| Message ID | 1381244455-3836-2-git-send-email-romainba@abilis.com |
|---|---|
| State | Changes Requested |
| Headers | show |
On Tue, Oct 08, 2013 at 05:00:55PM +0200, Romain Baeriswyl wrote: > Some legacy devices support ony I2C standard mode at 100kHz. > This patch allows to select the standard mode through the DTS > with the use of the existing clock-frequency parameter. > > When clock-frequency parameter is not set, the fast mode is selected. > Only when the parameter is set at 100000, the standard mode is selected. > > Signed-off-by: Romain Baeriswyl <romainba@abilis.com> > Reviewed-by: Christian Ruppert <christian.ruppert@abilis.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/9/13 4:56 PM, Mika Westerberg wrote:> On Tue, Oct 08, 2013 at 05:00:55PM +0200, Romain Baeriswyl wrote: >> Some legacy devices support ony I2C standard mode at 100kHz. >> This patch allows to select the standard mode through the DTS >> with the use of the existing clock-frequency parameter. >> >> When clock-frequency parameter is not set, the fast mode is selected. >> Only when the parameter is set at 100000, the standard mode is selected. >> >> Signed-off-by: Romain Baeriswyl <romainba@abilis.com> >> Reviewed-by: Christian Ruppert <christian.ruppert@abilis.com> > > Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> I don't have build environment for these patches right now, but both changes 1/2 and 2/2 look good. It's quite reasonable and makes the code readable to convert {3 => 300} into nsec based one. I should have done so from the beginning, thanks for doing this. Shinya -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Oct 08, 2013 at 05:00:55PM +0200, Romain Baeriswyl wrote: > Some legacy devices support ony I2C standard mode at 100kHz. > This patch allows to select the standard mode through the DTS > with the use of the existing clock-frequency parameter. > > When clock-frequency parameter is not set, the fast mode is selected. > Only when the parameter is set at 100000, the standard mode is selected. > > Signed-off-by: Romain Baeriswyl <romainba@abilis.com> > Reviewed-by: Christian Ruppert <christian.ruppert@abilis.com> Pretty much OK. One change needed, though: > --- > .../devicetree/bindings/i2c/i2c-designware.txt | 1 + > drivers/i2c/busses/i2c-designware-platdrv.c | 17 +++++++++++++++-- > 2 files changed, 16 insertions(+), 2 deletions(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > index 5199b0c..16d0bef 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > @@ -9,6 +9,7 @@ Required properties : > Recommended properties : > > - clock-frequency : desired I2C bus clock frequency in Hz. > + Only standard mode at 100kHz and fast mode at 400kHz are supported. This should not go the bindings doc, since this is a linux specific detail. It should go... > + if (clk_freq != 100000 && clk_freq != 400000) > + return -EINVAL; ... here as an dev_err message "Only x and y supported". Rest looks good, thanks!
diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt index 5199b0c..16d0bef 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt @@ -9,6 +9,7 @@ Required properties : Recommended properties : - clock-frequency : desired I2C bus clock frequency in Hz. + Only standard mode at 100kHz and fast mode at 400kHz are supported. Optional properties : - i2c-sda-hold-time-ns : should contain the SDA hold time in nanoseconds. diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 0d6fe47..5f06848 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -87,6 +87,7 @@ static int dw_i2c_probe(struct platform_device *pdev) struct i2c_adapter *adap; struct resource *mem; int irq, r; + u32 clk_freq; irq = platform_get_irq(pdev, 0); if (irq < 0) { @@ -122,6 +123,9 @@ static int dw_i2c_probe(struct platform_device *pdev) return PTR_ERR(dev->clk); clk_prepare_enable(dev->clk); + /* fast mode by default */ + clk_freq = 400000; + if (pdev->dev.of_node) { u32 ht = 0; u32 ic_clk = dev->get_clk_rate_khz(dev); @@ -136,6 +140,11 @@ static int dw_i2c_probe(struct platform_device *pdev) of_property_read_u32(pdev->dev.of_node, "i2c-scl-falling-time-ns", &dev->scl_falling_time); + + of_property_read_u32(pdev->dev.of_node, "clock-frequency", + &clk_freq); + if (clk_freq != 100000 && clk_freq != 400000) + return -EINVAL; } dev->functionality = @@ -145,8 +154,12 @@ static int dw_i2c_probe(struct platform_device *pdev) I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_I2C_BLOCK; - dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | - DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST; + if (clk_freq == 100000) + dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | + DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_STD; + else + dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | + DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST; /* Try first if we can configure the device from ACPI */ r = dw_i2c_acpi_configure(pdev);