[PATCH 0/4] Fix common issue in MAX* extcon drivers

[PATCH 0/4] Fix common issue in MAX* extcon drivers

[Marek Szyprowski]

Hi All

Most MAX* MUIC drivers unconditionally force UART path during probe.
This approach causes some issues, especially when board is booted with
non-UART cable connected to micro-USB port. For example, when USB cable is
connected, UART TX/RX lines are unconditionally short-circuited to USB
D+/D- lines. This is in turn recognized by a series of serial BREAK
signals and some random characters when USB host tries to perform
enumeration procedure.

To solve the above issue and keep UART console operational as early as
possible, set UART path only when USB ID reports UART capable cable.

This patchset fixes following MAX* extcon drivers: 8997, 14577, 77693
and 77843.

Tested on following Samsung boards: Trats (8997), Rinato (14577), Trats2
(77693) and TM2/TM2e (77843).

Best regards
Marek Szyprowski
Samsung R&D Institute Poland


Patch summary:

Marek Szyprowski (4):
  extcon: max77843: Avoid forcing UART path on drive probe
  extcon: max77693: Avoid forcing UART path on drive probe
  extcon: max14577: Avoid forcing UART path on drive probe
  extcon: max8997: Avoid forcing UART path on drive probe

 drivers/extcon/extcon-max14577.c | 15 +++++++++++++--
 drivers/extcon/extcon-max77693.c | 16 ++++++++++++++--
 drivers/extcon/extcon-max77843.c | 18 +++++++++++++++---
 drivers/extcon/extcon-max8997.c  | 15 +++++++++++++--
 4 files changed, 55 insertions(+), 9 deletions(-)

-- 
2.17.1

[PATCH 1/4] extcon: max77843: Avoid forcing UART path on drive probe

[Marek Szyprowski]

Driver unconditionally forces UART path during probe, probably to ensure
that one can get kernel serial log as soon as possible.

This approach causes some issues, especially when board is booted with
non-UART cable connected to micro-USB port. For example, when USB cable is
connected, UART TX/RX lines are unconditionally short-circuited to USB
D+/D- lines. This is in turn recognized by a series of serial BREAK
signals and some random characters when USB host tries to perform
enumeration procedure.

To solve the above issue and keep UART console operational as early as
possible, set UART path only when USB ID reports UART capable cable.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/extcon/extcon-max77843.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/extcon/extcon-max77843.c b/drivers/extcon/extcon-max77843.c
index b98cbd0362f5..a343a6ef3506 100644
--- a/drivers/extcon/extcon-max77843.c
+++ b/drivers/extcon/extcon-max77843.c
@@ -812,6 +812,8 @@ static int max77843_muic_probe(struct platform_device *pdev)
 	struct max77693_dev *max77843 = dev_get_drvdata(pdev->dev.parent);
 	struct max77843_muic_info *info;
 	unsigned int id;
+	int cable_type;
+	bool attached;
 	int i, ret;
 
 	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
@@ -856,9 +858,19 @@ static int max77843_muic_probe(struct platform_device *pdev)
 	/* Set ADC debounce time */
 	max77843_muic_set_debounce_time(info, MAX77843_DEBOUNCE_TIME_25MS);
 
-	/* Set initial path for UART */
-	max77843_muic_set_path(info, MAX77843_MUIC_CONTROL1_SW_UART, true,
-			       false);
+	/* Set initial path for UART when JIG is connected to get serial logs */
+	ret = regmap_bulk_read(max77843->regmap_muic,
+			MAX77843_MUIC_REG_STATUS1, info->status,
+			MAX77843_MUIC_STATUS_NUM);
+	if (ret) {
+		dev_err(info->dev, "Cannot read STATUS registers\n");
+		goto err_muic_irq;
+	}
+	cable_type = max77843_muic_get_cable_type(info, MAX77843_CABLE_GROUP_ADC,
+					 &attached);
+	if (attached && cable_type == MAX77843_MUIC_ADC_FACTORY_MODE_UART_OFF)
+		max77843_muic_set_path(info, MAX77843_MUIC_CONTROL1_SW_UART,
+				       true, false);
 
 	/* Check revision number of MUIC device */
 	ret = regmap_read(max77843->regmap_muic, MAX77843_MUIC_REG_ID, &id);
-- 
2.17.1

[PATCH 2/4] extcon: max77693: Avoid forcing UART path on drive probe

[Marek Szyprowski]

Driver unconditionally forces UART path during probe, probably to ensure
that one can get kernel serial log as soon as possible.

This approach causes some issues, especially when board is booted with
non-UART cable connected to micro-USB port. For example, when USB cable is
connected, UART TX/RX lines are unconditionally short-circuited to USB
D+/D- lines. This is in turn recognized by a series of serial BREAK
signals and some random characters when USB host tries to perform
enumeration procedure.

To solve the above issue and keep UART console operational as early as
possible, set UART path only when USB ID reports UART capable cable.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/extcon/extcon-max77693.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/extcon/extcon-max77693.c b/drivers/extcon/extcon-max77693.c
index a79537ebb671..32fc5a66ffa9 100644
--- a/drivers/extcon/extcon-max77693.c
+++ b/drivers/extcon/extcon-max77693.c
@@ -1072,6 +1072,8 @@ static int max77693_muic_probe(struct platform_device *pdev)
 	struct max77693_reg_data *init_data;
 	int num_init_data;
 	int delay_jiffies;
+	int cable_type;
+	bool attached;
 	int ret;
 	int i;
 	unsigned int id;
@@ -1212,8 +1214,18 @@ static int max77693_muic_probe(struct platform_device *pdev)
 		delay_jiffies = msecs_to_jiffies(DELAY_MS_DEFAULT);
 	}
 
-	/* Set initial path for UART */
-	 max77693_muic_set_path(info, info->path_uart, true);
+	/* Set initial path for UART when JIG is connected to get serial logs */
+	ret = regmap_bulk_read(info->max77693->regmap_muic,
+			MAX77693_MUIC_REG_STATUS1, info->status, 2);
+	if (ret) {
+		dev_err(info->dev, "failed to read MUIC register\n");
+		return ret;
+	}
+	cable_type = max77693_muic_get_cable_type(info,
+					   MAX77693_CABLE_GROUP_ADC, &attached);
+	if (attached && (cable_type == MAX77693_MUIC_ADC_FACTORY_MODE_UART_ON ||
+			 cable_type == MAX77693_MUIC_ADC_FACTORY_MODE_UART_OFF))
+		max77693_muic_set_path(info, info->path_uart, true);
 
 	/* Check revision number of MUIC device*/
 	ret = regmap_read(info->max77693->regmap_muic,
-- 
2.17.1

[PATCH 3/4] extcon: max14577: Avoid forcing UART path on drive probe

[Marek Szyprowski]

Driver unconditionally forces UART path during probe, probably to ensure
that one can get kernel serial log as soon as possible.

This approach causes some issues, especially when board is booted with
non-UART cable connected to micro-USB port. For example, when USB cable is
connected, UART TX/RX lines are unconditionally short-circuited to USB
D+/D- lines. This is in turn recognized by a series of serial BREAK
signals and some random characters when USB host tries to perform
enumeration procedure.

To solve the above issue and keep UART console operational as early as
possible, set UART path only when USB ID reports UART capable cable.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/extcon/extcon-max14577.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/extcon/extcon-max14577.c b/drivers/extcon/extcon-max14577.c
index 22d2feb1f8bc..32f663436e6e 100644
--- a/drivers/extcon/extcon-max14577.c
+++ b/drivers/extcon/extcon-max14577.c
@@ -657,6 +657,8 @@ static int max14577_muic_probe(struct platform_device *pdev)
 	struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
 	struct max14577_muic_info *info;
 	int delay_jiffies;
+	int cable_type;
+	bool attached;
 	int ret;
 	int i;
 	u8 id;
@@ -725,8 +727,17 @@ static int max14577_muic_probe(struct platform_device *pdev)
 	info->path_uart = CTRL1_SW_UART;
 	delay_jiffies = msecs_to_jiffies(DELAY_MS_DEFAULT);
 
-	/* Set initial path for UART */
-	max14577_muic_set_path(info, info->path_uart, true);
+	/* Set initial path for UART when JIG is connected to get serial logs */
+	ret = max14577_bulk_read(info->max14577->regmap,
+			MAX14577_MUIC_REG_STATUS1, info->status, 2);
+	if (ret) {
+		dev_err(info->dev, "Cannot read STATUS registers\n");
+		return ret;
+	}
+	cable_type = max14577_muic_get_cable_type(info, MAX14577_CABLE_GROUP_ADC,
+					 &attached);
+	if (attached && cable_type == MAX14577_MUIC_ADC_FACTORY_MODE_UART_OFF)
+		max14577_muic_set_path(info, info->path_uart, true);
 
 	/* Check revision number of MUIC device*/
 	ret = max14577_read_reg(info->max14577->regmap,
-- 
2.17.1

[PATCH 4/4] extcon: max8997: Avoid forcing UART path on drive probe

[Marek Szyprowski]

Driver unconditionally forces UART path during probe, probably to ensure
that one can get kernel serial log as soon as possible.

This approach causes some issues, especially when board is booted with
non-UART cable connected to micro-USB port. For example, when USB cable is
connected, UART TX/RX lines are unconditionally short-circuited to USB
D+/D- lines. This is in turn recognized by a series of serial BREAK
signals and some random characters when USB host tries to perform
enumeration procedure.

To solve the above issue and keep UART console operational as early as
possible, set UART path only when USB ID reports UART capable cable.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/extcon/extcon-max8997.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/extcon/extcon-max8997.c b/drivers/extcon/extcon-max8997.c
index bdabb2479e0d..632192d027bf 100644
--- a/drivers/extcon/extcon-max8997.c
+++ b/drivers/extcon/extcon-max8997.c
@@ -632,6 +632,8 @@ static int max8997_muic_probe(struct platform_device *pdev)
 	struct max8997_platform_data *pdata = dev_get_platdata(max8997->dev);
 	struct max8997_muic_info *info;
 	int delay_jiffies;
+	int cable_type;
+	bool attached;
 	int ret, i;
 
 	info = devm_kzalloc(&pdev->dev, sizeof(struct max8997_muic_info),
@@ -724,8 +726,17 @@ static int max8997_muic_probe(struct platform_device *pdev)
 		delay_jiffies = msecs_to_jiffies(DELAY_MS_DEFAULT);
 	}
 
-	/* Set initial path for UART */
-	 max8997_muic_set_path(info, info->path_uart, true);
+	/* Set initial path for UART when JIG is connected to get serial logs */
+	ret = max8997_bulk_read(info->muic, MAX8997_MUIC_REG_STATUS1,
+				2, info->status);
+	if (ret) {
+		dev_err(info->dev, "failed to read MUIC register\n");
+		return ret;
+	}
+	cable_type = max8997_muic_get_cable_type(info,
+					   MAX8997_CABLE_GROUP_ADC, &attached);
+	if (attached && cable_type == MAX8997_MUIC_ADC_FACTORY_MODE_UART_OFF)
+		max8997_muic_set_path(info, info->path_uart, true);
 
 	/* Set ADC debounce time */
 	max8997_muic_set_debounce_time(info, ADC_DEBOUNCE_TIME_25MS);
-- 
2.17.1

Re: [PATCH 0/4] Fix common issue in MAX* extcon drivers

[Chanwoo Choi]

Hi Marek,

On 2018년 11월 08일 22:45, Marek Szyprowski wrote:
> Hi All
> 
> Most MAX* MUIC drivers unconditionally force UART path during probe.
> This approach causes some issues, especially when board is booted with
> non-UART cable connected to micro-USB port. For example, when USB cable is
> connected, UART TX/RX lines are unconditionally short-circuited to USB
> D+/D- lines. This is in turn recognized by a series of serial BREAK
> signals and some random characters when USB host tries to perform
> enumeration procedure.
> 
> To solve the above issue and keep UART console operational as early as
> possible, set UART path only when USB ID reports UART capable cable.
> 
> This patchset fixes following MAX* extcon drivers: 8997, 14577, 77693
> and 77843.
> 
> Tested on following Samsung boards: Trats (8997), Rinato (14577), Trats2
> (77693) and TM2/TM2e (77843).
> 
> Best regards
> Marek Szyprowski
> Samsung R&D Institute Poland
> 
> 
> Patch summary:
> 
> Marek Szyprowski (4):
>   extcon: max77843: Avoid forcing UART path on drive probe
>   extcon: max77693: Avoid forcing UART path on drive probe
>   extcon: max14577: Avoid forcing UART path on drive probe
>   extcon: max8997: Avoid forcing UART path on drive probe
> 
>  drivers/extcon/extcon-max14577.c | 15 +++++++++++++--
>  drivers/extcon/extcon-max77693.c | 16 ++++++++++++++--
>  drivers/extcon/extcon-max77843.c | 18 +++++++++++++++---
>  drivers/extcon/extcon-max8997.c  | 15 +++++++++++++--
>  4 files changed, 55 insertions(+), 9 deletions(-)
> 

Applied them. Thanks.

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics