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linux/drivers/video/backlight/arcxcnn_bl.c
Olimpiu Dejeu e739c5bb20 backlight: Add support for Arctic Sand LED backlight driver chips 
This driver provides support for the Arctic Sand arc2c0608 chip,
and provides a framework to support future devices.

Signed-off-by: Olimpiu Dejeu <olimpiu@arcticsand.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2017-04-25 09:22:23 +01:00

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/*
* Backlight driver for ArcticSand ARC_X_C_0N_0N Devices
*
* Copyright 2016 ArcticSand, Inc.
* Author : Brian Dodge <bdodge@arcticsand.com>
*
* 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.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
enum arcxcnn_chip_id {
ARC2C0608
};
/**
* struct arcxcnn_platform_data
* @name : Backlight driver name (NULL will use default)
* @initial_brightness : initial value of backlight brightness
* @leden : initial LED string enables, upper bit is global on/off
* @led_config_0 : fading speed (period between intensity steps)
* @led_config_1 : misc settings, see datasheet
* @dim_freq : pwm dimming frequency if in pwm mode
* @comp_config : misc config, see datasheet
* @filter_config : RC/PWM filter config, see datasheet
* @trim_config : full scale current trim, see datasheet
*/
struct arcxcnn_platform_data {
const char *name;
u16 initial_brightness;
u8 leden;
u8 led_config_0;
u8 led_config_1;
u8 dim_freq;
u8 comp_config;
u8 filter_config;
u8 trim_config;
};
#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) ext. 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_ILED_DIM_PWM 0x00 /* config dim mode pwm */
#define ARCXCNN_ILED_DIM_INT 0x04 /* config dim mode internal */
#define ARCXCNN_LEDEN 0x06 /* LED Enable Register */
#define ARCXCNN_LEDEN_ISETEXT 0x80 /* Full-scale current set extern */
#define ARCXCNN_LEDEN_MASK 0x3F /* LED string enables mask */
#define ARCXCNN_LEDEN_BITS 0x06 /* Bits of 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_LSB_SHIFT 0x04 /* ISET LSB Left Shift */
#define ARCXCNN_WLED_ISET_MSB 0x08 /* LED ISET MSB (8 bits) */
#define ARCXCNN_DIMFREQ 0x09
#define ARCXCNN_COMP_CONFIG 0x0A
#define ARCXCNN_FILT_CONFIG 0x0B
#define ARCXCNN_IMAXTUNE 0x0C
#define ARCXCNN_ID_MSB 0x1E
#define ARCXCNN_ID_LSB 0x1F
#define MAX_BRIGHTNESS 4095
#define INIT_BRIGHT 60
struct arcxcnn {
struct i2c_client *client;
struct backlight_device *bl;
struct device *dev;
struct arcxcnn_platform_data *pdata;
};
static int arcxcnn_update_field(struct arcxcnn *lp, u8 reg, u8 mask, u8 data)
{
int ret;
u8 tmp;
ret = i2c_smbus_read_byte_data(lp->client, reg);
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 i2c_smbus_write_byte_data(lp->client, reg, tmp);
}
static int arcxcnn_set_brightness(struct arcxcnn *lp, u32 brightness)
{
int ret;
u8 val;
/* lower nibble of brightness goes in upper nibble of LSB register */
val = (brightness & 0xF) << ARCXCNN_WLED_ISET_LSB_SHIFT;
ret = i2c_smbus_write_byte_data(lp->client,
ARCXCNN_WLED_ISET_LSB, val);
if (ret < 0)
return ret;
/* remaining 8 bits of brightness go in MSB register */
val = (brightness >> 4);
return i2c_smbus_write_byte_data(lp->client,
ARCXCNN_WLED_ISET_MSB, val);
}
static int arcxcnn_bl_update_status(struct backlight_device *bl)
{
struct arcxcnn *lp = bl_get_data(bl);
u32 brightness = bl->props.brightness;
int ret;
if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
brightness = 0;
ret = arcxcnn_set_brightness(lp, brightness);
if (ret)
return ret;
/* set power-on/off/save modes */
return arcxcnn_update_field(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY,
(bl->props.power == 0) ? 0 : ARCXCNN_CMD_STDBY);
}
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_properties *props;
const char *name = lp->pdata->name ? : "arctic_bl";
props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL);
if (!props)
return -ENOMEM;
props->type = BACKLIGHT_PLATFORM;
props->max_brightness = MAX_BRIGHTNESS;
if (lp->pdata->initial_brightness > props->max_brightness)
lp->pdata->initial_brightness = props->max_brightness;
props->brightness = lp->pdata->initial_brightness;
lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
&arcxcnn_bl_ops, props);
return PTR_ERR_OR_ZERO(lp->bl);
}
static void arcxcnn_parse_dt(struct arcxcnn *lp)
{
struct device *dev = lp->dev;
struct device_node *node = dev->of_node;
u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS];
int ret;
/* device tree entry isn't required, defaults are OK */
if (!node)
return;
ret = of_property_read_string(node, "label", &lp->pdata->name);
if (ret < 0)
lp->pdata->name = NULL;
ret = of_property_read_u32(node, "default-brightness", &prog_val);
if (ret == 0)
lp->pdata->initial_brightness = prog_val;
ret = of_property_read_u32(node, "arc,led-config-0", &prog_val);
if (ret == 0)
lp->pdata->led_config_0 = (u8)prog_val;
ret = of_property_read_u32(node, "arc,led-config-1", &prog_val);
if (ret == 0)
lp->pdata->led_config_1 = (u8)prog_val;
ret = of_property_read_u32(node, "arc,dim-freq", &prog_val);
if (ret == 0)
lp->pdata->dim_freq = (u8)prog_val;
ret = of_property_read_u32(node, "arc,comp-config", &prog_val);
if (ret == 0)
lp->pdata->comp_config = (u8)prog_val;
ret = of_property_read_u32(node, "arc,filter-config", &prog_val);
if (ret == 0)
lp->pdata->filter_config = (u8)prog_val;
ret = of_property_read_u32(node, "arc,trim-config", &prog_val);
if (ret == 0)
lp->pdata->trim_config = (u8)prog_val;
ret = of_property_count_u32_elems(node, "led-sources");
if (ret < 0) {
lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */
} else {
num_entry = ret;
if (num_entry > ARCXCNN_LEDEN_BITS)
num_entry = ARCXCNN_LEDEN_BITS;
ret = of_property_read_u32_array(node, "led-sources", sources,
num_entry);
if (ret < 0) {
dev_err(dev, "led-sources node is invalid.\n");
return;
}
lp->pdata->leden = 0;
/* for each enable in source, set bit in led enable */
for (entry = 0; entry < num_entry; entry++) {
u8 onbit = 1 << sources[entry];
lp->pdata->leden |= onbit;
}
}
}
static int arcxcnn_probe(struct i2c_client *cl, const struct i2c_device_id *id)
{
struct arcxcnn *lp;
int ret;
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->pdata = dev_get_platdata(&cl->dev);
/* reset the device */
ret = i2c_smbus_write_byte_data(lp->client,
ARCXCNN_CMD, ARCXCNN_CMD_RESET);
if (ret)
goto probe_err;
if (!lp->pdata) {
lp->pdata = devm_kzalloc(lp->dev,
sizeof(*lp->pdata), GFP_KERNEL);
if (!lp->pdata)
return -ENOMEM;
/* Setup defaults based on power-on defaults */
lp->pdata->name = NULL;
lp->pdata->initial_brightness = INIT_BRIGHT;
lp->pdata->leden = ARCXCNN_LEDEN_MASK;
lp->pdata->led_config_0 = i2c_smbus_read_byte_data(
lp->client, ARCXCNN_FADECTRL);
lp->pdata->led_config_1 = i2c_smbus_read_byte_data(
lp->client, ARCXCNN_ILED_CONFIG);
/* insure dim mode is not default pwm */
lp->pdata->led_config_1 |= ARCXCNN_ILED_DIM_INT;
lp->pdata->dim_freq = i2c_smbus_read_byte_data(
lp->client, ARCXCNN_DIMFREQ);
lp->pdata->comp_config = i2c_smbus_read_byte_data(
lp->client, ARCXCNN_COMP_CONFIG);
lp->pdata->filter_config = i2c_smbus_read_byte_data(
lp->client, ARCXCNN_FILT_CONFIG);
lp->pdata->trim_config = i2c_smbus_read_byte_data(
lp->client, ARCXCNN_IMAXTUNE);
if (IS_ENABLED(CONFIG_OF))
arcxcnn_parse_dt(lp);
}
i2c_set_clientdata(cl, lp);
/* constrain settings to what is possible */
if (lp->pdata->initial_brightness > MAX_BRIGHTNESS)
lp->pdata->initial_brightness = MAX_BRIGHTNESS;
/* set initial brightness */
ret = arcxcnn_set_brightness(lp, lp->pdata->initial_brightness);
if (ret)
goto probe_err;
/* set other register values directly */
ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FADECTRL,
lp->pdata->led_config_0);
if (ret)
goto probe_err;
ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_ILED_CONFIG,
lp->pdata->led_config_1);
if (ret)
goto probe_err;
ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_DIMFREQ,
lp->pdata->dim_freq);
if (ret)
goto probe_err;
ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_COMP_CONFIG,
lp->pdata->comp_config);
if (ret)
goto probe_err;
ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FILT_CONFIG,
lp->pdata->filter_config);
if (ret)
goto probe_err;
ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_IMAXTUNE,
lp->pdata->trim_config);
if (ret)
goto probe_err;
/* set initial LED Enables */
arcxcnn_update_field(lp, ARCXCNN_LEDEN,
ARCXCNN_LEDEN_MASK, lp->pdata->leden);
ret = arcxcnn_backlight_register(lp);
if (ret)
goto probe_register_err;
backlight_update_status(lp->bl);
return 0;
probe_register_err:
dev_err(lp->dev,
"failed to register backlight.\n");
probe_err:
dev_err(lp->dev,
"failure ret: %d\n", ret);
return ret;
}
static int arcxcnn_remove(struct i2c_client *cl)
{
struct arcxcnn *lp = i2c_get_clientdata(cl);
/* disable all strings (ignore errors) */
i2c_smbus_write_byte_data(lp->client,
ARCXCNN_LEDEN, 0x00);
/* reset the device (ignore errors) */
i2c_smbus_write_byte_data(lp->client,
ARCXCNN_CMD, ARCXCNN_CMD_RESET);
lp->bl->props.brightness = 0;
backlight_update_status(lp->bl);
return 0;
}
static const struct of_device_id arcxcnn_dt_ids[] = {
{ .compatible = "arc,arc2c0608" },
{ }
};
MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids);
static const struct i2c_device_id arcxcnn_ids[] = {
{"arc2c0608", ARC2C0608},
{ }
};
MODULE_DEVICE_TABLE(i2c, arcxcnn_ids);
static struct i2c_driver arcxcnn_driver = {
.driver = {
.name = "arcxcnn_bl",
.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 <bdodge@arcticsand.com>");
MODULE_DESCRIPTION("ARCXCNN Backlight driver");
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