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 <[email protected]>
---
.../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
On Tue, Apr 9, 2013 at 10:26 AM, Michal Bachraty
<[email protected]> wrote:
> 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.
Michal,
does gapless tuning have any constraints? Can we use it for all rate
changes or determine the
need for pll reset by rate offset?
Sebastian
Hi Sebastian,
> does gapless tuning have any constraints? Can we use it for all rate
> changes or determine the
> need for pll reset by rate offset?
Today I made some test measurements ( switching from 22.5MHz to 32kHz, then to
50MHz, then to 1MHz) with good results: without any gaps and any side
frequences. So there are no constrains, and we can use it for any frequences.
Best,
Michal
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 <[email protected]>
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
On 04/12/2013 08:38 PM, Mike Turquette wrote:
> 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<[email protected]>
>
> 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.
Mike,
I have integrated the above function into clk-si5351 during development
(see clk-si5351 changelog from v6->v7). I think we can drop this patch,
as Michal added his Tested-by to clk-si5351.
Regards,
Sebastian