               |   4 --
 5 files changed, 139 insertions(+), 44 deletions(-)

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[PATCH 1/6] clk: provide static inline wrappers

[Sascha Hauer]

So that drivers can use clk_* functions without having to ifdef
them away.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/Kconfig    |  3 +++
 drivers/clk/Kconfig |  3 +++
 include/linux/clk.h | 39 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e7d8cdd..3a74837 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -34,6 +34,7 @@ config ARCH_AT91
 	select CLKDEV_LOOKUP
 	select HAS_DEBUG_LL
 	select HAVE_MACH_ARM_HEAD
+	select HAVE_CLK
 
 config ARCH_BCM2835
 	bool "Broadcom BCM2835 boards"
@@ -99,6 +100,7 @@ config ARCH_NOMADIK
 	bool "STMicroelectronics Nomadik"
 	select CPU_ARM926T
 	select CLOCKSOURCE_NOMADIK
+	select HAVE_CLK
 	help
 	  Support for the Nomadik platform by ST-Ericsson
 
@@ -133,6 +135,7 @@ config ARCH_VERSATILE
 	bool "ARM Versatile boards (ARM926EJ-S)"
 	select CPU_ARM926T
 	select GPIOLIB
+	select HAVE_CLK
 
 config ARCH_VEXPRESS
 	bool "ARM Vexpres boards"
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index a00e539..daf778a 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -1,8 +1,11 @@
+config HAVE_CLK
+	bool
 
 config CLKDEV_LOOKUP
 	bool
 
 config COMMON_CLK
+	select HAVE_CLK
 	bool
 
 config COMMON_CLK_OF_PROVIDER
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 0a565ef..6aed1de 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -19,12 +19,13 @@ struct device_d;
  * The base API.
  */
 
-
 /*
  * struct clk - an machine class defined object / cookie.
  */
 struct clk;
 
+#ifdef CONFIG_HAVE_CLK
+
 /**
  * clk_get - lookup and obtain a reference to a clock producer.
  * @dev: device for clock "consumer"
@@ -157,6 +158,42 @@ struct clk *clk_get_sys(const char *dev_id, const char *con_id);
 int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
 			struct device_d *dev);
 
+#else
+
+static inline struct clk *clk_get(struct device_d *dev, const char *id)
+{
+	return NULL;
+}
+
+static inline int clk_enable(struct clk *clk)
+{
+	return 0;
+}
+
+static inline void clk_disable(struct clk *clk)
+{
+}
+
+static inline unsigned long clk_get_rate(struct clk *clk)
+{
+	return 0;
+}
+
+static inline void clk_put(struct clk *clk)
+{
+}
+
+static inline long clk_round_rate(struct clk *clk, unsigned long rate)
+{
+	return 0;
+}
+
+static inline int clk_set_rate(struct clk *clk, unsigned long rate)
+{
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_COMMON_CLK
 struct clk_ops {
 	int		(*enable)(struct clk *clk);
-- 
1.8.3.2


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[PATCH 2/6] serial: ns16550: reorder functions to avoid forward declaration

[Sascha Hauer]

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/serial/serial_ns16550.c | 59 +++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 31 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index b7913aa..b792ba5 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -42,9 +42,6 @@
 #include "serial_ns16550.h"
 #include <ns16550.h>
 
-/*********** Private Functions **********************************/
-static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate);
-
 /**
  * @brief read register
  *
@@ -129,6 +126,34 @@ static inline unsigned int ns16550_calc_divisor(struct console_device *cdev,
 }
 
 /**
+ * @brief Set the baudrate for the uart port
+ *
+ * @param[in] cdev  console device
+ * @param[in] baud_rate baud rate to set
+ *
+ * @return  0-implied to support the baudrate
+ */
+static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
+{
+	unsigned int baud_divisor = ns16550_calc_divisor(cdev, baud_rate);
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
+
+	ns16550_write(cdev, LCR_BKSE, lcr);
+	ns16550_write(cdev, baud_divisor & 0xff, dll);
+	ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
+	ns16550_write(cdev, LCRVAL, lcr);
+	ns16550_write(cdev, MCRVAL, mcr);
+
+	if (plat->flags & NS16650_FLAG_DISABLE_FIFO)
+		ns16550_write(cdev, FCRVAL & ~FCR_FIFO_EN, fcr);
+	else
+		ns16550_write(cdev, FCRVAL, fcr);
+
+	return 0;
+}
+
+/**
  * @brief Initialize the device
  *
  * @param[in] cdev pointer to console device
@@ -192,34 +217,6 @@ static int ns16550_tstc(struct console_device *cdev)
 }
 
 /**
- * @brief Set the baudrate for the uart port
- *
- * @param[in] cdev  console device
- * @param[in] baud_rate baud rate to set
- *
- * @return  0-implied to support the baudrate
- */
-static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
-{
-	unsigned int baud_divisor = ns16550_calc_divisor(cdev, baud_rate);
-	struct NS16550_plat *plat = (struct NS16550_plat *)
-	    cdev->dev->platform_data;
-
-	ns16550_write(cdev, LCR_BKSE, lcr);
-	ns16550_write(cdev, baud_divisor & 0xff, dll);
-	ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
-	ns16550_write(cdev, LCRVAL, lcr);
-	ns16550_write(cdev, MCRVAL, mcr);
-
-	if (plat->flags & NS16650_FLAG_DISABLE_FIFO)
-		ns16550_write(cdev, FCRVAL & ~FCR_FIFO_EN, fcr);
-	else
-		ns16550_write(cdev, FCRVAL, fcr);
-
-	return 0;
-}
-
-/**
  * @brief Probe entry point -called on the first match for device
  *
  * @param[in] dev matched device
-- 
1.8.3.2


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[PATCH 3/6] serial: ns16550: introduce private struct

[Sascha Hauer]

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/serial/serial_ns16550.c | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index b792ba5..f9a17f4 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -42,6 +42,17 @@
 #include "serial_ns16550.h"
 #include <ns16550.h>
 
+struct ns16550_priv {
+	struct console_device cdev;
+	struct NS16550_plat plat;
+	int access_width;
+};
+
+static inline struct ns16550_priv *to_ns16550_priv(struct console_device *cdev)
+{
+	return container_of(cdev, struct ns16550_priv, cdev);
+}
+
 /**
  * @brief read register
  *
@@ -52,9 +63,10 @@
  */
 static uint32_t ns16550_read(struct console_device *cdev, uint32_t off)
 {
+	struct ns16550_priv *priv = to_ns16550_priv(cdev);
 	struct device_d *dev = cdev->dev;
-	struct NS16550_plat *plat = (struct NS16550_plat *)dev->platform_data;
-	int width = dev->resource[0].flags & IORESOURCE_MEM_TYPE_MASK;
+	struct NS16550_plat *plat = &priv->plat;
+	int width = priv->access_width;
 
 	off <<= plat->shift;
 
@@ -82,9 +94,10 @@ static uint32_t ns16550_read(struct console_device *cdev, uint32_t off)
 static void ns16550_write(struct console_device *cdev, uint32_t val,
 			  uint32_t off)
 {
+	struct ns16550_priv *priv = to_ns16550_priv(cdev);
 	struct device_d *dev = cdev->dev;
-	struct NS16550_plat *plat = (struct NS16550_plat *)dev->platform_data;
-	int width = dev->resource[0].flags & IORESOURCE_MEM_TYPE_MASK;
+	struct NS16550_plat *plat = &priv->plat;
+	int width = priv->access_width;
 
 	off <<= plat->shift;
 
@@ -117,8 +130,8 @@ static void ns16550_write(struct console_device *cdev, uint32_t val,
 static inline unsigned int ns16550_calc_divisor(struct console_device *cdev,
 					 unsigned int baudrate)
 {
-	struct NS16550_plat *plat = (struct NS16550_plat *)
-	    cdev->dev->platform_data;
+	struct ns16550_priv *priv = to_ns16550_priv(cdev);
+	struct NS16550_plat *plat = &priv->plat;
 	unsigned int clk = plat->clock;
 
 	return (clk / MODE_X_DIV / baudrate);
@@ -136,8 +149,8 @@ static inline unsigned int ns16550_calc_divisor(struct console_device *cdev,
 static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
 {
 	unsigned int baud_divisor = ns16550_calc_divisor(cdev, baud_rate);
-	struct NS16550_plat *plat = (struct NS16550_plat *)
-	    cdev->dev->platform_data;
+	struct ns16550_priv *priv = to_ns16550_priv(cdev);
+	struct NS16550_plat *plat = &priv->plat;
 
 	ns16550_write(cdev, LCR_BKSE, lcr);
 	ns16550_write(cdev, baud_divisor & 0xff, dll);
@@ -227,6 +240,7 @@ static int ns16550_tstc(struct console_device *cdev)
  */
 static int ns16550_probe(struct device_d *dev)
 {
+	struct ns16550_priv *priv;
 	struct console_device *cdev;
 	struct NS16550_plat *plat = (struct NS16550_plat *)dev->platform_data;
 
@@ -235,7 +249,12 @@ static int ns16550_probe(struct device_d *dev)
 		return -EINVAL;
 	dev->priv = dev_request_mem_region(dev, 0);
 
-	cdev = xzalloc(sizeof(*cdev));
+	priv = xzalloc(sizeof(*priv));
+
+	cdev = &priv->cdev;
+	priv->plat = *plat;
+
+	priv->access_width = dev->resource[0].flags & IORESOURCE_MEM_TYPE_MASK;
 
 	cdev->dev = dev;
 	if (plat->f_caps)
-- 
1.8.3.2


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[PATCH 4/6] serial: ns16550: remove f_caps from platform_data

[Sascha Hauer]

So far no user had the need to set the flags, so just remove them
from platform data.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/serial/serial_ns16550.c | 5 +----
 include/ns16550.h               | 4 ----
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index f9a17f4..dd50fc5 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -257,10 +257,7 @@ static int ns16550_probe(struct device_d *dev)
 	priv->access_width = dev->resource[0].flags & IORESOURCE_MEM_TYPE_MASK;
 
 	cdev->dev = dev;
-	if (plat->f_caps)
-		cdev->f_caps = plat->f_caps;
-	else
-		cdev->f_caps = CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR;
+	cdev->f_caps = CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR;
 	cdev->tstc = ns16550_tstc;
 	cdev->putc = ns16550_putc;
 	cdev->getc = ns16550_getc;
diff --git a/include/ns16550.h b/include/ns16550.h
index 27cb4cf..36aa5ff 100644
--- a/include/ns16550.h
+++ b/include/ns16550.h
@@ -33,10 +33,6 @@
 struct NS16550_plat {
 	/** Clock speed */
 	unsigned int clock;
-	/** Console capabilities:
-	 * CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR @see console.h
-	 */
-	unsigned char f_caps;
 	/**
 	 * register read access capability
 	 */
-- 
1.8.3.2


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[PATCH 5/6] serial: ns16550: Add clk support and make platform_data optional

[Sascha Hauer]

The clockrate was the only really needed field from platform data.
Add clk support to retrieve the clockrate and make platform data
optional.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/serial/serial_ns16550.c | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index dd50fc5..b010785 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -38,6 +38,7 @@
 #include <errno.h>
 #include <malloc.h>
 #include <io.h>
+#include <linux/clk.h>
 
 #include "serial_ns16550.h"
 #include <ns16550.h>
@@ -46,6 +47,7 @@ struct ns16550_priv {
 	struct console_device cdev;
 	struct NS16550_plat plat;
 	int access_width;
+	struct clk *clk;
 };
 
 static inline struct ns16550_priv *to_ns16550_priv(struct console_device *cdev)
@@ -243,10 +245,8 @@ static int ns16550_probe(struct device_d *dev)
 	struct ns16550_priv *priv;
 	struct console_device *cdev;
 	struct NS16550_plat *plat = (struct NS16550_plat *)dev->platform_data;
+	int ret;
 
-	/* we do expect platform specific data */
-	if (plat == NULL)
-		return -EINVAL;
 	dev->priv = dev_request_mem_region(dev, 0);
 
 	priv = xzalloc(sizeof(*priv));
@@ -254,6 +254,21 @@ static int ns16550_probe(struct device_d *dev)
 	cdev = &priv->cdev;
 	priv->plat = *plat;
 
+	if (!plat || !plat->clock) {
+		priv->clk = clk_get(dev, NULL);
+		if (IS_ERR(priv->clk)) {
+			ret = PTR_ERR(priv->clk);
+			goto err;
+		}
+		priv->plat.clock = clk_get_rate(priv->clk);
+	}
+
+	if (priv->plat.clock == 0) {
+		dev_err(dev, "no valid clockrate\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
 	priv->access_width = dev->resource[0].flags & IORESOURCE_MEM_TYPE_MASK;
 
 	cdev->dev = dev;
@@ -266,6 +281,11 @@ static int ns16550_probe(struct device_d *dev)
 	ns16550_serial_init_port(cdev);
 
 	return console_register(cdev);
+
+err:
+	free(priv);
+
+	return ret;
 }
 
 /**
-- 
1.8.3.2


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[PATCH 6/6] serial: ns16550: Add devicetree probe support

[Sascha Hauer]

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/serial/serial_ns16550.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
index b010785..ad3125a 100644
--- a/drivers/serial/serial_ns16550.c
+++ b/drivers/serial/serial_ns16550.c
@@ -231,6 +231,16 @@ static int ns16550_tstc(struct console_device *cdev)
 	return ((ns16550_read(cdev, lsr) & LSR_DR) != 0);
 }
 
+static void ns16550_probe_dt(struct device_d *dev, struct ns16550_priv *priv)
+{
+	struct device_node *np = dev->device_node;
+
+	if (!IS_ENABLED(CONFIG_OFDEVICE))
+		return;
+
+	of_property_read_u32(np, "reg-shift", &priv->plat.shift);
+}
+
 /**
  * @brief Probe entry point -called on the first match for device
  *
@@ -251,8 +261,12 @@ static int ns16550_probe(struct device_d *dev)
 
 	priv = xzalloc(sizeof(*priv));
 
+	if (plat)
+		priv->plat = *plat;
+	else
+		ns16550_probe_dt(dev, priv);
+
 	cdev = &priv->cdev;
-	priv->plat = *plat;
 
 	if (!plat || !plat->clock) {
 		priv->clk = clk_get(dev, NULL);
@@ -288,11 +302,20 @@ err:
 	return ret;
 }
 
+static struct of_device_id ns16550_serial_dt_ids[] = {
+	{
+		.compatible = "ns16550a",
+	}, {
+		/* sentinel */
+	},
+};
+
 /**
  * @brief Driver registration structure
  */
 static struct driver_d ns16550_serial_driver = {
 	.name = "ns16550_serial",
 	.probe = ns16550_probe,
+	.of_compatible = DRV_OF_COMPAT(ns16550_serial_dt_ids),
 };
 console_platform_driver(ns16550_serial_driver);
-- 
1.8.3.2


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