pmic: add stpmu1 support

This driver implements register read/write operations for STPMU1.

The STPMU1 PMIC provides 4 BUCKs, 6 LDOs, 1 VREF
and 2 power switches. It is accessed via an I2C interface.
This device is used with STM32MP1 SoCs.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/power/pmic/Kconfig b/drivers/power/pmic/Kconfig
index 5d49c93..40ab9f7 100644
--- a/drivers/power/pmic/Kconfig
+++ b/drivers/power/pmic/Kconfig
@@ -209,3 +209,11 @@
 	The TPS65910 is a PMIC containing 3 buck DC-DC converters, one boost
 	DC-DC converter, 8 LDOs and a RTC. This driver binds the SMPS and LDO
 	pmic children.
+
+config PMIC_STPMU1
+	bool "Enable support for STMicroelectronics STPMU1 PMIC"
+	depends on DM_PMIC && DM_I2C
+	---help---
+	The STPMU1 PMIC provides 4 BUCKs, 6 LDOs, 1 VREF and 2 power switches.
+	It is accessed via an I2C interface. The device is used with STM32MP1
+	SoCs. This driver implements register read/write operations.
diff --git a/drivers/power/pmic/Makefile b/drivers/power/pmic/Makefile
index fc19fdc..ad32068 100644
--- a/drivers/power/pmic/Makefile
+++ b/drivers/power/pmic/Makefile
@@ -23,6 +23,7 @@
 obj-$(CONFIG_$(SPL_)PMIC_PALMAS) += palmas.o
 obj-$(CONFIG_$(SPL_)PMIC_LP873X) += lp873x.o
 obj-$(CONFIG_$(SPL_)PMIC_LP87565) += lp87565.o
+obj-$(CONFIG_PMIC_STPMU1) += stpmu1.o
 
 obj-$(CONFIG_POWER_LTC3676) += pmic_ltc3676.o
 obj-$(CONFIG_POWER_MAX77696) += pmic_max77696.o
diff --git a/drivers/power/pmic/stpmu1.c b/drivers/power/pmic/stpmu1.c
new file mode 100644
index 0000000..4615365
--- /dev/null
+++ b/drivers/power/pmic/stpmu1.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier:	GPL-2.0+	BSD-3-Clause
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <i2c.h>
+#include <power/pmic.h>
+#include <power/stpmu1.h>
+
+#define STMPU1_NUM_OF_REGS 0x100
+
+static int stpmu1_reg_count(struct udevice *dev)
+{
+	return STMPU1_NUM_OF_REGS;
+}
+
+static int stpmu1_write(struct udevice *dev, uint reg, const uint8_t *buff,
+			int len)
+{
+	int ret;
+
+	ret = dm_i2c_write(dev, reg, buff, len);
+	if (ret)
+		dev_err(dev, "%s: failed to write register %#x :%d",
+			__func__, reg, ret);
+
+	return ret;
+}
+
+static int stpmu1_read(struct udevice *dev, uint reg, uint8_t *buff, int len)
+{
+	int ret;
+
+	ret = dm_i2c_read(dev, reg, buff, len);
+	if (ret)
+		dev_err(dev, "%s: failed to read register %#x : %d",
+			__func__, reg, ret);
+
+	return ret;
+}
+
+static struct dm_pmic_ops stpmu1_ops = {
+	.reg_count = stpmu1_reg_count,
+	.read = stpmu1_read,
+	.write = stpmu1_write,
+};
+
+static const struct udevice_id stpmu1_ids[] = {
+	{ .compatible = "st,stpmu1" },
+	{ }
+};
+
+U_BOOT_DRIVER(pmic_stpmu1) = {
+	.name = "stpmu1_pmic",
+	.id = UCLASS_PMIC,
+	.of_match = stpmu1_ids,
+	.ops = &stpmu1_ops,
+};