Re: [PATCH v1 1/2] mfd: rt4831: Adds support for Richtek RT4831 MFD core

[ChiYuan Huang <u0084500@gmail.com>]

Lee Jones <lee.jones@linaro.org> 於 2020年11月26日 週四 上午12:42寫道：
>
> On Mon, 02 Nov 2020, cy_huang wrote:
>
> > From: ChiYuan Huang <cy_huang@richtek.com>
> >
> > Adds support Richtek RT4831 MFD core.
> > RT4831 includes backlight and DSV part that can provode display panel
> > for postive and negative voltage and WLED driving.
> >
> > Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
> > ---
> >  drivers/mfd/Kconfig       |  11 +++++
> >  drivers/mfd/Makefile      |   1 +
> >  drivers/mfd/rt4831-core.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 131 insertions(+)
> >  create mode 100644 drivers/mfd/rt4831-core.c
> >
> > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > index 8b99a13..a22f002 100644
> > --- a/drivers/mfd/Kconfig
> > +++ b/drivers/mfd/Kconfig
> > @@ -1088,6 +1088,17 @@ config MFD_RDC321X
> >         southbridge which provides access to GPIOs and Watchdog using the
> >         southbridge PCI device configuration space.
> >
> > +config MFD_RT4831
> > +     tristate "Richtek RT4831 WLED and DSV IC"
>
> Please expand on WLED and DSV.
>
> This is documentation and should leave nothing to the imagination.
>
Rewrite to "Richtek RT4831 four channel WLED and display bias
voltage", is it okay?
> > +     depends on I2C
> > +     select MFD_CORE
> > +     select REGMAP_I2C
> > +     help
> > +       This enables support for the Richtek RT4831.
> > +       RT4831 includes WLED driver and DisplayBias voltage(+/-) regulator.
> > +       It's common used to provide the display power and to drive the
> > +       display backlight WLED.
>
> Please don't line-wrap unnecessarily.
>
> Please re-work the last sentence, as it doesn't quite make sense.
>
Rewrite the whole sentence like as below
"This enables support for the Richtek RT4831. It includes 4 channel
WLED driving and Display Bias voltage output. It's commonly used to
provide the LCD power and to drive LCD backlight."

> >  config MFD_RT5033
> >       tristate "Richtek RT5033 Power Management IC"
> >       depends on I2C
> > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> > index 1780019..4108141 100644
> > --- a/drivers/mfd/Makefile
> > +++ b/drivers/mfd/Makefile
> > @@ -235,6 +235,7 @@ obj-$(CONFIG_MFD_MENF21BMC)       += menf21bmc.o
> >  obj-$(CONFIG_MFD_HI6421_PMIC)        += hi6421-pmic-core.o
> >  obj-$(CONFIG_MFD_HI655X_PMIC)   += hi655x-pmic.o
> >  obj-$(CONFIG_MFD_DLN2)               += dln2.o
> > +obj-$(CONFIG_MFD_RT4831)     += rt4831-core.o
> >  obj-$(CONFIG_MFD_RT5033)     += rt5033.o
> >  obj-$(CONFIG_MFD_SKY81452)   += sky81452.o
> >
> > diff --git a/drivers/mfd/rt4831-core.c b/drivers/mfd/rt4831-core.c
> > new file mode 100644
> > index 00000000..5342959
> > --- /dev/null
> > +++ b/drivers/mfd/rt4831-core.c
> > @@ -0,0 +1,119 @@
> > +// SPDX-License-Identifier: GPL-2.0+
>
> No copyright?
>
Yes, I'll add the copyright like as below
/*
 * Copyright (c) 2020 Richtek Inc.
 *
 * Author: ChiYuan Huang <cy_huang@richtek.com>
 */
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/i2c.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/module.h>
> > +#include <linux/regmap.h>
> > +
> > +#define RT4831_REG_REVISION  0x01
> > +#define RT4831_REG_ENABLE    0x08
> > +#define RT4831_REG_I2CPROT   0x15
> > +
> > +#define RICHTEK_VID          0x03
> > +#define RT4831_VID_MASK              GENMASK(1, 0)
> > +#define RT4831_RESET_MASK    BIT(7)
> > +#define RT4831_I2CSAFETMR_MASK       BIT(0)
> > +
> > +static const struct mfd_cell rt4831_subdevs[] = {
> > +     OF_MFD_CELL("rt4831-backlight", NULL, NULL, 0, 0, "richtek,rt4831-backlight"),
> > +     MFD_CELL_NAME("rt4831-regulator")
> > +};
> > +
> > +static bool rt4831_is_accessible_reg(struct device *dev, unsigned int reg)
> > +{
> > +     if (reg >= RT4831_REG_REVISION && reg <= RT4831_REG_I2CPROT)
> > +             return true;
> > +     return false;
> > +}
> > +
> > +static const struct regmap_config rt4831_regmap_config = {
> > +     .reg_bits = 8,
> > +     .val_bits = 8,
> > +     .max_register = RT4831_REG_I2CPROT,
> > +
> > +     .readable_reg = rt4831_is_accessible_reg,
> > +     .writeable_reg = rt4831_is_accessible_reg,
> > +};
> > +
> > +static int rt4831_probe(struct i2c_client *client)
> > +{
> > +     struct gpio_desc *enable;
> > +     struct regmap *regmap;
> > +     unsigned int val;
> > +     int ret;
> > +
> > +     enable = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
> > +     if (IS_ERR(enable)) {
> > +             dev_err(&client->dev, "Failed to get chip enable gpio\n");
>
> "Failed to get 'enable' GPIO chip"
>
May I remove "chip" word? It seems redundant.
"Failed to get 'enable' GPIO" is better.
Because 'enable' is a physical input pin for RT4831.
> > +             return PTR_ERR(enable);
> > +     }
> > +
> > +     regmap = devm_regmap_init_i2c(client, &rt4831_regmap_config);
> > +     if (IS_ERR(regmap)) {
> > +             dev_err(&client->dev, "Failed to init regmap\n");
>
> "initialise"
>
Change to verb "initialize"
> > +             return PTR_ERR(regmap);
> > +     }
> > +
> > +     ret = regmap_read(regmap, RT4831_REG_REVISION, &val);
> > +     if (ret) {
> > +             dev_err(&client->dev, "Fail to get version id\n");
>
> "Failed to get H/W revision"
>
Ack
> > +             return ret;
> > +     }
> > +
> > +     if ((val & RT4831_VID_MASK) != RICHTEK_VID) {
> > +             dev_err(&client->dev, "VID not matched, val = 0x%02x\n", val);
> > +             return -ENODEV;
> > +     }
> > +
> > +     /*
> > +      * Used to prevent the abnormal shutdown.
> > +      * If SCL/SDA both keep low for one second to reset HW.
> > +      */
> > +     ret = regmap_update_bits(regmap, RT4831_REG_I2CPROT, RT4831_I2CSAFETMR_MASK,
> > +                              RT4831_I2CSAFETMR_MASK);
> > +     if (ret) {
> > +             dev_err(&client->dev, "Failed to enable I2C safety timer\n");
> > +             return ret;
> > +     }
> > +
> > +     return devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, rt4831_subdevs,
> > +                                 ARRAY_SIZE(rt4831_subdevs), NULL, 0, NULL);
> > +}
> > +
> > +static int rt4831_remove(struct i2c_client *client)
> > +{
> > +     struct regmap *regmap = dev_get_regmap(&client->dev, NULL);
> > +
> > +     /* Make sure all off before module removal */
>
> "Disable all <thing your disabling> are disabled before ..."
>
May I rewrite it to "Configure WLED driving and DSV output all to be
disabled before MFD module removal"?
> > +     return regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);
> > +}
> > +
> > +static void rt4831_shutdown(struct i2c_client *client)
> > +{
> > +     struct regmap *regmap = dev_get_regmap(&client->dev, NULL);
> > +
> > +     /* Make sure all off before machine shutdown */
>
> As above.
>
like as above ".... before 'machine shutdown'
> > +     regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);
> > +}
> > +
> > +static const struct of_device_id __maybe_unused rt4831_of_match[] = {
> > +     { .compatible = "richtek,rt4831", },
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(of, rt4831_of_match);
> > +
> > +static struct i2c_driver rt4831_driver = {
> > +     .driver = {
> > +             .name = "rt4831",
> > +             .of_match_table = of_match_ptr(rt4831_of_match),
> > +     },
> > +     .probe_new = rt4831_probe,
> > +     .remove = rt4831_remove,
> > +     .shutdown = rt4831_shutdown,
> > +};
> > +module_i2c_driver(rt4831_driver);
> > +
> > +MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
> > +MODULE_LICENSE("GPL v2");
>
> --
> Lee Jones [李琼斯]
> Senior Technical Lead - Developer Services
> Linaro.org │ Open source software for Arm SoCs
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