On Wed, 2016-04-13 at 20:16 +0800, Jisheng Zhang wrote: > Dear Andy, > > On Thu, 7 Apr 2016 21:05:35 +0300 Andy Shevchenko wrote: > > > > > On Wed, Apr 6, 2016 at 10:28 AM, Jisheng Zhang <jszhang@xxxxxxxxxxx> > > 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. > I'm sorry, I can't catch your meaning. Could you please kindly give > more > details? Or examples of "two groups of parameters" > --- + - 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. I'm referring to the above sentence. Something like There are two groups of values identifying i2c timings: 1. i2c-scl-falling-time-ns and i2c-sda-falling-time-ns 2. *-[hl]cnt The second group of parameters supersedes the first one. > > > + > > > + - 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 > > > > > > > -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html