[PATCH v4 2/2] regulator: add device tree support for max8997

Karol Lewandowski
2012-03-28T17:03:28Z

On 24.03.2012 10:49, Thomas Abraham wrote:

Hi Thomas!

> Add device tree based discovery support for max8997.
...
> +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
> + };
> +

Small note - driver supports[1] configuring following regulators by
using respective DT node names:

- EN32KHz_AP
- EN32KHz_CP
- ENVICHG
- ESAFEOUT1
- ESAFEOUT2
- CHARGER
- CHARGER_CV
- CHARGER_TOPOFF

I wonder if these should be mentioned in documentation too.

[1] These are used in e.g. mach-nuri.c

> diff --git a/drivers/regulator/max8997.c b/drivers/regulator/max8997.c> index 9657929..dce8aaf 100644

> --- a/drivers/regulator/max8997.c
> +++ b/drivers/regulator/max8997.c
..
> +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->id will be equal to ARRAY_SIZE(regulators) when one adds DT node
name (below "regulators") which is different from what can be found in
regulators[] table.

On my test machine this results in hard lockup - possibly because
something tries to access regulators[ARRAY_SIZE(regulators)]
later on.

Following patch fixes this on my machine (using DTS with misspelled LDO1 for LDx1):

diff --git a/drivers/regulator/max8997.c b/drivers/regulator/max8997.c
index dce8aaf..c20fd72 100644
--- a/drivers/regulator/max8997.c
+++ b/drivers/regulator/max8997.c
@@ -1011,6 +1011,13 @@ static int max8997_pmic_dt_parse_pdata(struct max8997_dev *iodev,
for (i = 0; i < ARRAY_SIZE(regulators); i++)
if (!of_node_cmp(reg_np->name, regulators[i].name))
break;
+
+ if (i == ARRAY_SIZE(regulators)) {
+ dev_warn(iodev->dev, "don't know how to configure regulator %s\n",
+ reg_np->name);
+ continue;
+ }
+
rdata->id = i;
rdata->initdata = of_get_regulator_init_data(
iodev->dev, reg_np);

Regards,
--
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform