From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Ruppert Subject: Re: [PATCH 1/2] pinmux: Add TB10x pinmux driver Date: Fri, 7 Jun 2013 13:32:09 +0200 Message-ID: <20130607113207.GE11875@ab42.lan> References: <20130522142824.GC4789@ab42.lan> <20130524115053.GB5203@ab42.lan> <20130603123001.GD31808@ab42.lan> <20130606141115.GA10345@ab42.lan> <20130606153030.GA19876@ab42.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-doc-owner@vger.kernel.org To: Haojian Zhuang Cc: Linus Walleij , Stephen Warren , Shiraz HASHIM , Patrice CHOTARD , "linux-kernel@vger.kernel.org" , Grant Likely , Rob Herring , Rob Landley , Sascha Leuenberger , Pierrick Hascoet , "devicetree-discuss@lists.ozlabs.org" , "linux-doc@vger.kernel.org" List-Id: devicetree@vger.kernel.org On Fri, Jun 07, 2013 at 08:00:57AM +0800, Haojian Zhuang wrote: > On 6 June 2013 23:30, Christian Ruppert wrote: > > On Thu, Jun 06, 2013 at 10:32:21PM +0800, Haojian Zhuang wrote: > >> On 6 June 2013 22:11, Christian Ruppert wrote: > >> > On Wed, Jun 05, 2013 at 09:44:27AM +0800, Haojian Zhuang wrote: > >> >> On 3 June 2013 20:30, Christian Ruppert wrote: > >> >> > OK, here's a simplified example of what we would like to do (= this seems > >> >> > pretty common so I suppose there is a way I haven't understoo= d). Our > >> >> > situation is slightly more complex but for the purpose of dis= cussion > >> >> > let's assume a chip with 8 pins which can be configured for t= he > >> >> > following functions: > >> >> > > >> >> > Pin GPIO-A I2C SPI0 SPI1 > >> >> > ------------------------------------ > >> >> > 1 GPIOA0 SDA MISO1 > >> >> > 2 GPIOA1 SCL MOSI1 > >> >> > 3 GPIOA2 SS1_B > >> >> > 4 GPIOA3 SCLK1 > >> >> > 5 GPIOA4 MISO0 > >> >> > 6 GPIOA5 MOSI0 > >> >> > 7 GPIOA6 SS0_B > >> >> > 8 GPIOA7 SCLK0 > >> >> > > >> >> > We can now define the following pinctrl-single: > >> >> > > >> >> > pinmux: pinmux@0xFFEE0000 { > >> >> > compatible =3D "pinctrl-single"; > >> >> > reg =3D <0xFFEE0000 0x8>; > >> >> > #address-cells =3D <1>; > >> >> > #size-cells =3D <0>; > >> >> > #gpio-range-cells =3D <3>; > >> >> > pinctrl-single,register-width =3D <32>; > >> >> > pinctrl-single,function-mask =3D <0xffffffff>; > >> >> > pinctrl-single,gpio-range =3D <&range 1 8 0>; > >> >> > gpioa_pins: pinmux_gpioa_pins { > >> >> > pinctrl-single,pins =3D <0x0 0 0x4 0> > >> >> > }; > >> >> > i2c_pins: pinmux_i2c_pins { > >> >> > pinctrl-single,pins =3D <0x0 1> > >> >> > }; > >> >> > spi0_pins: pinmux_spi0_pins { > >> >> > pinctrl-single,pins =3D <0x1 1> > >> >> <0x1 1>? > >> >> > >> >> If each pinmux register is only for one pin in your SoC. > >> >> I think that your definitions are wrong above. We use > >> >> register offset as the first argument, not pin number. > >> >> And the second argument should be pin function number. > >> > > >> > In our case each pinmux register (bit field) actually controls a= n entire > >> > group of pins. > >> > > >> >> If multiple pins are sharing one register with different bits, > >> >> you need to enable "pinctrl-single,bit-per-mux". > >> > > >> > Multiple pins are sharing the same bits in the same register. Do= you > >> > think this prevents us from using pinctrl-single? > >> > > >> Could you give me your register definition? Then I can understand = you > >> better. > > > > In our example, the register map would look a bit like the followin= g. > > Note that every register configures four pins at a time. > > > > Register 0x0: > > Mode GPIO-A I2C SPI1 > > Value 0x0 0x1 0x2 > > --------------------------- > > Pin1 GPIOA0 SDA MISO1 > > Pin2 GPIOA1 SCL MOSI1 > > Pin3 GPIOA2 SS1_B > > Pin4 GPIOA3 SCLK1 > > > > Register 0x4: > > Mode GPIO-A SPI0 > > Value 0x0 0x1 > > --------------------- > > Pin5 GPIOA4 MISO0 > > Pin6 GPIOA5 MOSI0 > > Pin7 GPIOA6 SS0_B > > Pin8 GPIOA7 SCLK0 > > >=20 > You said "Multiple pins are sharing the same bits in the same registe= r.". > I need to understand which bits you're talking about in your register= =2E In the above example, bits 0 and 1 of register 0x0 control pins 1 through 4 and bit 0 of register 0x4 controls pins 5 through 8. The moment you write a new value in either of those registers, all four pin= s will change functionality simultaneously. There is no way to control th= e functionality of each pin individually. Greetings, Christian --=20 Christian Ruppert , /| Tel: +41/(0)22 816 19-42 //| 3, Chemin du Pr=E9-F= leuri _// | bilis Systems CH-1228 Plan-les-Oua= tes