[PATCH v2 1/7] clk: qcom: Add shared RPMH clock driver for SM8550/SM8650/SA8775P

sa8775p was being handled by the generic clock stub, which just
no-ops every request. The RPMH_CXO_CLK (bi_tcxo_div2) it exposes is
identical on SM8550, SM8650 and SA8775P, so rather than bury it in the
sa8775p GCC driver, add a dedicated standalone RPMH clock driver shared
by all three SoCs. It reports the fixed CXO rate and accepts no-op
enable/set_rate requests.

Monaco-evk also uses the same RPMH clock driver as sa8775p (it's
rpmhcc DTS node has compatible "qcom,sa8775p-rpmh-clk").

Drop the sm8550/sm8650/sa8775p rpmh-clk compatibles from the generic
clock stub now that they are handled by the real driver.

Signed-off-by: Balaji Selvanathan <[email protected]>
---
 drivers/clk/clk-stub.c        |  3 ---
 drivers/clk/qcom/Kconfig      | 12 +++++++++
 drivers/clk/qcom/Makefile     |  1 +
 drivers/clk/qcom/clock-rpmh.c | 61 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk-stub.c b/drivers/clk/clk-stub.c
index 4a6c71016da..85e54841386 100644
--- a/drivers/clk/clk-stub.c
+++ b/drivers/clk/clk-stub.c
@@ -51,7 +51,6 @@ static struct clk_ops stub_clk_ops = {
 static const struct udevice_id stub_clk_ids[] = {
 	{ .compatible = "qcom,qcs615-rpmh-clk" },
 	{ .compatible = "qcom,rpmcc" },
-	{ .compatible = "qcom,sa8775p-rpmh-clk" },
 	{ .compatible = "qcom,sc7180-rpmh-clk" },
 	{ .compatible = "qcom,sc7280-rpmh-clk" },
 	{ .compatible = "qcom,sdm670-rpmh-clk" },
@@ -59,8 +58,6 @@ static const struct udevice_id stub_clk_ids[] = {
 	{ .compatible = "qcom,sm6350-rpmh-clk" },
 	{ .compatible = "qcom,sm8150-rpmh-clk" },
 	{ .compatible = "qcom,sm8250-rpmh-clk" },
-	{ .compatible = "qcom,sm8550-rpmh-clk" },
-	{ .compatible = "qcom,sm8650-rpmh-clk" },
 	{ }
 };
 
diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
index 9ad233c83ac..8596b93d4c4 100644
--- a/drivers/clk/qcom/Kconfig
+++ b/drivers/clk/qcom/Kconfig
@@ -87,9 +87,19 @@ config CLK_QCOM_QCS8300
 	  on the Snapdragon QCS8300 SoC. This driver supports the clocks
 	  and resets exposed by the GCC hardware block.
 
+config CLK_QCOM_RPMH
+	bool "Qualcomm RPMh clock driver"
+	depends on CLK
+	help
+	  Say Y here to enable support for the RPMh-managed clocks found on
+	  SoCs such as SM8550, SM8650 and SA8775P. These clocks are owned by
+	  the always-on subsystem; the driver only reports the fixed CXO rate
+	  (bi_tcxo_div2) and accepts no-op enable/set_rate requests.
+
 config CLK_QCOM_SA8775P
 	bool "Qualcomm SA8775 GCC"
 	select CLK_QCOM
+	select CLK_QCOM_RPMH
 	help
 	  Say Y here to enable support for the Global Clock Controller
 	  on the Snapdragon SA8775 SoC. This driver supports the clocks
@@ -153,6 +163,7 @@ config CLK_QCOM_SM8250
 config CLK_QCOM_SM8550
 	bool "Qualcomm SM8550 GCC"
 	select CLK_QCOM
+	select CLK_QCOM_RPMH
 	help
 	  Say Y here to enable support for the Global Clock Controller
 	  on the Snapdragon SM8550 SoC. This driver supports the clocks
@@ -161,6 +172,7 @@ config CLK_QCOM_SM8550
 config CLK_QCOM_SM8650
 	bool "Qualcomm SM8650 GCC"
 	select CLK_QCOM
+	select CLK_QCOM_RPMH
 	help
 	  Say Y here to enable support for the Global Clock Controller
 	  on the Snapdragon SM8650 SoC. This driver supports the clocks
diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index c0d95a6300e..f5630ae0f9c 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_CLK_QCOM_QCM2290) += clock-qcm2290.o
 obj-$(CONFIG_CLK_QCOM_QCS404) += clock-qcs404.o
 obj-$(CONFIG_CLK_QCOM_QCS8300) += clock-qcs8300.o
 obj-$(CONFIG_CLK_QCOM_QCS615) += clock-qcs615.o
+obj-$(CONFIG_CLK_QCOM_RPMH) += clock-rpmh.o
 obj-$(CONFIG_CLK_QCOM_SA8775P) += clock-sa8775p.o
 obj-$(CONFIG_CLK_QCOM_SC7280) += clock-sc7280.o
 obj-$(CONFIG_CLK_QCOM_SM6115) += clock-sm6115.o
diff --git a/drivers/clk/qcom/clock-rpmh.c b/drivers/clk/qcom/clock-rpmh.c
new file mode 100644
index 00000000000..69f2a751441
--- /dev/null
+++ b/drivers/clk/qcom/clock-rpmh.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * RPMh clock driver for Qualcomm SoCs
+ *
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <clk-uclass.h>
+#include <dm.h>
+#include <errno.h>
+#include <dt-bindings/clock/qcom,rpmh.h>
+
+/* On-board TCXO */
+#define TCXO_RATE	38400000
+
+/* bi_tcxo_div2 divided after RPMh output */
+#define TCXO_DIV2_RATE	(TCXO_RATE / 2)
+
+static ulong qcom_rpmh_clk_set_rate(struct clk *clk, ulong rate)
+{
+	return (clk->rate = rate);
+}
+
+static ulong qcom_rpmh_clk_get_rate(struct clk *clk)
+{
+	ulong cxo_rate = dev_get_driver_data(clk->dev);
+
+	switch (clk->id) {
+	case RPMH_CXO_CLK:
+		return cxo_rate;
+	default:
+		return clk->rate;
+	}
+}
+
+static int qcom_rpmh_clk_nop(struct clk *clk)
+{
+	return 0;
+}
+
+static struct clk_ops qcom_rpmh_clk_ops = {
+	.set_rate = qcom_rpmh_clk_set_rate,
+	.get_rate = qcom_rpmh_clk_get_rate,
+	.enable = qcom_rpmh_clk_nop,
+	.disable = qcom_rpmh_clk_nop,
+};
+
+static const struct udevice_id qcom_rpmh_clk_ids[] = {
+	{ .compatible = "qcom,sa8775p-rpmh-clk", .data = TCXO_DIV2_RATE },
+	{ .compatible = "qcom,sm8550-rpmh-clk", .data = TCXO_DIV2_RATE },
+	{ .compatible = "qcom,sm8650-rpmh-clk", .data = TCXO_DIV2_RATE },
+	{ }
+};
+
+U_BOOT_DRIVER(qcom_rpmh_clk) = {
+	.name		= "qcom_rpmh_clk",
+	.id		= UCLASS_CLK,
+	.of_match	= qcom_rpmh_clk_ids,
+	.ops		= &qcom_rpmh_clk_ops,
+	.flags		= DM_FLAG_DEFAULT_PD_CTRL_OFF,
+};

-- 
2.34.1