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Message-ID: <20220523084958.2723943-3-jjhiblot@traphandler.com>
Date: Mon, 23 May 2022 10:49:56 +0200
From: Jean-Jacques Hiblot <jjhiblot@...phandler.com>
To: Pavel Machek <pavel@....cz>
CC: Jean-Jacques Hiblot <jjhiblot@...phandler.com>,
<linux-kernel@...r.kernel.org>, <linux-leds@...r.kernel.org>
Subject: [PATCH 2/3] leds: Add driver for the TLC5925 LED controller
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 <jjhiblot@...phandler.com>
---
drivers/leds/Kconfig | 6 ++
drivers/leds/Makefile | 1 +
drivers/leds/leds-tlc5925.c | 157 ++++++++++++++++++++++++++++++++++++
3 files changed, 164 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..f33eff8b7333
--- /dev/null
+++ b/drivers/leds/leds-tlc5925.c
@@ -0,0 +1,157 @@
+// 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, "shift_register_length",
+ &max_num_leds, 1);
+ if (ret) {
+ dev_err(dev, "'shift_register_length' property is required.\n");
+ return -EINVAL;
+ }
+
+ if (max_num_leds % 8) {
+ dev_err(dev, "'shift_register_length' must be a multiple of 8\n");
+ return -EINVAL;
+ }
+
+ if (max_num_leds == 0) {
+ dev_err(dev, "'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 struct spi_driver tlc5925_driver = {
+ .probe = tlc5925_probe,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = tlc5925_dt_ids,
+ },
+};
+
+module_spi_driver(tlc5925_driver);
+
+MODULE_AUTHOR("Jean-Jacques Hiblot <jjhiblot@...phandler.com>");
+MODULE_DESCRIPTION("TLC5925 LED driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:tlc5925");
--
2.25.1
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