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authorMarek Szyprowski <m.szyprowski@samsung.com>2018-11-08 14:45:48 +0100
committerChanwoo Choi <cw00.choi@samsung.com>2018-11-12 09:17:13 +0900
commit3e34c819896091d0f1bbf6ece8a620552f8dc04e (patch)
tree6c9dec0d742c67e4cbe25a10a94d8ca832c2219b
parent5a196c29bb27d606c4bd82f6893462a39766ff7a (diff)
extcon: max8997: Avoid forcing UART path on drive probe
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> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
-rw-r--r--drivers/extcon/extcon-max8997.c15
1 files 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);