1 files changed, 90 insertions, 0 deletions
diff --git a/drivers/power/regulator/pmbus_generic.c b/drivers/power/regulator/pmbus_generic.c
new file mode 100644
index 00000000000..6ba50ce08f8
--- /dev/null
+++ b/drivers/power/regulator/pmbus_generic.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2026 Free Mobile, Vincent Jardin
+ *
+ * Generic PMBus 1.x compatible voltage regulator driver.
+ *
+ * Catch all driver bound to compatible = "pmbus" for chips that have
+ * no per chip driver under drivers/power/regulator/. The probe path
+ * detects the VOUT numeric format from VOUT_MODE bits[7:5]:
+ *
+ *   - 0  LINEAR16 with the exponent supplied via VOUT_MODE bits[4:0]
+ *   - 1  VID; mapped to pmbus_fmt_vid (decoder returns 0 today; per
+ *        chip driver still required to plug a VID table)
+ *   - 2  DIRECT; default coefficients m=1, b=0, R=0 (per chip
+ *        coefficients arrive via PMBUS_QUERY / PMBUS_COEFFICIENTS,
+ *        not yet consumed by U-Boot; values may need a per chip
+ *        driver if telemetry numbers are wrong)
+ *   - 3  IEEE754; mapped to pmbus_fmt_ieee754 (decoder returns 0
+ *        today; per chip driver required)
+ *
+ * Other sensor classes (VIN, IIN, IOUT, TEMPERATURE) default to
+ * LINEAR which is the spec baseline for compliant chips. If an
+ * operator sees wrong telemetry numbers on this driver, the answer
+ * is to write a per chip driver with the correct format[] / m / b / R.
+ *
+ * Adapted in spirit from linux/drivers/hwmon/pmbus/pmbus.c (the
+ * kernel's generic probe driver). The U-Boot version drops the
+ * page count auto detection (most generic compliant parts are
+ * single rail; multi rail chips are quirky enough to need a per
+ * chip driver) and the kernel hwmon publication layers.
+ */
+
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <pmbus.h>
+#include <power/regulator.h>
+
+#include "pmbus_helper.h"
+
+struct pmbus_generic_priv {
+	struct pmbus_regulator_priv base;	/* must be first */
+	struct pmbus_driver_info info;
+};
+
+static int pmbus_generic_probe(struct udevice *dev)
+{
+	struct pmbus_generic_priv *gpriv = dev_get_priv(dev);
+	struct pmbus_driver_info *info = &gpriv->info;
+	enum pmbus_sensor_classes c;
+	int ret;
+
+	info->pages = 1;
+	for (c = 0; c < PSC_NUM_CLASSES; c++) {
+		info->format[c] = pmbus_fmt_linear;
+		info->m[c] = 0;
+		info->b[c] = 0;
+		info->R[c] = 0;
+	}
+
+	ret = pmbus_regulator_probe_common(dev, info, 0);
+	if (ret)
+		return ret;
+
+	/*
+	 * Avoid reading non supported pages to avoid device's sticky
+	 * status.
+	 */
+	info->pages = dev_read_u32_default(dev, "pmbus,num-pages", 1);
+	if (info->pages < 1)
+		info->pages = 1;
+
+	pmbus_regulator_identify_vout(gpriv->base.i2c_dev, info);
+
+	return 0;
+}
+
+static const struct udevice_id pmbus_generic_ids[] = {
+	{ .compatible = "pmbus" },
+	{ }
+};
+
+U_BOOT_DRIVER(pmbus_generic_regulator) = {
+	.name      = "pmbus_generic_regulator",
+	.id        = UCLASS_REGULATOR,
+	.of_match  = pmbus_generic_ids,
+	.probe     = pmbus_generic_probe,
+	.ops       = &pmbus_regulator_ops,
+	.priv_auto = sizeof(struct pmbus_generic_priv),
+};