On 09/06/2022 18:57, Andy Shevchenko wrote:
On Thu, Jun 9, 2022 at 6:30 PM Jean-Jacques Hiblot
<jjhiblot@xxxxxxxxxxxxxxx> 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 <jjhiblot@xxxxxxxxxxxxxxx>
...
+#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);
