linux-kernel - Re: [PATCH] extcon: sm5502: Clear pending interrupts during initialization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 10 Oct 2019 16:33:12 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     Stephan Gerhold <stephan@...hold.net>,
        MyungJoo Ham <myungjoo.ham@...sung.com>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH] extcon: sm5502: Clear pending interrupts during
 initialization

On 19. 10. 8. 오후 7:54, 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.
> 
> Reading the interrupt status registers twice seems to be sufficient
> to make interrupts work in this situation.
> 
> Signed-off-by: Stephan Gerhold <stephan@...hold.net>
> ---
> This makes interrupts work on the Samsung Galaxy A5 (2015), which
> has recently gained mainline support [1].
> 
> I was not able to find a datasheet for SM5502, so this patch is
> merely based on testing and comparison with the downstream driver [2].
> 
> [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1329c1ab0730b521e6cd3051c56a2ff3d55f21e6
> [2]: https://protect2.fireeye.com/url?k=029d0042-5ffa4464-029c8b0d-0cc47a31384a-14ac0bce09798d1f&u=https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/SM-A500FU/drivers/misc/sm5502.c#L1566-L1578
> ---
>  drivers/extcon/extcon-sm5502.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/extcon/extcon-sm5502.c b/drivers/extcon/extcon-sm5502.c
> index dc43847ad2b0..c897f1aa4bf5 100644
> --- a/drivers/extcon/extcon-sm5502.c
> +++ b/drivers/extcon/extcon-sm5502.c
> @@ -539,6 +539,12 @@ static void sm5502_init_dev_type(struct sm5502_muic_info *info)
>  			val = info->reg_data[i].val;
>  		regmap_write(info->regmap, info->reg_data[i].reg, val);
>  	}
> +
> +	/* Clear pending interrupts */
> +	regmap_read(info->regmap, SM5502_REG_INT1, &reg_data);
> +	regmap_read(info->regmap, SM5502_REG_INT2, &reg_data);
> +	regmap_read(info->regmap, SM5502_REG_INT1, &reg_data);
> +	regmap_read(info->regmap, SM5502_REG_INT2, &reg_data);

It is not proper. Instead, initialize the SM5502_RET_INT1/2 with zero.

The reset value of SM5502_RET_INT1/2 are zero (0x00) as following:
If you can test it with h/w, please try to test it and then
send the modified patch. 

diff --git a/drivers/extcon/extcon-sm5502.c b/drivers/extcon/extcon-sm5502.c
index c897f1aa4bf5..e168f77a18ba 100644
--- a/drivers/extcon/extcon-sm5502.c
+++ b/drivers/extcon/extcon-sm5502.c
@@ -68,6 +68,14 @@ static struct reg_data sm5502_reg_data[] = {
                .reg = SM5502_REG_CONTROL,
                .val = SM5502_REG_CONTROL_MASK_INT_MASK,
                .invert = false,
+       }, {
+               .reg = SM5502_REG_INT1,
+               .val = SM5502_RET_INT1_MASK,
+               .invert = true,
+       }, {
+               .reg = SM5502_REG_INT2,
+               .val = SM5502_RET_INT1_MASK,
+               .invert = true,
        }, {
                .reg = SM5502_REG_INTMASK1,
                .val = SM5502_REG_INTM1_KP_MASK
diff --git a/drivers/extcon/extcon-sm5502.h b/drivers/extcon/extcon-sm5502.h
index 9dbb634d213b..5c4edb3e7fce 100644
--- a/drivers/extcon/extcon-sm5502.h
+++ b/drivers/extcon/extcon-sm5502.h
@@ -93,6 +93,8 @@ enum sm5502_reg {
 #define SM5502_REG_CONTROL_RAW_DATA_MASK       (0x1 << SM5502_REG_CONTROL_RAW_DATA_SHIFT)
 #define SM5502_REG_CONTROL_SW_OPEN_MASK                (0x1 << SM5502_REG_CONTROL_SW_OPEN_SHIFT)
 
+#define SM5502_RET_INT1_MASK                   (0xff)
+
 #define SM5502_REG_INTM1_ATTACH_SHIFT          0
 #define SM5502_REG_INTM1_DETACH_SHIFT          1
 #define SM5502_REG_INTM1_KP_SHIFT              2

>  }
>  
>  static int sm5022_muic_i2c_probe(struct i2c_client *i2c,
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics