sandbox: add: sandbox PMIC device drivers: I2C emul, pmic, regulator

This commit adds emulation of sandbox PMIC device, which includes:
- PMIC I2C emulation driver
- PMIC I/O driver (UCLASS_PMIC)
- PMIC regulator driver (UCLASS_REGULATOR)

The sandbox PMIC has 12 significant registers and 4 as padding to 16 bytes,
which allows using 'i2c md' command with the default count (16).

The sandbox PMIC provides regulators:
- 2x BUCK
- 2x LDO

Each, with adjustable output:
- Enable state
- Voltage
- Current limit (LDO1/BUCK1 only)
- Operation mode (different for BUCK and LDO)

Each attribute has it's own register, beside the enable state, which depends
on operation mode.

The header file: sandbox_pmic.h includes PMIC's default register values,
which are set on i2c pmic emul driver's probe() method.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested on sandbox:
Tested-by: Simon Glass <sjg@chromium.org>

4 files changed, 248 insertions, 1 deletions

diff --git a/drivers/power/pmic/Kconfig b/drivers/power/pmic/Kconfig
index d99d9e3a06..164f42143f 100644
--- a/drivers/power/pmic/Kconfig
+++ b/drivers/power/pmic/Kconfig
@@ -16,3 +16,28 @@ config DM_PMIC_MAX77686
 	---help---
 	This config enables implementation of driver-model pmic uclass features
 	for PMIC MAX77686. The driver implements read/write operations.
+
+config DM_PMIC_SANDBOX
+	bool "Enable Driver Model for emulated Sandbox PMIC "
+	depends on DM_PMIC
+	---help---
+	Enable the driver for Sandbox PMIC emulation. The emulated PMIC device
+	depends on two drivers:
+	- sandbox PMIC I/O driver - implements dm pmic operations
+	- sandbox PMIC i2c emul driver - emulates the PMIC's I2C transmission
+
+	A detailed information can be found in header: '<power/sandbox_pmic.h>'
+
+	The Sandbox PMIC info:
+	* I/O interface:
+	  - I2C chip address:       0x40
+	  - first register address: 0x0
+	  - register count:         0x10
+	* Adjustable outputs:
+	  - 2x LDO
+	  - 2x BUCK
+	  - Each, with a different operating conditions (header).
+	* Reset values:
+	  - set by i2c emul driver's probe() (defaults in header)
+
+	Driver binding info: doc/device-tree-bindings/pmic/sandbox.txt
diff --git a/drivers/power/pmic/Makefile b/drivers/power/pmic/Makefile
index 8cb993d0a7..ae86f041f3 100644
--- a/drivers/power/pmic/Makefile
+++ b/drivers/power/pmic/Makefile
@@ -6,12 +6,13 @@
 #
 
 obj-$(CONFIG_DM_PMIC) += pmic-uclass.o
+obj-$(CONFIG_DM_PMIC_MAX77686) += max77686.o
+obj-$(CONFIG_DM_PMIC_SANDBOX) += sandbox.o i2c_pmic_emul.o
 obj-$(CONFIG_POWER_LTC3676) += pmic_ltc3676.o
 obj-$(CONFIG_POWER_MAX8998) += pmic_max8998.o
 obj-$(CONFIG_POWER_MAX8997) += pmic_max8997.o
 obj-$(CONFIG_POWER_MUIC_MAX8997) += muic_max8997.o
 obj-$(CONFIG_POWER_MAX77686) += pmic_max77686.o
-obj-$(CONFIG_DM_PMIC_MAX77686) += max77686.o
 obj-$(CONFIG_POWER_PFUZE100) += pmic_pfuze100.o
 obj-$(CONFIG_POWER_TPS65090_I2C) += pmic_tps65090.o
 obj-$(CONFIG_POWER_TPS65090_EC) += pmic_tps65090_ec.o
diff --git a/drivers/power/pmic/i2c_pmic_emul.c b/drivers/power/pmic/i2c_pmic_emul.c
new file mode 100644
index 0000000000..aeab5c949a
--- /dev/null
+++ b/drivers/power/pmic/i2c_pmic_emul.c
@@ -0,0 +1,142 @@
+/*
+ *  Copyright (C) 2015 Samsung Electronics
+ *  Przemyslaw Marczak  <p.marczak@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <errno.h>
+#include <dm.h>
+#include <i2c.h>
+#include <power/pmic.h>
+#include <power/sandbox_pmic.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * struct sandbox_i2c_pmic_plat_data - platform data for the PMIC
+ *
+ * @rw_reg: PMICs register of the chip I/O transaction
+ * @reg:    PMICs registers array
+ */
+struct sandbox_i2c_pmic_plat_data {
+	u8 rw_reg;
+	u8 reg[SANDBOX_PMIC_REG_COUNT];
+};
+
+static int sandbox_i2c_pmic_read_data(struct udevice *emul, uchar chip,
+				      uchar *buffer, int len)
+{
+	struct sandbox_i2c_pmic_plat_data *plat = dev_get_platdata(emul);
+
+	if (plat->rw_reg + len > SANDBOX_PMIC_REG_COUNT) {
+		error("Request exceeds PMIC register range! Max register: %#x",
+		      SANDBOX_PMIC_REG_COUNT);
+		return -EFAULT;
+	}
+
+	debug("Read PMIC: %#x at register: %#x count: %d\n",
+	      (unsigned)chip & 0xff, plat->rw_reg, len);
+
+	memcpy(buffer, &plat->reg[plat->rw_reg], len);
+
+	return 0;
+}
+
+static int sandbox_i2c_pmic_write_data(struct udevice *emul, uchar chip,
+				       uchar *buffer, int len,
+				       bool next_is_read)
+{
+	struct sandbox_i2c_pmic_plat_data *plat = dev_get_platdata(emul);
+
+	/* Probe only */
+	if (!len)
+		return 0;
+
+	/* Set PMIC register for I/O */
+	plat->rw_reg = *buffer;
+
+	debug("Write PMIC: %#x at register: %#x count: %d\n",
+	      (unsigned)chip & 0xff, plat->rw_reg, len);
+
+	/* For read operation, set (write) only chip reg */
+	if (next_is_read)
+		return 0;
+
+	buffer++;
+	len--;
+
+	if (plat->rw_reg + len > SANDBOX_PMIC_REG_COUNT) {
+		error("Request exceeds PMIC register range! Max register: %#x",
+		      SANDBOX_PMIC_REG_COUNT);
+	}
+
+	memcpy(&plat->reg[plat->rw_reg], buffer, len);
+
+	return 0;
+}
+
+static int sandbox_i2c_pmic_xfer(struct udevice *emul, struct i2c_msg *msg,
+				 int nmsgs)
+{
+	int ret = 0;
+
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD);
+		if (msg->flags & I2C_M_RD) {
+			ret = sandbox_i2c_pmic_read_data(emul, msg->addr,
+							 msg->buf, msg->len);
+		} else {
+			ret = sandbox_i2c_pmic_write_data(emul, msg->addr,
+							  msg->buf, msg->len,
+							  next_is_read);
+		}
+
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int sandbox_i2c_pmic_ofdata_to_platdata(struct udevice *emul)
+{
+	struct sandbox_i2c_pmic_plat_data *plat = dev_get_platdata(emul);
+	const u8 *reg_defaults;
+
+	debug("%s:%d Setting PMIC default registers\n", __func__, __LINE__);
+
+	reg_defaults = fdtdec_locate_byte_array(gd->fdt_blob, emul->of_offset,
+						"reg-defaults",
+						SANDBOX_PMIC_REG_COUNT);
+
+	if (!reg_defaults) {
+		error("Property \"reg-defaults\" not found for device: %s!",
+		      emul->name);
+		return -EINVAL;
+	}
+
+	memcpy(&plat->reg, reg_defaults, SANDBOX_PMIC_REG_COUNT);
+
+	return 0;
+}
+
+struct dm_i2c_ops sandbox_i2c_pmic_emul_ops = {
+	.xfer = sandbox_i2c_pmic_xfer,
+};
+
+static const struct udevice_id sandbox_i2c_pmic_ids[] = {
+	{ .compatible = "sandbox,i2c-pmic" },
+	{ }
+};
+
+U_BOOT_DRIVER(sandbox_i2c_pmic_emul) = {
+	.name		= "sandbox_i2c_pmic_emul",
+	.id		= UCLASS_I2C_EMUL,
+	.of_match	= sandbox_i2c_pmic_ids,
+	.ofdata_to_platdata = sandbox_i2c_pmic_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct sandbox_i2c_pmic_plat_data),
+	.ops		= &sandbox_i2c_pmic_emul_ops,
+};
diff --git a/drivers/power/pmic/sandbox.c b/drivers/power/pmic/sandbox.c
new file mode 100644
index 0000000000..3e56acd5e2
--- /dev/null
+++ b/drivers/power/pmic/sandbox.c
@@ -0,0 +1,79 @@
+/*
+ *  Copyright (C) 2015 Samsung Electronics
+ *  Przemyslaw Marczak  <p.marczak@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <errno.h>
+#include <dm.h>
+#include <i2c.h>
+#include <power/pmic.h>
+#include <power/regulator.h>
+#include <power/sandbox_pmic.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static const struct pmic_child_info pmic_children_info[] = {
+	{ .prefix = SANDBOX_OF_LDO_PREFIX, .driver = SANDBOX_LDO_DRIVER },
+	{ .prefix = SANDBOX_OF_BUCK_PREFIX, .driver = SANDBOX_BUCK_DRIVER },
+	{ },
+};
+
+static int sandbox_pmic_reg_count(struct udevice *dev)
+{
+	return SANDBOX_PMIC_REG_COUNT;
+}
+
+static int sandbox_pmic_write(struct udevice *dev, uint reg,
+			      const uint8_t *buff, int len)
+{
+	if (dm_i2c_write(dev, reg, buff, len)) {
+		error("write error to device: %p register: %#x!", dev, reg);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int sandbox_pmic_read(struct udevice *dev, uint reg,
+			     uint8_t *buff, int len)
+{
+	if (dm_i2c_read(dev, reg, buff, len)) {
+		error("read error from device: %p register: %#x!", dev, reg);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int sandbox_pmic_bind(struct udevice *dev)
+{
+	if (!pmic_bind_children(dev, dev->of_offset, pmic_children_info))
+		error("%s:%d PMIC: %s - no child found!", __func__, __LINE__,
+							  dev->name);
+
+	/* Always return success for this device - allows for PMIC I/O */
+	return 0;
+}
+
+static struct dm_pmic_ops sandbox_pmic_ops = {
+	.reg_count = sandbox_pmic_reg_count,
+	.read = sandbox_pmic_read,
+	.write = sandbox_pmic_write,
+};
+
+static const struct udevice_id sandbox_pmic_ids[] = {
+	{ .compatible = "sandbox,pmic" },
+	{ }
+};
+
+U_BOOT_DRIVER(sandbox_pmic) = {
+	.name = "sandbox_pmic",
+	.id = UCLASS_PMIC,
+	.of_match = sandbox_pmic_ids,
+	.bind = sandbox_pmic_bind,
+	.ops = &sandbox_pmic_ops,
+};