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Date: Sat, 2 Feb 2019 15:39:55 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Dan Murphy <dmurphy@...com>
Cc: Jacek Anaszewski <jacek.anaszewski@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Linus Walleij <linus.walleij@...aro.org>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Pavel Machek <pavel@....cz>, Lee Jones <lee.jones@...aro.org>,
Sebastian Reichel <sre@...nel.org>,
Liam Girdwood <lgirdwood@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
devicetree <devicetree@...r.kernel.org>,
Linux Input <linux-input@...r.kernel.org>,
Linux LED Subsystem <linux-leds@...r.kernel.org>,
Linux PM list <linux-pm@...r.kernel.org>,
Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v3 09/11] leds: max77650: add LEDs support
pt., 1 lut 2019 o 21:15 Dan Murphy <dmurphy@...com> 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@...libre.com>
> >>
> >> 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@...libre.com>
> >> ---
> >> 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@...libre.com>
> >> +//
> >> +// 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", ®);
>
> 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@...libre.com>");
> >> +MODULE_LICENSE("GPL v2");
> >>
> >
> > Acked-by: Jacek Anaszewski <jacek.anaszewski@...il.com>
> >
>
>
> --
> ------------------
> Dan Murphy
Best regards,
Bartosz Golaszewski
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