| Message ID | 20211015081506.933180-15-miquel.raynal@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | TI AM437X ADC1 | expand |
Hi Miquel, I recently found that our BeagleBoneBlack with external touch screen stopped to find it. A git bisect revealed this patch (merged into v5.16-rc1) as the first bad: > Am 15.10.2021 um 10:14 schrieb Miquel Raynal <miquel.raynal@bootlin.com>: > > There is a single clock available in our node, which is named > "fck". The clock handler then points to adc_tsc_fck but no need to point > directly to it and do a full tree search. > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> > --- > drivers/mfd/ti_am335x_tscadc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c > index e2c4416f192d..8af44c08d925 100644 > --- a/drivers/mfd/ti_am335x_tscadc.c > +++ b/drivers/mfd/ti_am335x_tscadc.c > @@ -206,7 +206,7 @@ static int ti_tscadc_probe(struct platform_device *pdev) > * This frequency is valid since TSC_ADC_SS controller design > * assumes the OCP clock is at least 6x faster than the ADC clock. > */ > - clk = devm_clk_get(&pdev->dev, "adc_tsc_fck"); > + clk = devm_clk_get(&pdev->dev, NULL); > if (IS_ERR(clk)) { > dev_err(&pdev->dev, "failed to get TSC fck\n"); > err = PTR_ERR(clk); > -- > 2.27.0 > While I understand the reasons for this change there seems to be something missing now in the device tree because the clock isn't found any more. After knowing about the problem I could also locate the log entry: [ 4.456680] ti_am3359-tscadc 44e0d000.tscadc: failed to get TSC fck Reverting your patch makes it work again. Is there missing a change in the am335x-boneblack or am335x DTS? Our (private) DTS looks like this, i.e. we don't play with clocks inherited from mainline tree: #include "am335x-boneblack.dts" ... &tscadc { status = "okay"; tsc { ti,wires = <4>; ti,x-plate-resistance = <600>; ti,coordinate-readouts = <5>; ti,wire-config = <0x00 0x11 0x22 0x33>; }; adc { ti,adc-channels = <4 5 6 7>; }; }; BR and thanks, Nikolaus
Hi Nikolaus, hns@goldelico.com wrote on Fri, 4 Mar 2022 23:38:25 +0100: > Hi Miquel, > I recently found that our BeagleBoneBlack with external touch screen stopped > to find it. > > A git bisect revealed this patch (merged into v5.16-rc1) as the first bad: > > > Am 15.10.2021 um 10:14 schrieb Miquel Raynal <miquel.raynal@bootlin.com>: > > > > There is a single clock available in our node, which is named > > "fck". The clock handler then points to adc_tsc_fck but no need to point > > directly to it and do a full tree search. > > > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> > > --- > > drivers/mfd/ti_am335x_tscadc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c > > index e2c4416f192d..8af44c08d925 100644 > > --- a/drivers/mfd/ti_am335x_tscadc.c > > +++ b/drivers/mfd/ti_am335x_tscadc.c > > @@ -206,7 +206,7 @@ static int ti_tscadc_probe(struct platform_device *pdev) > > * This frequency is valid since TSC_ADC_SS controller design > > * assumes the OCP clock is at least 6x faster than the ADC clock. > > */ > > - clk = devm_clk_get(&pdev->dev, "adc_tsc_fck"); > > + clk = devm_clk_get(&pdev->dev, NULL); > > if (IS_ERR(clk)) { > > dev_err(&pdev->dev, "failed to get TSC fck\n"); > > err = PTR_ERR(clk); > > -- > > 2.27.0 > > > > While I understand the reasons for this change there seems to be something > missing now in the device tree because the clock isn't found any more. > > After knowing about the problem I could also locate the log entry: > > [ 4.456680] ti_am3359-tscadc 44e0d000.tscadc: failed to get TSC fck > > Reverting your patch makes it work again. Sorry for the wrong behavior on your side and thanks for the investigation. > Is there missing a change in the am335x-boneblack or am335x DTS? I've looked at the code and indeed the am33xx-clock.dtsi file defines the touchscreen clock, but unfortunately the am33xx-l4.dtsi file which defines the touchscreen node does not reference the clock. The bindings clearly require the clocks to be referenced but I believe this was not noticed until now because the clock exist and clk_get() did a lookup across the tree. On my side I tested it with an am437x SoC which uses another base device tree, which properly references the touchscreen clock where it's needed. I will send a patch (untested), can you give it a try and report if it fixes your issue? > > Our (private) DTS looks like this, i.e. we don't play with clocks inherited > from mainline tree: > > #include "am335x-boneblack.dts" > > ... > > &tscadc { > status = "okay"; > > tsc { > ti,wires = <4>; > ti,x-plate-resistance = <600>; > ti,coordinate-readouts = <5>; > ti,wire-config = <0x00 0x11 0x22 0x33>; > }; > > adc { > ti,adc-channels = <4 5 6 7>; > }; > }; > > BR and thanks, > Nikolaus Thanks, Miquèl
Hi Miquel, > Am 07.03.2022 um 12:10 schrieb Miquel Raynal <miquel.raynal@bootlin.com>: > > Hi Nikolaus, > > hns@goldelico.com wrote on Fri, 4 Mar 2022 23:38:25 +0100: > >> Hi Miquel, >> I recently found that our BeagleBoneBlack with external touch screen stopped >> to find it. >> >> A git bisect revealed this patch (merged into v5.16-rc1) as the first bad: >> >>> Am 15.10.2021 um 10:14 schrieb Miquel Raynal <miquel.raynal@bootlin.com>: >>> >>> There is a single clock available in our node, which is named >>> "fck". The clock handler then points to adc_tsc_fck but no need to point >>> directly to it and do a full tree search. >>> >>> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> >>> --- >>> drivers/mfd/ti_am335x_tscadc.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c >>> index e2c4416f192d..8af44c08d925 100644 >>> --- a/drivers/mfd/ti_am335x_tscadc.c >>> +++ b/drivers/mfd/ti_am335x_tscadc.c >>> @@ -206,7 +206,7 @@ static int ti_tscadc_probe(struct platform_device *pdev) >>> * This frequency is valid since TSC_ADC_SS controller design >>> * assumes the OCP clock is at least 6x faster than the ADC clock. >>> */ >>> - clk = devm_clk_get(&pdev->dev, "adc_tsc_fck"); >>> + clk = devm_clk_get(&pdev->dev, NULL); >>> if (IS_ERR(clk)) { >>> dev_err(&pdev->dev, "failed to get TSC fck\n"); >>> err = PTR_ERR(clk); >>> -- >>> 2.27.0 >>> >> >> While I understand the reasons for this change there seems to be something >> missing now in the device tree because the clock isn't found any more. >> >> After knowing about the problem I could also locate the log entry: >> >> [ 4.456680] ti_am3359-tscadc 44e0d000.tscadc: failed to get TSC fck >> >> Reverting your patch makes it work again. > > Sorry for the wrong behavior on your side and thanks for the > investigation. > >> Is there missing a change in the am335x-boneblack or am335x DTS? > > I've looked at the code and indeed the am33xx-clock.dtsi file defines > the touchscreen clock, but unfortunately the am33xx-l4.dtsi file which > defines the touchscreen node does not reference the clock. The bindings > clearly require the clocks to be referenced but I believe this was not > noticed until now because the clock exist and clk_get() did a lookup > across the tree. I had expected something like this. > > On my side I tested it with an am437x SoC which uses another base > device tree, which properly references the touchscreen clock where it's > needed. > > I will send a patch (untested), can you give it a try and report if it > fixes your issue? Yes, please. BR and thanks, Nikolaus
diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c index e2c4416f192d..8af44c08d925 100644 --- a/drivers/mfd/ti_am335x_tscadc.c +++ b/drivers/mfd/ti_am335x_tscadc.c @@ -206,7 +206,7 @@ static int ti_tscadc_probe(struct platform_device *pdev) * This frequency is valid since TSC_ADC_SS controller design * assumes the OCP clock is at least 6x faster than the ADC clock. */ - clk = devm_clk_get(&pdev->dev, "adc_tsc_fck"); + clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(clk)) { dev_err(&pdev->dev, "failed to get TSC fck\n"); err = PTR_ERR(clk);
There is a single clock available in our node, which is named "fck". The clock handler then points to adc_tsc_fck but no need to point directly to it and do a full tree search. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> --- drivers/mfd/ti_am335x_tscadc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)