On 06/21/2013 09:31 AM, Daniel Mack wrote:
On 21.06.2013 09:23, Lars-Peter Clausen wrote:
On 06/20/2013 07:29 PM, Daniel Mack wrote:
The ADAU1701 has 2 hardware pins to configure the PLL mode in accordance to the MCLK-to-LRCLK ratio. These pins have to be stable before the chip is released from reset, and a full reset cycle, including a new firmware download is needed whenever they change.
This patch adds GPIO properties to the DT bindings of the Codec, and implements makes the set_sysclk memorize the configured sysclk.
To avoid excessive reset cycles and firmware downloads, the default clock divider can be specified in DT as well. Whenever a ratio change is detected in the hw_params callback, the PLL mode lines are updates and a full reset cycle is issued.
Signed-off-by: Daniel Mack zonque@gmail.com
.../devicetree/bindings/sound/adi,adau1701.txt | 14 +++ sound/soc/codecs/adau1701.c | 107 +++++++++++++++++---- sound/soc/codecs/adau1701.h | 4 + 3 files changed, 104 insertions(+), 21 deletions(-)
diff --git a/Documentation/devicetree/bindings/sound/adi,adau1701.txt b/Documentation/devicetree/bindings/sound/adi,adau1701.txt index 3afeda7..a0d7e92 100644 --- a/Documentation/devicetree/bindings/sound/adi,adau1701.txt +++ b/Documentation/devicetree/bindings/sound/adi,adau1701.txt @@ -11,6 +11,19 @@ Optional properties:
- reset-gpio: A GPIO spec to define which pin is connected to the chip's !RESET pin. If specified, the driver will assert a hardware reset at probe time.
- adi,pll-clkdiv: The PLL clock divider, specifing the ratio between
MCLK and fsclk. The value is used to determine thecorrect state of the two mode pins below.Note that this value can be overridden at runtimeby passing the ADAU1701_CLKDIV_MCLK_LRCLK dividerwith ASoC calls. However, the chips needs a fullreset cycle and a new firmware download each timethe configuration changes.Considering that this is now done all automatically at runtime, do we actually still need this property?
Yes, I noticed that as well, but given that changing the PLL mode setup is expensive, and because we need some sort of firmware to start up at least, I wanted to provide a way to set these values up-front, so systems with stable clock dividers can minimize the number of firmware transfers.
Ok, fair enough, but the documentation for the property needs to be updated.
- Lars