[PATCH V2 0/2] Add SDHC interconnect bandwidth scaling

[PATCH V2 0/2] Add SDHC interconnect bandwidth scaling

[Pradeep P V K]

Add interconnect bandwidths for SDHC driver using OPP framework that
is required by SDHC driver based on the clock frequency and bus width
of the card. Otherwise, the system clocks may run at minimum clock
speed and thus affecting the performance.

This change is based on
[1] [Patch v8] Introduce OPP bandwidth bindings
(https://lkml.org/lkml/2020/5/12/493)

[2] [Patch v3 09/17] mmc: sdhci-msm: Fix error handling
for dev_pm_opp_of_add_table()
(https://lkml.org/lkml/2020/5/5/491)

[3] [RFC v6 2/2] dt-bindings: mmc: sdhci-msm: Add interconnect BW
scaling strings
(https://lkml.org/lkml/2020/3/23/409)

as there were no extra changes made on [3], retaining the Acked-by and
Reviewed-by sign-off from [3].

Pradeep P V K (2):
  mmc: sdhci-msm: Add interconnect bandwidth scaling support
  dt-bindings: mmc: sdhci-msm: Add interconnect BW scaling strings

 Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 18 ++++++++++++++++++
 drivers/mmc/host/sdhci-msm.c                        | 13 +++++++++++++
 2 files changed, 31 insertions(+)

-- 
changes since V1:
- Added dev_pm_opp_find_icc_paths() to check for icc paths.

[PATCH V2 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support

[Pradeep P V K]

Interconnect bandwidth scaling support is now added as a
part of OPP [1]. So, make sure interconnect driver is ready
before handling interconnect scaling.

This change is based on
[1] [Patch v8] Introduce OPP bandwidth bindings
(https://lkml.org/lkml/2020/5/12/493)

[2] [Patch v3] mmc: sdhci-msm: Fix error handling
for dev_pm_opp_of_add_table()
(https://lkml.org/lkml/2020/5/5/491)

Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
---
 drivers/mmc/host/sdhci-msm.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index b277dd7..a13ff1b 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/iopoll.h>
 #include <linux/regulator/consumer.h>
+#include <linux/interconnect.h>
 
 #include "sdhci-pltfm.h"
 #include "cqhci.h"
@@ -2070,6 +2071,18 @@ static int sdhci_msm_probe(struct platform_device *pdev)
 	}
 	msm_host->bulk_clks[0].clk = clk;
 
+	/* Make sure that ICC driver is ready for interconnect bandwdith
+	 * scaling before registering the device for OPP.
+	 */
+	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
+	if (ret) {
+		if (ret == -EPROBE_DEFER)
+			dev_info(&pdev->dev, "defer icc path: %d\n", ret);
+		else
+			dev_err(&pdev->dev, "failed to get icc path:%d\n", ret);
+		goto bus_clk_disable;
+	}
+
 	msm_host->opp_table = dev_pm_opp_set_clkname(&pdev->dev, "core");
 	if (IS_ERR(msm_host->opp_table)) {
 		ret = PTR_ERR(msm_host->opp_table);
-- 
1.9.1

Re: [PATCH V2 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support

[Matthias Kaehlcke]

On Thu, Jun 04, 2020 at 04:44:42PM +0530, Pradeep P V K wrote:
> Interconnect bandwidth scaling support is now added as a
> part of OPP [1]. So, make sure interconnect driver is ready
> before handling interconnect scaling.
> 
> This change is based on
> [1] [Patch v8] Introduce OPP bandwidth bindings
> (https://lkml.org/lkml/2020/5/12/493)
> 
> [2] [Patch v3] mmc: sdhci-msm: Fix error handling
> for dev_pm_opp_of_add_table()
> (https://lkml.org/lkml/2020/5/5/491)
> 
> Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
> ---
>  drivers/mmc/host/sdhci-msm.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index b277dd7..a13ff1b 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -14,6 +14,7 @@
>  #include <linux/slab.h>
>  #include <linux/iopoll.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/interconnect.h>
>  
>  #include "sdhci-pltfm.h"
>  #include "cqhci.h"
> @@ -2070,6 +2071,18 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>  	}
>  	msm_host->bulk_clks[0].clk = clk;
>  
> +	/* Make sure that ICC driver is ready for interconnect bandwdith
> +	 * scaling before registering the device for OPP.
> +	 */
> +	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
> +	if (ret) {
> +		if (ret == -EPROBE_DEFER)
> +			dev_info(&pdev->dev, "defer icc path: %d\n", ret);

I already commented on this on v1:

  This log seems to add little more than noise, or are there particular reasons
  why it is useful in this driver? Most drivers just return silently in case of
  deferred probing.

If you think the log is really needed please explain why.

Re: [PATCH V2 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support

[Sibi Sankar]

On 2020-06-04 22:39, Matthias Kaehlcke wrote:
> On Thu, Jun 04, 2020 at 04:44:42PM +0530, Pradeep P V K wrote:
>> Interconnect bandwidth scaling support is now added as a
>> part of OPP [1]. So, make sure interconnect driver is ready
>> before handling interconnect scaling.
>> 
>> This change is based on
>> [1] [Patch v8] Introduce OPP bandwidth bindings
>> (https://lkml.org/lkml/2020/5/12/493)
>> 
>> [2] [Patch v3] mmc: sdhci-msm: Fix error handling
>> for dev_pm_opp_of_add_table()
>> (https://lkml.org/lkml/2020/5/5/491)
>> 
>> Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
>> ---
>>  drivers/mmc/host/sdhci-msm.c | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>> 
>> diff --git a/drivers/mmc/host/sdhci-msm.c 
>> b/drivers/mmc/host/sdhci-msm.c
>> index b277dd7..a13ff1b 100644
>> --- a/drivers/mmc/host/sdhci-msm.c
>> +++ b/drivers/mmc/host/sdhci-msm.c
>> @@ -14,6 +14,7 @@
>>  #include <linux/slab.h>
>>  #include <linux/iopoll.h>
>>  #include <linux/regulator/consumer.h>
>> +#include <linux/interconnect.h>
>> 
>>  #include "sdhci-pltfm.h"
>>  #include "cqhci.h"
>> @@ -2070,6 +2071,18 @@ static int sdhci_msm_probe(struct 
>> platform_device *pdev)
>>  	}
>>  	msm_host->bulk_clks[0].clk = clk;
>> 
>> +	/* Make sure that ICC driver is ready for interconnect bandwdith
>> +	 * scaling before registering the device for OPP.
>> +	 */
>> +	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
>> +	if (ret) {
>> +		if (ret == -EPROBE_DEFER)
>> +			dev_info(&pdev->dev, "defer icc path: %d\n", ret);
> 
> I already commented on this on v1:
> 
>   This log seems to add little more than noise, or are there particular 
> reasons
>   why it is useful in this driver? Most drivers just return silently in 
> case of
>   deferred probing.
> 
> If you think the log is really needed please explain why.

Both the err logs seem redundant.
EPROBE_DEFERS are rather readily
noticeable through the return val.
dev_.._find_icc_paths already prints
err messages when we fail to get icc
paths.


-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.

Re: [PATCH V2 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support

[ppvk]

On 2020-06-05 00:04, Sibi Sankar wrote:
> On 2020-06-04 22:39, Matthias Kaehlcke wrote:
>> On Thu, Jun 04, 2020 at 04:44:42PM +0530, Pradeep P V K wrote:
>>> Interconnect bandwidth scaling support is now added as a
>>> part of OPP [1]. So, make sure interconnect driver is ready
>>> before handling interconnect scaling.
>>> 
>>> This change is based on
>>> [1] [Patch v8] Introduce OPP bandwidth bindings
>>> (https://lkml.org/lkml/2020/5/12/493)
>>> 
>>> [2] [Patch v3] mmc: sdhci-msm: Fix error handling
>>> for dev_pm_opp_of_add_table()
>>> (https://lkml.org/lkml/2020/5/5/491)
>>> 
>>> Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
>>> ---
>>>  drivers/mmc/host/sdhci-msm.c | 13 +++++++++++++
>>>  1 file changed, 13 insertions(+)
>>> 
>>> diff --git a/drivers/mmc/host/sdhci-msm.c 
>>> b/drivers/mmc/host/sdhci-msm.c
>>> index b277dd7..a13ff1b 100644
>>> --- a/drivers/mmc/host/sdhci-msm.c
>>> +++ b/drivers/mmc/host/sdhci-msm.c
>>> @@ -14,6 +14,7 @@
>>>  #include <linux/slab.h>
>>>  #include <linux/iopoll.h>
>>>  #include <linux/regulator/consumer.h>
>>> +#include <linux/interconnect.h>
>>> 
>>>  #include "sdhci-pltfm.h"
>>>  #include "cqhci.h"
>>> @@ -2070,6 +2071,18 @@ static int sdhci_msm_probe(struct 
>>> platform_device *pdev)
>>>  	}
>>>  	msm_host->bulk_clks[0].clk = clk;
>>> 
>>> +	/* Make sure that ICC driver is ready for interconnect bandwdith
>>> +	 * scaling before registering the device for OPP.
>>> +	 */
>>> +	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
>>> +	if (ret) {
>>> +		if (ret == -EPROBE_DEFER)
>>> +			dev_info(&pdev->dev, "defer icc path: %d\n", ret);
>> 
>> I already commented on this on v1:
>> 
>>   This log seems to add little more than noise, or are there 
>> particular reasons
>>   why it is useful in this driver? Most drivers just return silently 
>> in case of
>>   deferred probing.
>> 
>> If you think the log is really needed please explain why.
> 
Sorry. i forget to remove this print on V2. i will address this in my 
next patch set.

> Both the err logs seem redundant.
> EPROBE_DEFERS are rather readily
> noticeable through the return val.
> dev_.._find_icc_paths already prints
> err messages when we fail to get icc
> paths.

True. i will remove this too in my next patch set.

[PATCH V2 2/2] dt-bindings: mmc: sdhci-msm: Add interconnect BW scaling strings

[Pradeep P V K]

Add interconnect bandwidth scaling supported strings for qcom-sdhci
controller.

Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
index b8e1d2b..3b602fd 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
+++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
@@ -54,6 +54,21 @@ Required properties:
 - qcom,dll-config: Chipset and Platform specific value. Use this field to
 	specify the DLL_CONFIG register value as per Hardware Programming Guide.
 
+Optional Properties:
+* Following bus parameters are required for interconnect bandwidth scaling:
+- interconnects: Pairs of phandles and interconnect provider specifier
+		 to denote the edge source and destination ports of
+		 the interconnect path.
+
+- interconnect-names: For sdhc, we have two main paths.
+		1. Data path : sdhc to ddr
+		2. Config path : cpu to sdhc
+		For Data interconnect path the name supposed to be
+		is "sdhc-ddr" and for config interconnect path it is
+		"cpu-sdhc".
+		Please refer to Documentation/devicetree/bindings/
+		interconnect/ for more details.
+
 Example:
 
 	sdhc_1: sdhci@f9824900 {
@@ -71,6 +86,9 @@ Example:
 
 		clocks = <&gcc GCC_SDCC1_APPS_CLK>, <&gcc GCC_SDCC1_AHB_CLK>;
 		clock-names = "core", "iface";
+		interconnects = <&qnoc MASTER_SDCC_ID &qnoc SLAVE_DDR_ID>,
+				<&qnoc MASTER_CPU_ID &qnoc SLAVE_SDCC_ID>;
+		interconnect-names = "sdhc-ddr","cpu-sdhc";
 
 		qcom,dll-config = <0x000f642c>;
 		qcom,ddr-config = <0x80040868>;
-- 
1.9.1

=?y?q?=5BPATCH=C2=A0V3=200/2=5D=20Add=20SDHC=20interconnect=20bandwidth=20scaling=20?=

[Pradeep P V K]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=y, Size: 1200 bytes --]


Add interconnect bandwidths for SDHC driver using OPP framework that
is required by SDHC driver based on the clock frequency and bus width
of the card. Otherwise, the system clocks may run at minimum clock
speed and thus affecting the performance.

This change is based on
[1] [Patch v8] Introduce OPP bandwidth bindings
(https://lkml.org/lkml/2020/5/12/493)

[2] [Patch v3 09/17] mmc: sdhci-msm: Fix error handling
for dev_pm_opp_of_add_table()
(https://lkml.org/lkml/2020/5/5/491)

[3] [RFC v6 2/2] dt-bindings: mmc: sdhci-msm: Add interconnect BW
scaling strings
(https://lkml.org/lkml/2020/3/23/409)

as there were no extra changes made on [3], retaining the Acked-by and
Reviewed-by sign-off from [3].

Changes since V2:
- Removed debug error prints on icc path ready check.

changes since V1:
- Added dev_pm_opp_find_icc_paths() to check for icc paths.

Pradeep P V K (2):
  mmc: sdhci-msm: Add interconnect bandwidth scaling support
  dt-bindings: mmc: sdhci-msm: Add interconnect BW scaling strings

 Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 18 ++++++++++++++++++
 drivers/mmc/host/sdhci-msm.c                        |  8 ++++++++
 2 files changed, 26 insertions(+)

-- 
1.9.1

=?y?q?=5BPATCH=C2=A0V3=201/2=5D=20mmc=3A=20sdhci-msm=3A=20Add=20interconnect=20bandwidth=20scaling=20support?=

[Pradeep P V K]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=y, Size: 1376 bytes --]

Interconnect bandwidth scaling support is now added as a
part of OPP [1]. So, make sure interconnect driver is ready
before handling interconnect scaling.

This change is based on
[1] [Patch v8] Introduce OPP bandwidth bindings
(https://lkml.org/lkml/2020/5/12/493)

[2] [Patch v3] mmc: sdhci-msm: Fix error handling
for dev_pm_opp_of_add_table()
(https://lkml.org/lkml/2020/5/5/491)

Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
---
 drivers/mmc/host/sdhci-msm.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index b277dd7..a945e84 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/iopoll.h>
 #include <linux/regulator/consumer.h>
+#include <linux/interconnect.h>
 
 #include "sdhci-pltfm.h"
 #include "cqhci.h"
@@ -2070,6 +2071,13 @@ static int sdhci_msm_probe(struct platform_device *pdev)
 	}
 	msm_host->bulk_clks[0].clk = clk;
 
+	/* Make sure that ICC driver is ready for interconnect bandwdith
+	 * scaling before registering the device for OPP.
+	 */
+	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
+	if (ret)
+		goto bus_clk_disable;
+
 	msm_host->opp_table = dev_pm_opp_set_clkname(&pdev->dev, "core");
 	if (IS_ERR(msm_host->opp_table)) {
 		ret = PTR_ERR(msm_host->opp_table);
-- 
1.9.1

Re: [PATCH V3 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support

[Sibi Sankar]

Hey Pradeep,
Thanks for the patch.

On 2020-06-05 15:00, Pradeep P V K wrote:
> Interconnect bandwidth scaling support is now added as a
> part of OPP [1]. So, make sure interconnect driver is ready

can you please replace driver with paths
instead?

> before handling interconnect scaling.
> 
> This change is based on
> [1] [Patch v8] Introduce OPP bandwidth bindings
> (https://lkml.org/lkml/2020/5/12/493)
> 
> [2] [Patch v3] mmc: sdhci-msm: Fix error handling
> for dev_pm_opp_of_add_table()
> (https://lkml.org/lkml/2020/5/5/491)

sry didn't notice ^^ earlier
you might want to place these
comments and dependencies similar
to the following patch.
https://patchwork.kernel.org/patch/11573903/

> 
> Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
> ---
>  drivers/mmc/host/sdhci-msm.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-msm.c 
> b/drivers/mmc/host/sdhci-msm.c
> index b277dd7..a945e84 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -14,6 +14,7 @@
>  #include <linux/slab.h>
>  #include <linux/iopoll.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/interconnect.h>
> 
>  #include "sdhci-pltfm.h"
>  #include "cqhci.h"
> @@ -2070,6 +2071,13 @@ static int sdhci_msm_probe(struct 
> platform_device *pdev)
>  	}
>  	msm_host->bulk_clks[0].clk = clk;
> 
> +	/* Make sure that ICC driver is ready for interconnect bandwdith

typo /s/bandwdith/bandwidth

> +	 * scaling before registering the device for OPP.
> +	 */

/* Check for optional interconnect paths */
Maybe using ^^ would suffice since
that's what we are actually doing

Reviewed-by: Sibi Sankar <sibis@codeaurora.org>

> +	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
> +	if (ret)
> +		goto bus_clk_disable;
> +
>  	msm_host->opp_table = dev_pm_opp_set_clkname(&pdev->dev, "core");
>  	if (IS_ERR(msm_host->opp_table)) {
>  		ret = PTR_ERR(msm_host->opp_table);


-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.

Re: [PATCH V3 1/2] mmc: sdhci-msm: Add interconnect bandwidth scaling support

[ppvk]

Hi Sibi,

Thanks for the review.

On 2020-06-05 17:10, Sibi Sankar wrote:
> Hey Pradeep,
> Thanks for the patch.
> 
> On 2020-06-05 15:00, Pradeep P V K wrote:
>> Interconnect bandwidth scaling support is now added as a
>> part of OPP [1]. So, make sure interconnect driver is ready
> 
> can you please replace driver with paths
> instead?
> 
ok. I will address this in my next patch set.

>> before handling interconnect scaling.
>> 
>> This change is based on
>> [1] [Patch v8] Introduce OPP bandwidth bindings
>> (https://lkml.org/lkml/2020/5/12/493)
>> 
>> [2] [Patch v3] mmc: sdhci-msm: Fix error handling
>> for dev_pm_opp_of_add_table()
>> (https://lkml.org/lkml/2020/5/5/491)
> 
> sry didn't notice ^^ earlier
> you might want to place these
> comments and dependencies similar
> to the following patch.
> https://patchwork.kernel.org/patch/11573903/
> 
ok. will modify in my next patch.

>> 
>> Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
>> ---
>>  drivers/mmc/host/sdhci-msm.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>> 
>> diff --git a/drivers/mmc/host/sdhci-msm.c 
>> b/drivers/mmc/host/sdhci-msm.c
>> index b277dd7..a945e84 100644
>> --- a/drivers/mmc/host/sdhci-msm.c
>> +++ b/drivers/mmc/host/sdhci-msm.c
>> @@ -14,6 +14,7 @@
>>  #include <linux/slab.h>
>>  #include <linux/iopoll.h>
>>  #include <linux/regulator/consumer.h>
>> +#include <linux/interconnect.h>
>> 
>>  #include "sdhci-pltfm.h"
>>  #include "cqhci.h"
>> @@ -2070,6 +2071,13 @@ static int sdhci_msm_probe(struct 
>> platform_device *pdev)
>>  	}
>>  	msm_host->bulk_clks[0].clk = clk;
>> 
>> +	/* Make sure that ICC driver is ready for interconnect bandwdith
> 
> typo /s/bandwdith/bandwidth
> 
>> +	 * scaling before registering the device for OPP.
>> +	 */
> 
> /* Check for optional interconnect paths */
> Maybe using ^^ would suffice since
> that's what we are actually doing
> 
sure. i will re-modify the comments as suggested ^^ in my next patch.

> Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
> 
>> +	ret = dev_pm_opp_of_find_icc_paths(&pdev->dev, NULL);
>> +	if (ret)
>> +		goto bus_clk_disable;
>> +
>>  	msm_host->opp_table = dev_pm_opp_set_clkname(&pdev->dev, "core");
>>  	if (IS_ERR(msm_host->opp_table)) {
>>  		ret = PTR_ERR(msm_host->opp_table);

=?y?q?=5BPATCH=C2=A0V3=202/2=5D=20dt-bindings=3A=20mmc=3A=20sdhci-msm=3A=20Add=20interconnect=20BW=20scaling=20strings?=

[Pradeep P V K]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=y, Size: 1800 bytes --]

Add interconnect bandwidth scaling supported strings for qcom-sdhci
controller.

Signed-off-by: Pradeep P V K <ppvk@codeaurora.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
index b8e1d2b..3b602fd 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
+++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
@@ -54,6 +54,21 @@ Required properties:
 - qcom,dll-config: Chipset and Platform specific value. Use this field to
 	specify the DLL_CONFIG register value as per Hardware Programming Guide.
 
+Optional Properties:
+* Following bus parameters are required for interconnect bandwidth scaling:
+- interconnects: Pairs of phandles and interconnect provider specifier
+		 to denote the edge source and destination ports of
+		 the interconnect path.
+
+- interconnect-names: For sdhc, we have two main paths.
+		1. Data path : sdhc to ddr
+		2. Config path : cpu to sdhc
+		For Data interconnect path the name supposed to be
+		is "sdhc-ddr" and for config interconnect path it is
+		"cpu-sdhc".
+		Please refer to Documentation/devicetree/bindings/
+		interconnect/ for more details.
+
 Example:
 
 	sdhc_1: sdhci@f9824900 {
@@ -71,6 +86,9 @@ Example:
 
 		clocks = <&gcc GCC_SDCC1_APPS_CLK>, <&gcc GCC_SDCC1_AHB_CLK>;
 		clock-names = "core", "iface";
+		interconnects = <&qnoc MASTER_SDCC_ID &qnoc SLAVE_DDR_ID>,
+				<&qnoc MASTER_CPU_ID &qnoc SLAVE_SDCC_ID>;
+		interconnect-names = "sdhc-ddr","cpu-sdhc";
 
 		qcom,dll-config = <0x000f642c>;
 		qcom,ddr-config = <0x80040868>;
-- 
1.9.1