[U-Boot] [PATCH v2 0/2] serial: atmel_usart: Fix uart init and add clk support

[U-Boot] [PATCH v2 0/2] serial: atmel_usart: Fix uart init and add clk support

[Wenyou Yang]

The patches is rework the uart init to fix the early debug not work
in SPL, and add the clock support.

Changes in v2:
 - Fix the DBGU clock handling.
 - Add Reviewed-by tag.

Wenyou Yang (2):
  serial: atmel_usart: Fix early debug not work in SPL
  serial: atmel_usart: Add clk support

 drivers/serial/atmel_usart.c | 84 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 78 insertions(+), 6 deletions(-)

-- 
2.11.0

[U-Boot] [PATCH v2 1/2] serial: atmel_usart: Fix early debug not work in SPL

[Wenyou Yang]

Add the uart init function to be used on both probe and the early
debug uart init. For the latter, the input clock should be from
CONFIG_DEBUG_UART_CLOCK.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

Changes in v2: None

 drivers/serial/atmel_usart.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/serial/atmel_usart.c b/drivers/serial/atmel_usart.c
index 7674f97e8d..8b1e0d55a4 100644
--- a/drivers/serial/atmel_usart.c
+++ b/drivers/serial/atmel_usart.c
@@ -25,6 +25,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#ifndef CONFIG_DM_SERIAL
 static void atmel_serial_setbrg_internal(atmel_usart3_t *usart, int id,
 					 int baudrate)
 {
@@ -66,7 +67,6 @@ static void atmel_serial_activate(atmel_usart3_t *usart)
 	__udelay(100);
 }
 
-#ifndef CONFIG_DM_SERIAL
 static void atmel_serial_setbrg(void)
 {
 	atmel_serial_setbrg_internal((atmel_usart3_t *)CONFIG_USART_BASE,
@@ -138,12 +138,37 @@ struct atmel_serial_priv {
 	atmel_usart3_t *usart;
 };
 
+static void _atmel_serial_set_brg(atmel_usart3_t *usart,
+				  ulong usart_clk_rate, int baudrate)
+{
+	unsigned long divisor;
+
+	divisor = (usart_clk_rate / 16 + baudrate / 2) / baudrate;
+	writel(USART3_BF(CD, divisor), &usart->brgr);
+}
+
+void _atmel_serial_init(atmel_usart3_t *usart,
+			ulong usart_clk_rate, int baudrate)
+{
+	writel(USART3_BIT(RXDIS) | USART3_BIT(TXDIS), &usart->cr);
+
+	writel((USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL) |
+		USART3_BF(USCLKS, USART3_USCLKS_MCK) |
+		USART3_BF(CHRL, USART3_CHRL_8) |
+		USART3_BF(PAR, USART3_PAR_NONE) |
+		USART3_BF(NBSTOP, USART3_NBSTOP_1)), &usart->mr);
+
+	_atmel_serial_set_brg(usart, usart_clk_rate, baudrate);
+
+	writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr);
+	writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr);
+}
+
 int atmel_serial_setbrg(struct udevice *dev, int baudrate)
 {
 	struct atmel_serial_priv *priv = dev_get_priv(dev);
 
-	atmel_serial_setbrg_internal(priv->usart, 0 /* ignored */, baudrate);
-	atmel_serial_activate(priv->usart);
+	_atmel_serial_set_brg(priv->usart, get_usart_clk_rate(0), baudrate);
 
 	return 0;
 }
@@ -202,7 +227,8 @@ static int atmel_serial_probe(struct udevice *dev)
 	plat->base_addr = (uint32_t)addr_base;
 #endif
 	priv->usart = (atmel_usart3_t *)plat->base_addr;
-	atmel_serial_init_internal(priv->usart);
+
+	_atmel_serial_init(priv->usart, get_usart_clk_rate(0), gd->baudrate);
 
 	return 0;
 }
@@ -233,7 +259,7 @@ static inline void _debug_uart_init(void)
 {
 	atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_DEBUG_UART_BASE;
 
-	atmel_serial_setbrg_internal(usart, 0, CONFIG_BAUDRATE);
+	_atmel_serial_init(usart, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
 }
 
 static inline void _debug_uart_putc(int ch)
-- 
2.11.0

[U-Boot] [PATCH v2 2/2] serial: atmel_usart: Add clk support

[Wenyou Yang]

Add the clock support.

The clock handling of DBGU is different fromt the one of USART.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
---

Changes in v2:
 - Fix the DBGU clock handling.
 - Add Reviewed-by tag.

 drivers/serial/atmel_usart.c | 52 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

diff --git a/drivers/serial/atmel_usart.c b/drivers/serial/atmel_usart.c
index 8b1e0d55a4..453f8eb451 100644
--- a/drivers/serial/atmel_usart.c
+++ b/drivers/serial/atmel_usart.c
@@ -7,6 +7,7 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 #include <common.h>
+#include <clk.h>
 #include <dm.h>
 #include <errno.h>
 #include <watchdog.h>
@@ -133,9 +134,14 @@ __weak struct serial_device *default_serial_console(void)
 #endif
 
 #ifdef CONFIG_DM_SERIAL
+enum serial_clk_type {
+	CLK_TYPE_NORMAL = 0,
+	CLK_TYPE_DBGU,
+};
 
 struct atmel_serial_priv {
 	atmel_usart3_t *usart;
+	ulong usart_clk_rate;
 };
 
 static void _atmel_serial_set_brg(atmel_usart3_t *usart,
@@ -168,7 +174,7 @@ int atmel_serial_setbrg(struct udevice *dev, int baudrate)
 {
 	struct atmel_serial_priv *priv = dev_get_priv(dev);
 
-	_atmel_serial_set_brg(priv->usart, get_usart_clk_rate(0), baudrate);
+	_atmel_serial_set_brg(priv->usart, priv->usart_clk_rate, baudrate);
 
 	return 0;
 }
@@ -213,10 +219,39 @@ static const struct dm_serial_ops atmel_serial_ops = {
 	.setbrg = atmel_serial_setbrg,
 };
 
+static int atmel_serial_enable_clk(struct udevice *dev)
+{
+	struct atmel_serial_priv *priv = dev_get_priv(dev);
+	struct clk clk;
+	ulong clk_rate;
+	int ret;
+
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (ret)
+		return -EINVAL;
+
+	if (dev_get_driver_data(dev) == CLK_TYPE_NORMAL) {
+		ret = clk_enable(&clk);
+		if (ret)
+			return ret;
+	}
+
+	clk_rate = clk_get_rate(&clk);
+	if (!clk_rate)
+		return -EINVAL;
+
+	priv->usart_clk_rate = clk_rate;
+
+	clk_free(&clk);
+
+	return 0;
+}
+
 static int atmel_serial_probe(struct udevice *dev)
 {
 	struct atmel_serial_platdata *plat = dev->platdata;
 	struct atmel_serial_priv *priv = dev_get_priv(dev);
+	int ret;
 #if CONFIG_IS_ENABLED(OF_CONTROL)
 	fdt_addr_t addr_base;
 
@@ -228,14 +263,25 @@ static int atmel_serial_probe(struct udevice *dev)
 #endif
 	priv->usart = (atmel_usart3_t *)plat->base_addr;
 
-	_atmel_serial_init(priv->usart, get_usart_clk_rate(0), gd->baudrate);
+	ret = atmel_serial_enable_clk(dev);
+	if (ret)
+		return ret;
+
+	_atmel_serial_init(priv->usart, priv->usart_clk_rate, gd->baudrate);
 
 	return 0;
 }
 
 #if CONFIG_IS_ENABLED(OF_CONTROL)
 static const struct udevice_id atmel_serial_ids[] = {
-	{ .compatible = "atmel,at91sam9260-usart" },
+	{
+		.compatible = "atmel,at91sam9260-dbgu",
+		.data = CLK_TYPE_DBGU,
+	},
+	{
+		.compatible = "atmel,at91sam9260-usart",
+		.data = CLK_TYPE_NORMAL,
+	},
 	{ }
 };
 #endif
-- 
2.11.0