dm: regulator: add implementation of driver model regulator uclass

This commit introduces the implementation of dm regulator API.
Device tree support allows for auto binding. And by the basic
uclass operations, it allows to driving the devices in a common
way. For detailed informations, please look into the header file.

Core files:
- drivers/power/regulator-uclass.c - provides regulator common functions api
- include/power/regulator.h - define all structures required by the regulator

Changes:
- new uclass-id: UCLASS_REGULATOR
- new config: CONFIG_DM_REGULATOR

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

2 files changed, 385 insertions, 0 deletions

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index e7adf53..4d737f4 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -51,6 +51,7 @@ enum uclass_id {
 
 	/* Power Management */
 	UCLASS_PMIC,		/* PMIC I/O device */
+	UCLASS_REGULATOR,	/* REGULATOR device */
 
 	UCLASS_COUNT,
 	UCLASS_INVALID = -1,
diff --git a/include/power/regulator.h b/include/power/regulator.h
new file mode 100644
index 0000000..0302c1d
--- /dev/null
+++ b/include/power/regulator.h
@@ -0,0 +1,384 @@
+/*
+ *  Copyright (C) 2014-2015 Samsung Electronics
+ *  Przemyslaw Marczak <p.marczak@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _INCLUDE_REGULATOR_H_
+#define _INCLUDE_REGULATOR_H_
+
+/**
+ * U-Boot Voltage/Current Regulator
+ * ================================
+ *
+ * The regulator API is based on a driver model, with the device tree support.
+ * And this header describes the functions and data types for the uclass id:
+ * 'UCLASS_REGULATOR' and the regulator driver API.
+ *
+ * The regulator uclass - is based on uclass platform data which is allocated,
+ * automatically for each regulator device on bind and 'dev->uclass_platdata'
+ * points to it. The data type is: 'struct dm_regulator_uclass_platdata'.
+ * The uclass file: 'drivers/power/regulator/regulator-uclass.c'
+ *
+ * The regulator device - is based on driver's model 'struct udevice'.
+ * The API can use regulator name in two meanings:
+ * - devname  - the regulator device's name: 'dev->name'
+ * - platname - the device's platdata's name. So in the code it looks like:
+ *              'uc_pdata = dev->uclass_platdata'; 'name = uc_pdata->name'.
+ *
+ * The regulator device driver - provide an implementation of uclass operations
+ * pointed by 'dev->driver->ops' as a struct of type 'struct dm_regulator_ops'.
+ *
+ * To proper bind the regulator device, the device tree node should provide
+ * regulator constraints, like in the example below:
+ *
+ * ldo1 {
+ *      regulator-name = "VDD_MMC_1.8V";     (mandatory for bind)
+ *      regulator-min-microvolt = <1000000>; (optional)
+ *      regulator-max-microvolt = <1000000>; (optional)
+ *      regulator-min-microamp = <1000>;     (optional)
+ *      regulator-max-microamp = <1000>;     (optional)
+ *      regulator-always-on;                 (optional)
+ *      regulator-boot-on;                   (optional)
+ * };
+ *
+ * Please take a notice, that for the proper operation at least name constraint
+ * is needed, e.g. for call the device_by_platname(...).
+ *
+ * Regulator bind:
+ * For each regulator device, the device_bind() should be called with passed
+ * device tree offset. This is required for this uclass's '.post_bind' method,
+ * which do the scan on the device node, for the 'regulator-name' constraint.
+ * If the parent is not a PMIC device, and the child is not bind by function:
+ * 'pmic_bind_childs()', then it's recommended to bind the device by call to
+ * dm_scan_fdt_node() - this is usually done automatically for bus devices,
+ * as a post bind method.
+ * Having the device's name constraint, we can call regulator_by_platname(),
+ * to find interesting regulator. Before return, the regulator is probed,
+ * and the rest of its constraints are put into the device's uclass platform
+ * data, by the uclass regulator '.pre_probe' method.
+ *
+ * For more info about PMIC bind, please refer to file: 'include/power/pmic.h'
+ *
+ * Note:
+ * Please do not use the device_bind_by_name() function, since it pass '-1' as
+ * device node offset - and the bind will fail on uclass .post_bind method,
+ * because of missing 'regulator-name' constraint.
+ *
+ *
+ * Fixed Voltage/Current Regulator
+ * ===============================
+ *
+ * When fixed voltage regulator is needed, then enable the config:
+ * - CONFIG_DM_REGULATOR_FIXED
+ *
+ * The driver file: 'drivers/power/regulator/fixed.c', provides basic support
+ * for control the GPIO, and return the device tree constraint values.
+ *
+ * To bind the fixed voltage regulator device, we usually use a 'simple-bus'
+ * node as a parent. And 'regulator-fixed' for the driver compatible. This is
+ * the same as in the kernel. The example node of fixed regulator:
+ *
+ * simple-bus {
+ *     compatible = "simple-bus";
+ *     #address-cells = <1>;
+ *     #size-cells = <0>;
+ *
+ *     blue_led {
+ *         compatible = "regulator-fixed";
+ *         regulator-name = "VDD_LED_3.3V";
+ *         regulator-min-microvolt = <3300000>;
+ *         regulator-max-microvolt = <3300000>;
+ *         gpio = <&gpc1 0 GPIO_ACTIVE_LOW>;
+ *     };
+ * };
+ *
+ * The fixed regulator devices also provide regulator uclass platform data. And
+ * devices bound from such node, can use the regulator drivers API.
+*/
+
+/* enum regulator_type - used for regulator_*() variant calls */
+enum regulator_type {
+	REGULATOR_TYPE_LDO = 0,
+	REGULATOR_TYPE_BUCK,
+	REGULATOR_TYPE_DVS,
+	REGULATOR_TYPE_FIXED,
+	REGULATOR_TYPE_OTHER,
+};
+
+/**
+ * struct dm_regulator_mode - this structure holds an information about
+ * each regulator operation mode. Probably in most cases - an array.
+ * This will be probably a driver-static data, since it is device-specific.
+ *
+ * @id             - a driver-specific mode id
+ * @register_value - a driver-specific value for its mode id
+ * @name           - the name of mode - used for regulator command
+ * Note:
+ * The field 'id', should be always a positive number, since the negative values
+ * are reserved for the errno numbers when returns the mode id.
+ */
+struct dm_regulator_mode {
+	int id; /* Set only as >= 0 (negative value is reserved for errno) */
+	int register_value;
+	const char *name;
+};
+
+/**
+ * struct dm_regulator_uclass_platdata - pointed by dev->uclass_platdata, and
+ * allocated on each regulator bind. This structure holds an information
+ * about each regulator's constraints and supported operation modes.
+ * There is no "step" voltage value - so driver should take care of this.
+ *
+ * @type       - one of 'enum regulator_type'
+ * @mode       - pointer to the regulator mode (array if more than one)
+ * @mode_count - number of '.mode' entries
+ * @min_uV*    - minimum voltage (micro Volts)
+ * @max_uV*    - maximum voltage (micro Volts)
+ * @min_uA*    - minimum amperage (micro Amps)
+ * @max_uA*    - maximum amperage (micro Amps)
+ * @always_on* - bool type, true or false
+ * @boot_on*   - bool type, true or false
+ * @name**     - fdt regulator name - should be taken from the device tree
+ *
+ * Note:
+ * *  - set automatically on device probe by the uclass's '.pre_probe' method.
+ * ** - set automatically on device bind by the uclass's '.post_bind' method.
+ * The constraints: type, mode, mode_count, can be set by device driver, e.g.
+ * by the driver '.probe' method.
+ */
+struct dm_regulator_uclass_platdata {
+	enum regulator_type type;
+	struct dm_regulator_mode *mode;
+	int mode_count;
+	int min_uV;
+	int max_uV;
+	int min_uA;
+	int max_uA;
+	bool always_on;
+	bool boot_on;
+	const char *name;
+};
+
+/* Regulator device operations */
+struct dm_regulator_ops {
+	/**
+	 * The regulator output value function calls operates on a micro Volts.
+	 *
+	 * get/set_value - get/set output value of the given output number
+	 * @dev          - regulator device
+	 * Sets:
+	 * @uV           - set the output value [micro Volts]
+	 * Returns: output value [uV] on success or negative errno if fail.
+	 */
+	int (*get_value)(struct udevice *dev);
+	int (*set_value)(struct udevice *dev, int uV);
+
+	/**
+	 * The regulator output current function calls operates on a micro Amps.
+	 *
+	 * get/set_current - get/set output current of the given output number
+	 * @dev            - regulator device
+	 * Sets:
+	 * @uA           - set the output current [micro Amps]
+	 * Returns: output value [uA] on success or negative errno if fail.
+	 */
+	int (*get_current)(struct udevice *dev);
+	int (*set_current)(struct udevice *dev, int uA);
+
+	/**
+	 * The most basic feature of the regulator output is its enable state.
+	 *
+	 * get/set_enable - get/set enable state of the given output number
+	 * @dev           - regulator device
+	 * Sets:
+	 * @enable         - set true - enable or false - disable
+	 * Returns: true/false for get; or 0 / -errno for set.
+	 */
+	bool (*get_enable)(struct udevice *dev);
+	int (*set_enable)(struct udevice *dev, bool enable);
+
+	/**
+	 * The 'get/set_mode()' function calls should operate on a driver
+	 * specific mode definitions, which should be found in:
+	 * field 'mode' of struct mode_desc.
+	 *
+	 * get/set_mode - get/set operation mode of the given output number
+	 * @dev         - regulator device
+	 * Sets
+	 * @mode_id     - set output mode id (struct dm_regulator_mode->id)
+	 * Returns: id/0 for get/set on success or negative errno if fail.
+	 * Note:
+	 * The field 'id' of struct type 'dm_regulator_mode', should be always
+	 * positive number, since the negative is reserved for the error.
+	 */
+	int (*get_mode)(struct udevice *dev);
+	int (*set_mode)(struct udevice *dev, int mode_id);
+};
+
+/**
+ * regulator_mode: returns a pointer to the array of regulator mode info
+ *
+ * @dev        - pointer to the regulator device
+ * @modep      - pointer to the returned mode info array
+ * Returns     - count of modep entries on success or negative errno if fail.
+ */
+int regulator_mode(struct udevice *dev, struct dm_regulator_mode **modep);
+
+/**
+ * regulator_get_value: get microvoltage voltage value of a given regulator
+ *
+ * @dev    - pointer to the regulator device
+ * Returns - positive output value [uV] on success or negative errno if fail.
+ */
+int regulator_get_value(struct udevice *dev);
+
+/**
+ * regulator_set_value: set the microvoltage value of a given regulator.
+ *
+ * @dev    - pointer to the regulator device
+ * @uV     - the output value to set [micro Volts]
+ * Returns - 0 on success or -errno val if fails
+ */
+int regulator_set_value(struct udevice *dev, int uV);
+
+/**
+ * regulator_get_current: get microampere value of a given regulator
+ *
+ * @dev    - pointer to the regulator device
+ * Returns - positive output current [uA] on success or negative errno if fail.
+ */
+int regulator_get_current(struct udevice *dev);
+
+/**
+ * regulator_set_current: set the microampere value of a given regulator.
+ *
+ * @dev    - pointer to the regulator device
+ * @uA     - set the output current [micro Amps]
+ * Returns - 0 on success or -errno val if fails
+ */
+int regulator_set_current(struct udevice *dev, int uA);
+
+/**
+ * regulator_get_enable: get regulator device enable state.
+ *
+ * @dev    - pointer to the regulator device
+ * Returns - true/false of enable state
+ */
+bool regulator_get_enable(struct udevice *dev);
+
+/**
+ * regulator_set_enable: set regulator enable state
+ *
+ * @dev    - pointer to the regulator device
+ * @enable - set true or false
+ * Returns - 0 on success or -errno val if fails
+ */
+int regulator_set_enable(struct udevice *dev, bool enable);
+
+/**
+ * regulator_get_mode: get mode of a given device regulator
+ *
+ * @dev    - pointer to the regulator device
+ * Returns - positive  mode number on success or -errno val if fails
+ * Note:
+ * The regulator driver should return one of defined, mode number rather, than
+ * the raw register value. The struct type 'mode_desc' provides a field 'mode'
+ * for this purpose and register_value for a raw register value.
+ */
+int regulator_get_mode(struct udevice *dev);
+
+/**
+ * regulator_set_mode: set given regulator mode
+ *
+ * @dev    - pointer to the regulator device
+ * @mode   - mode type (field 'mode' of struct mode_desc)
+ * Returns - 0 on success or -errno value if fails
+ * Note:
+ * The regulator driver should take one of defined, mode number rather
+ * than a raw register value. The struct type 'regulator_mode_desc' has
+ * a mode field for this purpose and register_value for a raw register value.
+ */
+int regulator_set_mode(struct udevice *dev, int mode);
+
+/**
+ * regulator_by_platname_autoset_and_enable: setup the regulator given by
+ * its uclass's platform data '.name'. The setup depends on constraints found
+ * in device's uclass's platform data (struct dm_regulator_uclass_platdata):
+ * - Voltage value - will set - if '.min_uV' and '.max_uV' values are equal
+ * - Current limit - will set - if '.min_uA' and '.max_uA' values are equal
+ * - Enable - will set - if '.always_on' or '.boot_on' are set to true
+ *
+ * The function returns on first encountered error.
+ *
+ * @platname - expected string for dm_regulator_uclass_platdata .name field
+ * @devp      - returned pointer to the regulator device - if non-NULL passed
+ * @verbose   - (true/false) print regulator setup info, or be quiet
+ * Returns: 0 on success or negative value of errno.
+ *
+ * The returned 'regulator' device can be used with:
+ * - regulator_get/set_*
+ * For shorter call name, the below macro regulator_autoset() can be used.
+ */
+int regulator_by_platname_autoset_and_enable(const char *platname,
+					     struct udevice **devp,
+					     bool verbose);
+
+#define regulator_autoset(platname, devp, verbose) \
+	regulator_by_platname_autoset_and_enable(platname, devp, verbose)
+
+/**
+ * regulator_by_platname_list_autoset_and_enable: setup the regulators given by
+ * list of its uclass's platform data '.name'. The setup depends on constraints
+ * found in device's uclass's platform data. The function loops with calls to:
+ * regulator_by_platname_autoset_and_enable() for each name of list.
+ *
+ * @list_platname - an array of expected strings for .name field of each
+ *                  regulator's uclass platdata
+ * @list_entries  - number of regulator's name list entries
+ * @list_devp     - an array of returned pointers to the successfully setup
+ *                  regulator devices if non-NULL passed
+ * @verbose       - (true/false) print each regulator setup info, or be quiet
+ * Returns: 0 on successfully setup of all list entries or 1 otwerwise.
+ *
+ * The returned 'regulator' devices can be used with:
+ * - regulator_get/set_*
+ * For shorter call name, the below macro regulator_list_autoset() can be used.
+ */
+int regulator_by_platname_list_autoset_and_enable(const char *list_platname[],
+						  int list_entries,
+						  struct udevice *list_devp[],
+						  bool verbose);
+
+#define regulator_list_autoset(namelist, entries, devlist, verbose)      \
+	regulator_by_platname_list_autoset_and_enable(namelist, entries, \
+						      devlist, verbose)
+
+/**
+ * regulator_by_devname: returns the pointer to the pmic regulator device.
+ *                       Search by name, found in regulator device's name.
+ *
+ * @devname - expected string for 'dev->name' of regulator device
+ * @devp     - returned pointer to the regulator device
+ * Returns: 0 on success or negative value of errno.
+ *
+ * The returned 'regulator' device can be used with:
+ * - regulator_get/set_*
+ */
+int regulator_by_devname(const char *devname, struct udevice **devp);
+
+/**
+ * regulator_by_platname: returns the pointer to the pmic regulator device.
+ *                        Search by name, found in regulator uclass platdata.
+ *
+ * @platname - expected string for dm_regulator_uclass_platdata .name field
+ * @devp     - returned pointer to the regulator device
+ * Returns: 0 on success or negative value of errno.
+ *
+ * The returned 'regulator' device can be used with:
+ * - regulator_get/set_*
+ */
+int regulator_by_platname(const char *platname, struct udevice **devp);
+
+#endif /* _INCLUDE_REGULATOR_H_ */