Messages in this thread | | | Date | Thu, 7 Apr 2016 21:05:35 +0300 | Subject | Re: [PATCH] i2c: designware-platdrv: get fast/std speed scl high/low count from DT | From | Andy Shevchenko <> |
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On Wed, Apr 6, 2016 at 10:28 AM, Jisheng Zhang <jszhang@marvell.com> wrote: > Sometimes, it's convenient to define the scl's high/low count directly, > e.g HW people would do some measurement then directly give out the > optimum counts. Previously, we solved the sda falling time and scl > falling time by i2c_dw_scl_hcnt() and i2c_dw_scl_lcnt(), then put them > into dt, but what we really care isn't the sda/scl falling time. > > From another side, the dw_i2c_acpi_configure() on ACPI platform also > get hcnt/lcnt values rather than the sda/scl falling time from ACPI > method, we want similar feature for DT platforms. >
Instead of duplicating some words maybe better to explicitly define two groups of parameters and one which supersedes the other.
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > --- > Documentation/devicetree/bindings/i2c/i2c-designware.txt | 16 ++++++++++++++++ > drivers/i2c/busses/i2c-designware-platdrv.c | 8 ++++++++ > 2 files changed, 24 insertions(+) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > index fee26dc..05176fbf 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > @@ -20,6 +20,22 @@ Optional properties : > - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds. > This value which is by default 300ns is used to compute the tHIGH period. > > + - i2c-ss-scl-high-count : should contain the standard speed i2c clock SCL high > + count. If defined, the i2c-scl-falling-time-ns and i2c-sda-falling-time-ns > + will be ignored. > + > + - i2c-ss-scl-low-count : should contain the standard speed i2c clock SCL low > + count. If defined, the i2c-scl-falling-time-ns and i2c-sda-falling-time-ns > + will be ignored. > + > + - i2c-fs-scl-high-count : should contain the fast speed i2c clock SCL high > + count. If defined, the i2c-scl-falling-time-ns and i2c-sda-falling-time-ns > + will be ignored. > + > + - i2c-fs-scl-low-count : should contain the fast speed i2c clock SCL low > + count. If defined, the i2c-scl-falling-time-ns and i2c-sda-falling-time-ns > + will be ignored. > + > Example : > > i2c@f0000 { > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c > index d656657..8739a60 100644 > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > @@ -188,6 +188,14 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) > &dev->scl_falling_time); > device_property_read_u32(&pdev->dev, "clock-frequency", > &clk_freq); > + device_property_read_u16(&pdev->dev, "i2c-ss-scl-high-count", > + &dev->ss_hcnt); > + device_property_read_u16(&pdev->dev, "i2c-ss-scl-low-count", > + &dev->ss_lcnt); > + device_property_read_u16(&pdev->dev, "i2c-fs-scl-high-count", > + &dev->fs_hcnt); > + device_property_read_u16(&pdev->dev, "i2c-fs-scl-low-count", > + &dev->fs_lcnt); > } > > if (has_acpi_companion(&pdev->dev)) > -- > 2.8.0.rc3 >
-- With Best Regards, Andy Shevchenko
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