[U-Boot] i2c_set_bus_num freeze

From: Heiko Schocher <hs@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] i2c_set_bus_num freeze
Date: Fri, 27 Jan 2017 08:24:03 +0100	[thread overview]
Message-ID: <588AF593.3050204@denx.de> (raw)
In-Reply-To: <CAJ2oMhKPSuOw6mLcQErue_AfUJ1vi1ZLjajs44Me2uHygzSX+w@mail.gmail.com>

Hello Ran,

Am 27.01.2017 um 08:08 schrieb Ran Shalit:
>
>
> On Fri, Jan 27, 2017 at 8:46 AM, Heiko Schocher <hs at denx.de <mailto:hs@denx.de>> wrote:
>
>     Hello Ran,
>
>     Am 26.01.2017 um 18:42 schrieb Ran Shalit:
>
>         Hello,
>
>         I have some issue in u-boot trying to access bus #1.
>
>
>     On which hardware? Is the board in mainline?
>
>
> Yes, it's TI's dm8148 (ti81xx, ti814x)

Which defconfig do you use?

>         I can access bus #0, #2 with i2c dev 0/2
>
>         I can also access bus #0,1,2 from linux.
>
>         But on trying to access i2c #1 in u-boot in hangs:
>
>         The function i2c_set_bus_num get stuck .
>
>
>         ret = i2c_set_bus_num(1);
>
>         <<------- never gets here .........
>            if (ret)
>                printf("Failure changing bus number (%d)\n", ret);
>
>         It hangs in i2c_set_bus_num->i2c_init->
>
>         ......
>
>               printf("i2c_init 8\n");
>
>
>     You see this printf?
>
> Yes, it seems to get stuck here:
>
> if (readw (I2C_CON) & I2C_CON_EN) {
> <<--------- we never gets here !!!!!!!!!!!!!!!!!!!!!!!!!!!
> writew (0, I2C_CON);
>
>
>
>         bus_initialized[current_bus] = 1;
>         if (readw (I2C_CON) & I2C_CON_EN) {

Hmm... if I search for "bus_initialized" in mainline code:

$ grep -lr bus_initialized drivers/i2c/
drivers/i2c/mv_i2c.c

I only find the mv_i2c driver ... do you use current mainline code?

>         writew (0, I2C_CON);
>         udelay (50000);
>         }
>
>         writew(psc, I2C_PSC);
>         writew(scll, I2C_SCLL);
>         writew(sclh, I2C_SCLH);
>
>         /* own address */
>         writew (slaveadd, I2C_OA);
>         writew (I2C_CON_EN, I2C_CON);
>
>               printf("i2c_init 9\n");  <<------ never get printed ..................
>
>         I have seen a similar question, yet I am doing this access after u-boot
>         complete, and command prompt.
>
>         Is anyone familiar with this ?
>
>
>     Hmm.. no reason, why the last printf should not come ...
>
>     As I do not know, on which hw ... I just can speculate ...
>
>     Is the clock for the i2c subsystem 1 in the SoC enabled?
>
>
> TI's DM8148.
> I remember that I once used that code and it works, so I quite amazed that it stopped working now.
> The board had some changes from that time when I tried the code, and the sw too some minor changes
> (i2c eerom added in bus #0),  but I really don't understand why it doesn't work any more :(
>
> It might be clock issue, I'll check.

Thanks!

bye,
Heiko
>
>
>     bye,
>     Heiko
>
>
>         Regards,
>
>         Ran
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>
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>
>

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany