Re: [PATCH v2] clk: si5351: Allow user to define disabled state for every clock output

[Mike Turquette <mturquette-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

Quoting Marek Belisko (2013-05-02 22:33:27)
> From: Sebastian Hesselbarth <sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> This patch adds platform data and DT bindings to allow to overwrite
> the stored disabled state for each clock output.
> 
> Signed-off-by: Marek Belisko <marek.belisko-6oiIBCxl0MMjD8S081q9vkEOCMrvLtNR@public.gmane.org>
> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Taken into clk-next.

Thanks,
Mike

> ---
> Changes from v1->v2:
> Sebastian Hesselbarth send me updated version of patch which was based
> on v1. Resending with updates.
> 
>  .../devicetree/bindings/clock/silabs,si5351.txt    |    5 ++
>  drivers/clk/clk-si5351.c                           |   74 +++++++++++++++++++-
>  drivers/clk/clk-si5351.h                           |    1 +
>  include/linux/platform_data/si5351.h               |   18 +++++
>  4 files changed, 95 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/clock/silabs,si5351.txt b/Documentation/devicetree/bindings/clock/silabs,si5351.txt
> index cc37465..66c75b2 100644
> --- a/Documentation/devicetree/bindings/clock/silabs,si5351.txt
> +++ b/Documentation/devicetree/bindings/clock/silabs,si5351.txt
> @@ -44,6 +44,11 @@ Optional child node properties:
>  - silabs,multisynth-source: source pll A(0) or B(1) of corresponding multisynth
>    divider.
>  - silabs,pll-master: boolean, multisynth can change pll frequency.
> +- silabs,disable-state : clock output disable state, shall be
> +  0 = clock output is driven LOW when disabled
> +  1 = clock output is driven HIGH when disabled
> +  2 = clock output is FLOATING (HIGH-Z) when disabled
> +  3 = clock output is NEVER disabled
>  
>  ==Example==
>  
> diff --git a/drivers/clk/clk-si5351.c b/drivers/clk/clk-si5351.c
> index 8323c31..098f28b 100644
> --- a/drivers/clk/clk-si5351.c
> +++ b/drivers/clk/clk-si5351.c
> @@ -851,6 +851,41 @@ static int _si5351_clkout_set_drive_strength(
>         return 0;
>  }
>  
> +static int _si5351_clkout_set_disable_state(
> +       struct si5351_driver_data *drvdata, int num,
> +       enum si5351_disable_state state)
> +{
> +       u8 reg = (num < 4) ? SI5351_CLK3_0_DISABLE_STATE :
> +               SI5351_CLK7_4_DISABLE_STATE;
> +       u8 shift = (num < 4) ? (2 * num) : (2 * (num-4));
> +       u8 mask = SI5351_CLK_DISABLE_STATE_MASK << shift;
> +       u8 val;
> +
> +       if (num > 8)
> +               return -EINVAL;
> +
> +       switch (state) {
> +       case SI5351_DISABLE_LOW:
> +               val = SI5351_CLK_DISABLE_STATE_LOW;
> +               break;
> +       case SI5351_DISABLE_HIGH:
> +               val = SI5351_CLK_DISABLE_STATE_HIGH;
> +               break;
> +       case SI5351_DISABLE_FLOATING:
> +               val = SI5351_CLK_DISABLE_STATE_FLOAT;
> +               break;
> +       case SI5351_DISABLE_NEVER:
> +               val = SI5351_CLK_DISABLE_STATE_NEVER;
> +               break;
> +       default:
> +               return 0;
> +       }
> +
> +       si5351_set_bits(drvdata, reg, mask, val << shift);
> +
> +       return 0;
> +}
> +
>  static int si5351_clkout_prepare(struct clk_hw *hw)
>  {
>         struct si5351_hw_data *hwdata =
> @@ -1225,6 +1260,33 @@ static int si5351_dt_parse(struct i2c_client *client)
>                         }
>                 }
>  
> +               if (!of_property_read_u32(child, "silabs,disable-state",
> +                                         &val)) {
> +                       switch (val) {
> +                       case 0:
> +                               pdata->clkout[num].disable_state =
> +                                       SI5351_DISABLE_LOW;
> +                               break;
> +                       case 1:
> +                               pdata->clkout[num].disable_state =
> +                                       SI5351_DISABLE_HIGH;
> +                               break;
> +                       case 2:
> +                               pdata->clkout[num].disable_state =
> +                                       SI5351_DISABLE_FLOATING;
> +                               break;
> +                       case 3:
> +                               pdata->clkout[num].disable_state =
> +                                       SI5351_DISABLE_NEVER;
> +                               break;
> +                       default:
> +                               dev_err(&client->dev,
> +                                       "invalid disable state %d for clkout %d\n",
> +                                       val, num);
> +                               return -EINVAL;
> +                       }
> +               }
> +
>                 if (!of_property_read_u32(child, "clock-frequency", &val))
>                         pdata->clkout[num].rate = val;
>  
> @@ -1281,9 +1343,6 @@ static int si5351_i2c_probe(struct i2c_client *client,
>  
>         /* Disable interrupts */
>         si5351_reg_write(drvdata, SI5351_INTERRUPT_MASK, 0xf0);
> -       /* Set disabled output drivers to drive low */
> -       si5351_reg_write(drvdata, SI5351_CLK3_0_DISABLE_STATE, 0x00);
> -       si5351_reg_write(drvdata, SI5351_CLK7_4_DISABLE_STATE, 0x00);
>         /* Ensure pll select is on XTAL for Si5351A/B */
>         if (drvdata->variant != SI5351_VARIANT_C)
>                 si5351_set_bits(drvdata, SI5351_PLL_INPUT_SOURCE,
> @@ -1327,6 +1386,15 @@ static int si5351_i2c_probe(struct i2c_client *client,
>                                 n, pdata->clkout[n].drive);
>                         return ret;
>                 }
> +
> +               ret = _si5351_clkout_set_disable_state(drvdata, n,
> +                                               pdata->clkout[n].disable_state);
> +               if (ret) {
> +                       dev_err(&client->dev,
> +                               "failed set disable state of clkout%d to %d\n",
> +                               n, pdata->clkout[n].disable_state);
> +                       return ret;
> +               }
>         }
>  
>         /* register xtal input clock gate */
> diff --git a/drivers/clk/clk-si5351.h b/drivers/clk/clk-si5351.h
> index af41b50..c0dbf26 100644
> --- a/drivers/clk/clk-si5351.h
> +++ b/drivers/clk/clk-si5351.h
> @@ -81,6 +81,7 @@
>  
>  #define SI5351_CLK3_0_DISABLE_STATE            24
>  #define SI5351_CLK7_4_DISABLE_STATE            25
> +#define  SI5351_CLK_DISABLE_STATE_MASK         3
>  #define  SI5351_CLK_DISABLE_STATE_LOW          0
>  #define  SI5351_CLK_DISABLE_STATE_HIGH         1
>  #define  SI5351_CLK_DISABLE_STATE_FLOAT                2
> diff --git a/include/linux/platform_data/si5351.h b/include/linux/platform_data/si5351.h
> index 92dabca..5433439 100644
> --- a/include/linux/platform_data/si5351.h
> +++ b/include/linux/platform_data/si5351.h
> @@ -79,6 +79,23 @@ enum si5351_drive_strength {
>  };
>  
>  /**
> + * enum si5351_disable_state - Si5351 clock output disable state
> + * @SI5351_DISABLE_DEFAULT: default, do not change eeprom config
> + * @SI5351_DISABLE_LOW: CLKx is set to a LOW state when disabled
> + * @SI5351_DISABLE_HIGH: CLKx is set to a HIGH state when disabled
> + * @SI5351_DISABLE_FLOATING: CLKx is set to a FLOATING state when
> + *                             disabled
> + * @SI5351_DISABLE_NEVER: CLKx is NEVER disabled
> + */
> +enum si5351_disable_state {
> +       SI5351_DISABLE_DEFAULT = 0,
> +       SI5351_DISABLE_LOW,
> +       SI5351_DISABLE_HIGH,
> +       SI5351_DISABLE_FLOATING,
> +       SI5351_DISABLE_NEVER,
> +};
> +
> +/**
>   * struct si5351_clkout_config - Si5351 clock output configuration
>   * @clkout: clkout number
>   * @multisynth_src: multisynth source clock
> @@ -91,6 +108,7 @@ struct si5351_clkout_config {
>         enum si5351_multisynth_src multisynth_src;
>         enum si5351_clkout_src clkout_src;
>         enum si5351_drive_strength drive;
> +       enum si5351_disable_state disable_state;
>         bool pll_master;
>         unsigned long rate;
>  };
> -- 
> 1.7.9.5