Re: [PATCH] extcon: sm5502: Reset registers during initialization

From: Chanwoo Choi
Date: Thu Oct 10 2019 - 21:40:31 EST


On 19. 10. 11. ìì 12:47, Stephan Gerhold wrote:
> On some devices (e.g. Samsung Galaxy A5 (2015)), the bootloader
> seems to keep interrupts enabled for SM5502 when booting Linux.
> Changing the cable state (i.e. plugging in a cable) - until the driver
> is loaded - will therefore produce an interrupt that is never read.
>
> In this situation, the cable state will be stuck forever on the
> initial state because SM5502 stops sending interrupts.
> This can be avoided by clearing those pending interrupts after
> the driver has been loaded.
>
> One way to do this is to reset all registers to default state
> by writing to SM5502_REG_RESET. This ensures that we start from
> a clean state, with all interrupts disabled.
>
> Suggested-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
> ---
> drivers/extcon/extcon-sm5502.c | 4 ++++
> drivers/extcon/extcon-sm5502.h | 2 ++
> 2 files changed, 6 insertions(+)
>
> diff --git a/drivers/extcon/extcon-sm5502.c b/drivers/extcon/extcon-sm5502.c
> index dc43847ad2b0..b3d93baf4fc5 100644
> --- a/drivers/extcon/extcon-sm5502.c
> +++ b/drivers/extcon/extcon-sm5502.c
> @@ -65,6 +65,10 @@ struct sm5502_muic_info {
> /* Default value of SM5502 register to bring up MUIC device. */
> static struct reg_data sm5502_reg_data[] = {
> {
> + .reg = SM5502_REG_RESET,
> + .val = SM5502_REG_RESET_MASK,
> + .invert = true,
> + }, {
> .reg = SM5502_REG_CONTROL,
> .val = SM5502_REG_CONTROL_MASK_INT_MASK,
> .invert = false,
> diff --git a/drivers/extcon/extcon-sm5502.h b/drivers/extcon/extcon-sm5502.h
> index 9dbb634d213b..ce1f1ec310c4 100644
> --- a/drivers/extcon/extcon-sm5502.h
> +++ b/drivers/extcon/extcon-sm5502.h
> @@ -237,6 +237,8 @@ enum sm5502_reg {
> #define DM_DP_SWITCH_UART ((DM_DP_CON_SWITCH_UART <<SM5502_REG_MANUAL_SW1_DP_SHIFT) \
> | (DM_DP_CON_SWITCH_UART <<SM5502_REG_MANUAL_SW1_DM_SHIFT))
>
> +#define SM5502_REG_RESET_MASK (0x1)
> +
> /* SM5502 Interrupts */
> enum sm5502_irq {
> /* INT1 */
>

Applied it. Thanks.

When you send the patch on later, you better to specify the version
on patch title as following:
[PATCH v2] extcon: sm5502: Reset registers during initialization

--
Best Regards,
Chanwoo Choi
Samsung Electronics