Hi Andrew,
Am 16.11.2017 um 19:56 schrieb H. Nikolaus Schaller hns@goldelico.com:
Hi Andrew,
Am 16.11.2017 um 19:32 schrieb Andrew F. Davis afd@ti.com:
On 11/16/2017 12:18 PM, H. Nikolaus Schaller wrote:
Am 16.11.2017 um 18:08 schrieb Andrew F. Davis afd@ti.com:
On 11/16/2017 10:10 AM, H. Nikolaus Schaller wrote:
Hi Andrew,
Am 16.11.2017 um 16:53 schrieb Andrew F. Davis afd@ti.com:
On 11/16/2017 07:43 AM, H. Nikolaus Schaller wrote: > >> Am 16.11.2017 um 13:32 schrieb Tomi Valkeinen tomi.valkeinen@ti.com: >> >> On 16/11/17 10:50, H. Nikolaus Schaller wrote: >>> The vendor name was "toppoly" but other panels and the vendor list >>> have defined it as "tpo". So let's fix it in driver and bindings. >>> >>> Signed-off-by: H. Nikolaus Schaller hns@goldelico.com >>> --- >> >> >>> -MODULE_ALIAS("spi:toppoly,td028ttec1"); >>> +MODULE_ALIAS("spi:tpo,td028ttec1"); >> >> Doesn't this mean that the module won't load if you have old bindings? > > Hm. > > Well, I think it can load but doesn't automatically from DT strings which might > be unexpected. > >> Can't we have two module aliases? > > I think we can. Just a random example: > https://elixir.free-electrons.com/linux/latest/source/drivers/w1/slaves/w1_t... > > So we should keep both.
Even better would be to drop both MODULE_ALIAS and let the MODULE_DEVICE_TABLE macro define them for your from the SPI id table.
Why would that be better?
MODULE_ALIAS is ugly, you already have a table (usually) of device names that are supported by the driver, the module aliases should be generated from that table. This also keeps supported device list in one place.
As far as I see it will need more code and changes than adding one line of MODULE_ALIAS.
Although it doesn't look like this driver has an SPI id table, you should probably add one, I be interested to see if this module is always being matched through the "spi" or the "of" alias..
Could you please propose how that code should look like, so that I can test?
Sure,
start with $ udevadm monitor and see what string the kernel is looking for when trying to find a module for this device.
Well, the module is loaded automatically from DT at boot time well before I can start udevadm. So that is the most tricky part to setup the system to suppress this...
If it is only ever looking for "of:toppoly,td028ttec1", then you can drop the MODULE_ALIAS and be done as it was never getting used anyway.
Since it is an SPI client, I am sure it looks for "spi:something.
What I expect though is "spi:toppoly,td028ttec1", in which case you should add
static const struct spi_device_id td028ttec1_ids[] = { { "toppoly,td028ttec1", 0 }, { "tpo,td028ttec1", 0}, { /* sentinel */ } }; MODULE_DEVICE_TABLE(spi, td028ttec1_ids);
We already have a static const struct of_device_id td028ttec1_of_match[] table with the same information.
So we still have two places to keep in sync.
Or can we remove the td028ttec1_of_match[]? AFAIK not.
link to it in the td028ttec1_spi_driver struct: .id_table = td028ttec1_ids,
Then test again to see that the module still loads with the new and old DT string.
In total I am not really convinced that adding 7 lines of code is better than one (the "tpo," alias) that is tested and works...
And it looks like a lot of unplanned code testing for me which takes more than 5 minutes :)
So I'd prefer to leave that exercise of fixing the MODULE_ALIAS/DEVICE_TABLE to someone else...
That's fine, someday I'll probably get some script to do this for all the drivers that still have MODULE_ALIAS and an existing table.
That would be cool!
On a second thought, I think there is a quick experiment for this driver not needing to monitor events.
1st attempt: remove ALIASES => if it still loads it would be fine 2nd attempt: add your id table => if it loads again, it is fine if not, let's keep ALIASES.
Maybe I can try tomorrow.
I found time to give it a try and indeed:
1. with module_aliases
root@letux:~# lsmod | fgrep td028 panel_tpo_td028ttec1 16384 1 omapdss_base 16384 5 connector_analog_tv,encoder_opa362,panel_tpo_td028ttec1,omapdrm,omapdss root@letux:~# modprobe -c | fgrep td028 alias of:N*T*Comapdss,toppoly,td028ttec1 panel_tpo_td028ttec1 alias of:N*T*Comapdss,toppoly,td028ttec1C* panel_tpo_td028ttec1 alias of:N*T*Comapdss,tpo,td028ttec1 panel_tpo_td028ttec1 alias of:N*T*Comapdss,tpo,td028ttec1C* panel_tpo_td028ttec1 alias spi:toppoly,td028ttec1 panel_tpo_td028ttec1 alias spi:tpo,td028ttec1 panel_tpo_td028ttec1 root@letux:~#
=> two MODULE_ALIASEs are possible.
2. without module_aliases
No display and:
root@letux:~# lsmod | fgrep td028 root@letux:~# modprobe -c | fgrep td028 alias of:N*T*Comapdss,toppoly,td028ttec1 panel_tpo_td028ttec1 alias of:N*T*Comapdss,toppoly,td028ttec1C* panel_tpo_td028ttec1 alias of:N*T*Comapdss,tpo,td028ttec1 panel_tpo_td028ttec1 alias of:N*T*Comapdss,tpo,td028ttec1C* panel_tpo_td028ttec1 root@letux:~#
=> spi: entries are needed.
3. with MODULE_DEVICE_TABLE
Display is back and:
root@letux:~# lsmod | fgrep td028 panel_tpo_td028ttec1 16384 1 omapdss_base 16384 5 connector_analog_tv,encoder_opa362,panel_tpo_td028ttec1,omapdrm,omapdss root@letux:~# modprobe -c | fgrep td028 alias of:N*T*Comapdss,toppoly,td028ttec1 panel_tpo_td028ttec1 alias of:N*T*Comapdss,toppoly,td028ttec1C* panel_tpo_td028ttec1 alias of:N*T*Comapdss,tpo,td028ttec1 panel_tpo_td028ttec1 alias of:N*T*Comapdss,tpo,td028ttec1C* panel_tpo_td028ttec1 alias spi:toppoly,td028ttec1 panel_tpo_td028ttec1 alias spi:tpo,td028ttec1 panel_tpo_td028ttec1 root@letux:~#
=> MODULE_DEVICE_TABLE works equally well.
I have prepared a separate patch so that a first one adds another MODULE_ALIAS and the new one replaces both MODULE_ALIASes with MODULE_DEVICE_TABLE.
I will submit a [PATCH v3] asap.
BR and thanks, Nikolaus