Quoting Michal Bachraty (2013-04-09 01:26:15)
> For gapless tuning, there is no need for PLL reset and clkout power-down
> when tuning output. "silabs,gapless-tuning" parameter enables gapless tuning
> for specific clock output.
>
> Signed-off-by: Michal Bachraty <michal.bachraty@xxxxxxxxxxxxxxxxxxx>
Hi Michal,
This did not apply cleanly on the latest (v8) si5351 clk driver. Can
you refresh it? I do not plan on taking any more patches for 3.10 after
3.9-rc7 drops (likely on Sunday or Monday). So this patch may need to
wait until after the merge window.
Regards,
Mike
> ---
> .../devicetree/bindings/clock/silabs,si5351.txt | 2 ++
> drivers/clk/clk-si5351.c | 27 +++++++++++++++++---
> 2 files changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/clock/silabs,si5351.txt b/Documentation/devicetree/bindings/clock/silabs,si5351.txt
> index cc37465..e16ab2b 100644
> --- a/Documentation/devicetree/bindings/clock/silabs,si5351.txt
> +++ b/Documentation/devicetree/bindings/clock/silabs,si5351.txt
> @@ -44,6 +44,8 @@ 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,gapless-tuning: boolean, enable gapless (glitch-free) tuning. Depends on
> + "silabs,multisynth-source" parameter.
>
> ==Example==
>
> diff --git a/drivers/clk/clk-si5351.c b/drivers/clk/clk-si5351.c
> index e259cec..d3933a9 100644
> --- a/drivers/clk/clk-si5351.c
> +++ b/drivers/clk/clk-si5351.c
> @@ -54,6 +54,7 @@ struct si5351_hw_data {
> struct si5351_driver_data *drvdata;
> struct si5351_parameters params;
> unsigned char num;
> + unsigned char gapless_tuning;
> };
>
> struct si5351_driver_data {
> @@ -526,8 +527,10 @@ static int si5351_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> (hwdata->params.p2 == 0) ? SI5351_CLK_INTEGER_MODE : 0);
>
> /* reset pll */
> - val = (hwdata->num == 0) ? SI5351_PLL_RESET_A : SI5351_PLL_RESET_B;
> - si5351_set_bits(hwdata->drvdata, SI5351_PLL_RESET, val, val);
> + if (!hwdata->gapless_tuning) {
> + val = (hwdata->num == 0) ? SI5351_PLL_RESET_A : SI5351_PLL_RESET_B;
> + si5351_set_bits(hwdata->drvdata, SI5351_PLL_RESET, val, val);
> + }
>
> dev_dbg(&hwdata->drvdata->client->dev,
> "%s - %s: p1 = %lu, p2 = %lu, p3 = %lu, parent_rate = %lu, rate = %lu\n",
> @@ -1064,8 +1067,9 @@ static int si5351_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
> } while (1);
>
> /* powerdown clkout */
> - si5351_set_bits(hwdata->drvdata, SI5351_CLK0_CTRL + hwdata->num,
> - SI5351_CLK_POWERDOWN, SI5351_CLK_POWERDOWN);
> + if (!hwdata->gapless_tuning)
> + si5351_set_bits(hwdata->drvdata, SI5351_CLK0_CTRL + hwdata->num,
> + SI5351_CLK_POWERDOWN, SI5351_CLK_POWERDOWN);
>
> /* write output divider */
> switch (hwdata->num) {
> @@ -1117,6 +1121,7 @@ static void si5351_dt_setup(
> struct property *prop;
> const __be32 *p;
> unsigned int num, val;
> + int pll = -1;
>
> if (np == NULL)
> return;
> @@ -1167,6 +1172,8 @@ static void si5351_dt_setup(
> dev_warn(&client->dev,
> "unable to reparent multisynth %d to %d\n",
> num, val);
> + else
> + pll = val;
> }
>
> if (!of_property_read_u32(np, "silabs,clock-source", &val)) {
> @@ -1178,6 +1185,15 @@ static void si5351_dt_setup(
>
> if (!of_property_read_u32(np, "clock-frequency", &val))
> clk_set_rate(drvdata->onecell.clks[num], val);
> +
> + if (of_property_read_bool(np, "silabs,gapless-tuning")) {
> + if (pll >= 0) {
> + drvdata->clkout[num].gapless_tuning = 1;
> + drvdata->pll[pll].gapless_tuning = 1;
> + } else
> + dev_warn(&client->dev,
> + "unable to set gapless tuning");
> + }
> }
> }
>
> @@ -1294,6 +1310,7 @@ static int si5351_i2c_probe(struct i2c_client *client,
> drvdata->pll[0].num = 0;
> drvdata->pll[0].drvdata = drvdata;
> drvdata->pll[0].hw.init = &init;
> + drvdata->pll[0].gapless_tuning = 0;
> memset(&init, 0, sizeof(init));
> init.name = si5351_pll_names[0];
> init.ops = &si5351_pll_ops;
> @@ -1310,6 +1327,7 @@ static int si5351_i2c_probe(struct i2c_client *client,
> drvdata->pll[1].num = 1;
> drvdata->pll[1].drvdata = drvdata;
> drvdata->pll[1].hw.init = &init;
> + drvdata->pll[1].gapless_tuning = 0;
> memset(&init, 0, sizeof(init));
> if (drvdata->variant == SI5351_VARIANT_B) {
> init.name = si5351_pll_names[2];
> @@ -1380,6 +1398,7 @@ static int si5351_i2c_probe(struct i2c_client *client,
> drvdata->clkout[n].num = n;
> drvdata->clkout[n].drvdata = drvdata;
> drvdata->clkout[n].hw.init = &init;
> + drvdata->clkout[n].gapless_tuning = 0;
> memset(&init, 0, sizeof(init));
> init.name = si5351_clkout_names[n];
> init.ops = &si5351_clkout_ops;
> --
> 1.7.9.5
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