[PATCH 04/10] board: samsung: e850-96: Add PMIC code
Sam Protsenko
semen.protsenko at linaro.org
Thu Aug 7 00:27:04 CEST 2025
Add functions for configuring voltage regulators on S2MPU12 PMIC chip
for E850-96 board. The chip is accessed by commanding APM core (via
ACPM IPC protocol) to perform corresponding transfers over I3C bus.
The most important regulator being set up is LDO24 used for LAN9514 chip
power. As LAN9514 implements USB hub and Ethernet controller
functionality, it's crucial to enable and configure LDO24 to be able to
use it further. While at it, configure the rest of regulators that might
be needed later, both in the bootloader and in kernel.
Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
---
board/samsung/e850-96/Makefile | 2 +-
board/samsung/e850-96/pmic.c | 144 +++++++++++++++++++++++++++++++++
board/samsung/e850-96/pmic.h | 14 ++++
3 files changed, 159 insertions(+), 1 deletion(-)
create mode 100644 board/samsung/e850-96/pmic.c
create mode 100644 board/samsung/e850-96/pmic.h
diff --git a/board/samsung/e850-96/Makefile b/board/samsung/e850-96/Makefile
index 08eb8dca5bf7..76b8d47994e8 100644
--- a/board/samsung/e850-96/Makefile
+++ b/board/samsung/e850-96/Makefile
@@ -3,4 +3,4 @@
# Copyright (C) 2024, Linaro Limited
# Sam Protsenko <semen.protsenko at linaro.org>
-obj-y := e850-96.o fw.o acpm.o
+obj-y := e850-96.o fw.o acpm.o pmic.o
diff --git a/board/samsung/e850-96/pmic.c b/board/samsung/e850-96/pmic.c
new file mode 100644
index 000000000000..037fd4844c54
--- /dev/null
+++ b/board/samsung/e850-96/pmic.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2025 Linaro Ltd.
+ * Author: Sam Protsenko <semen.protsenko at linaro.org>
+ *
+ * This file contains functions for S2MPU12 PMIC regulators configuration.
+ *
+ * Example of voltage calculation for LDO24 and LDO32:
+ * - V_min = 1800 mV
+ * - V_step = 25 mV
+ * - V_wanted = 3300 mV
+ * - register value: (V_wanted - V_min) / V_step = 60 = 0x3c
+ *
+ * NOTE: 0x3c value might mean different voltage for other LDOs.
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include "pmic.h"
+
+/* PMIC definitions */
+#define S2MPU12_CHANNEL 0 /* I3C bus number of PMIC */
+#define S2MPU12_PM_ADDR 0x1 /* I3C slave addr of PM part */
+
+/* PMIC I3C registers */
+#define S2MPU12_PM_LDO1_CTRL 0x2b
+#define S2MPU12_PM_LDO_CTRL(n) (S2MPU12_PM_LDO1_CTRL + (n) - 1)
+
+/* LDOx_CTRL values */
+#define S2MPU12_LDO_CTRL_OUT_MASK (0x3 << 6)
+#define S2MPU12_LDO_CTRL_OUT_ALWAYS_ON (0x3 << 6)
+
+struct pmic_ldo {
+ u8 num; /* LDO number */
+ u8 en; /* "enable" bits value in LDOx_CTRL register */
+ u8 out; /* "output voltage" bits value in LDOx_CTRL register */
+};
+
+/* List of LDOs to enable only */
+static u8 pmic_ldos_en[] = {
+ 2, /* 1.8V/450mA: multiple lines */
+ 11, /* 3.0V/150mA: AVDD33_USB20 */
+ 23, /* 2.85V/800mA: VDD_EMMC_2P85 */
+ 27, /* 3.0V/150mA: MIPI_SWITCH_3V3 */
+ 28, /* 1.8V/150mA: HDMI_CONV_1V8 */
+ 30, /* 1.8V/150mA: NPU_VDD18 */
+};
+
+/* List of LDOs to enable and set output voltage */
+static struct pmic_ldo pmic_ldos_en_out[] = {
+ {
+ .num = 24, /* 3.0V/800mA: VDD_LAN (LAN9514) */
+ .en = S2MPU12_LDO_CTRL_OUT_ALWAYS_ON,
+ .out = 0x3c, /* means 3.3V for LDO24 */
+ }, {
+ .num = 32, /* 3.3V/300mA: CAM_VDD (RPi camera module) */
+ .en = S2MPU12_LDO_CTRL_OUT_ALWAYS_ON,
+ .out = 0x3c, /* means 3.3V for LDO32 */
+ },
+};
+
+/* Enable specified LDO */
+static int pmic_ldo_set_en(struct acpm *acpm, u8 ldo)
+{
+ const u8 reg = S2MPU12_PM_LDO_CTRL(ldo);
+ u8 val;
+ int err;
+
+ err = acpm_i3c_read(acpm, S2MPU12_CHANNEL, S2MPU12_PM_ADDR, reg, &val);
+ if (err)
+ return err;
+
+ val &= ~S2MPU12_LDO_CTRL_OUT_MASK;
+ val |= S2MPU12_LDO_CTRL_OUT_ALWAYS_ON;
+
+ return acpm_i3c_write(acpm, S2MPU12_CHANNEL, S2MPU12_PM_ADDR, reg, val);
+}
+
+/* Enable specified LDO and set its voltage to 0xc0 value */
+static int pmic_ldo_set_en_out(struct acpm *acpm, struct pmic_ldo *ldo)
+{
+ const u8 reg = S2MPU12_PM_LDO_CTRL(ldo->num);
+ const u8 val = ldo->en | ldo->out;
+
+ return acpm_i3c_write(acpm, S2MPU12_CHANNEL, S2MPU12_PM_ADDR, reg, val);
+}
+
+#ifdef DEBUG
+static void pmic_trace_ldo(struct acpm *acpm, u8 ldo)
+{
+ const u8 reg = S2MPU12_PM_LDO_CTRL(ldo);
+ u8 val;
+ int err;
+
+ err = acpm_i3c_read(acpm, S2MPU12_CHANNEL, S2MPU12_PM_ADDR, reg, &val);
+ if (err)
+ printf(" S2MPU12_PM_LDO%u_CTRL: Read error!\n", ldo);
+ else
+ printf(" S2MPU12_PM_LDO%u_CTRL: 0x%x\n", ldo, val);
+}
+
+static void pmic_trace_ldos(struct acpm *acpm)
+{
+ size_t i;
+
+ printf("Tracing LDOs...\n");
+ for (i = 0; i < ARRAY_SIZE(pmic_ldos_en); ++i)
+ pmic_trace_ldo(acpm, pmic_ldos_en[i]);
+ for (i = 0; i < ARRAY_SIZE(pmic_ldos_en_out); ++i)
+ pmic_trace_ldo(acpm, pmic_ldos_en_out[i].num);
+}
+#endif
+
+/**
+ * pmic_init() - Enable power regulators in S2MPU12 PMIC.
+ * @acpm: Data for I3C communication with PMIC over ACPM protocol
+ *
+ * Enable LDOs needed for devices used in the bootloader and kernel.
+ *
+ * Return: 0 on success or non-zero code on error.
+ */
+int pmic_init(struct acpm *acpm)
+{
+ size_t i;
+ int err;
+
+ for (i = 0; i < ARRAY_SIZE(pmic_ldos_en); ++i) {
+ err = pmic_ldo_set_en(acpm, pmic_ldos_en[i]);
+ if (err)
+ return -EIO;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(pmic_ldos_en_out); ++i) {
+ err = pmic_ldo_set_en_out(acpm, &pmic_ldos_en_out[i]);
+ if (err)
+ return -EIO;
+ }
+
+#ifdef DEBUG
+ pmic_trace_ldos(acpm);
+#endif
+
+ return 0;
+}
diff --git a/board/samsung/e850-96/pmic.h b/board/samsung/e850-96/pmic.h
new file mode 100644
index 000000000000..46624c2ebd46
--- /dev/null
+++ b/board/samsung/e850-96/pmic.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2025 Linaro Ltd.
+ * Sam Protsenko <semen.protsenko at linaro.org>
+ */
+
+#ifndef __E850_96_PMIC_H
+#define __E850_96_PMIC_H
+
+#include "acpm.h"
+
+int pmic_init(struct acpm *acpm);
+
+#endif /* __E850_96_PMIC_H */
--
2.39.5
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