clk: qcom: Add generic clkref_en support

Before XO refclk is distributed to PCIe/USB/eDP PHYs, it passes through
a QREF block. QREF is powered by dedicated LDO rails, and the clkref_en
register controls whether refclk is gated through to the PHY side.

These clkref controls are different from typical GCC branch clocks:
- only a single enable bit is present, without branch-style config bits
- regulators must be voted before enable and unvoted after disable

Model this as a dedicated clk_ref clock type with custom clk_ops instead
of reusing struct clk_branch semantics.

Also provide a common registration/probe API so the same clkref model
can be reused regardless of where clkref_en registers are placed, e.g.
TCSR on glymur and TLMM on SM8750.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260721-tcsr_qre_0721-v10-3-d2fa68c63b78@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

1 files changed, 67 insertions, 0 deletions

diff --git a/include/linux/clk/qcom.h b/include/linux/clk/qcom.h
new file mode 100644
index 000000000000..11ac2d42ff9e
--- /dev/null
+++ b/include/linux/clk/qcom.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2026, Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#ifndef __LINUX_CLK_QCOM_H
+#define __LINUX_CLK_QCOM_H
+
+#include <linux/clk-provider.h>
+#include <linux/errno.h>
+#include <linux/kconfig.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct device;
+struct platform_device;
+struct regulator_bulk_data;
+
+/**
+ * struct qcom_clk_ref_desc - descriptor for a clkref_en gate clock
+ * @name: clock name exposed to the common clock framework
+ * @offset: clkref_en register offset from the block base
+ * @regulator_names: optional supply names enabled while preparing the clock
+ * @num_regulators: number of entries in @regulator_names
+ */
+struct qcom_clk_ref_desc {
+	const char *name;
+	u32 offset;
+	const char * const *regulator_names;
+	unsigned int num_regulators;
+};
+
+/**
+ * struct qcom_clk_ref - per-clock data for a clkref_en gate clock
+ * @hw: common clock framework hardware clock handle
+ * @regmap: register map backing the clkref_en register
+ * @desc: clock descriptor copied at registration time
+ * @regulators: optional bulk regulator handles for @desc.regulator_names
+ */
+struct qcom_clk_ref {
+	struct clk_hw hw;
+	struct regmap *regmap;
+	struct qcom_clk_ref_desc desc;
+	struct regulator_bulk_data *regulators;
+};
+
+#if IS_ENABLED(CONFIG_COMMON_CLK_QCOM)
+
+int qcom_clk_ref_probe(struct platform_device *pdev,
+		       const struct regmap_config *config,
+		       const struct qcom_clk_ref_desc * const *descs,
+		       size_t num_clk_refs);
+
+#else
+
+static inline int
+qcom_clk_ref_probe(struct platform_device *pdev,
+		   const struct regmap_config *config,
+		   const struct qcom_clk_ref_desc * const *descs,
+		   size_t num_clk_refs)
+{
+	return -EOPNOTSUPP;
+}
+
+#endif
+
+#endif