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    SubjectRe: [PATCH v2 3/5] regulator: helper routine to extract regulator_init_data
    On Mon, Oct 10, 2011 at 09:49:36PM +0530, Rajendra Nayak wrote:
    > The helper routine is meant to be used by regulator drivers
    > to extract the regulator_init_data structure from the data
    > that is passed from device tree.
    > 'consumer_supplies' which is part of regulator_init_data is not extracted
    > as the regulator consumer mappings are passed through DT differently,
    > implemented in subsequent patches.
    > Similarly the regulator<-->parent/supply mapping is handled in
    > subsequent patches.
    >
    > Also add documentation for regulator bindings to be used to pass
    > regulator_init_data struct information from device tree.
    >
    > Signed-off-by: Rajendra Nayak <rnayak@ti.com>
    > ---
    > .../devicetree/bindings/regulator/regulator.txt | 44 +++++++++
    > drivers/regulator/Kconfig | 8 ++
    > drivers/regulator/Makefile | 1 +
    > drivers/regulator/of_regulator.c | 93 ++++++++++++++++++++
    > include/linux/regulator/of_regulator.h | 21 +++++
    > 5 files changed, 167 insertions(+), 0 deletions(-)
    > create mode 100644 Documentation/devicetree/bindings/regulator/regulator.txt
    > create mode 100644 drivers/regulator/of_regulator.c
    > create mode 100644 include/linux/regulator/of_regulator.h
    >
    > diff --git a/Documentation/devicetree/bindings/regulator/regulator.txt b/Documentation/devicetree/bindings/regulator/regulator.txt
    > new file mode 100644
    > index 0000000..a623fdd
    > --- /dev/null
    > +++ b/Documentation/devicetree/bindings/regulator/regulator.txt
    > @@ -0,0 +1,44 @@
    > +Voltage/Current Regulators
    > +
    > +Optional properties:
    > +- regulator-min-uV: smallest voltage consumers may set
    > +- regulator-max-uV: largest voltage consumers may set
    > +- regulator-uV-offset: Offset applied to voltages to compensate for voltage drops
    > +- regulator-min-uA: smallest current consumers may set
    > +- regulator-max-uA: largest current consumers may set
    > +- regulator-change-voltage: boolean, Output voltage can be changed by software
    > +- regulator-change-current: boolean, Output current can be chnaged by software
    > +- regulator-change-mode: boolean, Operating mode can be changed by software
    > +- regulator-change-status: boolean, Enable/Disable control for regulator exists
    > +- regulator-change-drms: boolean, Dynamic regulator mode switching is enabled
    > +- regulator-mode-fast: boolean, allow/set fast mode for the regulator
    > +- regulator-mode-normal: boolean, allow/set normal mode for the regulator
    > +- regulator-mode-idle: boolean, allow/set idle mode for the regulator
    > +- regulator-mode-standby: boolean, allow/set standby mode for the regulator
    > +- regulator-input-uV: Input voltage for regulator when supplied by another regulator
    > +- regulator-always-on: boolean, regulator should never be disabled
    > +- regulator-boot-on: bootloader/firmware enabled regulator
    > +- <name>-supply: phandle to the parent supply/regulator node
    > +
    > +Example:
    > +
    > + xyzreg: regulator@0 {

    Does this node have a compatible string? With looking at the code,
    I guess it has a compatible string in your dts file.

    > + regulator-min-uV = <1000000>;
    > + regulator-max-uV = <2500000>;
    > + regulator-mode-fast;
    > + regulator-change-voltage;
    > + regulator-always-on;
    > + vin-supply = <&vin>;
    > + };
    > +
    > +The same binding used by a regulator to reference its
    > +supply can be used by any consumer to reference its
    > +regulator/supply
    > +
    > +Example of a device node referencing a regulator node,
    > +
    > + devicenode: node@0x0 {
    > + ...
    > + ...
    > + <name>-supply = <&xyzreg>;
    > + };
    > diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
    > index c7fd2c0..981c92e 100644
    > --- a/drivers/regulator/Kconfig
    > +++ b/drivers/regulator/Kconfig
    > @@ -64,6 +64,14 @@ config REGULATOR_USERSPACE_CONSUMER
    >
    > If unsure, say no.
    >
    > +config OF_REGULATOR
    > + tristate "OF regulator helpers"
    > + depends on OF
    > + default y if OF
    > + help
    > + OpenFirmware regulator framework helper routines that can
    > + used by regulator drivers to extract data from device tree.
    > +
    > config REGULATOR_BQ24022
    > tristate "TI bq24022 Dual Input 1-Cell Li-Ion Charger IC"
    > help
    > diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
    > index 040d5aa..e6bc009 100644
    > --- a/drivers/regulator/Makefile
    > +++ b/drivers/regulator/Makefile
    > @@ -7,6 +7,7 @@ obj-$(CONFIG_REGULATOR) += core.o dummy.o
    > obj-$(CONFIG_REGULATOR_FIXED_VOLTAGE) += fixed.o
    > obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o
    > obj-$(CONFIG_REGULATOR_USERSPACE_CONSUMER) += userspace-consumer.o
    > +obj-$(CONFIG_OF_REGULATOR) += of_regulator.o
    >
    > obj-$(CONFIG_REGULATOR_AD5398) += ad5398.o
    > obj-$(CONFIG_REGULATOR_BQ24022) += bq24022.o
    > diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
    > new file mode 100644
    > index 0000000..9262d06
    > --- /dev/null
    > +++ b/drivers/regulator/of_regulator.c
    > @@ -0,0 +1,93 @@
    > +/*
    > + * OF helpers for regulator framework
    > + *
    > + * Copyright (C) 2011 Texas Instruments, Inc.
    > + * Rajendra Nayak <rnayak@ti.com>
    > + *
    > + * This program is free software; you can redistribute it and/or modify
    > + * it under the terms of the GNU General Public License as published by
    > + * the Free Software Foundation; either version 2 of the License, or
    > + * (at your option) any later version.
    > + */
    > +
    > +#include <linux/slab.h>
    > +#include <linux/of.h>
    > +#include <linux/regulator/machine.h>
    > +
    > +static void of_get_regulation_constraints(struct device_node *np,
    > + struct regulator_init_data **init_data)
    > +{
    > + const __be32 *min_uV, *max_uV, *uV_offset;
    > + const __be32 *min_uA, *max_uA, *input_uV;
    > + unsigned int valid_modes_mask = 0, valid_ops_mask = 0;
    > +
    > + min_uV = of_get_property(np, "regulator-min-uV", NULL);
    > + if (min_uV)
    > + (*init_data)->constraints.min_uV = be32_to_cpu(*min_uV);
    > + max_uV = of_get_property(np, "regulator-max-uV", NULL);
    > + if (max_uV)
    > + (*init_data)->constraints.max_uV = be32_to_cpu(*max_uV);
    > + uV_offset = of_get_property(np, "regulator-uV-offset", NULL);
    > + if (uV_offset)
    > + (*init_data)->constraints.uV_offset = be32_to_cpu(*uV_offset);
    > + min_uA = of_get_property(np, "regulator-min-uA", NULL);
    > + if (min_uA)
    > + (*init_data)->constraints.min_uA = be32_to_cpu(*min_uA);
    > + max_uA = of_get_property(np, "regulator-max-uA", NULL);
    > + if (max_uA)
    > + (*init_data)->constraints.max_uA = be32_to_cpu(*max_uA);
    > + input_uV = of_get_property(np, "regulator-input-uV", NULL);
    > + if (input_uV)
    > + (*init_data)->constraints.input_uV = be32_to_cpu(*input_uV);
    > +
    > + /* valid modes mask */
    > + if (of_find_property(np, "regulator-mode-fast", NULL))
    > + valid_modes_mask |= REGULATOR_MODE_FAST;
    > + if (of_find_property(np, "regulator-mode-normal", NULL))
    > + valid_modes_mask |= REGULATOR_MODE_NORMAL;
    > + if (of_find_property(np, "regulator-mode-idle", NULL))
    > + valid_modes_mask |= REGULATOR_MODE_IDLE;
    > + if (of_find_property(np, "regulator-mode-standby", NULL))
    > + valid_modes_mask |= REGULATOR_MODE_STANDBY;
    > +
    > + /* valid ops mask */
    > + if (of_find_property(np, "regulator-change-voltage", NULL))
    > + valid_ops_mask |= REGULATOR_CHANGE_VOLTAGE;
    > + if (of_find_property(np, "regulator-change-current", NULL))
    > + valid_ops_mask |= REGULATOR_CHANGE_CURRENT;
    > + if (of_find_property(np, "regulator-change-mode", NULL))
    > + valid_ops_mask |= REGULATOR_CHANGE_MODE;
    > + if (of_find_property(np, "regulator-change-status", NULL))
    > + valid_ops_mask |= REGULATOR_CHANGE_STATUS;
    > +
    > + (*init_data)->constraints.valid_modes_mask = valid_modes_mask;
    > + (*init_data)->constraints.valid_ops_mask = valid_ops_mask;
    > +
    > + if (of_find_property(np, "regulator-always-on", NULL))
    > + (*init_data)->constraints.always_on = true;
    > + if (of_find_property(np, "regulator-boot-on", NULL))
    > + (*init_data)->constraints.boot_on = true;
    > +}
    > +
    > +/**
    > + * of_get_regulator_init_data - extract regulator_init_data structure info
    > + * @dev: device requesting for regulator_init_data
    > + *
    > + * Populates regulator_init_data structure by extracting data from device
    > + * tree node, returns a pointer to the populated struture or NULL if memory
    > + * alloc fails.
    > + */
    > +struct regulator_init_data *of_get_regulator_init_data(struct device *dev)

    I remember that Mark ever had a comment on a previous regulator DT
    series from Haojian Zhuang, saying this DT parsing procedure can
    probably just be private to regulator core and invisible to regulator
    drivers. That said whenever regulator_register() gets called with
    parameter init_data as NULL, it should try to retrieve
    regulator_init_data from device tree. It will ease regulator drivers
    a little. They will only need to call regulator_register() with NULL
    init_data for DT case. More importantly, doing so will help solve the
    dual 'dev' problem I see below.

    > +{
    > + struct regulator_init_data *init_data;
    > +
    > + if (!dev->of_node)
    > + return NULL;
    > +
    > + init_data = devm_kzalloc(dev, sizeof(*init_data), GFP_KERNEL);
    > + if (!init_data)
    > + return NULL; /* Out of memory? */
    > +
    > + of_get_regulation_constraints(dev->of_node, &init_data);

    Beside the 'dev' here with of_node attached, there will be another
    'dev' created by regulator core function regulator_register(), which
    is wrapped by 'regulator_dev'.

    So we have two 'dev'. One is created by DT core with of_node attached,
    and used to retrieve regulator_init_data from device tree. Another one
    is created in regulator_register() and used by regulator core.

    IMO, this is not what we want. Instead of having two 'dev' for given
    regulator, we should use the same 'dev' created in regulator_register()
    to retrieve regulator_init_data from device tree, so that we do not need
    the 'dev' created by DT core. That said, with DT parsing procedure
    moved into regulator core, we can get of_node for given regulator and
    attach it to the 'dev' created by regulator core.

    Will elaborate it a little more in patch #5.

    Regards,
    Shawn

    > + return init_data;
    > +}
    > diff --git a/include/linux/regulator/of_regulator.h b/include/linux/regulator/of_regulator.h
    > new file mode 100644
    > index 0000000..c5a1ad6
    > --- /dev/null
    > +++ b/include/linux/regulator/of_regulator.h
    > @@ -0,0 +1,21 @@
    > +/*
    > + * OpenFirmware regulator support routines
    > + *
    > + */
    > +
    > +#ifndef __LINUX_OF_REG_H
    > +#define __LINUX_OF_REG_H
    > +
    > +#if defined(CONFIG_OF_REGULATOR)
    > +extern struct regulator_init_data
    > + *of_get_regulator_init_data(struct device *dev);
    > +#else
    > +static inline struct regulator_init_data
    > + *of_get_regulator_init_data(struct device *dev)
    > +{
    > + return NULL;
    > +}
    > +#endif /* CONFIG_OF_REGULATOR */
    > +
    > +#endif /* __LINUX_OF_REG_H */
    > +
    > --
    > 1.7.1
    >
    > _______________________________________________
    > devicetree-discuss mailing list
    > devicetree-discuss@lists.ozlabs.org
    > https://lists.ozlabs.org/listinfo/devicetree-discuss
    >



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