Hi David,
Thanks for the patch. Very nice driver. I have few comments
below.
On 02/23/2016 07:17 PM, David Rivshin (Allworx) wrote:
From: David Rivshin <drivshin@xxxxxxxxxxx>
The IS31FL32xx family of LED drivers are I2C devices with multiple
constant-current channels, each with independent 256-level PWM control.
HW Docs: http://www.issi.com/US/product-analog-fxled-driver.shtml
This has been tested on the IS31FL3236 and IS31FL3216 on an ARM
(TI am335x) platform.
The programming paradigm of these devices is similar in the following
ways:
- All registers are 8 bit
- All LED control registers are write-only
- Each LED channel has a PWM register (0-255)
- PWM register writes are shadowed until an Update register is poked
- All have a concept of Software Shutdown, which disables output
However, there are some differences in devices:
- 3236/3235 have a separate Control register for each LED,
(3218/3216 pack the enable bits into fewer registers)
- 3236/3235 have a per-channel current divisor setting
- 3236/3235 have a Global Control register that can turn off all LEDs
- 3216 is unique in a number of ways
- OUT9-OUT16 can be configured as GPIOs instead of LED controls
- LEDs can be programmed with an 8-frame animation, with
programmable delay between frames
- LEDs can be modulated by an input audio signal
- Max output current can be adjusted from 1/4 to 2x globally
- Has a Configuration register instead of a Shutdown register
This driver currently only supports the base PWM control function
of these devices. The following features of these devices are not
implemented, although it should be possible to add them in the future:
- All devices are capable of going into a lower-power "software
shutdown" mode.
- The is31fl3236 and is31fl3235 can reduce the max output current
per-channel with a divisor of 1, 2, 3, or 4.
- The is31fl3216 can use some LED channels as GPIOs instead.
- The is31fl3216 can animate LEDs in hardware.
- The is31fl3216 can modulate LEDs according to an audio input.
- The is31fl3216 can reduce/increase max output current globally.
Signed-off-by: David Rivshin <drivshin@xxxxxxxxxxx>
---
drivers/leds/Kconfig | 9 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-is31fl32xx.c | 442 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 452 insertions(+)
create mode 100644 drivers/leds/leds-is31fl32xx.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 1034696..8f6c46f 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -580,6 +580,15 @@ config LEDS_SN3218
This driver can also be built as a module. If so the module
will be called leds-sn3218.
+config LEDS_IS31FL32XX
+ tristate "Driver for ISSI IS31FL32XX I2C LED driver chip family"
2 x "[Dd]river".
How about:
"LED Support for ISSI IS31FL32XX I2C LED chip family" ?
+ depends on LEDS_CLASS && I2C && OF
+ help
+ Say Y here to include support for the ISSI 31FL32XX LED driver family.
s/driver/chip/
+ They are I2C devices with multiple constant-current channels, each
+ with independent 256-level PWM control. This will only work with
+ device tree enabled devices.
We can skip the last sentence I think.
+
comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"
config LEDS_BLINKM
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 89c9b6f..3fdf313 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_LEDS_KTD2692) += leds-ktd2692.o
obj-$(CONFIG_LEDS_POWERNV) += leds-powernv.o
obj-$(CONFIG_LEDS_SEAD3) += leds-sead3.o
obj-$(CONFIG_LEDS_SN3218) += leds-sn3218.o
+obj-$(CONFIG_LEDS_IS31FL32XX) += leds-is31fl32xx.o
# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
diff --git a/drivers/leds/leds-is31fl32xx.c b/drivers/leds/leds-is31fl32xx.c
new file mode 100644
index 0000000..8dea518
--- /dev/null
+++ b/drivers/leds/leds-is31fl32xx.c
@@ -0,0 +1,442 @@
+/*
+ * linux/drivers/leds-is31fl32xx.c
+ *
+ * Driver for ISSI IS31FL32xx family of I2C LED controllers
+ *
+ * Copyright 2015 Allworx Corp.
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * HW Docs: http://www.issi.com/US/product-analog-fxled-driver.shtml
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+
+#ifdef DEBUG
+ #undef dev_dbg
+ #define dev_dbg dev_info
+#endif
What's the benefit of the above?
+/* Used to indicate a device has no such register */
+#define IS31FL32XX_REG_NONE 0xFF
+
+#define IS31FL3216_CONFIG_REG 0x00
+#define IS31FL3216_LIGHTING_EFFECT_REG 0x03
+#define IS31FL3216_CHANNEL_CONFIG_REG 0x04
+
+struct is31fl32xx_priv;
+struct is31fl32xx_led_data {
+ struct led_classdev cdev;
+ u8 channel; /* 1-based, max priv->cdef->channels */
+ struct is31fl32xx_priv *priv;
+};
+
+struct is31fl32xx_priv {
+ const struct is31fl32xx_chipdef *cdef;
+ struct i2c_client *client;
+ unsigned int num_leds;
+ struct is31fl32xx_led_data leds[0];
Is there any specific reason for not having *leds here instead?
+};
+
+/**
+ * struct is31fl32xx_chipdef - chip-specific attributes
+ * @channels : Number of LED channels
+ * @shutdown_reg : address of Shutdown register (optional)
+ * @pwm_update_reg : address of PWM Update register
+ * @global_control_reg : address of Global Control register (optional)
+ * @reset_reg : address of Reset register (optional)
+ * @pwm_register_base : address of first PWM register
+ * @pwm_registers_reversed: : true if PWM registers count down instead of up
+ * @led_control_register_base : address of first LED control register (optional)
+ * @enable_bits_per_led_control_register: number of LEDs enable bits in each
+ * @reset_func: : pointer to reset function
+ *
+ * For all optional register addresses, the sentinel value %IS31FL32XX_REG_NONE
+ * indicates that this chip has no such register.
+ *
+ * If non-NULL, @reset_func will be called during probing to set all
+ * necessary registers to a known initialization state. This is needed
+ * for chips that do not have a @reset_reg.
+ *
+ * @enable_bits_per_led_control_register must be >=1 if
+ * @led_control_register_base != %IS31FL32XX_REG_NONE.
+ */
+struct is31fl32xx_chipdef {
+ u8 channels;
+ u8 shutdown_reg;
+ u8 pwm_update_reg;
+ u8 global_control_reg;
+ u8 reset_reg;
+ u8 pwm_register_base;
+ bool pwm_registers_reversed;
+ u8 led_control_register_base;
+ u8 enable_bits_per_led_control_register;
+ int (*reset_func)(struct is31fl32xx_priv *priv);
+};
+
+static const struct is31fl32xx_chipdef is31fl3236_cdef = {
+ .channels = 36,
+ .shutdown_reg = 0x00,
+ .pwm_update_reg = 0x25,
+ .global_control_reg = 0x4a,
+ .reset_reg = 0x4f,
+ .pwm_register_base = 0x01,
+ .led_control_register_base = 0x26,
+ .enable_bits_per_led_control_register = 1,
+};
+
+static const struct is31fl32xx_chipdef is31fl3235_cdef = {
+ .channels = 28,
+ .shutdown_reg = 0x00,
+ .pwm_update_reg = 0x25,
+ .global_control_reg = 0x4a,
+ .reset_reg = 0x4f,
+ .pwm_register_base = 0x05,
+ .led_control_register_base = 0x2a,
+ .enable_bits_per_led_control_register = 1,
+};
+
+static const struct is31fl32xx_chipdef is31fl3218_cdef = {
+ .channels = 18,
+ .shutdown_reg = 0x00,
+ .pwm_update_reg = 0x16,
+ .global_control_reg = IS31FL32XX_REG_NONE,
+ .reset_reg = 0x17,
+ .pwm_register_base = 0x01,
+ .led_control_register_base = 0x13,
+ .enable_bits_per_led_control_register = 6,
+};
+
+static int is31fl3216_reset(struct is31fl32xx_priv *priv);
+static const struct is31fl32xx_chipdef is31fl3216_cdef = {
+ .channels = 16,
+ .shutdown_reg = IS31FL32XX_REG_NONE,
+ .pwm_update_reg = 0xB0,
+ .global_control_reg = IS31FL32XX_REG_NONE,
+ .reset_reg = IS31FL32XX_REG_NONE,
+ .pwm_register_base = 0x10,
+ .pwm_registers_reversed = true,
+ .led_control_register_base = 0x01,
+ .enable_bits_per_led_control_register = 8,
+ .reset_func = is31fl3216_reset,
+};
+
+static int is31fl32xx_write(struct is31fl32xx_priv *priv, u8 reg, u8 val)
+{
+ int ret;
+
+ dev_dbg(&priv->client->dev, "writing register 0x%02X=0x%02X", reg, val);
+
+ ret = i2c_smbus_write_byte_data(priv->client, reg, val);
+ if (ret) {
+ dev_err(&priv->client->dev,
+ "register write to 0x%02X failed (error %d)",
+ reg, ret);
+ }
+ return ret;
+}
+
+/*
+ * Custom reset function for IS31FL3216 because it does not have a RESET
+ * register the way that the other IS31FL32xx chips do. We don't bother
+ * writing the GPIO and animation registers, because the registers we
+ * do write ensure those will have no effect.
+ */
+static int is31fl3216_reset(struct is31fl32xx_priv *priv)
+{
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < priv->cdef->channels; i++) {
+ ret = is31fl32xx_write(priv, priv->cdef->pwm_register_base+i,
+ 0x00);
+ if (ret)
+ return ret;
+ }
+ ret = is31fl32xx_write(priv, priv->cdef->pwm_update_reg, 0);
+ if (ret)
+ return ret;
+ ret = is31fl32xx_write(priv, IS31FL3216_LIGHTING_EFFECT_REG, 0x00);
+ if (ret)
+ return ret;
+ ret = is31fl32xx_write(priv, IS31FL3216_CHANNEL_CONFIG_REG, 0x00);
+ if (ret)
+ return ret;
+ ret = is31fl32xx_write(priv, IS31FL3216_CONFIG_REG, 0x00);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+
+static int is31fl32xx_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ const struct is31fl32xx_led_data *led_data =
+ container_of(led_cdev, struct is31fl32xx_led_data, cdev);
+ const struct is31fl32xx_chipdef *cdef = led_data->priv->cdef;
+ u8 pwm_register_offset;
+ int ret;
+
+ dev_dbg(led_cdev->dev, "%s: %d\n", __func__, brightness);
+
+ /* NOTE: led_data->channel is 1-based */
+ if (cdef->pwm_registers_reversed)
+ pwm_register_offset = cdef->channels - led_data->channel;
+ else
+ pwm_register_offset = led_data->channel - 1;
+
+ ret = is31fl32xx_write(led_data->priv,
+ cdef->pwm_register_base + pwm_register_offset,
+ brightness);
+ if (ret)
+ return ret;
I infer that nothing wrong happens in case current process is preempted
here by the call originating from the other sub-LED?
+ return is31fl32xx_write(led_data->priv, cdef->pwm_update_reg, 0);
+
+}
+
+static int is31fl32xx_init_regs(struct is31fl32xx_priv *priv)
+{
+ const struct is31fl32xx_chipdef *cdef = priv->cdef;
+ int ret;
+
+ if (cdef->reset_reg != IS31FL32XX_REG_NONE) {
+ ret = is31fl32xx_write(priv, cdef->reset_reg, 0);
+ if (ret)
+ return ret;
+ }
+ if (cdef->reset_func) {
+ ret = cdef->reset_func(priv);
+ if (ret)
+ return ret;
+ }
+ if (cdef->led_control_register_base != IS31FL32XX_REG_NONE) {
+ u8 value =
+ GENMASK(cdef->enable_bits_per_led_control_register-1, 0);
+ u8 num_regs = cdef->channels /
+ cdef->enable_bits_per_led_control_register;
+ int i;
+
+ for (i = 0; i < num_regs; i++) {
+ ret = is31fl32xx_write(priv,
+ cdef->led_control_register_base+i,
+ value);
+ if (ret)
+ return ret;
+ }
+ }
+ if (cdef->shutdown_reg != IS31FL32XX_REG_NONE) {
+ ret = is31fl32xx_write(priv, cdef->shutdown_reg, BIT(0));
+ if (ret)
+ return ret;
+ }
+ if (cdef->global_control_reg != IS31FL32XX_REG_NONE) {
+ ret = is31fl32xx_write(priv, cdef->global_control_reg, 0x00);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static inline size_t sizeof_is31fl32xx_priv(int num_leds)
+{
+ return sizeof(struct is31fl32xx_priv) +
+ (sizeof(struct is31fl32xx_led_data) * num_leds);
+}
+
+static int is31fl32xx_parse_child_dt(const struct device *dev,
+ const struct device_node *child,
+ struct is31fl32xx_led_data *led_data)
+{
+ struct led_classdev *cdev = &led_data->cdev;
+ int ret = 0;
+ u32 reg;
+
+ cdev->name = of_get_property(child, "label", NULL) ? : child->name;
+
+ ret = of_property_read_u32(child, "reg", ®);
+ if (ret || reg < 1 || reg > led_data->priv->cdef->channels) {
+ dev_err(dev,
+ "Child node %s does not have a valid reg property\n",
+ child->name);
+ return -EINVAL;
+ }
+ led_data->channel = reg;
+
+ cdev->default_trigger = of_get_property(child, "linux,default-trigger",
+ NULL);
+ cdev->brightness = LED_OFF;
devm_kzalloc secures that.
+ ret = of_property_read_u32(child, "max-brightness",
+ &cdev->max_brightness);
+ if (ret == -EINVAL) {
+ cdev->max_brightness = 255;
s/255/LED_FULL/
+ } else if (ret) {
+ dev_dbg(dev,
+ "Child node %s has an invalid max-brightness property\n",
+ child->name);
+ return -EINVAL;
+ }
+
+ cdev->brightness_set_blocking = is31fl32xx_brightness_set;
Please add empty line here.
+ return 0;
+}
+
+static struct is31fl32xx_led_data *is31fl32xx_find_led_data(
+ struct is31fl32xx_priv *priv,
+ u8 channel)
+{
+ size_t i;
+
+ for (i = 0; i < priv->num_leds; i++) {
+ if (priv->leds[i].channel == channel)
+ return &priv->leds[i];
+ }
Ditto.
+ return NULL;
+}
+
+static int is31fl32xx_parse_dt(struct device *dev,
+ struct is31fl32xx_priv *priv)
+{
+ struct device_node *child;
+
+ for_each_child_of_node(dev->of_node, child) {
+ struct is31fl32xx_led_data *led_data =
+ &priv->leds[priv->num_leds];
+ int ret = 0;
+ const struct is31fl32xx_led_data *other_led_data;
+
+ led_data->priv = priv;
+
+ ret = is31fl32xx_parse_child_dt(dev, child, led_data);
+ if (ret)
+ continue;
I prefer failing in such cases,
+
+ /* Detect if channel is already in use by another child */
+ other_led_data = is31fl32xx_find_led_data(priv,
+ led_data->channel);
+ if (other_led_data) {
+ dev_err(dev,
+ "%s ignored: channel %d already used by %s",
+ led_data->cdev.name,
+ led_data->channel,
+ other_led_data->cdev.name);
+ continue;
Ditto.
+ }
+
+ ret = devm_led_classdev_register(dev, &led_data->cdev);
+ if (ret == 0) {
+ priv->num_leds++;
+ } else {
+ dev_err(dev, "failed to register PWM led for %s: %d\n",
+ led_data->cdev.name, ret);
+ }
+ }
+
+ return 0;
+}
+
+static const struct of_device_id of_is31fl31xx_match[] = {
+ { .compatible = "issi,is31fl3236", .data = &is31fl3236_cdef, },
+ { .compatible = "issi,is31fl3235", .data = &is31fl3235_cdef, },
+ { .compatible = "issi,is31fl3218", .data = &is31fl3218_cdef, },
+ { .compatible = "issi,is31fl3216", .data = &is31fl3216_cdef, },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, of_is31fl31xx_match);
+
+static int is31fl32xx_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ const struct is31fl32xx_chipdef *cdef;
+ const struct of_device_id *of_dev_id;
+ struct device *dev = &client->dev;
+ struct is31fl32xx_priv *priv;
+ int count;
+ int ret = 0;
+
+ of_dev_id = of_match_device(of_is31fl31xx_match, dev);
+ if (!of_dev_id)
+ return -EINVAL;
+
+ cdef = of_dev_id->data;
+
+ count = of_get_child_count(dev->of_node);
+ if (!count)
+ return -EINVAL;
+
+ priv = devm_kzalloc(dev, sizeof_is31fl32xx_priv(count),
+ GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->client = client;
+ priv->cdef = cdef;
+ i2c_set_clientdata(client, priv);
+
+ ret = is31fl32xx_init_regs(priv);
+ if (ret)
+ return ret;
+
+ ret = is31fl32xx_parse_dt(dev, priv);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int is31fl32xx_remove(struct i2c_client *client)
+{
+ struct is31fl32xx_priv *priv = i2c_get_clientdata(client);
+
+ /* If there is a reset reg, then it does everything we need */
+ if (priv->cdef->reset_reg != IS31FL32XX_REG_NONE)
+ return is31fl32xx_write(priv, priv->cdef->reset_reg, 0);
+
+ /* If there is a reset func, then it does everything we need */
+ if (priv->cdef->reset_func)
+ return priv->cdef->reset_func(priv);
+
+ /* If we can't reset, then try just using software-shutdown mode */
+ if (priv->cdef->shutdown_reg != IS31FL32XX_REG_NONE)
+ return is31fl32xx_write(priv, priv->cdef->shutdown_reg, 0x00);
+
+ return 0;
+}
+
+/*
+ * i2c-core requires that id_table be non-NULL, even though
+ * it is not used for DeviceTree based instantiation.
+ */
+static const struct i2c_device_id is31fl31xx_id[] = {
+ {},
+};
+
+MODULE_DEVICE_TABLE(i2c, is31fl31xx_id);
+
+static struct i2c_driver is31fl32xx_driver = {
+ .driver = {
+ .name = "is31fl32xx",
+ .of_match_table = of_is31fl31xx_match,
+ },
+ .probe = is31fl32xx_probe,
+ .remove = is31fl32xx_remove,
+ .id_table = is31fl31xx_id,
+};
+
+module_i2c_driver(is31fl32xx_driver);
+
+MODULE_AUTHOR("David Rivshin <drivshin@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("ISSI IS31FL32xx LED driver");
+MODULE_LICENSE("GPL v2");
--
Best regards,
Jacek Anaszewski
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