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Message-Id: <20120313034306.16CF73E07E4@localhost>
Date: Mon, 12 Mar 2012 21:43:06 -0600
From: Grant Likely <grant.likely@...retlab.ca>
To: Thomas Abraham <thomas.abraham@...aro.org>,
linux-kernel@...r.kernel.org
Cc: k.lewandowsk@...sung.com, devicetree-discuss@...ts.ozlabs.org,
rob.herring@...xeda.com, kgene.kim@...sung.com,
broonie@...nsource.wolfsonmicro.com, myungjoo.ham@...sung.com,
kyungmin.park@...sung.com, dg77.kim@...sung.com,
linux-arm-kernel@...ts.infradead.org,
linux-samsung-soc@...r.kernel.org, Rajendra Nayak <rnayak@...com>
Subject: Re: [PATCH v3 2/2] regulator: add device tree support for max8997
On Thu, 23 Feb 2012 18:08:08 +0530, Thomas Abraham <thomas.abraham@...aro.org> wrote:
> Add device tree based discovery support for max8997.
>
> Cc: MyungJoo Ham <myungjoo.ham@...sung.com>
> Cc: Rajendra Nayak <rnayak@...com>
> Cc: Rob Herring <rob.herring@...xeda.com>
> Cc: Grant Likely <grant.likely@...retlab.ca>
> Signed-off-by: Thomas Abraham <thomas.abraham@...aro.org>
> ---
> .../devicetree/bindings/regulator/max8997-pmic.txt | 134 +++++++++++++++++++
> drivers/mfd/max8997.c | 72 ++++++++++-
> drivers/regulator/max8997.c | 139 +++++++++++++++++++-
> include/linux/mfd/max8997.h | 1 +
> 4 files changed, 344 insertions(+), 2 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/regulator/max8997-pmic.txt
>
> diff --git a/Documentation/devicetree/bindings/regulator/max8997-pmic.txt b/Documentation/devicetree/bindings/regulator/max8997-pmic.txt
> new file mode 100644
> index 0000000..d282635
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/regulator/max8997-pmic.txt
> @@ -0,0 +1,134 @@
> +* Maxim MAX8997 Voltage and Current Regulator
> +
> +The Maxim MAX8997 is a multi-function device which includes volatage and
> +current regulators, rtc, charger controller and other sub-blocks. It is
> +interfaced to the host controller using a i2c interface. Each sub-block is
> +addressed by the host system using different i2c slave address. This document
> +describes the bindings for 'pmic' sub-block of max8997.
> +
> +Required properties:
> +- compatible: Should be "maxim,max8997-pmic".
> +- reg: Specifies the i2c slave address of the pmic block. It should be 0x66.
> +
> +- max8997,pmic-buck1-dvs-voltage: A set of 8 voltage values in micro-volt (uV)
> + units for buck1 when changing voltage using gpio dvs. Refer to [1] below
> + for additional information.
> +
> +- max8997,pmic-buck2-dvs-voltage: A set of 8 voltage values in micro-volt (uV)
> + units for buck2 when changing voltage using gpio dvs. Refer to [1] below
> + for additional information.
> +
> +- max8997,pmic-buck5-dvs-voltage: A set of 8 voltage values in micro-volt (uV)
> + units for buck5 when changing voltage using gpio dvs. Refer to [1] below
> + for additional information.
> +
> +[1] If none of the 'max8997,pmic-buck[1/2/5]-uses-gpio-dvs' optional
> + property is specified, the 'max8997,pmic-buck[1/2/5]-dvs-voltage'
> + property should specify atleast one voltage level (which would be a
> + safe operating voltage).
> +
> + If either of the 'max8997,pmic-buck[1/2/5]-uses-gpio-dvs' optional
> + property is specified, then all the eigth voltage values for the
> + 'max8997,pmic-buck[1/2/5]-dvs-voltage' should be specified.
> +
> +Optional properties:
> +- interrupt-parent: Specifies the phandle of the interrupt controller to which
> + the interrupts from max8997 are delivered to.
> +- interrupts: Interrupt specifiers for two interrupt sources.
> + - First interrupt specifier is for 'irq1' interrupt.
> + - Second interrupt specifier is for 'alert' interrupt.
> +- max8997,pmic-buck1-uses-gpio-dvs: 'buck1' can be controlled by gpio dvs.
> +- max8997,pmic-buck2-uses-gpio-dvs: 'buck2' can be controlled by gpio dvs.
> +- max8997,pmic-buck5-uses-gpio-dvs: 'buck5' can be controlled by gpio dvs.
> +
> +Additional properties required if either of the optional properties are used:
> +- max8997,pmic-ignore-gpiodvs-side-effect: When GPIO-DVS mode is used for
> + multiple bucks, changing the voltage value of one of the bucks may affect
> + that of another buck, which is the side effect of the change (set_voltage).
> + Use this property to ignore such side effects and change the voltage.
> +
> +- max8997,pmic-buck125-default-dvs-idx: Default voltage setting selected from
> + the possible 8 options selectable by the dvs gpios. The value of this
> + property should be between 0 and 7. If not specified or if out of range, the
> + default value of this property is set to 0.
> +
> +- max8997,pmic-buck125-dvs-gpios: GPIO specifiers for three host gpio's used
> + for dvs. The format of the gpio specifier depends in the gpio controller.
> +
> +
> +Regulators: The regulators of max8997 that have to be instantiated should be
> +included in a sub-node named 'regulators'. Regulator nodes included in this
> +sub-node should be of the format as below. Note: The 'n' in LDOn and BUCKn
> +represents the LDO or BUCK number as per the datasheet of max8997.
> +
> + For LDO's:
> + LDOn {
> + standard regulator bindings here
> + };
> +
> + For BUCK's:
> + BUCKn {
> + standard regulator bindings here
> + };
> +
> +The bindings inside the regulator nodes use the standard regulator bindings
> +which are documented elsewhere.
> +
> +Example:
> +
> + max8997_pmic@66 {
> + compatible = "maxim,max8997-pmic";
> + interrupt-parent = <&wakeup_eint>;
> + reg = <0x66>;
> + interrupts = <4 0>, <3 0>;
> +
> + max8997,pmic-buck1-uses-gpio-dvs;
> + max8997,pmic-buck2-uses-gpio-dvs;
> + max8997,pmic-buck5-uses-gpio-dvs;
> +
> + max8997,pmic-ignore-gpiodvs-side-effect;
> + max8997,pmic-buck125-default-dvs-idx = <0>;
> +
> + max8997,pmic-buck125-dvs-gpios = <&gpx0 0 1 0 0>, /* SET1 */
> + <&gpx0 1 1 0 0>, /* SET2 */
> + <&gpx0 2 1 0 0>; /* SET3 */
> +
> + max8997,pmic-buck1-dvs-voltage = <1350000>, <1300000>,
> + <1250000>, <1200000>,
> + <1150000>, <1100000>,
> + <1000000>, <950000>;
> +
> + max8997,pmic-buck2-dvs-voltage = <1100000>, <1100000>,
> + <1100000>, <1100000>,
> + <1000000>, <1000000>,
> + <1000000>, <1000000>;
> +
> + max8997,pmic-buck5-dvs-voltage = <1200000>, <1200000>,
> + <1200000>, <1200000>,
> + <1200000>, <1200000>,
> + <1200000>, <1200000>;
> +
> + regulators {
> + ldo1_reg: LDO1 {
> + regulator-name = "VDD_ABB_3.3V";
> + regulator-min-microvolt = <3300000>;
> + regulator-max-microvolt = <3300000>;
> + };
> +
> + ldo2_reg: LDO2 {
> + regulator-name = "VDD_ALIVE_1.1V";
> + regulator-min-microvolt = <1100000>;
> + regulator-max-microvolt = <1100000>;
> + regulator-always-on;
> + };
> +
> + buck1_reg: BUCK1 {
> + regulator-name = "VDD_ARM_1.2V";
> + regulator-min-microvolt = <950000>;
> + regulator-max-microvolt = <1350000>;
> + regulator-always-on;
> + regulator-boot-on;
> + };
> + };
> + };
> +
Good documentation
> diff --git a/drivers/mfd/max8997.c b/drivers/mfd/max8997.c
> index 20ecad3..13180be 100644
> --- a/drivers/mfd/max8997.c
> +++ b/drivers/mfd/max8997.c
> @@ -23,6 +23,7 @@
>
> #include <linux/slab.h>
> #include <linux/i2c.h>
> +#include <linux/of_irq.h>
> #include <linux/interrupt.h>
> #include <linux/pm_runtime.h>
> #include <linux/module.h>
> @@ -123,6 +124,60 @@ int max8997_update_reg(struct i2c_client *i2c, u8 reg, u8 val, u8 mask)
> }
> EXPORT_SYMBOL_GPL(max8997_update_reg);
>
> +#ifdef CONFIG_OF
> +/*
> + * Only the common platform data elements for max8997 are parsed here from the
> + * device tree. Other sub-modules of max8997 such as pmic, rtc and others have
> + * to parse their own platform data elements from device tree.
> + *
> + * The max8997 platform data structure is instantiated here and the drivers for
> + * the sub-modules need not instantiate another instance while parsing their
> + * platform data.
> + */
> +static int max8997_i2c_parse_dt_pdata(struct device *dev,
> + struct max8997_platform_data **pdata)
> +{
> + struct max8997_platform_data *pd;
> +
> + pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
> + if (!pd) {
> + dev_err(dev, "could not allocate memory for pdata\n");
> + return -ENOMEM;
> + }
> +
> + pd->ono = irq_of_parse_and_map(dev->of_node, 1);
> +
> + /*
> + * ToDo: the 'wakeup' member in the platform data is more of a linux
> + * specfic information. Hence, there is no binding for that yet and
> + * not parsed here.
> + */
> +
> + *pdata = pd;
> + return 0;
> +}
> +#else
> +static int max8997_i2c_parse_dt_pdata(struct device *dev,
> + struct max8997_platform_data **pdata)
> +{
> + return 0;
> +}
> +#endif
> +
> +static struct of_device_id __devinitdata max8997_pmic_dt_match[];
Move the actual definition of this structure up to here so that a forward
declaration becomes unnecessary.
> +static inline int max8997_i2c_get_driver_data(struct i2c_client *i2c,
> + const struct i2c_device_id *id)
> +{
> +#ifdef CONFIG_OF
> + if (i2c->dev.of_node) {
> + const struct of_device_id *match;
> + match = of_match_node(max8997_pmic_dt_match, i2c->dev.of_node);
> + return (int)match->data;
> + }
> +#endif
> + return (int)id->driver_data;
> +}
> +
> static int max8997_i2c_probe(struct i2c_client *i2c,
> const struct i2c_device_id *id)
> {
> @@ -137,9 +192,16 @@ static int max8997_i2c_probe(struct i2c_client *i2c,
> i2c_set_clientdata(i2c, max8997);
> max8997->dev = &i2c->dev;
> max8997->i2c = i2c;
> - max8997->type = id->driver_data;
> + max8997->type = max8997_i2c_get_driver_data(i2c, id);
> max8997->irq = i2c->irq;
>
> + if (max8997->dev->of_node) {
> + ret = max8997_i2c_parse_dt_pdata(max8997->dev, &pdata);
> + if (ret)
> + goto err;
> + i2c->dev.platform_data = pdata;
This line is illegal. Drivers must *not* change the value of dev->platform_data.
instead the valid pdata pointer needs to be stored in the max8997 private data
structure.
> + }
> +
If you tweak the definition of max8997_i2c_parse_dt_pdata() then this block can
be simplified to:
pdata = max8997_i2c_parse_dt_pdata(max8997->dev, &pdata);
if (!pdata)
pdata = i2c->dev.platform_data,
if (!pdata)
goto err;
Otherwise, the patch looks pretty good. (although seeing the decode function
has got me thinking that we need a much better way of decoding the dt data).
g.
>
> @@ -429,11 +491,19 @@ const struct dev_pm_ops max8997_pm = {
> .restore = max8997_restore,
> };
>
> +#ifdef CONFIG_OF
> +static struct of_device_id __devinitdata max8997_pmic_dt_match[] = {
> + { .compatible = "maxim,max8997-pmic", .data = TYPE_MAX8997 },
> + {},
> +};
> +#endif
> +
> static struct i2c_driver max8997_i2c_driver = {
> .driver = {
> .name = "max8997",
> .owner = THIS_MODULE,
> .pm = &max8997_pm,
> + .of_match_table = of_match_ptr(max8997_pmic_dt_match),
> },
> .probe = max8997_i2c_probe,
> .remove = max8997_i2c_remove,
> diff --git a/drivers/regulator/max8997.c b/drivers/regulator/max8997.c
> index bb7cd9d..b31c4c9 100644
> --- a/drivers/regulator/max8997.c
> +++ b/drivers/regulator/max8997.c
> @@ -25,6 +25,7 @@
> #include <linux/delay.h>
> #include <linux/err.h>
> #include <linux/gpio.h>
> +#include <linux/of_gpio.h>
> #include <linux/slab.h>
> #include <linux/module.h>
> #include <linux/platform_device.h>
> @@ -32,6 +33,7 @@
> #include <linux/regulator/machine.h>
> #include <linux/mfd/max8997.h>
> #include <linux/mfd/max8997-private.h>
> +#include <linux/regulator/of_regulator.h>
>
> struct max8997_data {
> struct device *dev;
> @@ -958,6 +960,134 @@ static struct regulator_desc regulators[] = {
> },
> };
>
> +#ifdef CONFIG_OF
> +static int max8997_pmic_dt_parse_dvs_gpio(struct max8997_dev *iodev,
> + struct max8997_platform_data *pdata,
> + struct device_node *pmic_np)
> +{
> + int i, gpio;
> +
> + for (i = 0; i < 3; i++) {
> + gpio = of_get_named_gpio(pmic_np,
> + "max8997,pmic-buck125-dvs-gpios", i);
> + if (!gpio_is_valid(gpio)) {
> + dev_err(iodev->dev, "invalid gpio[%d]: %d\n", i, gpio);
> + return -EINVAL;
> + }
> + pdata->buck125_gpios[i] = gpio;
> + }
> + return 0;
> +}
> +
> +static int max8997_pmic_dt_parse_pdata(struct max8997_dev *iodev,
> + struct max8997_platform_data *pdata)
> +{
> + struct device_node *pmic_np, *regulators_np, *reg_np;
> + struct max8997_regulator_data *rdata;
> + unsigned int i, dvs_voltage_nr = 1, ret;
> +
> + pmic_np = iodev->dev->of_node;
> + if (!pmic_np) {
> + dev_err(iodev->dev, "could not find pmic sub-node\n");
> + return -ENODEV;
> + }
> +
> + regulators_np = of_find_node_by_name(pmic_np, "regulators");
> + if (!regulators_np) {
> + dev_err(iodev->dev, "could not find regulators sub-node\n");
> + return -EINVAL;
> + }
> +
> + /* count the number of regulators to be supported in pmic */
> + pdata->num_regulators = 0;
> + for_each_child_of_node(regulators_np, reg_np)
> + pdata->num_regulators++;
> +
> + rdata = devm_kzalloc(iodev->dev, sizeof(*rdata) *
> + pdata->num_regulators, GFP_KERNEL);
> + if (!rdata) {
> + dev_err(iodev->dev, "could not allocate memory for "
> + "regulator data\n");
> + return -ENOMEM;
> + }
> +
> + pdata->regulators = rdata;
> + for_each_child_of_node(regulators_np, reg_np) {
> + for (i = 0; i < ARRAY_SIZE(regulators); i++)
> + if (!of_node_cmp(reg_np->name, regulators[i].name))
> + break;
> + rdata->id = i;
> + rdata->initdata = of_get_regulator_init_data(
> + iodev->dev, reg_np);
> + rdata->reg_node = reg_np;
> + rdata++;
> + }
> +
> + if (of_get_property(pmic_np, "max8997,pmic-buck1-uses-gpio-dvs", NULL))
> + pdata->buck1_gpiodvs = true;
> +
> + if (of_get_property(pmic_np, "max8997,pmic-buck2-uses-gpio-dvs", NULL))
> + pdata->buck2_gpiodvs = true;
> +
> + if (of_get_property(pmic_np, "max8997,pmic-buck5-uses-gpio-dvs", NULL))
> + pdata->buck5_gpiodvs = true;
> +
> + if (pdata->buck1_gpiodvs || pdata->buck2_gpiodvs ||
> + pdata->buck5_gpiodvs) {
> + ret = max8997_pmic_dt_parse_dvs_gpio(iodev, pdata, pmic_np);
> + if (ret)
> + return -EINVAL;
> +
> + if (of_property_read_u32(pmic_np,
> + "max8997,pmic-buck125-default-dvs-idx",
> + &pdata->buck125_default_idx)) {
> + pdata->buck125_default_idx = 0;
> + } else {
> + if (pdata->buck125_default_idx >= 8) {
> + pdata->buck125_default_idx = 0;
> + dev_info(iodev->dev, "invalid value for "
> + "default dvs index, using 0 instead\n");
> + }
> + }
> +
> + if (of_get_property(pmic_np,
> + "max8997,pmic-ignore-gpiodvs-side-effect", NULL))
> + pdata->ignore_gpiodvs_side_effect = true;
> +
> + dvs_voltage_nr = 8;
> + }
> +
> + if (of_property_read_u32_array(pmic_np,
> + "max8997,pmic-buck1-dvs-voltage",
> + pdata->buck1_voltage, dvs_voltage_nr)) {
> + dev_err(iodev->dev, "buck1 voltages not specified\n");
> + return -EINVAL;
> + }
> +
> + if (of_property_read_u32_array(pmic_np,
> + "max8997,pmic-buck2-dvs-voltage",
> + pdata->buck2_voltage, dvs_voltage_nr)) {
> + dev_err(iodev->dev, "buck2 voltages not specified\n");
> + return -EINVAL;
> + }
> +
> + if (of_property_read_u32_array(pmic_np,
> + "max8997,pmic-buck5-dvs-voltage",
> + pdata->buck5_voltage, dvs_voltage_nr)) {
> + dev_err(iodev->dev, "buck5 voltages not specified\n");
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +#else
> +static int max8997_pmic_dt_parse_pdata(struct max8997_dev *iodev,
> + struct max8997_platform_data *pdata)
> +{
> + return 0;
> +}
> +#endif /* CONFIG_OF */
> +
> static __devinit int max8997_pmic_probe(struct platform_device *pdev)
> {
> struct max8997_dev *iodev = dev_get_drvdata(pdev->dev.parent);
> @@ -968,6 +1098,12 @@ static __devinit int max8997_pmic_probe(struct platform_device *pdev)
> int i, ret, size;
> u8 max_buck1 = 0, max_buck2 = 0, max_buck5 = 0;
>
> + if (iodev->dev->of_node) {
> + ret = max8997_pmic_dt_parse_pdata(iodev, pdata);
> + if (ret)
> + return ret;
> + }
> +
> if (!pdata) {
> dev_err(pdev->dev.parent, "No platform init data supplied.\n");
> return -ENODEV;
> @@ -1146,7 +1282,8 @@ static __devinit int max8997_pmic_probe(struct platform_device *pdev)
> regulators[id].n_voltages = 16;
>
> rdev[i] = regulator_register(®ulators[id], max8997->dev,
> - pdata->regulators[i].initdata, max8997, NULL);
> + pdata->regulators[i].initdata, max8997,
> + pdata->regulators[i].reg_node);
> if (IS_ERR(rdev[i])) {
> ret = PTR_ERR(rdev[i]);
> dev_err(max8997->dev, "regulator init failed for %d\n",
> diff --git a/include/linux/mfd/max8997.h b/include/linux/mfd/max8997.h
> index 818486c..ba92375 100644
> --- a/include/linux/mfd/max8997.h
> +++ b/include/linux/mfd/max8997.h
> @@ -75,6 +75,7 @@ enum max8998_regulators {
> struct max8997_regulator_data {
> int id;
> struct regulator_init_data *initdata;
> + struct device_node *reg_node;
> };
>
> enum max8997_muic_usb_type {
> --
> 1.6.6.rc2
>
--
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies,Ltd.
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