> -----Original Message-----
> From: Wolfram Sang <wsa@xxxxxxxxxxxxx>
> Sent: Saturday, June 01, 2019 3:44 PM
> To: Vadim Pasternak <vadimp@xxxxxxxxxxxx>
> Cc: linux-i2c@xxxxxxxxxxxxxxx; Michael Shych <michaelsh@xxxxxxxxxxxx>
> Subject: Re: [PATCH v1 i2c-next] i2c: mlxcpld: prevent devices from being
> unbounded from driver via sysfs
>
>
> > 'i2c_mlxcpld' is a platform drivers and it registered via
> > platform_driver_probe() and can be bound to devices only once, upon
> > registration.
>
> ?? No, it isn't. If it was, the driver core would have prevented these attributes
> (post 2009 kernels at least).
Hi Wolfram,
Thank you very much for your input.
Yes, I see my statement was wrong.
I performed more debug with option CONFIG_DEBUG_TEST_DRIVER_REMOVE.
And I think I found the issue.
In code from 'mlx-platform' driver, I pointed out in commit text,
'mlx-platform' registers 'i2c_mlxcpld' device and then registers few
underlying 'i2c-mux-reg' devices:
priv->pdev_i2c = platform_device_register_simple("i2c_mlxcpld", nr,
NULL, 0);
...
for (i = 0; i < ARRAY_SIZE(mlxplat_mux_data); i++) {
priv->pdev_mux[i] = platform_device_register_resndata(
&mlxplat_dev->dev,
"i2c-mux-reg", i, NULL,
0, &mlxplat_mux_data[i],
sizeof(mlxplat_mux_data[i]));
But it seems for priv->pdev_mux[i] entries,
platform_device_register_resndata() should be called with parent device
priv->pdev_i2c->dev instead of mlxplat_dev->dev, since "i2c-mux-reg
parent is device, created by "i2c_mlxcpld".
This change solves the issue I found with DEBUG_TEST_DRIVER_REMOVE.
And it also seems to be a possible source for some other issues.
I am going to send a path with this fix to platform.
--- a/drivers/platform/x86/mlx-platform.c
+++ b/drivers/platform/x86/mlx-platform.c
@@ -2032,7 +2032,7 @@ static int __init mlxplat_init(void)
for (i = 0; i < ARRAY_SIZE(mlxplat_mux_data); i++) {
priv->pdev_mux[i] = platform_device_register_resndata(
- &mlxplat_dev->dev,
+ &priv->pdev_i2c->dev,
"i2c-mux-reg", i, NULL,
0, &mlxplat_mux_data[i],
sizeof(mlxplat_mux_data[i]));
Thank you,
Vadim.
