[PATCH v3 0/6] clk: qcom: msm8996: add APCS clock driver

[PATCH v3 0/6] clk: qcom: msm8996: add APCS clock driver

[Dmitry Baryshkov]

The sys_apcs_aux clock can be used by CPU and CBF clock drivers to drive
those clocks from GPLL0 while doing initial setup. Add simple driver to
setup and export this clock.

Changes since v2:
- Added the conditional clause to schema forbidding usage of clocks and
  clock-names on platforms which do not pass additional clocks to the
  APCS device node (Krzysztof)
- Added SDX55 compat string
- Moved MSM8976 compat to the list of platforms using syscon.

Changes since v1:
- Removed the clk.h header inclusion (Stephen)
- Changed the module license from GPL v2 to bare GPL.

Dmitry Baryshkov (6):
  dt-bindings: mailbox: qcom: add SDX55 compatible
  dt-bindings: mailbox: qcom: enable syscon compatible for msm8976
  dt-bindings: mailbox: qcom: correct the list of platforms using clocks
  dt-bindings: mailbox: qcom: add #clock-cells to msm8996 example
  mailbox: qcom-apcs-ipc: enable APCS clock device for MSM8996
  clk: qcom: add the driver for the MSM8996 APCS clocks

 .../mailbox/qcom,apcs-kpss-global.yaml        | 37 ++++++---
 drivers/clk/qcom/Makefile                     |  2 +-
 drivers/clk/qcom/apcs-msm8996.c               | 76 +++++++++++++++++++
 drivers/mailbox/qcom-apcs-ipc-mailbox.c       |  2 +-
 4 files changed, 106 insertions(+), 11 deletions(-)
 create mode 100644 drivers/clk/qcom/apcs-msm8996.c

-- 
2.39.0

[PATCH v3 1/6] dt-bindings: mailbox: qcom: add SDX55 compatible

[Dmitry Baryshkov]

The commit 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55
APCS") added SDX55 compatible string to one of clock-selection
conditions, but failed to add one to the main schema's compatible list.
Fix this omission.

Fixes: 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55 APCS")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 .../devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml       | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
index 943f9472ae10..36deddca1524 100644
--- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
+++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
@@ -39,6 +39,7 @@ properties:
               - qcom,msm8953-apcs-kpss-global
               - qcom,msm8994-apcs-kpss-global
               - qcom,qcs404-apcs-apps-global
+              - qcom,sdx55-apcs-gcc
           - const: syscon
   reg:
     maxItems: 1
-- 
2.39.0

Re: [PATCH v3 1/6] dt-bindings: mailbox: qcom: add SDX55 compatible

[Krzysztof Kozlowski]

On 17/01/2023 23:30, Dmitry Baryshkov wrote:
> The commit 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55
> APCS") added SDX55 compatible string to one of clock-selection
> conditions, but failed to add one to the main schema's compatible list.
> Fix this omission.
> 
> Fixes: 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55 APCS")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v3 2/6] dt-bindings: mailbox: qcom: enable syscon compatible for msm8976

[Dmitry Baryshkov]

On msm8976 platform APCS also uses syscon compatible, so move it to the
block of compatibles using SoC-compat together with syscon.

Fixes: 60545466180e ("dt-bindings: mailbox: qcom,apcs-kpss-global: Add syscon const for relevant entries")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 .../devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
index 36deddca1524..ecc286ab49ef 100644
--- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
+++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
@@ -20,7 +20,6 @@ properties:
           - enum:
               - qcom,ipq6018-apcs-apps-global
               - qcom,ipq8074-apcs-apps-global
-              - qcom,msm8976-apcs-kpss-global
               - qcom,msm8996-apcs-hmss-global
               - qcom,msm8998-apcs-hmss-global
               - qcom,qcm2290-apcs-hmss-global
@@ -37,6 +36,7 @@ properties:
               - qcom,msm8916-apcs-kpss-global
               - qcom,msm8939-apcs-kpss-global
               - qcom,msm8953-apcs-kpss-global
+              - qcom,msm8976-apcs-kpss-global
               - qcom,msm8994-apcs-kpss-global
               - qcom,qcs404-apcs-apps-global
               - qcom,sdx55-apcs-gcc
-- 
2.39.0

Re: [PATCH v3 2/6] dt-bindings: mailbox: qcom: enable syscon compatible for msm8976

[Krzysztof Kozlowski]

On 17/01/2023 23:30, Dmitry Baryshkov wrote:
> On msm8976 platform APCS also uses syscon compatible, so move it to the
> block of compatibles using SoC-compat together with syscon.
> 
> Fixes: 60545466180e ("dt-bindings: mailbox: qcom,apcs-kpss-global: Add syscon const for relevant entries")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---


Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v3 3/6] dt-bindings: mailbox: qcom: correct the list of platforms using clocks

[Dmitry Baryshkov]

Only three platforms require `pll' and `aux' clocks: msm8916, msm8939
and qcs404. Correct the list of platforms in the corresponding clause.

Fixes: 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55 APCS")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 .../mailbox/qcom,apcs-kpss-global.yaml        | 33 ++++++++++++++-----
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
index ecc286ab49ef..7d8de7a16984 100644
--- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
+++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
@@ -72,15 +72,8 @@ allOf:
         compatible:
           enum:
             - qcom,msm8916-apcs-kpss-global
-            - qcom,msm8994-apcs-kpss-global
-            - qcom,msm8996-apcs-hmss-global
-            - qcom,msm8998-apcs-hmss-global
+            - qcom,msm8939-apcs-kpss-global
             - qcom,qcs404-apcs-apps-global
-            - qcom,sc7180-apss-shared
-            - qcom,sdm660-apcs-hmss-global
-            - qcom,sdm845-apss-shared
-            - qcom,sm6125-apcs-hmss-global
-            - qcom,sm8150-apss-shared
     then:
       properties:
         clocks:
@@ -124,6 +117,30 @@ allOf:
           items:
             - const: pll
             - const: xo
+
+  - if:
+      properties:
+        compatible:
+          enum:
+            - qcom,msm8953-apcs-kpss-global
+            - qcom,msm8976-apcs-kpss-global
+            - qcom,msm8994-apcs-kpss-global
+            - qcom,msm8996-apcs-hmss-global
+            - qcom,msm8998-apcs-hmss-global
+            - qcom,qcm2290-apcs-hmss-global
+            - qcom,sc7180-apss-shared
+            - qcom,sc8180x-apss-shared
+            - qcom,sdm660-apcs-hmss-global
+            - qcom,sdm845-apss-shared
+            - qcom,sm4250-apcs-hmss-global
+            - qcom,sm6115-apcs-hmss-global
+            - qcom,sm6125-apcs-hmss-global
+            - qcom,sm8150-apss-shared
+    then:
+      properties:
+        clocks: false
+        clock-names: false
+
   - if:
       properties:
         compatible:
-- 
2.39.0

Re: [PATCH v3 3/6] dt-bindings: mailbox: qcom: correct the list of platforms using clocks

[Krzysztof Kozlowski]

On 17/01/2023 23:30, Dmitry Baryshkov wrote:
> Only three platforms require `pll' and `aux' clocks: msm8916, msm8939
> and qcs404. Correct the list of platforms in the corresponding clause.
> 
> Fixes: 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55 APCS")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>  .../mailbox/qcom,apcs-kpss-global.yaml        | 33 ++++++++++++++-----
>  1 file changed, 25 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
> index ecc286ab49ef..7d8de7a16984 100644
> --- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
> +++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
> @@ -72,15 +72,8 @@ allOf:
>          compatible:
>            enum:
>              - qcom,msm8916-apcs-kpss-global
> -            - qcom,msm8994-apcs-kpss-global
> -            - qcom,msm8996-apcs-hmss-global
> -            - qcom,msm8998-apcs-hmss-global
> +            - qcom,msm8939-apcs-kpss-global
>              - qcom,qcs404-apcs-apps-global
> -            - qcom,sc7180-apss-shared
> -            - qcom,sdm660-apcs-hmss-global
> -            - qcom,sdm845-apss-shared
> -            - qcom,sm6125-apcs-hmss-global
> -            - qcom,sm8150-apss-shared
>      then:
>        properties:
>          clocks:
> @@ -124,6 +117,30 @@ allOf:
>            items:
>              - const: pll
>              - const: xo
> +
> +  - if:
> +      properties:
> +        compatible:
> +          enum:
> +            - qcom,msm8953-apcs-kpss-global
> +            - qcom,msm8976-apcs-kpss-global
> +            - qcom,msm8994-apcs-kpss-global
> +            - qcom,msm8996-apcs-hmss-global
> +            - qcom,msm8998-apcs-hmss-global
> +            - qcom,qcm2290-apcs-hmss-global
> +            - qcom,sc7180-apss-shared
> +            - qcom,sc8180x-apss-shared
> +            - qcom,sdm660-apcs-hmss-global
> +            - qcom,sdm845-apss-shared
> +            - qcom,sm4250-apcs-hmss-global
> +            - qcom,sm6115-apcs-hmss-global
> +            - qcom,sm6125-apcs-hmss-global
> +            - qcom,sm8150-apss-shared

Isn't this in multiple places now? This doesn't match what you remove
either.

Best regards,
Krzysztof

Re: [PATCH v3 3/6] dt-bindings: mailbox: qcom: correct the list of platforms using clocks

[Dmitry Baryshkov]

On 18/01/2023 13:41, Krzysztof Kozlowski wrote:
> On 17/01/2023 23:30, Dmitry Baryshkov wrote:
>> Only three platforms require `pll' and `aux' clocks: msm8916, msm8939
>> and qcs404. Correct the list of platforms in the corresponding clause.
>>
>> Fixes: 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55 APCS")
>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>> ---
>>   .../mailbox/qcom,apcs-kpss-global.yaml        | 33 ++++++++++++++-----
>>   1 file changed, 25 insertions(+), 8 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
>> index ecc286ab49ef..7d8de7a16984 100644
>> --- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
>> +++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
>> @@ -72,15 +72,8 @@ allOf:
>>           compatible:
>>             enum:
>>               - qcom,msm8916-apcs-kpss-global
>> -            - qcom,msm8994-apcs-kpss-global
>> -            - qcom,msm8996-apcs-hmss-global
>> -            - qcom,msm8998-apcs-hmss-global
>> +            - qcom,msm8939-apcs-kpss-global
>>               - qcom,qcs404-apcs-apps-global
>> -            - qcom,sc7180-apss-shared
>> -            - qcom,sdm660-apcs-hmss-global
>> -            - qcom,sdm845-apss-shared
>> -            - qcom,sm6125-apcs-hmss-global
>> -            - qcom,sm8150-apss-shared
>>       then:
>>         properties:
>>           clocks:
>> @@ -124,6 +117,30 @@ allOf:
>>             items:
>>               - const: pll
>>               - const: xo
>> +
>> +  - if:
>> +      properties:
>> +        compatible:
>> +          enum:
>> +            - qcom,msm8953-apcs-kpss-global
>> +            - qcom,msm8976-apcs-kpss-global
>> +            - qcom,msm8994-apcs-kpss-global
>> +            - qcom,msm8996-apcs-hmss-global
>> +            - qcom,msm8998-apcs-hmss-global
>> +            - qcom,qcm2290-apcs-hmss-global
>> +            - qcom,sc7180-apss-shared
>> +            - qcom,sc8180x-apss-shared
>> +            - qcom,sdm660-apcs-hmss-global
>> +            - qcom,sdm845-apss-shared
>> +            - qcom,sm4250-apcs-hmss-global
>> +            - qcom,sm6115-apcs-hmss-global
>> +            - qcom,sm6125-apcs-hmss-global
>> +            - qcom,sm8150-apss-shared
> 
> Isn't this in multiple places now? This doesn't match what you remove
> either.

Yes, I addsd several platforms. I can split this into two patches: one 
moving the platforms and another one adding missing platforms. Would you 
prefer it?

> 
> Best regards,
> Krzysztof
> 

-- 
With best wishes
Dmitry

Re: [PATCH v3 3/6] dt-bindings: mailbox: qcom: correct the list of platforms using clocks

[Krzysztof Kozlowski]

On 18/01/2023 14:04, Dmitry Baryshkov wrote:
> On 18/01/2023 13:41, Krzysztof Kozlowski wrote:
>> On 17/01/2023 23:30, Dmitry Baryshkov wrote:
>>> Only three platforms require `pll' and `aux' clocks: msm8916, msm8939
>>> and qcs404. Correct the list of platforms in the corresponding clause.
>>>
>>> Fixes: 0d17014e9189 ("dt-bindings: mailbox: Add binding for SDX55 APCS")
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
>>> ---
>>>   .../mailbox/qcom,apcs-kpss-global.yaml        | 33 ++++++++++++++-----
>>>   1 file changed, 25 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
>>> index ecc286ab49ef..7d8de7a16984 100644
>>> --- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
>>> +++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
>>> @@ -72,15 +72,8 @@ allOf:
>>>           compatible:
>>>             enum:
>>>               - qcom,msm8916-apcs-kpss-global
>>> -            - qcom,msm8994-apcs-kpss-global
>>> -            - qcom,msm8996-apcs-hmss-global
>>> -            - qcom,msm8998-apcs-hmss-global
>>> +            - qcom,msm8939-apcs-kpss-global
>>>               - qcom,qcs404-apcs-apps-global
>>> -            - qcom,sc7180-apss-shared
>>> -            - qcom,sdm660-apcs-hmss-global
>>> -            - qcom,sdm845-apss-shared
>>> -            - qcom,sm6125-apcs-hmss-global
>>> -            - qcom,sm8150-apss-shared
>>>       then:
>>>         properties:
>>>           clocks:
>>> @@ -124,6 +117,30 @@ allOf:
>>>             items:
>>>               - const: pll
>>>               - const: xo
>>> +
>>> +  - if:
>>> +      properties:
>>> +        compatible:
>>> +          enum:
>>> +            - qcom,msm8953-apcs-kpss-global
>>> +            - qcom,msm8976-apcs-kpss-global
>>> +            - qcom,msm8994-apcs-kpss-global
>>> +            - qcom,msm8996-apcs-hmss-global
>>> +            - qcom,msm8998-apcs-hmss-global
>>> +            - qcom,qcm2290-apcs-hmss-global
>>> +            - qcom,sc7180-apss-shared
>>> +            - qcom,sc8180x-apss-shared
>>> +            - qcom,sdm660-apcs-hmss-global
>>> +            - qcom,sdm845-apss-shared
>>> +            - qcom,sm4250-apcs-hmss-global
>>> +            - qcom,sm6115-apcs-hmss-global
>>> +            - qcom,sm6125-apcs-hmss-global
>>> +            - qcom,sm8150-apss-shared
>>
>> Isn't this in multiple places now? This doesn't match what you remove
>> either.
> 
> Yes, I addsd several platforms. I can split this into two patches: one 
> moving the platforms and another one adding missing platforms. Would you 
> prefer it?

Yes, plus you now duplicated entries, didn't you? As I pointed - some of
them are in multiple places now.

Best regards,
Krzysztof

[PATCH v3 4/6] dt-bindings: mailbox: qcom: add #clock-cells to msm8996 example

[Dmitry Baryshkov]

Add the #clock-cells property to the MSM8996 example, as the APCS block
is going to provide the `sys_apcs_aux' clock to the consumers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 .../devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml       | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
index 7d8de7a16984..1633aa82fc84 100644
--- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
+++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.yaml
@@ -166,6 +166,7 @@ examples:
         reg = <0x9820000 0x1000>;
 
         #mbox-cells = <1>;
+        #clock-cells = <0>;
     };
 
     rpm-glink {
-- 
2.39.0

Re: [PATCH v3 4/6] dt-bindings: mailbox: qcom: add #clock-cells to msm8996 example

[Krzysztof Kozlowski]

On 17/01/2023 23:30, Dmitry Baryshkov wrote:
> Add the #clock-cells property to the MSM8996 example, as the APCS block
> is going to provide the `sys_apcs_aux' clock to the consumers.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

[PATCH v3 5/6] mailbox: qcom-apcs-ipc: enable APCS clock device for MSM8996

[Dmitry Baryshkov]

MSM8996 also has the clock-related part of the APCS mailbox device.
Follow the usual pattern and create a child device to handle these
clocks.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/mailbox/qcom-apcs-ipc-mailbox.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mailbox/qcom-apcs-ipc-mailbox.c b/drivers/mailbox/qcom-apcs-ipc-mailbox.c
index 0e9f9cba8668..bd61dacb44ba 100644
--- a/drivers/mailbox/qcom-apcs-ipc-mailbox.c
+++ b/drivers/mailbox/qcom-apcs-ipc-mailbox.c
@@ -42,7 +42,7 @@ static const struct qcom_apcs_ipc_data msm8994_apcs_data = {
 };
 
 static const struct qcom_apcs_ipc_data msm8996_apcs_data = {
-	.offset = 16, .clk_name = NULL
+	.offset = 16, .clk_name = "qcom-apcs-msm8996-clk"
 };
 
 static const struct qcom_apcs_ipc_data apps_shared_apcs_data = {
-- 
2.39.0

[PATCH v3 6/6] clk: qcom: add the driver for the MSM8996 APCS clocks

[Dmitry Baryshkov]

Add a simple driver handling the APCS clocks on MSM8996. For now it
supports just a single aux clock, linking GPLL0 to CPU and CBF clocks.

Note, there is little sense in registering sys_apcs_aux as a child of
gpll0. The PLL is always-on. And listing the gpll0 as a property of the
apcs would delay its probing until the GCC has been probed (while we
would like for the apcs to be probed as early as possible).

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/clk/qcom/Makefile       |  2 +-
 drivers/clk/qcom/apcs-msm8996.c | 76 +++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/qcom/apcs-msm8996.c

diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index 6c589f671003..98523c48c541 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -52,7 +52,7 @@ obj-$(CONFIG_MSM_MMCC_8998) += mmcc-msm8998.o
 obj-$(CONFIG_QCOM_A53PLL) += a53-pll.o
 obj-$(CONFIG_QCOM_A7PLL) += a7-pll.o
 obj-$(CONFIG_QCOM_CLK_APCS_MSM8916) += apcs-msm8916.o
-obj-$(CONFIG_QCOM_CLK_APCC_MSM8996) += clk-cpu-8996.o
+obj-$(CONFIG_QCOM_CLK_APCC_MSM8996) += apcs-msm8996.o clk-cpu-8996.o
 obj-$(CONFIG_QCOM_CLK_APCS_SDX55) += apcs-sdx55.o
 obj-$(CONFIG_QCOM_CLK_RPM) += clk-rpm.o
 obj-$(CONFIG_QCOM_CLK_RPMH) += clk-rpmh.o
diff --git a/drivers/clk/qcom/apcs-msm8996.c b/drivers/clk/qcom/apcs-msm8996.c
new file mode 100644
index 000000000000..7e46ea8ed444
--- /dev/null
+++ b/drivers/clk/qcom/apcs-msm8996.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Qualcomm APCS clock controller driver
+ *
+ * Copyright (c) 2022, Linaro Limited
+ * Author: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
+ */
+
+#include <linux/bits.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define APCS_AUX_OFFSET	0x50
+
+#define APCS_AUX_DIV_MASK GENMASK(17, 16)
+#define APCS_AUX_DIV_2 0x1
+
+static int qcom_apcs_msm8996_clk_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device *parent = dev->parent;
+	struct regmap *regmap;
+	struct clk_hw *hw;
+	unsigned int val;
+	int ret = -ENODEV;
+
+	regmap = dev_get_regmap(parent, NULL);
+	if (!regmap) {
+		dev_err(dev, "failed to get regmap: %d\n", ret);
+		return ret;
+	}
+
+	regmap_read(regmap, APCS_AUX_OFFSET, &val);
+	regmap_update_bits(regmap, APCS_AUX_OFFSET, APCS_AUX_DIV_MASK,
+			   FIELD_PREP(APCS_AUX_DIV_MASK, APCS_AUX_DIV_2));
+
+	/* Hardware mandated delay */
+	udelay(5);
+
+	/*
+	 * Register the clock as fixed rate instead of being a child of gpll0
+	 * to let the driver register probe as early as possible.
+	 */
+	hw = devm_clk_hw_register_fixed_rate(dev, "sys_apcs_aux", NULL, 0, 300000000);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw);
+}
+
+static struct platform_driver qcom_apcs_msm8996_clk_driver = {
+	.probe = qcom_apcs_msm8996_clk_probe,
+	.driver = {
+		.name = "qcom-apcs-msm8996-clk",
+	},
+};
+
+/* Register early enough to fix the clock to be used for other cores */
+static int __init qcom_apcs_msm8996_clk_init(void)
+{
+	return platform_driver_register(&qcom_apcs_msm8996_clk_driver);
+}
+postcore_initcall(qcom_apcs_msm8996_clk_init);
+
+static void __exit qcom_apcs_msm8996_clk_exit(void)
+{
+	platform_driver_unregister(&qcom_apcs_msm8996_clk_driver);
+}
+module_exit(qcom_apcs_msm8996_clk_exit);
+
+MODULE_AUTHOR("Dmitry Baryshkov <dmitry.baryshkov@linaro.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Qualcomm MSM8996 APCS clock driver");
-- 
2.39.0