Re: [PATCH 1/6] HID: intel-ish-hid: add support for MODULE_DEVICE_TABLE()

From: Hans de Goede <hdegoede@redhat.com>
To: "Thomas Weißschuh" <linux@weissschuh.net>, linux-input@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
	Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
	Jiri Kosina <jkosina@suse.cz>,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH 1/6] HID: intel-ish-hid: add support for MODULE_DEVICE_TABLE()
Date: Mon, 1 Nov 2021 10:58:56 +0100	[thread overview]
Message-ID: <cd712bd7-cce7-58fb-d644-ced4fc0c76b1@redhat.com> (raw)
In-Reply-To: <20211029152901.297939-2-linux@weissschuh.net>

Hi,

On 10/29/21 17:28, Thomas Weißschuh wrote:
> This allows to selectively autoload drivers for ISH devices.
> Currently all ISH drivers are loaded for all systems having any ISH
> device.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> 
> ---
> 
> Cc: linux-kbuild@vger.kernel.org
> Cc: linux-input@vger.kernel.org
> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> Cc: Jiri Kosina <jkosina@suse.cz>
> Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Michal Marek <michal.lkml@markovi.net>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> ---
>  include/linux/mod_devicetable.h   | 13 +++++++++++++
>  scripts/mod/devicetable-offsets.c |  3 +++
>  scripts/mod/file2alias.c          | 24 ++++++++++++++++++++++++
>  3 files changed, 40 insertions(+)
> 
> diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> index ae2e75d15b21..befbf53c4b7c 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -895,4 +895,17 @@ struct dfl_device_id {
>  	kernel_ulong_t driver_data;
>  };
>  
> +/* ISHTP (Integrated Sensor Hub Transport Protocol) */
> +
> +#define ISHTP_MODULE_PREFIX	"ishtp:"
> +
> +/**
> + * struct ishtp_device_id - ISHTP device identifier
> + * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
> + * @context: pointer to driver specific data
> + */
> +struct ishtp_device_id {
> +	guid_t guid;

The kdoc comment documents a context pointer, but this is missing from the
actual struct. Having some sort of driver_data (1) field here would be good IMHO.

Regards,

Hans

1) "context" is fine, but AFAIK almost all other foo_device_id structs call this
driver_data, so that would be more consistent IMHO.

> +};
> +
>  #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
> index cc3625617a0e..c0d3bcb99138 100644
> --- a/scripts/mod/devicetable-offsets.c
> +++ b/scripts/mod/devicetable-offsets.c
> @@ -259,5 +259,8 @@ int main(void)
>  	DEVID_FIELD(dfl_device_id, type);
>  	DEVID_FIELD(dfl_device_id, feature_id);
>  
> +	DEVID(ishtp_device_id);
> +	DEVID_FIELD(ishtp_device_id, guid);
> +
>  	return 0;
>  }
> diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
> index 49aba862073e..5258247d78ac 100644
> --- a/scripts/mod/file2alias.c
> +++ b/scripts/mod/file2alias.c
> @@ -115,6 +115,17 @@ static inline void add_uuid(char *str, uuid_le uuid)
>  		uuid.b[12], uuid.b[13], uuid.b[14], uuid.b[15]);
>  }
>  
> +static inline void add_guid(char *str, guid_t guid)
> +{
> +	int len = strlen(str);
> +
> +	sprintf(str + len, "%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
> +		guid.b[3], guid.b[2], guid.b[1], guid.b[0],
> +		guid.b[5], guid.b[4], guid.b[7], guid.b[6],
> +		guid.b[8], guid.b[9], guid.b[10], guid.b[11],
> +		guid.b[12], guid.b[13], guid.b[14], guid.b[15]);
> +}
> +
>  /**
>   * Check that sizeof(device_id type) are consistent with size of section
>   * in .o file. If in-consistent then userspace and kernel does not agree
> @@ -1380,6 +1391,18 @@ static int do_mhi_entry(const char *filename, void *symval, char *alias)
>  	return 1;
>  }
>  
> +/* Looks like: ishtp:{guid} */
> +static int do_ishtp_entry(const char *filename, void *symval, char *alias)
> +{
> +	DEF_FIELD(symval, ishtp_device_id, guid);
> +
> +	strcpy(alias, ISHTP_MODULE_PREFIX "{");
> +	add_guid(alias, guid);
> +	strcat(alias, "}");
> +
> +	return 1;
> +}
> +
>  static int do_auxiliary_entry(const char *filename, void *symval, char *alias)
>  {
>  	DEF_FIELD_ADDR(symval, auxiliary_device_id, name);
> @@ -1499,6 +1522,7 @@ static const struct devtable devtable[] = {
>  	{"auxiliary", SIZE_auxiliary_device_id, do_auxiliary_entry},
>  	{"ssam", SIZE_ssam_device_id, do_ssam_entry},
>  	{"dfl", SIZE_dfl_device_id, do_dfl_entry},
> +	{"ishtp", SIZE_ishtp_device_id, do_ishtp_entry},
>  };
>  
>  /* Create MODULE_ALIAS() statements.
> 