Re: [PATCH v3 4/5] regulator: qcom: Add labibb driver

From: Bjorn Andersson
Date: Thu May 28 2020 - 22:05:32 EST


On Thu 28 May 08:46 PDT 2020, Sumit Semwal wrote:

> From: Nisha Kumari <nishakumari@xxxxxxxxxxxxxx>
>
> Qualcomm platforms have LAB(LCD AMOLED Boost)/IBB(Inverting Buck Boost)
> regulators, labibb for short, which are used as power supply for
> LCD Mode displays.
>
> This patch adds labibb regulator driver for pmi8998 PMIC, found on
> SDM845 platforms.
>
> Signed-off-by: Nisha Kumari <nishakumari@xxxxxxxxxxxxxx>
> Signed-off-by: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
>
> --
> v2: sumits: reworked the driver for more common code, and addressed
> review comments from v1
> v3: sumits: addressed review comments from v2; moved to use core
> regulator features like enable_time, off_on_delay, and the newly
> added poll_enabled_time. Moved the check_enabled functionality
> to core framework via poll_enabled_time.
>
> ---
> drivers/regulator/Kconfig | 10 +
> drivers/regulator/Makefile | 1 +
> drivers/regulator/qcom-labibb-regulator.c | 224 ++++++++++++++++++++++
> 3 files changed, 235 insertions(+)
> create mode 100644 drivers/regulator/qcom-labibb-regulator.c
>
> diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
> index f4b72cb098ef..58704a9fd05d 100644
> --- a/drivers/regulator/Kconfig
> +++ b/drivers/regulator/Kconfig
> @@ -1167,5 +1167,15 @@ config REGULATOR_WM8994
> This driver provides support for the voltage regulators on the
> WM8994 CODEC.
>
> +config REGULATOR_QCOM_LABIBB
> + tristate "QCOM LAB/IBB regulator support"
> + depends on SPMI || COMPILE_TEST
> + help
> + This driver supports Qualcomm's LAB/IBB regulators present on the
> + Qualcomm's PMIC chip pmi8998. QCOM LAB and IBB are SPMI
> + based PMIC implementations. LAB can be used as positive
> + boost regulator and IBB can be used as a negative boost regulator
> + for LCD display panel.
> +
> endif
>
> diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
> index 6610ee001d9a..5b313786c0e8 100644
> --- a/drivers/regulator/Makefile
> +++ b/drivers/regulator/Makefile
> @@ -87,6 +87,7 @@ obj-$(CONFIG_REGULATOR_MT6323) += mt6323-regulator.o
> obj-$(CONFIG_REGULATOR_MT6358) += mt6358-regulator.o
> obj-$(CONFIG_REGULATOR_MT6380) += mt6380-regulator.o
> obj-$(CONFIG_REGULATOR_MT6397) += mt6397-regulator.o
> +obj-$(CONFIG_REGULATOR_QCOM_LABIBB) += qcom-labibb-regulator.o
> obj-$(CONFIG_REGULATOR_QCOM_RPM) += qcom_rpm-regulator.o
> obj-$(CONFIG_REGULATOR_QCOM_RPMH) += qcom-rpmh-regulator.o
> obj-$(CONFIG_REGULATOR_QCOM_SMD_RPM) += qcom_smd-regulator.o
> diff --git a/drivers/regulator/qcom-labibb-regulator.c b/drivers/regulator/qcom-labibb-regulator.c
> new file mode 100644
> index 000000000000..634d08461c6e
> --- /dev/null
> +++ b/drivers/regulator/qcom-labibb-regulator.c
> @@ -0,0 +1,225 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +// Copyright (c) 2020, The Linux Foundation. All rights reserved.
> +
> +#include <linux/module.h>
> +#include <linux/of_irq.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/driver.h>
> +#include <linux/regulator/of_regulator.h>
> +
> +#define REG_PERPH_TYPE 0x04
> +#define QCOM_LAB_TYPE 0x24
> +#define QCOM_IBB_TYPE 0x20
> +
> +#define REG_LABIBB_STATUS1 0x08
> +#define REG_LABIBB_ENABLE_CTL 0x46
> +#define LABIBB_STATUS1_VREG_OK_BIT BIT(7)
> +#define LABIBB_CONTROL_ENABLE BIT(7)
> +
> +#define LAB_ENABLE_CTL_MASK BIT(7)
> +#define IBB_ENABLE_CTL_MASK (BIT(7) | BIT(6))
> +
> +#define LABIBB_ENABLE_TIME 1000
> +#define LAB_POLL_ENABLED_TIME (LABIBB_ENABLE_TIME * 2)
> +#define IBB_POLL_ENABLED_TIME (LABIBB_ENABLE_TIME * 10)
> +#define LABIBB_OFF_ON_DELAY (8200)
> +
> +struct labibb_regulator {
> + struct regulator_desc desc;
> + struct device *dev;
> + struct regmap *regmap;
> + struct regulator_dev *rdev;
> + u16 base;
> + u8 type;
> +};
> +
> +struct labibb_regulator_data {
> + u16 base;
> + const char *name;
> + u8 type;
> + unsigned int poll_enabled_time;
> +};
> +
> +static int qcom_labibb_regulator_is_enabled(struct regulator_dev *rdev)
> +{
> + int ret;
> + unsigned int val;
> + struct labibb_regulator *reg = rdev_get_drvdata(rdev);
> +
> + ret = regmap_read(reg->regmap, reg->base + REG_LABIBB_STATUS1, &val);
> + if (ret < 0) {
> + dev_err(reg->dev, "Read register failed ret = %d\n", ret);
> + return ret;
> + }
> + return !!(val & LABIBB_STATUS1_VREG_OK_BIT);
> +}
> +
> +static int qcom_labibb_regulator_enable(struct regulator_dev *rdev)
> +{
> + int ret;
> + struct labibb_regulator *reg = rdev_get_drvdata(rdev);
> +
> + ret = regulator_enable_regmap(rdev);
> + if (ret < 0)
> + dev_err(reg->dev, "Write failed: enable %s regulator\n",
> + reg->desc.name);

If you return a negative value the various callers of
_regulator_do_enable() and _regulator_do_disable() will print an error
message for you.

As such you don't need these wrappers and should be able to just specify
regulator_enable_regmap and regulator_disable_regmap as you enable and
disable functions in qcom_labibb_ops directly.

> +
> + return ret;
> +}
> +
> +static int qcom_labibb_regulator_disable(struct regulator_dev *rdev)
> +{
> + int ret = 0;
> + struct labibb_regulator *reg = rdev_get_drvdata(rdev);
> +
> + ret = regulator_disable_regmap(rdev);
> + if (ret < 0)
> + dev_err(reg->dev, "Disable failed: disable %s\n",
> + reg->desc.name);
> +
> + return ret;
> +}
> +
> +static struct regulator_ops qcom_labibb_ops = {
> + .enable = qcom_labibb_regulator_enable,
> + .disable = qcom_labibb_regulator_disable,
> + .is_enabled = qcom_labibb_regulator_is_enabled,
> +};
> +
> +static int register_labibb_regulator(struct labibb_regulator *reg,
> + const struct labibb_regulator_data *reg_data,
> + struct device_node *of_node)
> +{
> + struct regulator_config cfg = {};
> +
> + reg->base = reg_data->base;
> + reg->type = reg_data->type;
> + reg->desc.enable_reg = reg->base + REG_LABIBB_ENABLE_CTL;
> + reg->desc.enable_val = LABIBB_CONTROL_ENABLE;
> + reg->desc.of_match = reg_data->name;
> + reg->desc.name = reg_data->name;
> + reg->desc.owner = THIS_MODULE;
> + reg->desc.type = REGULATOR_VOLTAGE;
> + reg->desc.ops = &qcom_labibb_ops;
> +
> + reg->desc.enable_time = LABIBB_ENABLE_TIME;
> + reg->desc.poll_enabled_time = reg_data->poll_enabled_time;
> + reg->desc.off_on_delay = LABIBB_OFF_ON_DELAY;
> +
> + cfg.dev = reg->dev;
> + cfg.driver_data = reg;
> + cfg.regmap = reg->regmap;
> + cfg.of_node = of_node;
> +
> + reg->rdev = devm_regulator_register(reg->dev, &reg->desc, &cfg);
> + return PTR_ERR_OR_ZERO(reg->rdev);

If you change the return type to struct regulator_dev *, you can clean
this up by just:

return devm_regulator_register()

And then if (IS_ERR()) that in the caller.

> +}
> +
> +static const struct labibb_regulator_data pmi8998_labibb_data[] = {
> + {0xde00, "lab", QCOM_LAB_TYPE, LAB_POLL_ENABLED_TIME},
> + {0xdc00, "ibb", QCOM_IBB_TYPE, IBB_POLL_ENABLED_TIME},
> + { },
> +};
> +
> +static const struct of_device_id qcom_labibb_match[] = {
> + { .compatible = "qcom,pmi8998-lab-ibb", .data = &pmi8998_labibb_data},
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, qcom_labibb_match);
> +
> +static int qcom_labibb_regulator_probe(struct platform_device *pdev)
> +{
> + struct labibb_regulator *labibb_reg;
> + struct device *dev;
> + struct device_node *child;
> + const struct of_device_id *match;
> + const struct labibb_regulator_data *reg_data;
> + struct regmap *reg_regmap;
> + unsigned int type;
> + int ret;
> +
> + reg_regmap = dev_get_regmap(pdev->dev.parent, NULL);
> + if (!reg_regmap) {
> + dev_err(&pdev->dev, "Couldn't get parent's regmap\n");
> + return -ENODEV;
> + }
> +
> + dev = &pdev->dev;

Do this as you declare "dev" above.

> +
> + match = of_match_device(qcom_labibb_match, &pdev->dev);
> + if (!match)
> + return -ENODEV;
> +
> + for (reg_data = match->data; reg_data->name; reg_data++) {
> + child = of_get_child_by_name(pdev->dev.of_node, reg_data->name);
> +
> + /* TODO: This validates if the type of regulator is indeed
> + * what's mentioned in DT.
> + * I'm not sure if this is needed, but we'll keep it for now.
> + */
> + ret = regmap_read(reg_regmap, reg_data->base + REG_PERPH_TYPE,
> + &type);
> + if (ret < 0) {
> + dev_err(dev,
> + "Peripheral type read failed ret=%d\n",
> + ret);
> + return -EINVAL;
> + }
> +
> + if ((type != QCOM_LAB_TYPE) && (type != QCOM_IBB_TYPE)) {

Given that you don't actually validate the information in DT, but rather
just check that the data in the pmi8998_labibb_data is accurate this is
merely a sanity check during development. So I think you should reduce
this to:

if (WARN_ON(type != reg_data->type))
return -EINVAL;

You can thereby remove the TODO comment above as well.


What you should do though is check that "child" is not NULL - to catch
the case where the DT doesn't specify both lab and ibb.

> + dev_err(dev,
> + "qcom_labibb: unknown peripheral type\n");
> + return -EINVAL;
> + } else if (type != reg_data->type) {
> + dev_err(dev,
> + "qcom_labibb: type %x doesn't match DT %x\n",
> + type, reg_data->type);
> + return -EINVAL;
> + }
> +
> + labibb_reg = devm_kzalloc(&pdev->dev, sizeof(*labibb_reg),
> + GFP_KERNEL);
> + if (!labibb_reg)
> + return -ENOMEM;
> +
> + labibb_reg->regmap = reg_regmap;
> + labibb_reg->dev = dev;
> +
> + switch (reg_data->type) {
> + case QCOM_LAB_TYPE:
> + labibb_reg->desc.enable_mask = LAB_ENABLE_CTL_MASK;

All other parts of labibb_reg->desc are filled out inside
register_labibb_regulator(), pass the mask as an argument instead to
consolidate the setup.

> + break;
> +
> + case QCOM_IBB_TYPE:
> + labibb_reg->desc.enable_mask = IBB_ENABLE_CTL_MASK;
> + break;
> + }
> +
> + dev_info(dev, "Registering %s regulator\n", child->full_name);
> +
> + ret = register_labibb_regulator(labibb_reg, reg_data, child);
> + if (ret < 0) {
> + dev_err(dev,
> + "qcom_labibb: error registering %s : %d\n",
> + child->full_name, ret);
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static struct platform_driver qcom_labibb_regulator_driver = {
> + .driver = {
> + .name = "qcom-lab-ibb-regulator",
> + .of_match_table = qcom_labibb_match,
> + },
> + .probe = qcom_labibb_regulator_probe,
> +};

I think you should drop the tabs before the various = in this
definition.

Regards,
Bjorn

> +module_platform_driver(qcom_labibb_regulator_driver);
> +
> +MODULE_DESCRIPTION("Qualcomm labibb driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.26.2
>