dm: pmic: add implementation of driver model pmic uclass

This commit introduces the PMIC uclass implementation.
It allows providing the basic I/O interface for PMIC devices.
For the multi-function PMIC devices, this can be used as I/O
parent device, for each IC's interface. Then, each PMIC particular
function can be provided by the child device's operations, and the
child devices will use its parent for read/write by the common API.

Core files:
- 'include/power/pmic.h'
- 'drivers/power/pmic/pmic-uclass.c'

The old pmic framework is still kept and is independent.

For more detailed informations, please look into the header file.

Changes:
- new uclass-id: UCLASS_PMIC
- new config: CONFIG_DM_PMIC

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

drivers/power/Kconfig

+menu "Power"
+
+source "drivers/power/pmic/Kconfig"
+
 config AXP221_POWER
 	boolean "axp221 / axp223 pmic support"
 	depends on MACH_SUN6I || MACH_SUN8I
@@ -73,3 +77,5 @@ config AXP221_ELDO3_VOLT
 	disable eldo3. On some A31(s) tablets it might be used to supply
 	1.2V for the SSD2828 chip (converter of parallel LCD interface
 	into MIPI DSI).
+
+endmenu

drivers/power/pmic/Kconfig

+config DM_PMIC
+	bool "Enable Driver Model for PMIC drivers (UCLASS_PMIC)"
+	depends on DM
+	---help---
+	This config enables the driver-model PMIC support.
+	UCLASS_PMIC - designed to provide an I/O interface for PMIC devices.
+	For the multi-function PMIC devices, this can be used as parent I/O
+	device for each IC's interface. Then, each children uses its parent
+	for read/write. For detailed description, please refer to the files:
+	- 'drivers/power/pmic/pmic-uclass.c'
+	- 'include/power/pmic.h'

drivers/power/pmic/Makefile

@@ -5,6 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
+obj-$(CONFIG_DM_PMIC) += pmic-uclass.o
 obj-$(CONFIG_POWER_LTC3676) += pmic_ltc3676.o
 obj-$(CONFIG_POWER_MAX8998) += pmic_max8998.o
 obj-$(CONFIG_POWER_MAX8997) += pmic_max8997.o

drivers/power/pmic/pmic-uclass.c

+/*
+ * Copyright (C) 2014-2015 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 <dm/lists.h>
+#include <dm/device-internal.h>
+#include <dm/uclass-internal.h>
+#include <power/pmic.h>
+#include <linux/ctype.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static ulong str_get_num(const char *ptr, const char *maxptr)
+{
+	if (!ptr || !maxptr)
+		return 0;
+
+	while (!isdigit(*ptr) && ptr++ < maxptr);
+
+	return simple_strtoul(ptr, NULL, 0);
+}
+
+int pmic_bind_childs(struct udevice *pmic, int offset,
+		     const struct pmic_child_info *child_info)
+{
+	const struct pmic_child_info *info;
+	const void *blob = gd->fdt_blob;
+	struct driver *drv;
+	struct udevice *child;
+	const char *node_name;
+	int node_name_len;
+	int bind_count = 0;
+	int node;
+	int prefix_len;
+	int ret;
+
+	debug("%s for '%s' at node offset: %d\n", __func__, pmic->name,
+	      pmic->of_offset);
+
+	for (node = fdt_first_subnode(blob, offset);
+	     node > 0;
+	     node = fdt_next_subnode(blob, node)) {
+		node_name = fdt_get_name(blob, node, &node_name_len);
+
+		debug("* Found child node: '%s' at offset:%d\n", node_name,
+								 node);
+
+		child = NULL;
+		info = child_info;
+		while (info->prefix) {
+			prefix_len = strlen(info->prefix);
+			if (strncasecmp(info->prefix, node_name, prefix_len) ||
+			    !info->driver) {
+				info++;
+				continue;
+			}
+
+			debug("  - compatible prefix: '%s'\n", info->prefix);
+
+			drv = lists_driver_lookup_name(info->driver);
+			if (!drv) {
+				debug("  - driver: '%s' not found!\n",
+				      info->driver);
+				continue;
+			}
+
+			debug("  - found child driver: '%s'\n", drv->name);
+
+			ret = device_bind(pmic, drv, node_name, NULL,
+					  node, &child);
+			if (ret) {
+				debug("  - child binding error: %d\n", ret);
+				continue;
+			}
+
+			debug("  - bound child device: '%s'\n", child->name);
+
+			child->driver_data = str_get_num(node_name +
+							 prefix_len,
+							 node_name +
+							 node_name_len);
+
+			debug("  - set 'child->driver_data': %lu\n",
+			      child->driver_data);
+			break;
+		}
+
+		if (child)
+			bind_count++;
+		else
+			debug("  - compatible prefix not found\n");
+	}
+
+	debug("Bound: %d childs for PMIC: '%s'\n", bind_count, pmic->name);
+	return bind_count;
+}
+
+int pmic_get(const char *name, struct udevice **devp)
+{
+	return uclass_get_device_by_name(UCLASS_PMIC, name, devp);
+}
+
+int pmic_reg_count(struct udevice *dev)
+{
+	const struct dm_pmic_ops *ops = dev_get_driver_ops(dev);
+	if (!ops)
+		return -ENOSYS;
+
+	return ops->reg_count;
+}
+
+int pmic_read(struct udevice *dev, uint reg, uint8_t *buffer, int len)
+{
+	const struct dm_pmic_ops *ops = dev_get_driver_ops(dev);
+	int ret;
+
+	if (!buffer)
+		return -EFAULT;
+
+	if (!ops || !ops->read)
+		return -ENOSYS;
+
+	ret = ops->read(dev, reg, buffer, len);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+int pmic_write(struct udevice *dev, uint reg, const uint8_t *buffer, int len)
+{
+	const struct dm_pmic_ops *ops = dev_get_driver_ops(dev);
+	int ret;
+
+	if (!buffer)
+		return -EFAULT;
+
+	if (!ops || !ops->write)
+		return -ENOSYS;
+
+	ret = ops->write(dev, reg, buffer, len);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+UCLASS_DRIVER(pmic) = {
+	.id		= UCLASS_PMIC,
+	.name		= "pmic",
+};

include/dm/uclass-id.h

@@ -49,6 +49,9 @@ enum uclass_id {
 	UCLASS_USB_DEV_GENERIC,	/* USB generic device */
 	UCLASS_USB_HUB,		/* USB hub */
 
+	/* Power Management */
+	UCLASS_PMIC,		/* PMIC I/O device */
+
 	UCLASS_COUNT,
 	UCLASS_INVALID = -1,
 };

include/power/pmic.h

 /*
+ *  Copyright (C) 2014-2015 Samsung Electronics
+ *  Przemyslaw Marczak <p.marczak@samsung.com>
+ *
  *  Copyright (C) 2011-2012 Samsung Electronics
  *  Lukasz Majewski <l.majewski@samsung.com>
  *
@@ -9,10 +12,13 @@
 #define __CORE_PMIC_H_
 
 #include <linux/list.h>
+#include <spi.h>
 #include <i2c.h>
 #include <power/power_chrg.h>
 
 enum { PMIC_I2C, PMIC_SPI, PMIC_NONE};
+
+#ifdef CONFIG_POWER
 enum { I2C_PMIC, I2C_NUM, };
 enum { PMIC_READ, PMIC_WRITE, };
 enum { PMIC_SENSOR_BYTE_ORDER_LITTLE, PMIC_SENSOR_BYTE_ORDER_BIG, };
@@ -77,7 +83,189 @@ struct pmic {
 	struct pmic *parent;
 	struct list_head list;
 };
+#endif /* CONFIG_POWER */
+
+#ifdef CONFIG_DM_PMIC
+/**
+ * U-Boot PMIC Framework
+ * =====================
+ *
+ * UCLASS_PMIC - The is designed to provide an I/O interface for PMIC devices.
+ *
+ * For the multi-function PMIC devices, this can be used as parent I/O device
+ * for each IC's interface. Then, each children uses its parent for read/write.
+ *
+ * The driver model tree could look like this:
+ *
+ *_ root device
+ * |_ BUS 0 device (e.g. I2C0)                 - UCLASS_I2C/SPI/...
+ * | |_ PMIC device (READ/WRITE ops)           - UCLASS_PMIC
+ * |   |_ REGULATOR device (ldo/buck/... ops)  - UCLASS_REGULATOR
+ * |   |_ CHARGER device (charger ops)         - UCLASS_CHARGER (in the future)
+ * |   |_ MUIC device (microUSB connector ops) - UCLASS_MUIC    (in the future)
+ * |   |_ ...
+ * |
+ * |_ BUS 1 device (e.g. I2C1)                 - UCLASS_I2C/SPI/...
+ *   |_ PMIC device (READ/WRITE ops)           - UCLASS_PMIC
+ *     |_ RTC device (rtc ops)                 - UCLASS_RTC     (in the future)
+ *
+ * We can find two PMIC cases in boards design:
+ * - single I/O interface
+ * - multiple I/O interfaces
+ * We bind single PMIC device for each interface, to provide an I/O as a parent,
+ * of proper child devices. Each child usually implements a different function,
+ * controlled by the same interface.
+ *
+ * The binding should be done automatically. If device tree nodes/subnodes are
+ * proper defined, then:
+ *
+ * |_ the ROOT driver will bind the device for I2C/SPI node:
+ *   |_ the I2C/SPI driver should bind a device for pmic node:
+ *     |_ the PMIC driver should bind devices for its childs:
+ *       |_ regulator (child)
+ *       |_ charger   (child)
+ *       |_ other     (child)
+ *
+ * The same for other device nodes, for multi-interface PMIC.
+ *
+ * Note:
+ * Each PMIC interface driver should use a different compatible string.
+ *
+ * If each pmic child device driver need access the PMIC-specific registers,
+ * it need know only the register address and the access can be done through
+ * the parent pmic driver. Like in the example:
+ *
+ *_ root driver
+ * |_ dev: bus I2C0                                         - UCLASS_I2C
+ * | |_ dev: my_pmic (read/write)              (is parent)  - UCLASS_PMIC
+ * |   |_ dev: my_regulator (set value/etc..)  (is child)   - UCLASS_REGULATOR
+ *
+ * To ensure such device relationship, the pmic device driver should also bind
+ * all its child devices, like in the example below. It should be done by call
+ * the 'pmic_bind_childs()' - please refer to the description of this function
+ * in this header file. This function, should be called in the driver's '.bind'
+ * method.
+ *
+ * For the example driver, please refer the MAX77686 driver:
+ * - 'drivers/power/pmic/max77686.c'
+ */
+
+/**
+ * struct dm_pmic_ops - PMIC device I/O interface
+ *
+ * Should be implemented by UCLASS_PMIC device drivers. The standard
+ * device operations provides the I/O interface for it's childs.
+ *
+ * @reg_count: devices register count
+ * @read:      read 'len' bytes at "reg" and store it into the 'buffer'
+ * @write:     write 'len' bytes from the 'buffer' to the register at 'reg' address
+ */
+struct dm_pmic_ops {
+	int reg_count;
+	int (*read)(struct udevice *dev, uint reg, uint8_t *buffer, int len);
+	int (*write)(struct udevice *dev, uint reg, const uint8_t *buffer,
+		     int len);
+};
+
+/* enum pmic_op_type - used for various pmic devices operation calls,
+ * for reduce a number of lines with the same code for read/write or get/set.
+ *
+ * @PMIC_OP_GET - get operation
+ * @PMIC_OP_SET - set operation
+*/
+enum pmic_op_type {
+	PMIC_OP_GET,
+	PMIC_OP_SET,
+};
+
+/**
+ * struct pmic_child_info - basic device's child info for bind child nodes with
+ * the driver by the node name prefix and driver name. This is a helper struct
+ * for function: pmic_bind_childs().
+ *
+ * @prefix - child node name prefix (or its name if is unique or single)
+ * @driver - driver name for the sub-node with prefix
+ */
+struct pmic_child_info {
+	const char *prefix;
+	const char *driver;
+};
+
+/* drivers/power/pmic-uclass.c */
+
+/**
+ * pmic_bind_childs() - bind drivers for given parent pmic, using child info
+ * found in 'child_info' array.
+ *
+ * @pmic       - pmic device - the parent of found child's
+ * @child_info - N-childs info array
+ * @return a positive number of childs, or 0 if no child found (error)
+ *
+ * Note: For N-childs the child_info array should have N+1 entries and the last
+ * entry prefix should be NULL - the same as for drivers compatible.
+ *
+ * For example, a single prefix info (N=1):
+ * static const struct pmic_child_info bind_info[] = {
+ *     { .prefix = "ldo", .driver = "ldo_driver" },
+ *     { },
+ * };
+ *
+ * This function is useful for regulator sub-nodes:
+ * my_regulator@0xa {
+ *     reg = <0xa>;
+ *     (pmic - bind automatically by compatible)
+ *     compatible = "my_pmic";
+ *     ...
+ *     (pmic's childs - bind by pmic_bind_childs())
+ *     (nodes prefix: "ldo", driver: "my_regulator_ldo")
+ *     ldo1 { ... };
+ *     ldo2 { ... };
+ *
+ *     (nodes prefix: "buck", driver: "my_regulator_buck")
+ *     buck1 { ... };
+ *     buck2 { ... };
+ * };
+ */
+int pmic_bind_childs(struct udevice *pmic, int offset,
+		     const struct pmic_child_info *child_info);
+
+/**
+ * pmic_get: get the pmic device using its name
+ *
+ * @name - device name
+ * @devp - returned pointer to the pmic device
+ * @return 0 on success or negative value of errno.
+ *
+ * The returned devp device can be used with pmic_read/write calls
+ */
+int pmic_get(const char *name, struct udevice **devp);
+
+/**
+ * pmic_reg_count: get the pmic register count
+ *
+ * The required pmic device can be obtained by 'pmic_get()'
+ *
+ * @dev - pointer to the UCLASS_PMIC device
+ * @return register count value on success or negative value of errno.
+ */
+int pmic_reg_count(struct udevice *dev);
+
+/**
+ * pmic_read/write: read/write to the UCLASS_PMIC device
+ *
+ * The required pmic device can be obtained by 'pmic_get()'
+ *
+ * @pmic   - pointer to the UCLASS_PMIC device
+ * @reg    - device register offset
+ * @buffer - pointer to read/write buffer
+ * @len    - byte count for read/write
+ * @return 0 on success or negative value of errno.
+ */
+int pmic_read(struct udevice *dev, uint reg, uint8_t *buffer, int len);
+int pmic_write(struct udevice *dev, uint reg, const uint8_t *buffer, int len);
+#endif /* CONFIG_DM_PMIC */
 
+#ifdef CONFIG_POWER
 int pmic_init(unsigned char bus);
 int power_init_board(void);
 int pmic_dialog_init(unsigned char bus);
@@ -88,6 +276,7 @@ int pmic_probe(struct pmic *p);
 int pmic_reg_read(struct pmic *p, u32 reg, u32 *val);
 int pmic_reg_write(struct pmic *p, u32 reg, u32 val);
 int pmic_set_output(struct pmic *p, u32 reg, int ldo, int on);
+#endif
 
 #define pmic_i2c_addr (p->hw.i2c.addr)
 #define pmic_i2c_tx_num (p->hw.i2c.tx_num)