Jingoo,
Are you still reviewing Backlight patches?
> 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
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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