Re: [PATCH v7] clk: add si5351 i2c common clock driver

[Sebastian Hesselbarth <sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

[-- Attachment #1.1: Type: text/plain, Size: 3444 bytes --]

On Wed, Apr 10, 2013 at 4:48 PM, Michal Bachraty <
michal.bachraty-6oiIBCxl0MMjD8S081q9vkEOCMrvLtNR@public.gmane.org> wrote:

> Hi Sebastian,
> This driver doesn't work for me. In my case, u-boot initializes si-5351 and
> power down unused clocks while booting kernel.  there is need for power up
> clocks as was in previous versions of your driver.
> See patch, whre the problem is fixed:
>
> @@ -992,6 +992,10 @@ static long si5351_clkout_round_rate(struct clk_hw
> *hw,
> unsigned long rate,
>                 } while (1);
>         }
>         rate = *parent_rate >> rdiv;
> +
> +       /* powerup clkout */
> +       si5351_set_bits(hwdata->drvdata, SI5351_CLK0_CTRL + hwdata->num,
> +                       SI5351_CLK_POWERDOWN, 0);
>
>         dev_dbg(&hwdata->drvdata->client->dev,
>                 "%s - %s: rdiv = %u, parent_rate = %lu, rate = %lu\n",
>
> With this lines, driver works well.
>

Hmm, is there any driver using the clock output? Does it
clk_prepare_enable() the clock?
I tend not to mess with anything the bootloader or eeprom config left
disabled. It works
for me, but here the driver will prepare/enable the clock prior use.


> Also,
>
> > > +==Example==
> > > +
> > > +/* 25MHz reference crystal */
> > > +ref25: ref25M {
> > > +   compatible = "fixed-clock";
> > > +   #clock-cells = <0>;
> > > +   clock-frequency = <25000000>;
> > > +};
> > > +
> > > +i2c-master-node {
> > > +
> > > +   /* Si5351a msop10 i2c clock generator */
> > > +   si5351a: clock-generator@60 {
> > > +           compatible = "silabs,si5351a-msop";
> > > +           reg = <0x60>;
> > > +           #address-cells = <1>;
> > > +           #size-cells = <0>;
> > > +           #clock-cells = <1>;
> > > +
> > > +           /* connect xtal input to 25MHz reference */
> > > +           clocks = <&ref25>;
> > > +
> > > +           /* connect xtal input as source of pll0 and pll1 */
> > > +           silabs,pll-source = <0 0>, <1 0>;
> > > +
> > > +           /*
> > > +            * overwrite clkout0 configuration with:
> > > +            * - 8mA output drive strength
> > > +            * - pll0 as clock source of multisynth0
> > > +            * - multisynth0 as clock source of output divider
> > > +            * - multisynth0 can change pll0
> > > +            * - set initial clock frequency of 74.25MHz
> > > +            */
> > > +           clkout0 {
> > > +                   reg = <0>;
> > > +                   silabs,drive-strength = <8>;
> > > +                   silabs,multisynth-source = <0>;
> > > +                   silabs,clock-source = <0>;
> > > +                   silabs,pll-master;
> > > +                   clock-frequency = <74250000>;
> > > +           };
> > > +
> > > +           /*
> > > +            * overwrite clkout1 configuration with:
> > > +            * - 4mA output drive strength
> > > +            * - pll1 as clock source of multisynth1
> > > +            * - multisynth1 as clock source of output divider
> > > +            * - multisynth1 can change pll1
> > > +            */
> > > +           clkout1 {
> > > +                   reg = <1>;
> > > +                   silabs,drive-strength = <4>;
> > > +                   silabs,multisynth-source = <1>;
> > > +                   silabs,clock-source = <0>;
> > > +                   pll-master;
> > > +           };
> > > +
>  Is definition of pll-master in clkout1 correct? should not be silabs,pll-
> master ?
>

Good catch.

Sebastian

[-- Attachment #1.2: Type: text/html, Size: 4849 bytes --]

[-- Attachment #2: Type: text/plain, Size: 192 bytes --]

_______________________________________________
devicetree-discuss mailing list
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org
https://lists.ozlabs.org/listinfo/devicetree-discuss