[PATCH v3 0/2] Add LPASS VA CSR HeartBeat pulse clock support

[PATCH v3 0/2] Add LPASS VA CSR HeartBeat pulse clock support

[Sarath Ganapathiraju]

The LPASS VA CSR block contains rate generator hardware that produces
a HeartBeat Pulse (also known as RateGen Pulse). This pulse
synchronizes the start of the DMAs and Codec Interfaces for the audio
usecases and can serve as a periodic wakeup source for the DSP.

This series adds the DT binding and driver support to model this
rate generator as a clock provider.

Patch 1 adds the YAML binding for the new qcom,hawi-lpass-va-csr
clock provider node under Documentation/devicetree/bindings/clock/.

Patch 2 adds the lpass-va-csr driver under drivers/clk/qcom that
registers the lpass_heartbeat_pulse clock and enables/disables the
rate generator via regmap when the clock consumer requests it.

Signed-off-by: Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>
---
Changes in v3:
- Moved the qcom,lpass-va-csr binding from
  Documentation/devicetree/bindings/sound/ to
  Documentation/devicetree/bindings/clock/ since it is a pure clock
  provider with no ASoC dependency (Krzysztof).
- Moved the driver from sound/soc/codecs/ to drivers/clk/qcom/ for
  the same reason; sound/soc/codecs/Kconfig now selects
  QCOM_CLK_LPASS_VA_CSR instead of carrying the driver (Krzysztof).
- Rewrote the binding description to explain the hardware instead of
  duplicating schema text (Krzysztof).
- Dropped redundant reg and "#clock-cells" descriptions from the
  binding (Krzysztof).
- Switched from unevaluatedProperties to additionalProperties: false
  in the binding (Krzysztof).
- Renamed the example node to the generic clock-controller@7ee0000
  (Krzysztof).
- Dropped the qcom,lpass-va-macro binding extension patch — no
  in-tree user yet; will be resubmitted with the hawi DTSI changes.
- Link to v2: https://lore.kernel.org/linux-arm-msm/20260717-master-v2-0-ae200627ad62@oss.qualcomm.com/


Sarath Ganapathiraju (2):
  dt-bindings: clock: qcom: Add LPASS VA CSR HeartBeat pulse clock
  clk: qcom: Add LPASS VA CSR heartbeat pulse clock

 .../bindings/clock/qcom,lpass-va-csr.yaml     |  49 ++++++
 drivers/clk/qcom/Kconfig                      |  12 ++
 drivers/clk/qcom/Makefile                     |   1 +
 drivers/clk/qcom/lpass-va-csr.c               | 143 ++++++++++++++++++
 sound/soc/codecs/Kconfig                      |   1 +
 5 files changed, 206 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/qcom,lpass-va-csr.yaml
 create mode 100644 drivers/clk/qcom/lpass-va-csr.c

-- 
2.34.1

[PATCH v3 0/2] Add LPASS VA CSR HeartBeat pulse clock support

[Sarath Ganapathiraju via B4 Relay]

The LPASS VA CSR block contains rate generator hardware that produces
a HeartBeat Pulse (also known as RateGen Pulse). This pulse
synchronizes the start of the DMAs and Codec Interfaces for the audio
usecases and can serve as a periodic wakeup source for the DSP.

This series adds the DT binding and driver support to model this
rate generator as a clock provider.

Patch 1 adds the YAML binding for the new qcom,hawi-lpass-va-csr
clock provider node under Documentation/devicetree/bindings/clock/.

Patch 2 adds the lpass-va-csr driver under drivers/clk/qcom that
registers the lpass_heartbeat_pulse clock and enables/disables the
rate generator via regmap when the clock consumer requests it.

Changes in v3:
- Moved the qcom,lpass-va-csr binding from
  Documentation/devicetree/bindings/sound/ to
  Documentation/devicetree/bindings/clock/ since it is a pure clock
  provider with no ASoC dependency (Krzysztof).
- Moved the driver from sound/soc/codecs/ to drivers/clk/qcom/ for
  the same reason; sound/soc/codecs/Kconfig now selects
  QCOM_CLK_LPASS_VA_CSR instead of carrying the driver (Krzysztof).
- Rewrote the binding description to explain the hardware instead of
  duplicating schema text (Krzysztof).
- Dropped redundant reg and "#clock-cells" descriptions from the
  binding (Krzysztof).
- Switched from unevaluatedProperties to additionalProperties: false
  in the binding (Krzysztof).
- Renamed the example node to the generic clock-controller@7ee0000
  (Krzysztof).
- Dropped the qcom,lpass-va-macro binding extension patch — no
  in-tree user yet; will be resubmitted with the hawi DTSI changes.
- Link to v2: https://lore.kernel.org/linux-arm-msm/20260717-master-v2-0-ae200627ad62@oss.qualcomm.com/

---
To: Bjorn Andersson <andersson@kernel.org>
To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Brian Masney <bmasney@redhat.com>
To: Rob Herring <robh@kernel.org>
To: Krzysztof Kozlowski <krzk+dt@kernel.org>
To: Conor Dooley <conor+dt@kernel.org>
To: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
To: Liam Girdwood <lgirdwood@gmail.com>
To: Mark Brown <broonie@kernel.org>
To: Jaroslav Kysela <perex@perex.cz>
To: Takashi Iwai <tiwai@suse.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-sound@vger.kernel.org
Cc: prasad.kumpatla@oss.qualcomm.com
Cc: konrad.dybcio@oss.qualcomm.com

---
Sarath Ganapathiraju (2):
      dt-bindings: clock: qcom: Add LPASS VA CSR HeartBeat pulse clock
      clk: qcom: Add LPASS VA CSR heartbeat pulse clock

 .../bindings/clock/qcom,lpass-va-csr.yaml          |  49 +++++++
 drivers/clk/qcom/Kconfig                           |  12 ++
 drivers/clk/qcom/Makefile                          |   1 +
 drivers/clk/qcom/lpass-va-csr.c                    | 143 +++++++++++++++++++++
 sound/soc/codecs/Kconfig                           |   1 +
 5 files changed, 206 insertions(+)
---
base-commit: a6092686b891422f5ba0106b5e0962aecd480b05
change-id: 20260722-master-5651ff5cd8f9

Best regards,
--  
Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>

[PATCH v3 1/2] dt-bindings: clock: qcom: Add LPASS VA CSR HeartBeat pulse clock

[Sarath Ganapathiraju via B4 Relay]

From: Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>

Add a binding for the Qualcomm LPASS VA CSR rate generator node that
exposes the lpass_heartbeat_pulse clock on hawi.

The HeartBeat Pulse (also known as RateGen Pulse) synchronizes the
start of the DMAs and Codec Interfaces for the audio usecase and can
serve as a periodic wakeup source for the DSP.

Signed-off-by: Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>
---
 .../bindings/clock/qcom,lpass-va-csr.yaml          | 49 ++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/qcom,lpass-va-csr.yaml b/Documentation/devicetree/bindings/clock/qcom,lpass-va-csr.yaml
new file mode 100644
index 000000000000..b4bc33a86640
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/qcom,lpass-va-csr.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/qcom,lpass-va-csr.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm LPASS VA CSR heartbeat pulse clock provider
+
+maintainers:
+  - Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
+  - Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>
+
+description:
+  The LPASS (Low Power Audio Subsystem) VA CSR block contains a rate
+  generator that produces a periodic HeartBeat Pulse, also known as
+  the RateGen Pulse. This pulse synchronizes the start of DMAs and
+  Codec Interfaces for audio usecases and can serve as a periodic
+  wakeup source for the DSP.
+
+properties:
+  compatible:
+    enum:
+      - qcom,hawi-lpass-va-csr
+
+  reg:
+    maxItems: 1
+
+  "#clock-cells":
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - "#clock-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+
+      clock-controller@7ee0000 {
+        compatible = "qcom,hawi-lpass-va-csr";
+        reg = <0x0 0x07ee0000 0x0 0xe000>;
+        #clock-cells = <0>;
+      };
+    };

-- 
2.34.1

[PATCH v3 2/2] clk: qcom: Add LPASS VA CSR heartbeat pulse clock

[Sarath Ganapathiraju via B4 Relay]

From: Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>

The HeartBeat Pulse (also known as RateGen Pulse) synchronizes the
start of the DMAs and Codec Interfaces for the audio usecases and
can serve as a periodic wakeup source for the DSP.

Add the LPASS VA CSR driver that models the rate generator as a clock
provider so it is enabled and disabled automatically alongside the
other clocks during runtime PM resume and suspend.

Signed-off-by: Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>
---
 drivers/clk/qcom/Kconfig        |  12 ++++
 drivers/clk/qcom/Makefile       |   1 +
 drivers/clk/qcom/lpass-va-csr.c | 143 ++++++++++++++++++++++++++++++++++++++++
 sound/soc/codecs/Kconfig        |   1 +
 4 files changed, 157 insertions(+)

diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index 63f271aff177..6ebdccfe37e0 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -1998,6 +1998,18 @@ config CLK_GFM_LPASS_SM8250
 	  Support for the Glitch Free Mux (GFM) Low power audio
           subsystem (LPASS) clocks found on SM8250 SoCs.
 
+config QCOM_CLK_LPASS_VA_CSR
+	tristate "Qualcomm LPASS VA CSR heartbeat pulse clock provider"
+	depends on COMMON_CLK
+	select REGMAP_MMIO
+	help
+	  Qualcomm LPASS VA CSR block contains the rate generator hardware
+	  that produces the HeartBeat Pulse (also known as RateGen Pulse).
+	  This driver models the rate generator as a clock provider so
+	  that consumers can enable or disable it via the common clock
+	  framework, and it can be used to synchronize the start of DMAs
+	  and Codec Interfaces or as a periodic wakeup source for the DSP.
+
 config SM_VIDEOCC_8450
 	tristate "SM8450 Video Clock Controller"
 	depends on ARM64 || COMPILE_TEST
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index db7689ee5dc6..2be7da737eba 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_CLK_ELIZA_DISPCC) += dispcc-eliza.o
 obj-$(CONFIG_CLK_ELIZA_GCC) += gcc-eliza.o
 obj-$(CONFIG_CLK_ELIZA_TCSRCC) += tcsrcc-eliza.o
 obj-$(CONFIG_CLK_GFM_LPASS_SM8250) += lpass-gfm-sm8250.o
+obj-$(CONFIG_QCOM_CLK_LPASS_VA_CSR) += lpass-va-csr.o
 obj-$(CONFIG_CLK_GLYMUR_CAMCC) += camcc-glymur.o
 obj-$(CONFIG_CLK_GLYMUR_DISPCC) += dispcc-glymur.o
 obj-$(CONFIG_CLK_GLYMUR_EVACC) += evacc-glymur.o
diff --git a/drivers/clk/qcom/lpass-va-csr.c b/drivers/clk/qcom/lpass-va-csr.c
new file mode 100644
index 000000000000..1d0805789e25
--- /dev/null
+++ b/drivers/clk/qcom/lpass-va-csr.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of_clk.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define LPASS_RATE_GEN_CTRL		0xd000
+#define LPASS_RATE_GEN_COUNTER_0	0xd004
+#define LPASS_RATE_GEN_DELAY		0xd010
+
+#define LPASS_RATE_GEN_MAX_REG		LPASS_RATE_GEN_DELAY
+
+#define LPASS_RG_CTRL_EN		BIT(0)
+
+struct lpass_va_csr_data {
+	u32 counter_0;
+	u32 delay;
+};
+
+static const struct lpass_va_csr_data hawi_csr_data = {
+	.counter_0 = 0x960,
+	.delay = 0x16,
+};
+
+static const struct regmap_config lpass_rate_gen_regmap_config = {
+	.name = "lpass_rate_gen",
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = LPASS_RATE_GEN_MAX_REG,
+	.cache_type = REGCACHE_MAPLE,
+};
+
+struct lpass_va_csr {
+	struct regmap *regmap;
+	const struct lpass_va_csr_data *data;
+	struct clk_hw hb_hw;
+};
+
+#define to_lpass_va_csr(_hw) container_of(_hw, struct lpass_va_csr, hb_hw)
+
+static int heartbeat_pulse_prepare(struct clk_hw *hw)
+{
+	struct lpass_va_csr *csr = to_lpass_va_csr(hw);
+	int ret;
+
+	ret = regmap_write(csr->regmap, LPASS_RATE_GEN_COUNTER_0, csr->data->counter_0);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(csr->regmap, LPASS_RATE_GEN_DELAY, csr->data->delay);
+	if (ret)
+		return ret;
+
+	return regmap_set_bits(csr->regmap, LPASS_RATE_GEN_CTRL, LPASS_RG_CTRL_EN);
+}
+
+static void heartbeat_pulse_unprepare(struct clk_hw *hw)
+{
+	struct lpass_va_csr *csr = to_lpass_va_csr(hw);
+
+	regmap_clear_bits(csr->regmap, LPASS_RATE_GEN_CTRL, LPASS_RG_CTRL_EN);
+}
+
+static int heartbeat_pulse_is_prepared(struct clk_hw *hw)
+{
+	struct lpass_va_csr *csr = to_lpass_va_csr(hw);
+
+	return regmap_test_bits(csr->regmap, LPASS_RATE_GEN_CTRL, LPASS_RG_CTRL_EN);
+}
+
+static const struct clk_ops heartbeat_pulse_ops = {
+	.prepare = heartbeat_pulse_prepare,
+	.unprepare = heartbeat_pulse_unprepare,
+	.is_prepared = heartbeat_pulse_is_prepared,
+};
+
+static int lpass_va_csr_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct lpass_va_csr *csr;
+	struct clk_init_data init = {
+		.name = "lpass_heartbeat_pulse",
+		.ops = &heartbeat_pulse_ops,
+	};
+	void __iomem *base;
+	int ret;
+
+	csr = devm_kzalloc(dev, sizeof(*csr), GFP_KERNEL);
+	if (!csr)
+		return -ENOMEM;
+
+	csr->data = of_device_get_match_data(dev);
+	if (!csr->data)
+		return dev_err_probe(dev, -EINVAL, "no variant data for compatible\n");
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	csr->regmap = devm_regmap_init_mmio(dev, base,
+					    &lpass_rate_gen_regmap_config);
+	if (IS_ERR(csr->regmap))
+		return dev_err_probe(dev, PTR_ERR(csr->regmap),
+				     "failed to init regmap\n");
+
+	csr->hb_hw.init = &init;
+
+	ret = devm_clk_hw_register(dev, &csr->hb_hw);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register heartbeat clock\n");
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, &csr->hb_hw);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to add clock provider\n");
+
+	return 0;
+}
+
+static const struct of_device_id lpass_va_csr_dt_match[] = {
+	{ .compatible = "qcom,hawi-lpass-va-csr", .data = &hawi_csr_data },
+	{}
+};
+MODULE_DEVICE_TABLE(of, lpass_va_csr_dt_match);
+
+static struct platform_driver lpass_va_csr_driver = {
+	.driver = {
+		.name = "qcom-lpass-va-csr",
+		.of_match_table = lpass_va_csr_dt_match,
+	},
+	.probe = lpass_va_csr_probe,
+};
+
+module_platform_driver(lpass_va_csr_driver);
+
+MODULE_DESCRIPTION("Qualcomm LPASS VA CSR heartbeat pulse clock provider");
+MODULE_LICENSE("GPL");
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 76e90144ea91..704401faa147 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -2907,6 +2907,7 @@ config SND_SOC_LPASS_VA_MACRO
 	depends on PM_CLK
 	select REGMAP_MMIO
 	select SND_SOC_LPASS_MACRO_COMMON
+	select QCOM_CLK_LPASS_VA_CSR
 	tristate "Qualcomm VA Macro in LPASS(Low Power Audio SubSystem)"
 
 config SND_SOC_LPASS_RX_MACRO

-- 
2.34.1

Re: [PATCH v3 2/2] clk: qcom: Add LPASS VA CSR heartbeat pulse clock

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Missing PM runtime enablement in lpass-va-csr causes a synchronous external abort when CCF reads the hardware state.
--

--- Patch [2]: [PATCH v3 2/2] clk: qcom: Add LPASS VA CSR heartbeat pulse clock ---
commit f6c6796cc5343493b52dddf79a9e09e549136b51
Author: Sarath Ganapathiraju <sarath.ganapathiraju@oss.qualcomm.com>

clk: qcom: Add LPASS VA CSR heartbeat pulse clock

Adds the LPASS VA CSR driver to model the rate generator as a clock provider.
This synchronizes the start of DMAs and Codec Interfaces and can serve as a
periodic wakeup source for the DSP.

> diff --git a/drivers/clk/qcom/lpass-va-csr.c b/drivers/clk/qcom/lpass-va-csr.c
> new file mode 100644
> index 0000000000000..1d0805789e25a
> --- /dev/null
> +++ b/drivers/clk/qcom/lpass-va-csr.c

[ ... ]

> +static int heartbeat_pulse_is_prepared(struct clk_hw *hw)
> +{
> +	struct lpass_va_csr *csr = to_lpass_va_csr(hw);
> +
> +	return regmap_test_bits(csr->regmap, LPASS_RATE_GEN_CTRL, LPASS_RG_CTRL_EN);

[Severity: High]
Could this MMIO read cause a synchronous external abort?

When CCF calls the .is_prepared callback (e.g., during late boot via
clk_disable_unused() or a debugfs read from clk_summary), this executes an
unprotected MMIO read. If the LPASS hardware is power-gated at this time, the
unpowered access can crash the system.

> +}

[ ... ]

> +static int lpass_va_csr_probe(struct platform_device *pdev)
> +{

[ ... ]

> +	csr->hb_hw.init = &init;
> +
> +	ret = devm_clk_hw_register(dev, &csr->hb_hw);

[Severity: High]
Is a call to devm_pm_runtime_enable() missing before clock registration?

Without PM runtime enabled on the device beforehand, CCF's
clk_pm_runtime_get() sees core->rpm_enabled as false and skips acquiring the
power domain. This leaves the hardware unpowered and vulnerable to crashes
during the .is_prepared checks.

> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to register heartbeat clock\n");
> +
> +	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, &csr->hb_hw);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to add clock provider\n");
> +
> +	return 0;
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260723-master-v3-0-3d67b79b0515@oss.qualcomm.com?part=2