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Date:   Tue, 30 Jun 2020 21:22:07 +0200
From:   Andreas Kemnade <andreas@kemnade.info>
To:     Jonathan =?UTF-8?B?TmV1c2Now6RmZXI=?= <j.neuschaefer@gmx.net>
Cc:     linux-kernel@vger.kernel.org, Lee Jones <lee.jones@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Uwe =?UTF-8?B?S2xlaW5lLUvDtm5pZw==?= 
        <u.kleine-koenig@pengutronix.de>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Heiko Stuebner <heiko.stuebner@theobroma-systems.com>,
        Stephan Gerhold <stephan@gerhold.net>,
        Lubomir Rintel <lkundrak@v3.sk>,
        Mark Brown <broonie@kernel.org>, allen <allen.chen@ite.com.tw>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        devicetree@vger.kernel.org, linux-pwm@vger.kernel.org,
        linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Heiko Stuebner <heiko@sntech.de>,
        Josua Mayer <josua.mayer@jm0.eu>
Subject: Re: [RFC PATCH 00/10] Netronix embedded controller driver for Kobo
 and Tolino ebook readers
Message-ID: <20200630212207.018ad355@aktux>
In-Reply-To: <20200630071523.GA2983@latitude>
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        <20200630084051.66feadea@aktux>
        <20200630071523.GA2983@latitude>
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On Tue, 30 Jun 2020 09:15:23 +0200
Jonathan Neusch=C3=A4fer <j.neuschaefer@gmx.net> wrote:

> On Tue, Jun 30, 2020 at 08:40:51AM +0200, Andreas Kemnade wrote:
> [...]
> > got a chance to test it on a Tolino Shine 2 HD.
> > It uses the RTC from the RC5T619 but backlight seems to go via MSP430
> > EC.
> >=20
> > I got this.
> >=20
> > [    1.453603] ntxec 0-0043: Netronix embedded controller version f110 =
detected.
> > [   10.723638] ntxec-rtc 21a0000.i2c:embedded-controller@43:rtc: regist=
ered as rtc0
> > [   10.775276] ntxec-pwm: probe of 21a0000.i2c:embedded-controller@43:p=
wm failed with error -5 =20
>=20
> Hmm, -EIO from the PWM driver.
>
Weird...
IOMUXC_SW_PAD_CTL_PAD_I2C1_SDA/SCL is identical between
vendor kernel (heavily patched 3.0.35) and patched mainline.
                       =20
MX6SL_PAD_I2C1_SCL__I2C1_SCL     0x4001f8b1
MX6SL_PAD_I2C1_SDA__I2C1_SDA     0x4001f8b1

root@tolino2:~# i2cset -f 0 0x43 0xa3 0x0001 w
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will write to device file /dev/i2c-0, chip address 0x43, data address
0xa3, data 0x01, mode word.
Continue? [Y/n]=20
Error: Write failed
root@tolino2:~# i2cset -f 0 0x43 0xa3 0x0000 w
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will write to device file /dev/i2c-0, chip address 0x43, data address
0xa3, data 0x00, mode word.
Continue? [Y/n]=20
Error: Write failed

but backlight gets toggled. Same behavior on vendor kernel and
in vendor uboot.
That smells.

Regards,
Andreas