> On 21.12.2015, at 13:42, Stefan Wahren <info@xxxxxxxxxxxxxx> wrote:
>
> Hi Martin,
>
>> here the corresponding section for i2s in /arch/arm/boot/dts/bcm2835.dtsi:
>> i2s: i2s@7e203000 {
>> compatible = "brcm,bcm2835-i2s";
>> reg = <0x7e203000 0x20>,
>> <0x7e101098 0x02>;
>>
>> dmas = <&dma 2>,
>> <&dma 3>;
>> dma-names = "tx", "rx";
>> status = "disabled";
>> };
>
> unfortunately i don't have a i2s interface, but thanks for the remark.
I received one just today...
>
> It looks like the i2s driver programm the clock by itself instead of using the clock framework. So the second register entry should be removed from the i2s node.
I started looking and found that drivers/clk/bcm/clk-bcm2835.c
does not include the PWM clock either.
Anyway - looking at: sound/soc/bcm/bcm2835-i2s.c
it seems that right now this driver makes use of
a different parent-clock depending of the requested clock
I guess Eric needs to look into this portion to put it into the generic clock_code…
It is way more complicated than just using a fixed clock...
>>
>> Note that actually the PCM/I2S reg-range should be (off by 4):
>> reg = <0x7e203000 0x24>;
>> (see also: https://github.com/raspberrypi/linux/pull/1079)
>
> Any chance that Robert (patch author) can send a proper patch to linux-rpi-kernel for the of by 4 issue?
as we need to remove the second register-set anyway we need to make
modifications in the same location anyway.
Looks probably something like this for the device-tree:
diff --git a/arch/arm/boot/dts/bcm2835.dtsi b/arch/arm/boot/dts/bcm2835.dtsi
index aef64de..288d678 100644
--- a/arch/arm/boot/dts/bcm2835.dtsi
+++ b/arch/arm/boot/dts/bcm2835.dtsi
@@ -120,8 +120,9 @@
i2s: i2s@7e203000 {
compatible = "brcm,bcm2835-i2s";
- reg = <0x7e203000 0x20>,
- <0x7e101098 0x02>;
+ reg = <0x7e203000 0x24>;
+ clocks = <&clocks BCM2835_CLOCK_PWM>,
+ <&clocks BCM2835_CLOCK_VPU>;
dmas = <&dma 2>,
<&dma 3>;
diff --git a/include/dt-bindings/clock/bcm2835.h b/include/dt-bindings/clock/bcm
index d323efa..61f1d20 100644
--- a/include/dt-bindings/clock/bcm2835.h
+++ b/include/dt-bindings/clock/bcm2835.h
@@ -43,5 +43,6 @@
#define BCM2835_CLOCK_TSENS 27
#define BCM2835_CLOCK_EMMC 28
#define BCM2835_CLOCK_PERI_IMAGE 29
+#define BCM2835_CLOCK_PWM 30
-#define BCM2835_CLOCK_COUNT 30
+#define BCM2835_CLOCK_COUNT 31
And obviously more changes to the clock driver itself to support it:
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -807,6 +807,17 @@ static const struct bcm2835_clock_data bcm2835_clock_emmc_d
.frac_bits = 8,
};
+/* PWM/I2S clock */
+static const struct bcm2835_clock_data bcm2835_clock_pwm_data = {
+ .name = "pwm",
+ .num_mux_parents = ARRAY_SIZE(bcm2835_clock_per_parents),
+ .parents = bcm2835_clock_per_parents,
+ .ctl_reg = CM_PWMCTL,
+ .div_reg = CM_PWMDIV,
+ .int_bits = 4,
+ .frac_bits = 8,
+};
+
struct bcm2835_pll {
struct clk_hw hw;
struct bcm2835_cprman *cprman;
@@ -1537,6 +1548,8 @@ static int bcm2835_clk_probe(struct platform_device *pdev)
bcm2835_register_clock(cprman, &bcm2835_clock_hsm_data);
clks[BCM2835_CLOCK_EMMC] =
bcm2835_register_clock(cprman, &bcm2835_clock_emmc_data);
+ clks[BCM2835_CLOCK_PWM] =
+ bcm2835_register_clock(cprman, &bcm2835_clock_pwm_data);
/*
* CM_PERIICTL (and CM_PERIACTL, CM_SYSCTL and CM_VPUCTL if
And obviously many more changes to sound/soc/bcm/bcm2835-i2s.c
to remove the clock code and use the clock framework instead.
The biggest thing is the selection of the clock to use - the current code
either uses the OSC or PLLD.
@Eric: ist there some means to do that?
Thanks,
Martin--
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