[v4,2/2] leds: bd2606mvv: Driver for the Rohm 6 Channel i2c LED driver
Commit Message
The device provides 6 channels which can be individually
turned off and on but groups of two channels share a common brightness
register.
Limitation: The GPIO to enable the device is not used yet.
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
---
drivers/leds/Kconfig | 11 +++
drivers/leds/Makefile | 1 +
drivers/leds/leds-bd2606mvv.c | 143 ++++++++++++++++++++++++++++++++++
3 files changed, 155 insertions(+)
create mode 100644 drivers/leds/leds-bd2606mvv.c
Comments
Hi!
> The device provides 6 channels which can be individually
> turned off and on but groups of two channels share a common brightness
> register.
Yeah, well.. Turn it into 3-channel controller with brightness or
6-channel on/off one... You can't really share brightness.
> +++ b/drivers/leds/Kconfig
> @@ -551,6 +551,17 @@ config LEDS_REGULATOR
> help
> This option enables support for regulator driven LEDs.
>
> +config LEDS_BD2606MVV
> + tristate "LED driver for BD2606MVV"
> + depends on LEDS_CLASS
> + depends on I2C
> + select REGMAP_I2C
> + help
> + This option enables support for BD2606MVV LED driver chips
> + accessed via the I2C bus. It supports setting brightness, with
> + the limitiation that there are groups of two channels sharing
> + a brightness setting, but not the on/off setting.
> +
This driver can be used as a module...
> +static int
> +bd2606mvv_brightness_set(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + struct bd2606mvv_led *led = ldev_to_led(led_cdev);
> + struct bd2606mvv_priv *priv = led->priv;
> + int err;
> +
> + if (brightness == 0)
> + return regmap_update_bits(priv->regmap,
> + BD2606_REG_PWRCNT,
> + 1 << led->led_no,
> + 0);
> +
> + /* shared brightness register */
> + err = regmap_write(priv->regmap, led->led_no / 2,
> + brightness);
> + if (err)
> + return err;
Yeah. No.
Best regards,
Pavel
Hi Pavel,
On Fri, 14 Apr 2023 14:18:56 +0200
Pavel Machek <pavel@ucw.cz> wrote:
> Hi!
>
> > The device provides 6 channels which can be individually
> > turned off and on but groups of two channels share a common brightness
> > register.
>
> Yeah, well.. Turn it into 3-channel controller with brightness or
> 6-channel on/off one... You can't really share brightness.
>
No, I cannot change the hardware, so it is a 6-channel with limitations.
And the devicetree has to describe the hardware and not the driver.
What is discussable is just how the driver should deal with that:
I see 5 possibilities.
a) ignore the shared brightness problem (status quo)
b) never set a brightness other than full on/off
c) ignore one led of each pair (not register it at all{
d) couple also the on/off of the pairs, so present to
userspace only max. 3 leds.
e) allow full brightness control where independently possible,
if LEDs are defined where that leads to conflicts,
register them with max_brightness=1 and use them
in on/off mode.
My preference were a) or e), the most possible usages.
e) has a cleaner interface to the userspace.
I would not upstream b)
Regards,
Andreas
> > +++ b/drivers/leds/Kconfig
> > @@ -551,6 +551,17 @@ config LEDS_REGULATOR
> > help
> > This option enables support for regulator driven LEDs.
> >
> > +config LEDS_BD2606MVV
> > + tristate "LED driver for BD2606MVV"
> > + depends on LEDS_CLASS
> > + depends on I2C
> > + select REGMAP_I2C
> > + help
> > + This option enables support for BD2606MVV LED driver chips
> > + accessed via the I2C bus. It supports setting brightness, with
> > + the limitiation that there are groups of two channels sharing
> > + a brightness setting, but not the on/off setting.
> > +
>
> This driver can be used as a module...
>
>
> > +static int
> > +bd2606mvv_brightness_set(struct led_classdev *led_cdev,
> > + enum led_brightness brightness)
> > +{
> > + struct bd2606mvv_led *led = ldev_to_led(led_cdev);
> > + struct bd2606mvv_priv *priv = led->priv;
> > + int err;
> > +
> > + if (brightness == 0)
> > + return regmap_update_bits(priv->regmap,
> > + BD2606_REG_PWRCNT,
> > + 1 << led->led_no,
> > + 0);
> > +
> > + /* shared brightness register */
> > + err = regmap_write(priv->regmap, led->led_no / 2,
> > + brightness);
> > + if (err)
> > + return err;
>
> Yeah. No.
>
> Best regards,
> Pavel
Hi!
> > > The device provides 6 channels which can be individually
> > > turned off and on but groups of two channels share a common brightness
> > > register.
> >
> > Yeah, well.. Turn it into 3-channel controller with brightness or
> > 6-channel on/off one... You can't really share brightness.
> >
> No, I cannot change the hardware, so it is a 6-channel with limitations.
> And the devicetree has to describe the hardware and not the driver.
Device tree is okay, I commented on the driver.
> What is discussable is just how the driver should deal with that:
>
> I see 5 possibilities.
> a) ignore the shared brightness problem (status quo)
> b) never set a brightness other than full on/off
> c) ignore one led of each pair (not register it at all{
> d) couple also the on/off of the pairs, so present to
> userspace only max. 3 leds.
> e) allow full brightness control where independently possible,
> if LEDs are defined where that leads to conflicts,
> register them with max_brightness=1 and use them
> in on/off mode.
>
> My preference were a) or e), the most possible usages.
> e) has a cleaner interface to the userspace.
b) c) e) are acceptable to me. So I guess e) is preffered.
BR, Pavel
Hi!
> > > +config LEDS_BD2606MVV
> > > + tristate "LED driver for BD2606MVV"
> > > + depends on LEDS_CLASS
> > > + depends on I2C
> > > + select REGMAP_I2C
> > > + help
> > > + This option enables support for BD2606MVV LED driver chips
> > > + accessed via the I2C bus. It supports setting brightness, with
> > > + the limitiation that there are groups of two channels sharing
> > > + a brightness setting, but not the on/off setting.
> > > +
> >
> > This driver can be used as a module...
And I was pointing this out before...
BR,
Pavel
@@ -551,6 +551,17 @@ config LEDS_REGULATOR
help
This option enables support for regulator driven LEDs.
+config LEDS_BD2606MVV
+ tristate "LED driver for BD2606MVV"
+ depends on LEDS_CLASS
+ depends on I2C
+ select REGMAP_I2C
+ help
+ This option enables support for BD2606MVV LED driver chips
+ accessed via the I2C bus. It supports setting brightness, with
+ the limitiation that there are groups of two channels sharing
+ a brightness setting, but not the on/off setting.
+
config LEDS_BD2802
tristate "LED driver for BD2802 RGB LED"
depends on LEDS_CLASS
@@ -17,6 +17,7 @@ obj-$(CONFIG_LEDS_ARIEL) += leds-ariel.o
obj-$(CONFIG_LEDS_AW2013) += leds-aw2013.o
obj-$(CONFIG_LEDS_BCM6328) += leds-bcm6328.o
obj-$(CONFIG_LEDS_BCM6358) += leds-bcm6358.o
+obj-$(CONFIG_LEDS_BD2606MVV) += leds-bd2606mvv.o
obj-$(CONFIG_LEDS_BD2802) += leds-bd2802.o
obj-$(CONFIG_LEDS_BLINKM) += leds-blinkm.o
obj-$(CONFIG_LEDS_CLEVO_MAIL) += leds-clevo-mail.o
new file mode 100644
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 Andreas Kemnade
+ *
+ * Datasheet:
+ * https://fscdn.rohm.com/en/products/databook/datasheet/ic/power/led_driver/bd2606mvv_1-e.pdf
+ */
+
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define BD2606_MAX_LEDS 6
+#define BD2606_MAX_BRIGHTNESS 63
+#define BD2606_REG_PWRCNT 3
+#define ldev_to_led(c) container_of(c, struct bd2606mvv_led, ldev)
+
+struct bd2606mvv_led {
+ unsigned int led_no;
+ struct led_classdev ldev;
+ struct bd2606mvv_priv *priv;
+};
+
+struct bd2606mvv_priv {
+ struct bd2606mvv_led leds[BD2606_MAX_LEDS];
+ struct regmap *regmap;
+};
+
+static int
+bd2606mvv_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct bd2606mvv_led *led = ldev_to_led(led_cdev);
+ struct bd2606mvv_priv *priv = led->priv;
+ int err;
+
+ if (brightness == 0)
+ return regmap_update_bits(priv->regmap,
+ BD2606_REG_PWRCNT,
+ 1 << led->led_no,
+ 0);
+
+ /* shared brightness register */
+ err = regmap_write(priv->regmap, led->led_no / 2,
+ brightness);
+ if (err)
+ return err;
+
+ return regmap_update_bits(priv->regmap,
+ BD2606_REG_PWRCNT,
+ 1 << led->led_no,
+ 1 << led->led_no);
+}
+
+static const struct regmap_config bd2606mvv_regmap = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = 0x3,
+};
+
+static int bd2606mvv_probe(struct i2c_client *client)
+{
+ struct fwnode_handle *np, *child;
+ struct device *dev = &client->dev;
+ struct bd2606mvv_priv *priv;
+ bool active[BD2606_MAX_LEDS] = { 0 };
+ int err, reg;
+
+ np = dev_fwnode(dev);
+ if (!np)
+ return -ENODEV;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->regmap = devm_regmap_init_i2c(client, &bd2606mvv_regmap);
+ if (IS_ERR(priv->regmap)) {
+ err = PTR_ERR(priv->regmap);
+ dev_err(dev, "Failed to allocate register map: %d\n", err);
+ return err;
+ }
+
+ i2c_set_clientdata(client, priv);
+
+ fwnode_for_each_available_child_node(np, child) {
+ struct bd2606mvv_led *led;
+ struct led_init_data init_data = {};
+
+ init_data.fwnode = child;
+
+ err = fwnode_property_read_u32(child, "reg", ®);
+ if (err) {
+ fwnode_handle_put(child);
+ return err;
+ }
+ if (reg < 0 || reg >= BD2606_MAX_LEDS ||
+ active[reg]) {
+ fwnode_handle_put(child);
+ return -EINVAL;
+ }
+ led = &priv->leds[reg];
+
+ active[reg] = true;
+ led->priv = priv;
+ led->led_no = reg;
+ led->ldev.brightness_set_blocking = bd2606mvv_brightness_set;
+ led->ldev.max_brightness = BD2606_MAX_BRIGHTNESS;
+ err = devm_led_classdev_register_ext(dev, &led->ldev,
+ &init_data);
+ if (err < 0) {
+ fwnode_handle_put(child);
+ return dev_err_probe(dev, err,
+ "couldn't register LED %s\n",
+ led->ldev.name);
+ }
+ }
+ return 0;
+}
+
+static const struct of_device_id __maybe_unused of_bd2606mvv_leds_match[] = {
+ { .compatible = "rohm,bd2606mvv", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, of_bd2606mvv_leds_match);
+
+static struct i2c_driver bd2606mvv_driver = {
+ .driver = {
+ .name = "leds-bd2606mvv",
+ .of_match_table = of_match_ptr(of_bd2606mvv_leds_match),
+ },
+ .probe_new = bd2606mvv_probe,
+};
+
+module_i2c_driver(bd2606mvv_driver);
+
+MODULE_AUTHOR("Andreas Kemnade <andreas@kemnade.info>");
+MODULE_DESCRIPTION("BD2606 LED driver");
+MODULE_LICENSE("GPL");