Re: [PATCH v3 09/11] leds: max77650: add LEDs support

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pt., 1 lut 2019 o 21:15 Dan Murphy <dmurphy@xxxxxx> napisał(a):
>
> Hi
>
> On 2/1/19 1:45 PM, Jacek Anaszewski wrote:
> > Hi Bartosz,
> >
> > Thanks for the update.
> >
> > On 2/1/19 10:47 AM, Bartosz Golaszewski wrote:
> >> From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> >>
> >> This adds basic support for LEDs for the max77650 PMIC. The device has
> >> three current sinks for driving LEDs.
> >>
> >> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> >> ---
> >>   drivers/leds/Kconfig         |   6 ++
> >>   drivers/leds/Makefile        |   1 +
> >>   drivers/leds/leds-max77650.c | 147 +++++++++++++++++++++++++++++++++++
> >>   3 files changed, 154 insertions(+)
> >>   create mode 100644 drivers/leds/leds-max77650.c
> >>
> >> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> >> index a72f97fca57b..6e7a8f51eccc 100644
> >> --- a/drivers/leds/Kconfig
> >> +++ b/drivers/leds/Kconfig
> >> @@ -608,6 +608,12 @@ config LEDS_TLC591XX
> >>         This option enables support for Texas Instruments TLC59108
> >>         and TLC59116 LED controllers.
> >>   +config LEDS_MAX77650
> >> +    tristate "LED support for Maxim MAX77650 PMIC"
> >> +    depends on MFD_MAX77650
> >> +    help
> >> +      LEDs driver for MAX77650 family of PMICs from Maxim Integrated."
> >> +
> >>   config LEDS_MAX77693
> >>       tristate "LED support for MAX77693 Flash"
> >>       depends on LEDS_CLASS_FLASH
> >> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> >> index 4c1b0054f379..f48b2404dbb7 100644
> >> --- a/drivers/leds/Makefile
> >> +++ b/drivers/leds/Makefile
> >> @@ -61,6 +61,7 @@ obj-$(CONFIG_LEDS_MC13783)        += leds-mc13783.o
> >>   obj-$(CONFIG_LEDS_NS2)            += leds-ns2.o
> >>   obj-$(CONFIG_LEDS_NETXBIG)        += leds-netxbig.o
> >>   obj-$(CONFIG_LEDS_ASIC3)        += leds-asic3.o
> >> +obj-$(CONFIG_LEDS_MAX77650)        += leds-max77650.o
> >>   obj-$(CONFIG_LEDS_MAX77693)        += leds-max77693.o
> >>   obj-$(CONFIG_LEDS_MAX8997)        += leds-max8997.o
> >>   obj-$(CONFIG_LEDS_LM355x)        += leds-lm355x.o
> >> diff --git a/drivers/leds/leds-max77650.c b/drivers/leds/leds-max77650.c
> >> new file mode 100644
> >> index 000000000000..6b74ce9cac12
> >> --- /dev/null
> >> +++ b/drivers/leds/leds-max77650.c
> >> @@ -0,0 +1,147 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +//
> >> +// Copyright (C) 2018 BayLibre SAS
> >> +// Author: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
> >> +//
> >> +// LED driver for MAXIM 77650/77651 charger/power-supply.
> >> +
> >> +#include <linux/i2c.h>
> >> +#include <linux/leds.h>
> >> +#include <linux/mfd/max77650.h>
> >> +#include <linux/module.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/regmap.h>
> >> +
> >> +#define MAX77650_LED_NUM_LEDS        3
> >> +
> >> +#define MAX77650_LED_A_BASE        0x40
> >> +#define MAX77650_LED_B_BASE        0x43
> >> +
> >> +#define MAX77650_LED_BR_MASK        GENMASK(4, 0)
> >> +#define MAX77650_LED_EN_MASK        GENMASK(7, 6)
> >> +
> >> +#define MAX77650_LED_MAX_BRIGHTNESS    MAX77650_LED_BR_MASK
> >> +
> >> +/* Enable EN_LED_MSTR. */
> >> +#define MAX77650_LED_TOP_DEFAULT    BIT(0)
> >> +
> >> +#define MAX77650_LED_ENABLE        GENMASK(7, 6)
> >> +#define MAX77650_LED_DISABLE        0x00
> >> +
> >> +#define MAX77650_LED_A_DEFAULT        MAX77650_LED_DISABLE
> >> +/* 100% on duty */
> >> +#define MAX77650_LED_B_DEFAULT        GENMASK(3, 0)
> >> +
> >> +struct max77650_led {
> >> +    struct led_classdev cdev;
> >> +    struct regmap *map;
> >> +    unsigned int regA;
> >> +    unsigned int regB;
>
> Please don't use camel case.
>

Sorry, but this is pointless nitpicking. The registers are referred to
in the manual as LED[012]_A and LED[012]_B so these variable names
reflect that. The difference between ThisKindOfCamelCase and regA/regB
is obvious. It's much more readable than for example rega or reg_a. I
also used the same approach in the regulator module and there were no
complaints.

> >> +};
> >> +
> >> +static struct max77650_led *max77650_to_led(struct led_classdev *cdev)
> >> +{
> >> +    return container_of(cdev, struct max77650_led, cdev);
> >> +}
> >> +
> >> +static int max77650_led_brightness_set(struct led_classdev *cdev,
> >> +                       enum led_brightness brightness)
> >> +{
> >> +    struct max77650_led *led = max77650_to_led(cdev);
> >> +    int val, mask;
> >> +
>
> The register value and bits are only 8 bit why an int?
>

Because regmap_update_bits() deals with 32-bit integers. There's no
hurt and it's less confusing.

> >> +    mask = MAX77650_LED_BR_MASK | MAX77650_LED_EN_MASK;
> >> +
> >> +    if (brightness == LED_OFF)
> >> +        val = MAX77650_LED_DISABLE;
> >> +    else
> >> +        val = MAX77650_LED_ENABLE | brightness;
> >> +
> >> +    return regmap_update_bits(led->map, led->regA, mask, val);
> >> +}
> >> +
> >> +static int max77650_led_probe(struct platform_device *pdev)
> >> +{
> >> +    struct device_node *of_node, *child;
> >> +    struct max77650_led *leds, *led;
> >> +    struct device *parent;
> >> +    struct device *dev;
> >> +    struct regmap *map;
> >> +    const char *label;
> >> +    int rv, num_leds;
> >> +    u32 reg;
> >> +
> >> +    dev = &pdev->dev;
> >> +    parent = dev->parent;
> >> +    of_node = dev->of_node;
> >> +
> >> +    if (!of_node)
> >> +        return -ENODEV;
> >> +
> >> +    leds = devm_kcalloc(dev, sizeof(*leds),
> >> +                MAX77650_LED_NUM_LEDS, GFP_KERNEL);
> >> +    if (!leds)
> >> +        return -ENOMEM;
> >> +
> >> +    map = dev_get_regmap(dev->parent, NULL);
> >> +    if (!map)
> >> +        return -ENODEV;
> >> +
> >> +    num_leds = of_get_child_count(of_node);
> >> +    if (!num_leds || num_leds > MAX77650_LED_NUM_LEDS)
> >> +        return -ENODEV;
> >> +
> >> +    for_each_child_of_node(of_node, child) {
> >> +        rv = of_property_read_u32(child, "reg", &reg);
>
> Can we use the fwnode_property_read_u32 call here?
> And the same for all below as well?
>
>

Of course we can. But why? This is a low-power PMIC. Is there really a
chance that a non-DT system will want to use it? If so - we will be
able to convert it if needed. For now: I'd stick with of_* functions.

> >> +        if (rv || reg >= MAX77650_LED_NUM_LEDS)
> >> +            return -EINVAL;
> >> +
> >> +        led = &leds[reg];
> >> +        led->map = map;
> >> +        led->regA = MAX77650_LED_A_BASE + reg;
> >> +        led->regB = MAX77650_LED_B_BASE + reg;
> >> +        led->cdev.brightness_set_blocking = max77650_led_brightness_set;
> >> +        led->cdev.max_brightness = MAX77650_LED_MAX_BRIGHTNESS;
> >> +
> >> +        label = of_get_property(child, "label", NULL);
> >> +        if (!label) {
> >> +            led->cdev.name = "max77650::";
> >> +        } else {
> >> +            led->cdev.name = devm_kasprintf(dev, GFP_KERNEL,
> >> +                            "max77650:%s", label);
> >> +            if (!led->cdev.name)
> >> +                return -ENOMEM;
> >> +        }
> >> +
> >> +        of_property_read_string(child, "linux,default-trigger",
> >> +                    &led->cdev.default_trigger);
> >> +
> >> +        rv = devm_of_led_classdev_register(dev, child, &led->cdev);
> >> +        if (rv)
> >> +            return rv;
> >> +
> >> +        rv = regmap_write(map, led->regA, MAX77650_LED_A_DEFAULT);
> >> +        if (rv)
> >> +            return rv;
> >> +
> >> +        rv = regmap_write(map, led->regB, MAX77650_LED_B_DEFAULT);
> >> +        if (rv)
> >> +            return rv;
> >> +    }
> >> +
> >> +    return regmap_write(map,
> >> +                MAX77650_REG_CNFG_LED_TOP,
> >> +                MAX77650_LED_TOP_DEFAULT);
> >> +}
> >> +
> >> +static struct platform_driver max77650_led_driver = {
> >> +    .driver = {
> >> +        .name = "max77650-led",
> >> +    },
> >> +    .probe = max77650_led_probe,
> >> +};
> >> +module_platform_driver(max77650_led_driver);
> >> +
> >> +MODULE_DESCRIPTION("MAXIM 77650/77651 LED driver");
> >> +MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>");
> >> +MODULE_LICENSE("GPL v2");
> >>
> >
> > Acked-by: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx>
> >
>
>
> --
> ------------------
> Dan Murphy

Best regards,
Bartosz Golaszewski




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