[PATCH v3 5/5] i2c: mt7621: make device reset optional

[Benjamin Larsson]

Hi.

On 5/20/26 00:32, Christian Marangi wrote:
> Airoha SoC that makes use of the same Mediatek I2C driver/logic doesn't
> have reset line for I2C so use optional device_reset variant.
>
> Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
> ---
>   drivers/i2c/busses/i2c-mt7621.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-mt7621.c b/drivers/i2c/busses/i2c-mt7621.c
> index 3cde43c57a2b..fb9d9701bb10 100644
> --- a/drivers/i2c/busses/i2c-mt7621.c
> +++ b/drivers/i2c/busses/i2c-mt7621.c
> @@ -91,7 +91,7 @@ static void mtk_i2c_reset(struct mtk_i2c *i2c)
>   	u32 reg;
>   	int ret;
>   
> -	ret = device_reset(i2c->adap.dev.parent);
> +	ret = device_reset_optional(i2c->adap.dev.parent);
>   	if (ret)
>   		dev_err(i2c->dev, "I2C reset failed!\n");
>   


Can you elaborate on this one? I get this:

root at XGX-B-00e092000160:~# devmem 0x1fbf8040
0x00C7800C
root at XGX-B-00e092000160:~# devmem 0x1FB00834 32 0x10000
root at XGX-B-00e092000160:~# devmem 0x1fbf8040
[  396.658742] pbus timeout interrupt ERR ADDR=1fbf8040
[  396.663845] CPU: 0 PID: 5622 Comm: sleep Tainted: P  O      5.4.55 #0
[  396.671117] Hardware name: XGX-B (DT)
[  396.674884] Call trace:
[  396.677394]  dump_backtrace+0x0/0x120
[  396.681111]  show_stack+0x14/0x20
[  396.684478]  dump_stack+0xac/0xec
[  396.687900]  bus_timeout_interrupt+0x54/0x70
[  396.692223]  __handle_irq_event_percpu+0x3c/0x140
[  396.696978]  handle_irq_event+0x4c/0xec
[  396.700920]  handle_fasteoi_irq+0xbc/0x21c
[  396.705069]  __handle_domain_irq+0x6c/0xd0
[  396.709218]  gic_handle_irq+0x8c/0x190
[  396.713019]  el1_irq+0xf0/0x1c0
[  396.716217]  __do_softirq+0x98/0x264
[  396.719847]  irq_exit+0x98/0xe0
[  396.723118]  __handle_domain_irq+0x74/0xd0
[  396.727268]  gic_handle_irq+0x8c/0x190
[  396.731070]  el1_irq+0xf0/0x1c0
[  396.734320]  tlb_flush+0xf8/0x260
[  396.737693]  tlb_finish_mmu+0x48/0xe0
[  396.741417]  exit_mmap+0xc0/0x170
[  396.744841]  mmput+0x44/0x120
[  396.747872]  do_exit+0x2b4/0x8ec
[  396.751161]  do_group_exit+0x34/0x9c
[  396.754794]  __wake_up_parent+0x0/0x2c
[  396.758651]  el0_svc_handler+0x8c/0x150
[  396.762545]  el0_svc+0x8/0x208
0xDEADBEEF
root at XGX-B-00e092000160:~# devmem 0x1FB00834 32 0x00000
root at XGX-B-00e092000160:~# devmem 0x1fbf8040
0x0000800C


and

root at XGX-B-00e092000160:~# devmem 0x1fbf8140
0x00318013
root at XGX-B-00e092000160:~# devmem 0x1FB00830 32 0x00040
root at XGX-B-00e092000160:~# devmem 0x1fbf8140
[  611.730070] pbus timeout interrupt ERR ADDR=1fbf8140
[  611.735197] CPU: 0 PID: 2651 Comm: ux-manager Tainted: P    O      
5.4.55 #0
[  611.742925] Hardware name: XGX-B (DT)
[  611.746697] Call trace:
[  611.749222]  dump_backtrace+0x0/0x120
[  611.752960]  show_stack+0x14/0x20
[  611.756424]  dump_stack+0xac/0xec
[  611.759801]  bus_timeout_interrupt+0x54/0x70
[  611.764145]  __handle_irq_event_percpu+0x3c/0x140
[  611.769001]  handle_irq_event+0x4c/0xec
[  611.772912]  handle_fasteoi_irq+0xbc/0x21c
[  611.777077]  __handle_domain_irq+0x6c/0xd0
[  611.781312]  gic_handle_irq+0x8c/0x190
[  611.785117]  el1_irq+0xf0/0x1c0
[  611.788335]  __do_softirq+0x98/0x264
[  611.792032]  irq_exit+0x98/0xe0
[  611.795249]  __handle_domain_irq+0x74/0xd0
[  611.799411]  gic_handle_irq+0x8c/0x190
[  611.803303]  el1_irq+0xf0/0x1c0
[  611.806518]  bgpio_read32+0x4/0x20
[  611.809995]  gpiod_get_value_cansleep+0x44/0x100
[  611.814742]  value_show+0x2c/0x64
[  611.818114]  dev_attr_show+0x1c/0x54
[  611.821760]  sysfs_kf_read+0x54/0xc0
[  611.825396]  kernfs_fop_read+0xac/0x300
[  611.829355]  __vfs_read+0x18/0x3c
[  611.832741]  vfs_read+0xc8/0x150
[  611.836028]  ksys_read+0x58/0xd4
[  611.839369]  __arm64_sys_read+0x18/0x20
[  611.843264]  el0_svc_handler+0x8c/0x150
[  611.847166]  el0_svc+0x8/0x208
0xDEADBEEF
root at XGX-B-00e092000160:~# devmem 0x1FB00830 32 0x00000
root at XGX-B-00e092000160:~# devmem 0x1fbf8140
0x00008000

When I look at the current dts:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/airoha/en7581.dtsi?h=v7.1-rc4#n322

it looks like the resets are just crossed with regards to the nodes.


MvH

Benjamin Larsson