Re: [PATCH v2 3/4] leds: tps68470: Add LED control for tps68470

From: Kate Hsuan <hpa@redhat.com>
To: Dan Scally <dan.scally@ideasonboard.com>
Cc: Pavel Machek <pavel@ucw.cz>, Lee Jones <lee@kernel.org>,
	linux-leds@vger.kernel.org, platform-driver-x86@vger.kernel.org,
	Hans de Goede <hdegoede@redhat.com>,
	Daniel Scally <djrscally@gmail.com>,
	Mark Gross <markgross@kernel.org>
Subject: Re: [PATCH v2 3/4] leds: tps68470: Add LED control for tps68470
Date: Mon, 13 Mar 2023 11:21:09 +0800	[thread overview]
Message-ID: <CAEth8oGnoTb9JrfKN7v61biWAoH39LnXw4OtXQQCvy+9J7f2_Q@mail.gmail.com> (raw)
In-Reply-To: <6644d2ef-10c8-43df-987c-b688d3f75f11@ideasonboard.com>

Hi,

On Fri, Mar 10, 2023 at 6:43 PM Dan Scally <dan.scally@ideasonboard.com> wrote:
>
> Hi Kate - thanks for the v2
>
> On 10/03/2023 09:56, Kate Hsuan wrote:
> > There are two LED controllers, LEDA indicator LED and LEDB flash LED for
> > tps68470. LEDA can be enabled by setting TPS68470_ILEDCTL_ENA. Moreover,
> > tps68470 provides four levels of power status for LEDB. If the
> > properties called "ti,ledb-current" can be found, the current will be
> > set according to the property values. These two LEDs can be controlled
> > through the LED class of sysfs (tps68470-leda and tps68470-ledb).
> >
> > Signed-off-by: Kate Hsuan <hpa@redhat.com>
> > ---
> >   drivers/leds/Kconfig         |  12 +++
> >   drivers/leds/Makefile        |   1 +
> >   drivers/leds/leds-tps68470.c | 182 +++++++++++++++++++++++++++++++++++
> >   3 files changed, 195 insertions(+)
> >   create mode 100644 drivers/leds/leds-tps68470.c
> >
> > diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> > index 9dbce09eabac..fd26036b3c61 100644
> > --- a/drivers/leds/Kconfig
> > +++ b/drivers/leds/Kconfig
> > @@ -827,6 +827,18 @@ config LEDS_TPS6105X
> >         It is a single boost converter primarily for white LEDs and
> >         audio amplifiers.
> >
> > +config LEDS_TPS68470
> > +     tristate "LED support for TI TPS68470"
> > +     depends on LEDS_CLASS
> > +     depends on INTEL_SKL_INT3472
> > +     help
> > +       This driver supports TPS68470 PMIC with LED chip.
> > +       It provide two LED controllers, including an indicator LED
> > +       and a flash LED.
>
> s/provide/provides. Also maybe "It provides two LED controllers, with the ability to drive 2

I'll revise the description in the v3 patch.

> indicator LEDs and 2 flash LEDs". I actually got the WLED part working now finally so I'll send
> patches on top of this series if that's ok?

Sounds good! That would be great! Thank you

>
> > +
> > +       To compile this driver as a module, choose M and it will be
> > +       called leds-tps68470
> > +
> >   config LEDS_IP30
> >       tristate "LED support for SGI Octane machines"
> >       depends on LEDS_CLASS
> > diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> > index d30395d11fd8..b284bc0daa98 100644
> > --- a/drivers/leds/Makefile
> > +++ b/drivers/leds/Makefile
> > @@ -84,6 +84,7 @@ obj-$(CONFIG_LEDS_TURRIS_OMNIA)             += leds-turris-omnia.o
> >   obj-$(CONFIG_LEDS_WM831X_STATUS)    += leds-wm831x-status.o
> >   obj-$(CONFIG_LEDS_WM8350)           += leds-wm8350.o
> >   obj-$(CONFIG_LEDS_WRAP)                     += leds-wrap.o
> > +obj-$(CONFIG_LEDS_TPS68470)          += leds-tps68470.o
> >
> >   # LED SPI Drivers
> >   obj-$(CONFIG_LEDS_CR0014114)                += leds-cr0014114.o
> > diff --git a/drivers/leds/leds-tps68470.c b/drivers/leds/leds-tps68470.c
> > new file mode 100644
> > index 000000000000..98bb56153690
> > --- /dev/null
> > +++ b/drivers/leds/leds-tps68470.c
> > @@ -0,0 +1,182 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * LED driver for TPS68470 PMIC
> > + *
> > + * Copyright (C) 2023 Red Hat
> > + *
> > + * Authors:
> > + *   Kate Hsuan <hpa@redhat.com>
> > + */
> > +
> > +#include <linux/gpio/driver.h>
>
> Not needed I think?

removed

>
> > +#include <linux/mfd/tps68470.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/leds.h>
>
> Alphabetical order?

Okay.

> > +
> > +#define lcdev_to_led(led_cdev) \
> > +     container_of(led_cdev, struct tps68470_led, lcdev)
> > +
> > +#define led_to_tps68470(led, index) \
> > +     container_of(led, struct tps68470_device, leds[index])
> > +
> > +enum tps68470_led_ids {
> > +     TPS68470_ILED_A,
> > +     TPS68470_ILED_B,
> > +     TPS68470_NUM_LEDS
> > +};
> > +
> > +static const char *tps68470_led_names[] = {
> > +     [TPS68470_ILED_A] = "tps68470-iled_a",
> > +     [TPS68470_ILED_B] = "tps68470-iled_b",
> > +};
> > +
> > +struct tps68470_led {
> > +     unsigned int led_id;
> > +     struct led_classdev lcdev;
> > +};
> > +
> > +struct tps68470_device {
> > +     struct device *dev;
> > +     struct regmap *regmap;
> > +     struct tps68470_led leds[TPS68470_NUM_LEDS];
> > +};
> > +
> > +enum ctrlb_current {
> > +     CTRLB_2MA       = 0,
> > +     CTRLB_4MA       = 1,
> > +     CTRLB_8MA       = 2,
> > +     CTRLB_16MA      = 3,
> > +};
> > +
> > +static int tps68470_brightness_set(struct led_classdev *led_cdev, enum led_brightness brightness)
> > +{
> > +     struct tps68470_led *led = lcdev_to_led(led_cdev);
> > +     struct tps68470_device *tps68470 = led_to_tps68470(led, led->led_id);
> > +     struct regmap *regmap = tps68470->regmap
> This would work fine as is...but I would maybe add something like
>
>         if (state > LED_ON)
>                 return -EINVAL;
>
> So that brightness values of > 1 aren't just silently accepted...or does the LED core already
> prevent that? If so it's fine.

I think it is unnecessary.
The LED framework already handles this. Since we already set
"max_brightness" for the device, the framework will check the
"brightness" value and make sure the value isn't greater than
"max_brightness".

>
> > +
> > +     switch (led->led_id) {
> > +     case TPS68470_ILED_A:
> > +             return regmap_update_bits(regmap, TPS68470_REG_ILEDCTL, TPS68470_ILEDCTL_ENA,
> > +                                       brightness ? TPS68470_ILEDCTL_ENA : 0);
> > +     case TPS68470_ILED_B:
> > +             return regmap_update_bits(regmap, TPS68470_REG_ILEDCTL, TPS68470_ILEDCTL_ENB,
> > +                                       brightness ? TPS68470_ILEDCTL_ENB : 0);
> > +     }
> > +     return -EINVAL;
> > +}
> > +
> > +static enum led_brightness tps68470_brightness_get(struct led_classdev *led_cdev)
> > +{
> > +     struct tps68470_led *led = lcdev_to_led(led_cdev);
> > +     struct tps68470_device *tps68470 = led_to_tps68470(led, led->led_id);
> > +     struct regmap *regmap = tps68470->regmap;
> > +     int ret = 0;
> > +     int value = 0;
> > +
> > +     ret =  regmap_read(regmap, TPS68470_REG_ILEDCTL, &value);
> > +     if (ret)
> > +             goto error;
>
> Just return dev_err_probe(led_cdev->dev, -EINVAL, "failed on reading register\n") here imo.

Okay.

> > +
> > +     switch (led->led_id) {
> > +     case TPS68470_ILED_A:
> > +             value = value & TPS68470_ILEDCTL_ENA;
> > +             break;
> > +     case TPS68470_ILED_B:
> > +             value = value & TPS68470_ILEDCTL_ENB;
> > +             break;
> > +     }
> > +
> > +     return value ? LED_ON : LED_OFF;
> > +
> > +error:
> > +     dev_err(led_cdev->dev, "Failed on reading register\n");
> > +     return -EINVAL;
> > +}
> > +
> > +static int tps68470_leds_probe(struct platform_device *pdev)
> > +{
> > +     int i = 0;
> > +     int ret = 0;
> > +     unsigned int curr;
> > +     struct tps68470_device *tps68470;
> > +     struct tps68470_led *led;
> > +     struct led_classdev *lcdev;
> > +
> > +     tps68470 = devm_kzalloc(&pdev->dev, sizeof(struct tps68470_device),
> > +                             GFP_KERNEL);
>
> No -ENOMEM check here?
>

I'll add a return value check here in the v3 patch.

> > +     tps68470->dev = &pdev->dev;
> > +     tps68470->regmap = dev_get_drvdata(pdev->dev.parent);
> > +
> > +     for (i = 0; i < TPS68470_NUM_LEDS; i++) {
> > +             led = &tps68470->leds[i];
> > +             lcdev = &led->lcdev;
> > +
> > +             led->led_id = i;
> > +
> > +             lcdev->name = devm_kasprintf(tps68470->dev, GFP_KERNEL, "%s::%s",
> > +                                          tps68470_led_names[i], LED_FUNCTION_INDICATOR);
> > +             if (!lcdev->name)
> > +                     return -ENOMEM;
> > +
> > +             lcdev->max_brightness = 1;
> > +             lcdev->brightness = 0;
> > +             lcdev->brightness_set_blocking = tps68470_brightness_set;
> > +             lcdev->brightness_get = tps68470_brightness_get;
> > +             lcdev->dev = &pdev->dev;
> > +
> > +             ret = devm_led_classdev_register(tps68470->dev, lcdev);
> > +             if (ret) {
> > +                     dev_err_probe(tps68470->dev, ret,
> > +                                   "error registering led\n");
> > +                     goto err_exit;
> > +             }
> > +     }
> > +
> > +     /* configure LEDB current if the properties can be got */
> > +     if (!device_property_read_u32(&pdev->dev, "ti,ledb-current", &curr)) {
> > +             switch (curr) {
> > +             case  2:
> > +                     curr = CTRLB_2MA;
> > +                     break;
> > +             case  4:
> > +                     curr = CTRLB_4MA;
> > +                     break;
> > +             case  8:
> > +                     curr = CTRLB_8MA;
> > +                     break;
> > +             case 16:
> > +                     curr = CTRLB_16MA;
> > +                     break;
> > +             default:
> > +                     dev_err(&pdev->dev, "Invalid LEDB curr value: %d\n", curr);
> > +                     return -EINVAL;
>
> There's no jump to err_exit here...I think that this whole section should go above the registration
> of the LEDS...and probably also into its own function.

Okay.

>
> > +             }
> > +             ret = regmap_update_bits(tps68470->regmap, TPS68470_REG_ILEDCTL,
> > +                                      TPS68470_ILEDCTL_CTRLB, curr);
> > +     }
> > +
> > +err_exit:
> > +     if (ret) {
> > +             for (i = 0; i < TPS68470_NUM_LEDS; i++) {
> > +                     if (tps68470->leds[i].lcdev.name)
> > +                             devm_led_classdev_unregister(&pdev->dev,
> > +                                                          &tps68470->leds[i].lcdev);
> > +             }
> > +     }
> > +
> > +     return ret;
> > +}
> > +static struct platform_driver tps68470_led_driver = {
> > +     .driver = {
> > +                .name = "tps68470-led",
> > +     },
> > +     .probe = tps68470_leds_probe,
> > +};
> > +
> > +module_platform_driver(tps68470_led_driver);
> > +
> > +MODULE_ALIAS("platform:tps68470-led");
> > +MODULE_DESCRIPTION("LED driver for TPS68470 PMIC");
> > +MODULE_LICENSE("GPL v2");
>

Thank you

-- 
BR,
Kate