Re: [PATCH v2 3/5] regulator: helper routine to extract regulator_init_data

[Shawn Guo <shawn.guo@freescale.com>]

On Thu, Oct 20, 2011 at 05:39:32PM +0530, Rajendra Nayak wrote:
> On Thursday 20 October 2011 11:44 AM, Shawn Guo wrote:
> >On Thu, Oct 20, 2011 at 10:48:58AM +0530, Rajendra Nayak wrote:
> >>>Let's look at mc13892-regulator driver.  There are 23 regulators defined
> >>>in array mc13892_regulators.  Needless to say, there is a dev behind
> >>>mc13892-regulator driver.  And when getting probed, this driver will
> >>>call regulator_register() to register those 23 regulators individually.
> >>>That said, for non-dt world, we have 1 + 23 'dev' with that 1 as the
> >>>parent of all other 23 'dev' (wrapped by regulator_dev).  But with the
> >>>current DT implementation, we will have at least 1 + 23 * 2 'dev'.
> >>>These extra 23 'dev' is totally new with DT.
> >>>
> >>
> >>but thats only because the mc13892-regulator driver is implemeted in
> >>such a way that all the regulators on the platform are bundled in as
> >>*one* device.
> >
> >I did not look into too many regulator drivers, but I expect this is
> >way that most regulator drivers are implemented in.  Having
> >mc13892-regulator being probed 23 times to register these 23 regulators
> >just makes less sense to me.
> >
> >>It would again depend on how you would pass these from
> >>the DT, if you indeed stick to the same way of bundling all regulators
> >>as one device from DT, the mc13892-regulator probe would just get called
> >>once and there would be one device associated, no?
> >>
> >Yes, I indeed would stick to the same way of bundling the registration
> >of all regulators with mc13892-regulator being probed once.  The problem
> >I have with the current regulator core DT implementation is that it
> >assumes the device_node of rdev->dev (dev wrapped in regulator_dev) is
> >being attached to rdev->dev.parent rather than itself.  Back to
> >mc13892-regulator example, that said, it requires the dev of
> >mc13892-regulator have the device_node of individual regulator attached
> >to.  IOW, the current implementation forces mc13892-regulator to be
> >probed 23 times to register those 23 regulators.  This is wrong to me.
> 
> I think I now understand to some extent the problem that you seem to be
> reporting. It is mainly with drivers which bundle all regulators and
> pass them as one device and would want to do so with DT too.
> 
> however I am still not clear on how what you seem to suggest would
> solve this problem. Note that not all drivers do it this way, and
> there are drivers where each regulator is considered as one device
> and I suspect they would remain that way with DT too. And hence we
> need to support both.
> 
> Do you have any RFC patch/code which could explain better what you are
> suggesting we do here?
> >
Here is what I changed based on your patches.  It only changes
drivers/regulator/core.c.

---8<-------
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 9a5ebbe..8fe132d 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1211,7 +1211,7 @@ static struct regulator *_regulator_get(struct device *dev, const char *id,
                node = of_get_regulator(dev, id);
                if (node)
                        list_for_each_entry(rdev, &regulator_list, list)
-                               if (node == rdev->dev.parent->of_node)
+                               if (node == rdev->dev.of_node)
                                        goto found;
        }
        list_for_each_entry(map, &regulator_map_list, list) {
@@ -2642,9 +2642,6 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
            regulator_desc->type != REGULATOR_CURRENT)
                return ERR_PTR(-EINVAL);

-       if (!init_data)
-               return ERR_PTR(-EINVAL);
-
        /* Only one of each should be implemented */
        WARN_ON(regulator_desc->ops->get_voltage &&
                regulator_desc->ops->get_voltage_sel);
@@ -2675,12 +2672,8 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
        INIT_LIST_HEAD(&rdev->list);
        BLOCKING_INIT_NOTIFIER_HEAD(&rdev->notifier);

-       /* preform any regulator specific init */
-       if (init_data->regulator_init) {
-               ret = init_data->regulator_init(rdev->reg_data);
-               if (ret < 0)
-                       goto clean;
-       }
+       /* find device_node and attach it */
+       rdev->dev.of_node = of_find_node_by_name(NULL, regulator_desc->name);

        /* register with sysfs */
        rdev->dev.class = &regulator_class;
@@ -2693,6 +2686,20 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
                goto clean;
        }

+       if (!init_data) {
+               /* try to get init_data from device tree */
+               init_data = of_get_regulator_init_data(&rdev->dev);
+               if (!init_data)
+                       return ERR_PTR(-EINVAL);
+       }
+
+       /* preform any regulator specific init */
+       if (init_data->regulator_init) {
+               ret = init_data->regulator_init(rdev->reg_data);
+               if (ret < 0)
+                       goto clean;
+       }
+
        dev_set_drvdata(&rdev->dev, rdev);

        /* set regulator constraints */
@@ -2719,7 +2726,7 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
                        node = of_get_regulator(dev, supply);
                        if (node)
                                list_for_each_entry(r, &regulator_list, list)
-                                       if (node == r->dev.parent->of_node)
+                                       if (node == r->dev.of_node)
                                                goto found;
                }

------->8---

And my dts file looks like something below.

	ecspi@70010000 { /* ECSPI1 */
		fsl,spi-num-chipselects = <2>;
		cs-gpios = <&gpio3 24 0>, /* GPIO4_24 */
			   <&gpio3 25 0>; /* GPIO4_25 */
		status = "okay";

		pmic: mc13892@0 {
			#address-cells = <1>;
			#size-cells = <0>;
			compatible = "fsl,mc13892";
			spi-max-frequency = <6000000>;
			reg = <0>;
			mc13xxx-irq-gpios = <&gpio0 8 0>; /* GPIO1_8 */

			regulators {
				sw1reg: mc13892_sw1 {
					regulator-min-uV = <600000>;
					regulator-max-uV = <1375000>;
					regulator-change-voltage;
					regulator-boot-on;
					regulator-always-on;
				};

				sw2reg: mc13892_sw2 {
					regulator-min-uV = <900000>;
					regulator-max-uV = <1850000>;
					regulator-change-voltage;
					regulator-boot-on;
					regulator-always-on;
				};

				......
			};

			leds {
				......
			};

			buttons {
				......
			};
		};

		flash: at45db321d@1 {
			......
		};
	};
};

-- 
Regards,
Shawn