Re: [PATCH v4 2/2] leds: add LED driver for EL15203000 board

Oleh Kravchenko
2019-08-27T20:44:09Z

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Hello Jacek,

what status of linux-leds.git?
git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds.git

Is it outdated? Because I have a errors:
drivers/leds/leds-el15203000.c:234:9: error: variable ‘init_data’ has initializer but incomplete type
struct led_init_data init_data = {};
^~~~~~~~~~~~~

18.08.19 16:47, Jacek Anaszewski пише:
> Hi Oleh,
>
> Please find my review remarks below.
>
> On 8/8/19 10:32 PM, Oleh Kravchenko wrote:
>> This patch adds a LED class driver for the RGB LEDs found on
>> the Crane Merchandising System EL15203000 LEDs board
>> (aka RED LEDs board).
>>
>> Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
>> ---
>> .../testing/sysfs-class-led-driver-el15203000 | 22 +
>> drivers/leds/Kconfig | 13 +
>> drivers/leds/Makefile | 1 +
>> drivers/leds/leds-el15203000.c | 478 ++++++++++++++++++
>> 4 files changed, 514 insertions(+)
>> create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-el15203000
>> create mode 100644 drivers/leds/leds-el15203000.c
>>
>> diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-el15203000 b/Documentation/ABI/testing/sysfs-class-led-driver-el15203000
>> new file mode 100644
>> index 000000000000..91a483e493d9
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-class-led-driver-el15203000
>> @@ -0,0 +1,22 @@
>> +What: /sys/class/leds/<led>/hw_pattern
>> +Date: August 2019
>> +KernelVersion: 5.3
>> +Description:
>> + Specify a hardware pattern for the EL15203000 LED.
>> + The LEDs board supports only predefined patterns by firmware
>> + for specific LEDs.
>> +
>> + Breathing mode for Screen frame light tube:
>> + "0 4000 1 4000"
>> +
>> + Cascade mode for Pipe LED:
>> + "1 800 2 800 4 800 8 800 16 800 1 800 2 800 4 800 8 800 16 800"
>
> There's no point in repeating same sequence. Just require to provide it
> once:
>
> "1 800 2 800 4 800 8 800 16 800"
>
>> +
>> + Inverted cascade mode for Pipe LED:
>> + "30 800 29 800 27 800 23 800 15 800 30 800 29 800 27 800 23 800 15 800"
>
> The same story:
>
> "30 800 29 800 27 800 23 800 15 800"
>
>> +
>> + Bounce mode for Pipe LED:
>> + "1 800 2 800 4 800 8 800 16 800 16 800 8 800 4 800 2 800 1 800"
>> +
>> + Inverted bounce mode for Pipe LED:
>> + "30 800 29 800 27 800 23 800 15 800 15 800 23 800 27 800 29 800 30 800"
>
> These can be left as they are now.
>
>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
>> index 760f73a49c9f..0cbdb9ba5213 100644
>> --- a/drivers/leds/Kconfig
>> +++ b/drivers/leds/Kconfig
>> @@ -129,6 +129,19 @@ config LEDS_CR0014114
>> To compile this driver as a module, choose M here: the module
>> will be called leds-cr0014114.
>>
>> +config LEDS_EL15203000
>> + tristate "LED Support for Crane EL15203000"
>> + depends on LEDS_CLASS
>> + depends on SPI
>> + depends on OF
>> + help
>> + This option enables support for EL15203000 LED Board
>> + (aka RED LED board) which is widely used in coffee vending
>> + machines produced by Crane Merchandising Systems.
>> +
>> + To compile this driver as a module, choose M here: the module
>> + will be called leds-el15203000.
>> +
>> config LEDS_LM3530
>> tristate "LCD Backlight driver for LM3530"
>> depends on LEDS_CLASS
>> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
>> index 1e9702ebffee..1f193ffc2feb 100644
>> --- a/drivers/leds/Makefile
>> +++ b/drivers/leds/Makefile
>> @@ -85,6 +85,7 @@ obj-$(CONFIG_LEDS_LM3601X) += leds-lm3601x.o
>> # LED SPI Drivers
>> obj-$(CONFIG_LEDS_CR0014114) += leds-cr0014114.o
>> obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
>> +obj-$(CONFIG_LEDS_EL15203000) += leds-el15203000.o
>>
>> # LED Userspace Drivers
>> obj-$(CONFIG_LEDS_USER) += uleds.o
>> diff --git a/drivers/leds/leds-el15203000.c b/drivers/leds/leds-el15203000.c
>> new file mode 100644
>> index 000000000000..c62da5ec6630
>> --- /dev/null
>> +++ b/drivers/leds/leds-el15203000.c
>> @@ -0,0 +1,478 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright (c) 2019 Crane Merchandising Systems. All rights reserved.
>> +// Copyright (C) 2019 Oleh Kravchenko <oleg@kaa.org.ua>
>> +
>> +#include <linux/delay.h>
>> +#include <linux/leds.h>
>> +#include <linux/limits.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/spi/spi.h>
>> +#include <uapi/linux/uleds.h>
>> +
>> +/*
>> + * EL15203000 SPI protocol description:
>> + * +-----+------------+
>> + * | LED | BRIGHTNESS |
>> + * +-----+------------+
>> + * | 1 | 1 |
>> + * +-----+------------+
>> + * (*) LEDs MCU board expects 20 msec delay per byte.
>> + *
>> + * LEDs:
>> + * +----------+--------------+-------------------------------------------+
>> + * | ID | NAME | DESCRIPTION |
>> + * +----------+--------------+-------------------------------------------+
>> + * | 'P' 0x50 | Pipe | Consists from 5 LEDs, controlled by board |
>> + * +----------+--------------+-------------------------------------------+
>> + * | 'S' 0x53 | Screen frame | Light tube around the screen |
>> + * +----------+--------------+-------------------------------------------+
>> + * | 'V' 0x56 | Vending area | Highlights a cup of coffee |
>> + * +----------+--------------+-------------------------------------------+
>> + *
>> + * BRIGHTNESS:
>> + * +----------+-----------------+--------------+--------------+
>> + * | VALUES | PIPE | SCREEN FRAME | VENDING AREA |
>> + * +----------+-----------------+--------------+--------------+
>> + * | '0' 0x30 | Off |
>> + * +----------+-----------------------------------------------+
>> + * | '1' 0x31 | On |
>> + * +----------+-----------------+--------------+--------------+
>> + * | '2' 0x32 | Cascade | Breathing |
>> + * +----------+-----------------+--------------+
>> + * | '3' 0x33 | Inverse cascade |
>> + * +----------+-----------------+
>> + * | '4' 0x34 | Bounce |
>> + * +----------+-----------------+
>> + * | '5' 0x35 | Inverse bounce |
>> + * +----------+-----------------+
>> + */
>> +
>> +/* EL15203000 default settings */
>> +#define EL_FW_DELAY_USEC 20000
>> +
>> +enum el15203000_brightness {
>
> Please change 'brightness' to 'command' or so. Brightness is misleading
> since this device supports in fact only one level of brightness for
> non-pattern use case.
>
>> + /* for all LEDs */
>> + EL_OFF = '0',
>> + EL_ON = '1',
>> +
>> + /* for Screen LED */
>> + EL_SCREEN_BREATHING = '2',
>> +
>> + /* for Pipe LED */
>> + EL_PIPE_CASCADE = '2',
>> + EL_PIPE_INV_CASCADE = '3',
>> + EL_PIPE_BOUNCE = '4',
>> + EL_PIPE_INV_BOUNCE = '5',
>> +};
>> +
>> +struct el15203000_led {
>> + struct el15203000 *priv;
>> + struct led_classdev ldev;
>> + char name[LED_MAX_NAME_SIZE];
>
> This field will not be needed if we switch to
> devm_led_classdev_register_ext().
>
>> + u8 reg;
>> +};
>> +
>> +struct el15203000 {
>> + struct device *dev;
>> + struct mutex lock;
>> + struct spi_device *spi;
>> + unsigned long delay;
>> + size_t count;
>> + struct el15203000_led leds[];
>> +};
>> +
>> +static int el15203000_cmd(struct el15203000_led *led, u8 brightness)
>> +{
>> + int ret;
>> + u8 cmd[2];
>> + size_t i;
>> + unsigned long jdelay, udelay, now;
>> +
>> + mutex_lock(&led->priv->lock);
>> +
>> + dev_dbg(led->priv->dev, "Set brightness of %s to %d",
>> + led->name, brightness);
>> +
>> + /* to avoid SPI mistiming with firmware we should wait some time */
>> + now = jiffies;
>> + if (time_after(led->priv->delay, now)) {
>> + jdelay = led->priv->delay - now;
>> + udelay = jiffies_to_usecs(jdelay);
>> +
>> + dev_dbg(led->priv->dev, "Wait %luus (%lu jiffies) to sync",
>> + udelay, jdelay);
>> +
>> + usleep_range(udelay, udelay + 1);
>> + }
>> +
>> + cmd[0] = led->reg;
>> + cmd[1] = brightness;
>> +
>> + for (i = 0; i < ARRAY_SIZE(cmd); i++) {
>> + if (i)
>> + usleep_range(EL_FW_DELAY_USEC,
>> + EL_FW_DELAY_USEC + 1);
>> +
>> + ret = spi_write(led->priv->spi, &cmd[i], sizeof(cmd[i]));
>> + if (ret) {
>> + dev_err(led->priv->dev,
>> + "spi_write() error %d", ret);
>> + break;
>> + }
>> + }
>> +
>> + led->priv->delay = jiffies + usecs_to_jiffies(EL_FW_DELAY_USEC);
>> +
>> + mutex_unlock(&led->priv->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static int el15203000_set_blocking(struct led_classdev *ldev,
>> + enum led_brightness brightness)
>> +{
>> + struct el15203000_led *led = container_of(ldev,
>> + struct el15203000_led,
>> + ldev);
>> +
>> + return el15203000_cmd(led, brightness == LED_OFF ? EL_OFF : EL_ON);
>> +}
>> +
>> +static int led_pattern_cmp(const struct led_pattern *p1, u32 p1_len,
>> + const struct led_pattern *p2, u32 p2_len)
>> +{
>> + u32 i;
>> +
>> + if (p1_len != p2_len)
>> + return -1;
>> +
>> + for (i = 0; i < p1_len; i ++)
>> + if (p1[i].delta_t != p2[i].delta_t ||
>> + p1[i].brightness != p2[i].brightness)
>> + return -1;
>> +
>> + return 0;
>> +}
>> +
>> +int el15203000_pattern_set_S(struct led_classdev *ldev,
>> + struct led_pattern *pattern,
>> + u32 len, int repeat)
>> +{
>> + struct el15203000_led *led = container_of(ldev,
>> + struct el15203000_led,
>> + ldev);
>> + struct led_pattern scr_pattern[] = {{
>> + .delta_t = 4000,
>> + .brightness = 0,
>> + }, {
>> + .delta_t = 4000,
>> + .brightness = 1,
>> + }};
>> +
>> + if (repeat > 0)
>> + return -EINVAL;
>> +
>> + if (led_pattern_cmp(scr_pattern, ARRAY_SIZE(scr_pattern), pattern, len))
>> + return -EINVAL;
>> +
>> + dev_dbg(led->priv->dev, "Breathing mode for '%s'", led->name);
>> +
>> + return el15203000_cmd(led, EL_SCREEN_BREATHING);
>> +}
>> +
>> +int el15203000_pattern_set_P(struct led_classdev *ldev,
>> + struct led_pattern *pattern,
>> + u32 len, int repeat)
>> +{
>> + struct el15203000_led *led = container_of(ldev,
>> + struct el15203000_led,
>> + ldev);
>> +
>> + struct led_pattern cascade[] = {{
>> + .delta_t = 800,
>> + .brightness = 1,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 2,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 4,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 8,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 16,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 1,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 2,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 4,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 8,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 16,
>> + }};
>> +
>> + struct led_pattern inv_cascade[] = {{
>> + .delta_t = 800,
>> + .brightness = 30,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 29,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 27,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 23,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 15,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 30,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 29,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 27,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 23,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 15,
>> + }};
>> +
>> + struct led_pattern bounce[] = {{
>> + .delta_t = 800,
>> + .brightness = 1,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 2,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 4,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 8,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 16,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 16,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 8,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 4,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 2,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 1,
>> + }};
>> +
>> + struct led_pattern inv_bounce[] = {{
>> + .delta_t = 800,
>> + .brightness = 30,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 29,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 27,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 23,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 15,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 15,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 23,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 27,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 29,
>> + }, {
>> + .delta_t = 800,
>> + .brightness = 30,
>> + }};
>
> There is no need for these arrays. We can come up with formulas for
> validating the pattern tuples. Basically all of them involve differences
> in brightness being powers of two:
>
> "1 800 2 800 4 800 8 800 16 800"
>
> Here each next step should be equal to (1 << i) staring from i = 0.
>
> "30 800 29 800 27 800 23 800 15 800"
>
> brightness = 30;
> for (i = 0; i < pattern_len; i++) {
> br_diff = (i > 0) ? (1 << (i - 1)) : 0;
> brightness -= br_diff;
> }
>
> "1 800 2 800 4 800 8 800 16 800 16 800 8 800 4 800 2 800 1 800"
>
> "30 800 29 800 27 800 23 800 15 800 15 800 23 800 27 800 29 800 30 800"
>
> Above two can be handled by slightly modifying what I proposed above.
>
> And for delta_t just require by default always 800.
>
>> + if (repeat > 0)
>> + return -EINVAL;
>> +
>> + if (!led_pattern_cmp(cascade, ARRAY_SIZE(cascade), pattern, len)) {
>> + dev_dbg(led->priv->dev, "Cascade mode for '%s'", led->name);
>> + return el15203000_cmd(led, EL_PIPE_CASCADE);
>> + } else if (!led_pattern_cmp(inv_cascade, ARRAY_SIZE(inv_cascade), pattern, len)) {
>> + dev_dbg(led->priv->dev, "Inverse cascade mode for '%s'", led->name);
>> + return el15203000_cmd(led, EL_PIPE_INV_CASCADE);
>> + } else if (!led_pattern_cmp(bounce, ARRAY_SIZE(bounce), pattern, len)) {
>> + dev_dbg(led->priv->dev, "Bounce mode for '%s'", led->name);
>> + return el15203000_cmd(led, EL_PIPE_BOUNCE);
>> + } else if (!led_pattern_cmp(inv_bounce, ARRAY_SIZE(inv_bounce), pattern, len)) {
>> + dev_dbg(led->priv->dev, "Inverse bounce mode for '%s'", led->name);
>> + return el15203000_cmd(led, EL_PIPE_INV_BOUNCE);
>> + }
>> +
>> + return -EINVAL;
>> +}
>> +
>> +int el15203000_pattern_clear(struct led_classdev *ldev)
>> +{
>> + struct el15203000_led *led = container_of(ldev,
>> + struct el15203000_led,
>> + ldev);
>> +
>> + return el15203000_cmd(led, EL_OFF);
>> +}
>> +
>> +static int el15203000_probe_dt(struct el15203000 *priv)
>> +{
>> + size_t i = 0;
>> + struct el15203000_led *led;
>> + struct fwnode_handle *child;
>> + int ret;
>> + const char *str;
>> + u32 reg;
>> +
>> + device_for_each_child_node(priv->dev, child) {
> struct led_init_data init_data = {};
>
> Please add above declaration here.
>
>> + led = &priv->leds[i];
>> +
>> + ret = fwnode_property_read_u32(child, "reg", &reg);
>> + if (ret) {
>> + dev_err(priv->dev, "LED without ID number");
>> + fwnode_handle_put(child);
>> +
>> + return ret;
>> + }
>> +
>> + if (reg > U8_MAX) {
>> + dev_err(priv->dev, "LED value %d is invalid", reg);
>> + fwnode_handle_put(child);
>> +
>> + return -EINVAL;
>> + }
>> +
>> + led->reg = reg;
>> +
>> + ret = fwnode_property_read_string(child, "label", &str);
>> + if (ret)
>> + str = ":";
>> + snprintf(led->name, sizeof(led->name), "el15203000:%s", str);
>
> And instead of the four above lines please just do the below assignment:
>
> init_data.fwnode = child;
>
> but let's do it right before calling devm_led_classdev_register_ext().
>
>> +
>> + fwnode_property_read_string(child, "linux,default-trigger",
>> + &led->ldev.default_trigger);
>> +
>> + led->ldev.max_brightness = LED_ON;
>> + led->priv = priv;
>> + led->ldev.name = led->name;
>
> Please also remove the above line.
>
>> + led->ldev.brightness_set_blocking = el15203000_set_blocking;
>> +
>> + if (reg == 'S') {
>> + led->ldev.pattern_set = el15203000_pattern_set_S;
>> + led->ldev.pattern_clear = el15203000_pattern_clear;
>> + } else if (reg == 'P') {
>> + led->ldev.pattern_set = el15203000_pattern_set_P;
>> + led->ldev.pattern_clear = el15203000_pattern_clear;
>> + }
>> +
>> + ret = devm_led_classdev_register(priv->dev, &led->ldev);
>
> And here let's switch to the new LED registration API:
>
> ret = devm_led_classdev_register_ext(priv->dev, &led->ldev, &init_data);
>
>
>> + if (ret) {
>> + dev_err(priv->dev,
>> + "failed to register LED device %s, err %d",
>> + led->name, ret);
>> + fwnode_handle_put(child);
>> + return ret;
>> + }
>> +
>> + i++;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int el15203000_probe(struct spi_device *spi)
>> +{
>> + struct el15203000 *priv;
>> + size_t count;
>> + int ret;
>> +
>> + count = device_get_child_node_count(&spi->dev);
>> + if (!count) {
>> + dev_err(&spi->dev, "LEDs are not defined in device tree!");
>> + return -ENODEV;
>> + }
>> +
>> + priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
>> + GFP_KERNEL);
>> + if (!priv)
>> + return -ENOMEM;
>> +
>> + mutex_init(&priv->lock);
>> + priv->count = count;
>> + priv->dev = &spi->dev;
>> + priv->spi = spi;
>> + priv->delay = jiffies -
>> + usecs_to_jiffies(EL_FW_DELAY_USEC);
>> +
>> + ret = el15203000_probe_dt(priv);
>> + if (ret)
>> + return ret;
>> +
>> + spi_set_drvdata(spi, priv);
>> + dev_dbg(priv->dev, "%zd LEDs registered", priv->count);
>
> Please remove this debug log.
>
>> +
>> + return 0;
>> +}
>> +
>> +static int el15203000_remove(struct spi_device *spi)
>> +{
>> + struct el15203000 *priv = spi_get_drvdata(spi);
>> +
>> + mutex_destroy(&priv->lock);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id el15203000_dt_ids[] = {
>> + { .compatible = "crane,el15203000", },
>> + {},
>> +};
>> +
>> +MODULE_DEVICE_TABLE(of, el15203000_dt_ids);
>> +
>> +static struct spi_driver el15203000_driver = {
>> + .probe = el15203000_probe,
>> + .remove = el15203000_remove,
>> + .driver = {
>> + .name = KBUILD_MODNAME,
>> + .of_match_table = el15203000_dt_ids,
>> + },
>> +};
>> +
>> +module_spi_driver(el15203000_driver);
>> +
>> +MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
>> +MODULE_DESCRIPTION("el15203000 LED driver");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_ALIAS("spi:el15203000");
>>
>
> Please also fix the issues checkpatch.pl complains about.
>

--
Best regards,
Oleh Kravchenko

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