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.
Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
---
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
--
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