This is the driver for the Arctic Sand Technologies Inc. ARCXCNN LED
backlight IC family
Signed-off-by: Olimpiu Dejeu <olimpiu@xxxxxxxxxxxxxx>
---
drivers/video/backlight/Kconfig | 7 +
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/arcxcnn_bl.c | 510 +++++++++++++++++++++++++++++++++++
include/linux/i2c/arcxcnn.h | 42 +++
4 files changed, 560 insertions(+)
create mode 100644 drivers/video/backlight/arcxcnn_bl.c
create mode 100644 include/linux/i2c/arcxcnn.h
diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 5a3eb2e..19ee87d 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -444,6 +444,13 @@ config BACKLIGHT_BD6107
help
If you have a Rohm BD6107 say Y to enable the backlight driver.
+config BACKLIGHT_ARCXCNN
+ tristate "Backlight driver for the Arctic Sands ARCxCnnnn family"
+ depends on I2C
+ help
+ If you have an ARCxCnnnn family backlight say Y to enable
+ the backlight driver.
+
endif # BACKLIGHT_CLASS_DEVICE
endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index bb82002..9d7f3ec 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -53,3 +53,4 @@ obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o
obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o
obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o
obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o
+obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o
diff --git a/drivers/video/backlight/arcxcnn_bl.c b/drivers/video/backlight/arcxcnn_bl.c
new file mode 100644
index 0000000..7adfca3
--- /dev/null
+++ b/drivers/video/backlight/arcxcnn_bl.c
@@ -0,0 +1,510 @@
+/*
+ * Backlight driver for Arctic Sands ARC_X_C_0N_0N Devices
+ *
+ * Copyright 2016 Arctic Sands Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/backlight.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/pwm.h>
+#include <linux/regulator/consumer.h>
+
+#include "linux/i2c/arcxcnn.h"
+
+#define ARCXCNN_CMD (0x00) /* Command Register */
+#define ARCXCNN_CMD_STDBY (0x80) /* I2C Standby */
+#define ARCXCNN_CMD_RESET (0x40) /* Reset */
+#define ARCXCNN_CMD_BOOST (0x10) /* Boost */
+#define ARCXCNN_CMD_OVP_MASK (0x0C) /* --- Over Voltage Threshold */
+#define ARCXCNN_CMD_OVP_XXV (0x0C) /* <rsvrd> Over Voltage Threshold */
+#define ARCXCNN_CMD_OVP_20V (0x08) /* 20v Over Voltage Threshold */
+#define ARCXCNN_CMD_OVP_24V (0x04) /* 24v Over Voltage Threshold */
+#define ARCXCNN_CMD_OVP_31V (0x00) /* 31.4v Over Voltage Threshold */
+#define ARCXCNN_CMD_EXT_COMP (0x01) /* part (0) or full (1) external comp */
+
+#define ARCXCNN_CONFIG (0x01) /* Configuration */
+#define ARCXCNN_STATUS1 (0x02) /* Status 1 */
+#define ARCXCNN_STATUS2 (0x03) /* Status 2 */
+#define ARCXCNN_FADECTRL (0x04) /* Fading Control */
+#define ARCXCNN_ILED_CONFIG (0x05) /* ILED Configuration */
+
+#define ARCXCNN_LEDEN (0x06) /* LED Enable Register */
+#define ARCXCNN_LEDEN_ISETEXT (0x80) /* Full-scale current set externally */
+#define ARCXCNN_LEDEN_MASK (0x3F) /* LED string enables */
+#define ARCXCNN_LEDEN_LED1 (0x01)
+#define ARCXCNN_LEDEN_LED2 (0x02)
+#define ARCXCNN_LEDEN_LED3 (0x04)
+#define ARCXCNN_LEDEN_LED4 (0x08)
+#define ARCXCNN_LEDEN_LED5 (0x10)
+#define ARCXCNN_LEDEN_LED6 (0x20)
+
+#define ARCXCNN_WLED_ISET_LSB (0x07) /* LED ISET LSB (in upper nibble) */
+#define ARCXCNN_WLED_ISET_MSB (0x08) /* LED ISET MSB (8 bits) */
+
+#define DEFAULT_BL_NAME "arctic_bl"
+#define MAX_BRIGHTNESS 4095
+
+static int s_no_reset_on_remove;
+module_param_named(noreset, s_no_reset_on_remove, int, 0644);
+MODULE_PARM_DESC(noreset, "No reset on module removal");
+
+static int s_ibright = 60;
+module_param_named(ibright, s_ibright, int, 0644);
+MODULE_PARM_DESC(ibright, "Initial brightness (when no plat data)");
+
+static int s_iledstr = 0x3F;
+module_param_named(iledstr, s_iledstr, int, 0644);
+MODULE_PARM_DESC(iledstr, "Initial LED String (when no plat data)");
+
+static int s_retries = 2; /* 1 == only one try */
+module_param_named(retries, s_retries, int, 0644);
+MODULE_PARM_DESC(retries, "I2C retries attempted");
+
+enum arcxcnn_brightness_ctrl_mode {
+ PWM_BASED = 1,
+ REGISTER_BASED,
+};
+
+struct arcxcnn;
+
+struct arcxcnn {
+ char chipname[64];
+ enum arcxcnn_chip_id chip_id;
+ enum arcxcnn_brightness_ctrl_mode mode;
+ struct i2c_client *client;
+ struct backlight_device *bl;
+ struct device *dev;
+ struct arcxcnn_platform_data *pdata;
+ struct pwm_device *pwm;
+ struct regulator *supply; /* regulator for VDD input */
+};
+
+static int arcxcnn_write_byte(struct arcxcnn *lp, u8 reg, u8 data)
+{
+ s32 ret = -1;
+ int att;
+
+ for (att = 0; att < s_retries; att++) {
+ ret = i2c_smbus_write_byte_data(lp->client, reg, data);
+ if (ret >= 0)
+ return 0;
+ }
+ return ret;
+}
+
+static u8 arcxcnn_read_byte(struct arcxcnn *lp, u8 reg)
+{
+ int val;
+ int att;
+
+ for (att = 0; att < s_retries; att++) {
+ val = i2c_smbus_read_byte_data(lp->client, reg);
+ if (val >= 0)
+ return (u8)val;
+ }
+ return 0;
+}
+
+static int arcxcnn_update_bit(struct arcxcnn *lp, u8 reg, u8 mask, u8 data)
+{
+ int ret, att;
+ u8 tmp;
+
+ for (att = 0, ret = -1; att < s_retries; att++) {
+ ret = i2c_smbus_read_byte_data(lp->client, reg);
+ if (ret >= 0)
+ break;
+ }
+ if (ret < 0) {
+ dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
+ return ret;
+ }
+
+ tmp = (u8)ret;
+ tmp &= ~mask;
+ tmp |= data & mask;
+
+ return arcxcnn_write_byte(lp, reg, tmp);
+}
+
+static int arcxcnn_set_brightness(struct arcxcnn *lp, u32 brightness)
+{
+ int ret;
+ u8 val;
+
+ val = (brightness & 0xF) << 4;
+ ret = arcxcnn_write_byte(lp, ARCXCNN_WLED_ISET_LSB, val);
+ if (ret < 0)
+ return ret;
+ val = (brightness >> 4);
+ ret = arcxcnn_write_byte(lp, ARCXCNN_WLED_ISET_MSB, val);
+ return ret;
+}
+
+static void arcxcnn_pwm_ctrl(struct arcxcnn *lp, int br, int max_br)
+{
+ unsigned int period = lp->pdata->period_ns;
+ unsigned int duty = br * period / max_br;
+ struct pwm_device *pwm;
+
+ /* request pwm device with the consumer name */
+ if (!lp->pwm) {
+ pwm = devm_pwm_get(lp->dev, lp->chipname);
+ if (IS_ERR(pwm))
+ return;
+
+ lp->pwm = pwm;
+ }
+
+ pwm_config(lp->pwm, duty, period);
+ if (duty)
+ pwm_enable(lp->pwm);
+ else
+ pwm_disable(lp->pwm);
+}
+
+static int arcxcnn_bl_update_status(struct backlight_device *bl)
+{
+ struct arcxcnn *lp = bl_get_data(bl);
+ u32 brightness = bl->props.brightness;
+
+ if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
+ brightness = 0;
+
+ /* set brightness */
+ if (lp->mode == PWM_BASED)
+ arcxcnn_pwm_ctrl(lp, brightness, bl->props.max_brightness);
+ else if (lp->mode == REGISTER_BASED)
+ arcxcnn_set_brightness(lp, brightness);
+
+ /* set power-on/off/save modes */
+ if (bl->props.power == 0)
+ /* take out of standby */
+ arcxcnn_update_bit(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY, 0);
+ else
+ /* 1-3 == power save, 4 = off
+ * place in low-power standby mode
+ */
+ arcxcnn_update_bit(lp, ARCXCNN_CMD,
+ ARCXCNN_CMD_STDBY, ARCXCNN_CMD_STDBY);
+ return 0;
+}
+
+static const struct backlight_ops arcxcnn_bl_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = arcxcnn_bl_update_status,
+};
+
+static int arcxcnn_backlight_register(struct arcxcnn *lp)
+{
+ struct backlight_device *bl;
+ struct backlight_properties props;
+ struct arcxcnn_platform_data *pdata = lp->pdata;
+ const char *name = pdata->name ? : DEFAULT_BL_NAME;
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_PLATFORM;
+ props.max_brightness = MAX_BRIGHTNESS;
+
+ if (pdata->initial_brightness > props.max_brightness)
+ pdata->initial_brightness = props.max_brightness;
+
+ props.brightness = pdata->initial_brightness;
+
+ bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
+ &arcxcnn_bl_ops, &props);
+ if (IS_ERR(bl))
+ return PTR_ERR(bl);
+
+ lp->bl = bl;
+
+ return 0;
+}
+
+static ssize_t arcxcnn_get_chip_id(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct arcxcnn *lp = dev_get_drvdata(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
+}
+
+static ssize_t arcxcnn_get_led_str(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct arcxcnn *lp = dev_get_drvdata(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%02X\n", lp->pdata->ledstr);
+}
+
+static ssize_t arcxcnn_set_led_str(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct arcxcnn *lp = dev_get_drvdata(dev);
+ unsigned long ledstr;
+
+ if (kstrtoul(buf, 0, &ledstr))
+ return 0;
+
+ if (ledstr != lp->pdata->ledstr) {
+ /* don't allow 0 for ledstr, use power to turn all off */
+ if (ledstr == 0)
+ return 0;
+ lp->pdata->ledstr = ledstr & 0x3F;
+ arcxcnn_update_bit(lp, ARCXCNN_LEDEN,
+ ARCXCNN_LEDEN_MASK, lp->pdata->ledstr);
+ }
+ return len;
+}
+
+static ssize_t arcxcnn_get_bl_ctl_mode(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct arcxcnn *lp = dev_get_drvdata(dev);
+ char *strmode = NULL;
+
+ if (lp->mode == PWM_BASED)
+ strmode = "pwm based";
+ else if (lp->mode == REGISTER_BASED)
+ strmode = "register based";
+
+ return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
+}
+
+static DEVICE_ATTR(chip_id, 0444, arcxcnn_get_chip_id, NULL);
+static DEVICE_ATTR(led_str, 0664, arcxcnn_get_led_str, arcxcnn_set_led_str);
+static DEVICE_ATTR(bl_ctl_mode, 0444, arcxcnn_get_bl_ctl_mode, NULL);
+
+static struct attribute *arcxcnn_attributes[] = {
+ &dev_attr_chip_id.attr,
+ &dev_attr_led_str.attr,
+ &dev_attr_bl_ctl_mode.attr,
+ NULL,
+};
+
+static const struct attribute_group arcxcnn_attr_group = {
+ .attrs = arcxcnn_attributes,
+};
+
+#ifdef CONFIG_OF
+static int arcxcnn_parse_dt(struct arcxcnn *lp)
+{
+ struct device *dev = lp->dev;
+ struct device_node *node = dev->of_node;
+ u32 prog_length, prog_val;
+
+ if (!node) {
+ dev_err(dev, "no platform data\n");
+ return -EINVAL;
+ }
+
+ of_property_read_string(node, "bl-name", &lp->pdata->name);
+ of_property_read_u32(node, "init-brt", &prog_val);
+ lp->pdata->initial_brightness = prog_val;
+ of_property_read_u32(node, "pwm-period", &lp->pdata->period_ns);
+
+ if (lp->pdata->initial_brightness > MAX_BRIGHTNESS)
+ lp->pdata->initial_brightness = MAX_BRIGHTNESS;
+
+ /* Fill program from platform data if defined
+ */
+ lp->pdata->prog_entries = 0;
+ prog_length = of_get_child_count(node);
+ if (prog_length > 0) {
+ struct device_node *child;
+ u32 i = 0;
+
+ for_each_child_of_node(node, child) {
+ if (i >= ARCXCNN_MAX_PROGENTRIES)
+ break;
+ of_property_read_u32(child, "prg-addr", &prog_val);
+ lp->pdata->prog_addr[i] = (u8)prog_val;
+ of_property_read_u32(child, "prg-data", &prog_val);
+ lp->pdata->prog_data[i] = (u8)prog_val;
+ i++;
+ }
+ lp->pdata->prog_entries = i;
+ }
+ return 0;
+}
+#else
+static int arcxcnn_parse_dt(struct arcxcnn *lp)
+{
+ return -EINVAL;
+}
+#endif
+
+static int arcxcnn_probe(struct i2c_client *cl, const struct i2c_device_id *id)
+{
+ struct arcxcnn *lp;
+ int ret;
+ u32 i;
+ u8 regval;
+ u16 chipid;
+
+ if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+ return -EIO;
+
+ lp = devm_kzalloc(&cl->dev, sizeof(*lp), GFP_KERNEL);
+ if (!lp)
+ return -ENOMEM;
+
+ lp->client = cl;
+ lp->dev = &cl->dev;
+ lp->chip_id = id->driver_data;
+ lp->pdata = dev_get_platdata(&cl->dev);
+
+ if (!lp->pdata) {
+ lp->pdata = devm_kzalloc(lp->dev,
+ sizeof(*lp->pdata), GFP_KERNEL);
+ if (!lp->pdata)
+ return -ENOMEM;
+
+ /* no platform data, parse the device-tree for info. if there
+ * is no device tree entry, we are being told we exist because
+ * user-land said so, so make up the info we need
+ */
+ ret = arcxcnn_parse_dt(lp);
+ if (ret < 0) {
+ /* no device tree, use defaults based on parms
+ */
+ lp->pdata->name = NULL;
+ lp->pdata->initial_brightness = s_ibright;
+ lp->pdata->ledstr = s_iledstr;
+ lp->pdata->period_ns = 0;
+ lp->pdata->prog_entries = 0;
+
+ /* example of prog use: uncomment to test
+ lp->pdata->prog_addr[0] = 0x06;
+ lp->pdata->prog_data[0] = 0x15;
+ lp->pdata->prog_entries = 1;
+ */
+ }
+ }
+
+ if (lp->pdata->period_ns > 0)
+ lp->mode = PWM_BASED;
+ else
+ lp->mode = REGISTER_BASED;
+
+ i2c_set_clientdata(cl, lp);
+
+ /* read device ID */
+ regval = arcxcnn_read_byte(lp, 0x1E);
+ chipid = regval;
+ chipid <<= 8;
+ regval = arcxcnn_read_byte(lp, 0x1F);
+ chipid |= regval;
+
+ /* make sure it belongs to this driver
+ * TODO - handle specific ids
+ */
+ if (chipid != 0x02A5) {
+ #if 1
+ dev_info(&cl->dev, "Chip Id is %04X\n", chipid);
+ #else
+ dev_err(&cl->dev, "%04X is not ARC2C\n", chipid);
+ return -ENODEV;
+ #endif
+ }
+ /* reset the device */
+ arcxcnn_write_byte(lp, ARCXCNN_CMD, ARCXCNN_CMD_RESET);
+
+ /* set initial brightness */
+ arcxcnn_set_brightness(lp, lp->pdata->initial_brightness);
+
+ /* enable internal register mode for brightness */
+ arcxcnn_write_byte(lp, ARCXCNN_ILED_CONFIG, 0x57);
+
+ /* set initial LED Strings */
+ arcxcnn_update_bit(lp, ARCXCNN_LEDEN,
+ ARCXCNN_LEDEN_MASK, lp->pdata->ledstr);
+
+ snprintf(lp->chipname, sizeof(lp->chipname),
+ "%s-%04X", id->name, chipid);
+
+ ret = arcxcnn_backlight_register(lp);
+ if (ret) {
+ dev_err(lp->dev,
+ "failed to register backlight. err: %d\n", ret);
+ return ret;
+ }
+
+ ret = sysfs_create_group(&lp->dev->kobj, &arcxcnn_attr_group);
+ if (ret) {
+ dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
+ return ret;
+ }
+
+ /* playback program now that its all installed */
+ for (i = 0; i < lp->pdata->prog_entries; i++) {
+ arcxcnn_write_byte(lp, lp->pdata->prog_addr[i],
+ lp->pdata->prog_data[i]);
+ /*
+ printk(KERN_ALERT "%02X, %02X\n",
+ lp->pdata->prog_addr[i], lp->pdata->prog_data[i]);
+ */
+ }
+
+ backlight_update_status(lp->bl);
+ return 0;
+}
+
+static int arcxcnn_remove(struct i2c_client *cl)
+{
+ struct arcxcnn *lp = i2c_get_clientdata(cl);
+
+ if (!s_no_reset_on_remove) {
+ /* disable all strings */
+ arcxcnn_write_byte(lp, ARCXCNN_LEDEN, 0x00);
+ /* reset the device */
+ arcxcnn_write_byte(lp, ARCXCNN_CMD, ARCXCNN_CMD_RESET);
+ }
+ lp->bl->props.brightness = 0;
+ backlight_update_status(lp->bl);
+ if (lp->supply)
+ regulator_disable(lp->supply);
+ sysfs_remove_group(&lp->dev->kobj, &arcxcnn_attr_group);
+
+ return 0;
+}
+
+static const struct of_device_id arcxcnn_dt_ids[] = {
+ { .compatible = "arc,arcxcnn" },
+ { .compatible = "arc,arc2c0608" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids);
+
+/* Note that the device/chip ID is not fixed in silicon so
+ * auto-probing of these devices on the bus is most likely
+ * not possible, use device tree to set i2c bus address
+ */
+static const struct i2c_device_id arcxcnn_ids[] = {
+ {"arcxcnn", ARCXCNN},
+ {"arc2c0608", ARC2C0608},
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, arcxcnn_ids);
+
+static struct i2c_driver arcxcnn_driver = {
+ .driver = {
+ .name = "arcxcnn",
+ .of_match_table = of_match_ptr(arcxcnn_dt_ids),
+ },
+ .probe = arcxcnn_probe,
+ .remove = arcxcnn_remove,
+ .id_table = arcxcnn_ids,
+};
+
+module_i2c_driver(arcxcnn_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Brian Dodge <bdodge09@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("ARCXCNN Backlight driver");
diff --git a/include/linux/i2c/arcxcnn.h b/include/linux/i2c/arcxcnn.h
new file mode 100644
index 0000000..a9b7922
--- /dev/null
+++ b/include/linux/i2c/arcxcnn.h
@@ -0,0 +1,42 @@
+/*
+ * Backlight driver for Arctic Sands ARC2C0608 Backlight Devices
+ *
+ * Copyright 2016 Arctic Sands Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef _ARCXCNN_H
+#define _ARCXCNN_H
+
+enum arcxcnn_chip_id {
+ ARCXCNN,
+ ARC2C0608
+};
+
+enum arcxcnn_brightness_source {
+ ARCXCNN_PWM_ONLY,
+ ARCXCNN_I2C_ONLY = 2,
+};
+
+#define ARCXCNN_MAX_PROGENTRIES 48 /* max a/v pairs for custom */
+
+/**
+ * struct arcxcnn_platform_data
+ * @name : Backlight driver name. If it is not defined, default name is set.
+ * @initial_brightness : initial value of backlight brightness
+ * @period_ns : platform specific pwm period value. unit is nano.
+ Only valid when mode is PWM_BASED.
+ * @led_str : initial LED string
+ */
+struct arcxcnn_platform_data {
+ const char *name;
+ u16 initial_brightness;
+ unsigned int period_ns;
+ u8 ledstr;
+ u8 prog_addr[ARCXCNN_MAX_PROGENTRIES];
+ u8 prog_data[ARCXCNN_MAX_PROGENTRIES];
+ u32 prog_entries;
+};
+
+#endif
--
1.9.1
--
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