The TLC5925 is a 16-channels constant-current LED sink driver.
It is controlled via SPI but doesn't offer a register-based interface.
Instead it contains a shift register and latches that convert the
serial input into a parallel output.
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
---
drivers/leds/Kconfig | 6 ++
drivers/leds/Makefile | 1 +
drivers/leds/leds-tlc5925.c | 164 ++++++++++++++++++++++++++++++++++++
3 files changed, 171 insertions(+)
create mode 100644 drivers/leds/leds-tlc5925.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a49979f41eee..b17eb01210ba 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -658,6 +658,12 @@ config LEDS_TLC591XX
This option enables support for Texas Instruments TLC59108
and TLC59116 LED controllers.
+config LEDS_TLC5925
+ tristate "LED driver for TLC5925 controller"
+ depends on LEDS_CLASS && SPI
+ help
+ This option enables support for Texas Instruments TLC5925.
+
config LEDS_MAX77650
tristate "LED support for Maxim MAX77650 PMIC"
depends on LEDS_CLASS && MFD_MAX77650
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 4fd2f92cd198..9d15b88d482f 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_LEDS_SYSCON) += leds-syscon.o
obj-$(CONFIG_LEDS_TCA6507) += leds-tca6507.o
obj-$(CONFIG_LEDS_TI_LMU_COMMON) += leds-ti-lmu-common.o
obj-$(CONFIG_LEDS_TLC591XX) += leds-tlc591xx.o
+obj-$(CONFIG_LEDS_TLC5925) += leds-tlc5925.o
obj-$(CONFIG_LEDS_TPS6105X) += leds-tps6105x.o
obj-$(CONFIG_LEDS_TURRIS_OMNIA) += leds-turris-omnia.o
obj-$(CONFIG_LEDS_WM831X_STATUS) += leds-wm831x-status.o
diff --git a/drivers/leds/leds-tlc5925.c b/drivers/leds/leds-tlc5925.c
new file mode 100644
index 000000000000..2c50ba10bdbf
--- /dev/null
+++ b/drivers/leds/leds-tlc5925.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * The driver supports controllers with a very simple SPI protocol:
+ * - the data is deserialized in a shift-register when CS is asserted
+ * - the data is latched when CS is de-asserted
+ * - the LED are either on or off (no control of the brightness)
+ *
+ * Supported devices:
+ * - "ti,tlc5925": Low-Power 16-Channel Constant-Current LED Sink Driver
+ * https://www.ti.com/lit/ds/symlink/tlc5925.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/property.h>
+#include <linux/workqueue.h>
+
+struct single_led_priv {
+ int idx;
+ struct led_classdev cdev;
+};
+
+struct tlc5925_leds_priv {
+ int max_num_leds;
+ u8 *state;
+ spinlock_t lock;
+ struct single_led_priv leds[];
+};
+
+static int tlc5925_brightness_set_blocking(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct spi_device *spi = to_spi_device(cdev->dev->parent);
+ struct tlc5925_leds_priv *priv = spi_get_drvdata(spi);
+ struct single_led_priv *led = container_of(cdev,
+ struct single_led_priv,
+ cdev);
+ int index = led->idx;
+
+ spin_lock(&priv->lock);
+ if (brightness)
+ priv->state[index / 8] |= (1 << (index % 8));
+ else
+ priv->state[index / 8] &= ~(1 << (index % 8));
+ spin_unlock(&priv->lock);
+
+ return spi_write(spi, priv->state, priv->max_num_leds / 8);
+}
+
+
+static int tlc5925_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct fwnode_handle *child;
+ struct tlc5925_leds_priv *priv;
+ int ret;
+ int max_num_leds, count;
+ struct gpio_descs *gpios;
+
+ count = device_get_child_node_count(dev);
+ if (!count) {
+ dev_err(dev, "no led defined.\n");
+ return -ENODEV;
+ }
+
+ ret = device_property_read_u32_array(dev, "ti,shift-register-length",
+ &max_num_leds, 1);
+ if (ret) {
+ dev_err(dev, "'ti,shift-register-length' property is required.\n");
+ return -EINVAL;
+ }
+
+ if (max_num_leds % 8) {
+ dev_err(dev, "'ti,shift-register-length' must be a multiple of 8\n");
+ return -EINVAL;
+ }
+
+ if (max_num_leds == 0) {
+ dev_err(dev, "'ti,shift-register-length' must be greater than 0\n");
+ return -EINVAL;
+ }
+
+ /* Assert all the OE/ lines */
+ gpios = devm_gpiod_get_array(dev, "output-enable-b", GPIOD_OUT_LOW);
+ if (IS_ERR(gpios)) {
+ dev_err(dev, "Unable to get the 'output-enable-b' gpios\n");
+ return PTR_ERR(gpios);
+ }
+
+ priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ spin_lock_init(&priv->lock);
+
+ priv->state = devm_kzalloc(dev, DIV_ROUND_UP(max_num_leds, 8), GFP_KERNEL);
+ if (!priv->state)
+ return -ENOMEM;
+
+ priv->max_num_leds = max_num_leds;
+
+ device_for_each_child_node(dev, child) {
+ struct led_init_data init_data = {.fwnode = child};
+ struct led_classdev *cdev;
+ u32 idx;
+
+ ret = fwnode_property_read_u32_array(child, "reg", &idx, 1);
+ if (ret || idx >= max_num_leds) {
+ dev_err(dev, "%s: invalid reg value. Ignoring.\n",
+ fwnode_get_name(child));
+ fwnode_handle_put(child);
+ continue;
+ }
+
+ count--;
+ priv->leds[count].idx = idx;
+ cdev = &(priv->leds[count].cdev);
+ cdev->brightness = LED_OFF;
+ cdev->max_brightness = 1;
+ cdev->brightness_set_blocking = tlc5925_brightness_set_blocking;
+
+ ret = devm_led_classdev_register_ext(dev, cdev, &init_data);
+ if (ret) {
+ dev_err(dev, "%s: cannot create LED device.\n",
+ fwnode_get_name(child));
+ fwnode_handle_put(child);
+ continue;
+ }
+ }
+
+ spi_set_drvdata(spi, priv);
+
+ return 0;
+}
+
+static const struct of_device_id tlc5925_dt_ids[] = {
+ { .compatible = "ti,tlc5925", },
+ {},
+};
+
+static const struct spi_device_id tlc5925_id[] = {
+ {"tlc5925", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, tlc5925_id);
+
+static struct spi_driver tlc5925_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = tlc5925_dt_ids,
+ },
+ .id_table = tlc5925_id,
+ .probe = tlc5925_probe,
+};
+
+module_spi_driver(tlc5925_driver);
+
+MODULE_AUTHOR("Jean-Jacques Hiblot <[email protected]>");
+MODULE_DESCRIPTION("TLC5925 LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:tlc5925");
--
2.25.1
On Thu, Jun 9, 2022 at 6:30 PM Jean-Jacques Hiblot
<[email protected]> wrote:
>
> The TLC5925 is a 16-channels constant-current LED sink driver.
> It is controlled via SPI but doesn't offer a register-based interface.
> Instead it contains a shift register and latches that convert the
> serial input into a parallel output.
Can you add Datasheet: tag here with the corresponding URL? Rationale
is to get a link to the datasheet by just browsing Git log without
browsing the source code, which will benefit via Web UIs.
> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
...
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/leds.h>
> +#include <linux/err.h>
> +#include <linux/spi/spi.h>
> +#include <linux/property.h>
> +#include <linux/workqueue.h>
Keep it sorted?
...
> +struct single_led_priv {
> + int idx;
> + struct led_classdev cdev;
For pointer arithmetics it's better to swap these two members.
> +};
> +
> +struct tlc5925_leds_priv {
> + int max_num_leds;
> + u8 *state;
unsigned long? DECLARE_BITMAP() ?
> + spinlock_t lock;
> + struct single_led_priv leds[];
> +};
...
> + if (brightness)
> + priv->state[index / 8] |= (1 << (index % 8));
> + else
> + priv->state[index / 8] &= ~(1 << (index % 8));
assign_bit()
...
> + return spi_write(spi, priv->state, priv->max_num_leds / 8);
BITS_TO_BYTES() ?
...
> + count = device_get_child_node_count(dev);
> + if (!count) {
> + dev_err(dev, "no led defined.\n");
> + return -ENODEV;
return dev_err_probe(...);
here and everywhere in ->probe() and Co.
> + }
...
> + ret = device_property_read_u32_array(dev, "ti,shift-register-length",
> + &max_num_leds, 1);
Always an array of 1 element? call device_property_read_u32().
...
> + if (max_num_leds % 8) {
> + dev_err(dev, "'ti,shift-register-length' must be a multiple of 8\n");
> + return -EINVAL;
> + }
Is this really fatal? I would rather issue a warning and go on if it
has at least 8 there. So the idea is to use a minimum that holds
multiple of 8.
...
> + /* Assert all the OE/ lines */
> + gpios = devm_gpiod_get_array(dev, "output-enable-b", GPIOD_OUT_LOW);
> + if (IS_ERR(gpios)) {
> + dev_err(dev, "Unable to get the 'output-enable-b' gpios\n");
> + return PTR_ERR(gpios);
> + }
You have to use dev_err_probe() here, otherwise it will spam logs a
lot in case of deferred probe.
...
> + priv->state = devm_kzalloc(dev, DIV_ROUND_UP(max_num_leds, 8), GFP_KERNEL);
devm_bitmap_zalloc()
...
> + device_for_each_child_node(dev, child) {
> + struct led_init_data init_data = {.fwnode = child};
Missed spaces.
> + struct led_classdev *cdev;
> + u32 idx;
> +
> + ret = fwnode_property_read_u32_array(child, "reg", &idx, 1);
fwnode_property_read_u32()
> + if (ret || idx >= max_num_leds) {
> + dev_err(dev, "%s: invalid reg value. Ignoring.\n",
> + fwnode_get_name(child));
> + fwnode_handle_put(child);
> + continue;
Either dev_warn + continue, or dev_err + return dev_err_probe().
> + }
> +
> + count--;
> + priv->leds[count].idx = idx;
> + cdev = &(priv->leds[count].cdev);
> + cdev->brightness = LED_OFF;
> + cdev->max_brightness = 1;
> + cdev->brightness_set_blocking = tlc5925_brightness_set_blocking;
> +
> + ret = devm_led_classdev_register_ext(dev, cdev, &init_data);
> + if (ret) {
Ditto.
> + dev_err(dev, "%s: cannot create LED device.\n",
> + fwnode_get_name(child));
> + fwnode_handle_put(child);
> + continue;
> + }
> + }
...
> +static const struct of_device_id tlc5925_dt_ids[] = {
> + { .compatible = "ti,tlc5925", },
> + {},
No comma for terminator entry.
> +};
Where is the MODULE_DEVICE_TABLE() for this one?
...
> +
No need for this blank line.
> +module_spi_driver(tlc5925_driver);
--
With Best Regards,
Andy Shevchenko
On 09/06/2022 18:57, Andy Shevchenko wrote:
> On Thu, Jun 9, 2022 at 6:30 PM Jean-Jacques Hiblot
> <[email protected]> wrote:
>> The TLC5925 is a 16-channels constant-current LED sink driver.
>> It is controlled via SPI but doesn't offer a register-based interface.
>> Instead it contains a shift register and latches that convert the
>> serial input into a parallel output.
> Can you add Datasheet: tag here with the corresponding URL? Rationale
> is to get a link to the datasheet by just browsing Git log without
> browsing the source code, which will benefit via Web UIs.
>> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
> ...
>
>> +#include <linux/module.h>
>> +#include <linux/slab.h>
>> +#include <linux/leds.h>
>> +#include <linux/err.h>
>> +#include <linux/spi/spi.h>
>> +#include <linux/property.h>
>> +#include <linux/workqueue.h>
> Keep it sorted?
>
> ...
>
>> +struct single_led_priv {
>> + int idx;
>> + struct led_classdev cdev;
> For pointer arithmetics it's better to swap these two members.
>
>> +};
>> +
>> +struct tlc5925_leds_priv {
>> + int max_num_leds;
>> + u8 *state;
> unsigned long? DECLARE_BITMAP() ?
>
>> + spinlock_t lock;
>> + struct single_led_priv leds[];
>> +};
> ...
>
>> + if (brightness)
>> + priv->state[index / 8] |= (1 << (index % 8));
>> + else
>> + priv->state[index / 8] &= ~(1 << (index % 8));
> assign_bit()
>
> ...
>
>> + return spi_write(spi, priv->state, priv->max_num_leds / 8);
> BITS_TO_BYTES() ?
>
> ...
>
>> + count = device_get_child_node_count(dev);
>> + if (!count) {
>> + dev_err(dev, "no led defined.\n");
>> + return -ENODEV;
> return dev_err_probe(...);
>
> here and everywhere in ->probe() and Co.
>
>> + }
> ...
>
>> + ret = device_property_read_u32_array(dev, "ti,shift-register-length",
>> + &max_num_leds, 1);
> Always an array of 1 element? call device_property_read_u32().
>
> ...
>
>> + if (max_num_leds % 8) {
>> + dev_err(dev, "'ti,shift-register-length' must be a multiple of 8\n");
>> + return -EINVAL;
>> + }
> Is this really fatal? I would rather issue a warning and go on if it
> has at least 8 there. So the idea is to use a minimum that holds
> multiple of 8.
It is more than likely that it will always be a multiple of 8 here.
We could in theory use a non-multiple of 8 (some LEDs of the first or
last chips of the chain are not populated).
I didn't think it would add a significant benefit in memory usage. In
terms of SPI usage it wouldn't change anything.
Thanks for your feedback.
> ...
>
>> + /* Assert all the OE/ lines */
>> + gpios = devm_gpiod_get_array(dev, "output-enable-b", GPIOD_OUT_LOW);
>> + if (IS_ERR(gpios)) {
>> + dev_err(dev, "Unable to get the 'output-enable-b' gpios\n");
>> + return PTR_ERR(gpios);
>> + }
> You have to use dev_err_probe() here, otherwise it will spam logs a
> lot in case of deferred probe.
>
> ...
>
>> + priv->state = devm_kzalloc(dev, DIV_ROUND_UP(max_num_leds, 8), GFP_KERNEL);
> devm_bitmap_zalloc()
>
> ...
>
>> + device_for_each_child_node(dev, child) {
>> + struct led_init_data init_data = {.fwnode = child};
> Missed spaces.
>
>> + struct led_classdev *cdev;
>> + u32 idx;
>> +
>> + ret = fwnode_property_read_u32_array(child, "reg", &idx, 1);
> fwnode_property_read_u32()
>
>> + if (ret || idx >= max_num_leds) {
>> + dev_err(dev, "%s: invalid reg value. Ignoring.\n",
>> + fwnode_get_name(child));
>> + fwnode_handle_put(child);
>> + continue;
> Either dev_warn + continue, or dev_err + return dev_err_probe().
>
>> + }
>> +
>> + count--;
>> + priv->leds[count].idx = idx;
>> + cdev = &(priv->leds[count].cdev);
>> + cdev->brightness = LED_OFF;
>> + cdev->max_brightness = 1;
>> + cdev->brightness_set_blocking = tlc5925_brightness_set_blocking;
>> +
>> + ret = devm_led_classdev_register_ext(dev, cdev, &init_data);
>> + if (ret) {
> Ditto.
>
>> + dev_err(dev, "%s: cannot create LED device.\n",
>> + fwnode_get_name(child));
>> + fwnode_handle_put(child);
>> + continue;
>> + }
>> + }
> ...
>
>> +static const struct of_device_id tlc5925_dt_ids[] = {
>> + { .compatible = "ti,tlc5925", },
>> + {},
> No comma for terminator entry.
>
>> +};
> Where is the MODULE_DEVICE_TABLE() for this one?
>
> ...
>
>> +
> No need for this blank line.
>
>> +module_spi_driver(tlc5925_driver);
On Thu 2022-06-09 18:57:24, Andy Shevchenko wrote:
> On Thu, Jun 9, 2022 at 6:30 PM Jean-Jacques Hiblot
> <[email protected]> wrote:
> >
> > The TLC5925 is a 16-channels constant-current LED sink driver.
> > It is controlled via SPI but doesn't offer a register-based interface.
> > Instead it contains a shift register and latches that convert the
> > serial input into a parallel output.
>
> Can you add Datasheet: tag here with the corresponding URL? Rationale
> is to get a link to the datasheet by just browsing Git log without
> browsing the source code, which will benefit via Web UIs.
If you want to add datasheet url, add it as a comment to the source,
not to the git log.
Thanks,
Pavel
--
People of Russia, stop Putin before his war on Ukraine escalates.
On Mon, Jun 27, 2022 at 10:49 AM Pavel Machek <[email protected]> wrote:
>
> On Thu 2022-06-09 18:57:24, Andy Shevchenko wrote:
> > On Thu, Jun 9, 2022 at 6:30 PM Jean-Jacques Hiblot
> > <[email protected]> wrote:
> > >
> > > The TLC5925 is a 16-channels constant-current LED sink driver.
> > > It is controlled via SPI but doesn't offer a register-based interface.
> > > Instead it contains a shift register and latches that convert the
> > > serial input into a parallel output.
> >
> > Can you add Datasheet: tag here with the corresponding URL? Rationale
> > is to get a link to the datasheet by just browsing Git log without
> > browsing the source code, which will benefit via Web UIs.
>
> If you want to add datasheet url, add it as a comment to the source,
> not to the git log.
I don't see anything wrong with having it in the Git log. Do you?
(Note, I'm not objecting to have it in the code at the same time)
P.S. Can you review the three patches of the series [1] that have been
submitted day 1 after closing the merge window? It's already a few
weeks passed, or even months if you take into account that the top of
that series has been sent before separately.
[1]: https://lore.kernel.org/linux-leds/[email protected]/
--
With Best Regards,
Andy Shevchenko