// SPDX-License-Identifier: GPL-2.0
/*
* AS3711 PMIC backlight driver, using DCDC Step Up Converters
*
* Copyright (C) 2012 Renesas Electronics Corporation
* Author: Guennadi Liakhovetski, <[email protected]>
*/
#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fb.h>
#include <linux/kernel.h>
#include <linux/mfd/as3711.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
enum as3711_bl_type {
AS3711_BL_SU1,
AS3711_BL_SU2,
};
struct as3711_bl_data {
bool powered;
enum as3711_bl_type type;
int brightness;
struct backlight_device *bl;
};
struct as3711_bl_supply {
struct as3711_bl_data su1;
struct as3711_bl_data su2;
const struct as3711_bl_pdata *pdata;
struct as3711 *as3711;
};
static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
{
switch (su->type) {
case AS3711_BL_SU1:
return container_of(su, struct as3711_bl_supply, su1);
case AS3711_BL_SU2:
return container_of(su, struct as3711_bl_supply, su2);
}
return NULL;
}
static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
unsigned int brightness)
{
struct as3711_bl_supply *supply = to_supply(data);
struct as3711 *as3711 = supply->as3711;
const struct as3711_bl_pdata *pdata = supply->pdata;
int ret = 0;
/* Only all equal current values are supported */
if (pdata->su2_auto_curr1)
ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
brightness);
if (!ret && pdata->su2_auto_curr2)
ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
brightness);
if (!ret && pdata->su2_auto_curr3)
ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
brightness);
return ret;
}
static int as3711_set_brightness_v(struct as3711 *as3711,
unsigned int brightness,
unsigned int reg)
{
if (brightness > 31)
return -EINVAL;
return regmap_update_bits(as3711->regmap, reg, 0xf0,
brightness << 4);
}
static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
{
struct as3711 *as3711 = supply->as3711;
int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
3, supply->pdata->su2_fbprot);
if (!ret)
ret = regmap_update_bits(as3711->regmap,
AS3711_STEPUP_CONTROL_2, 1, 0);
if (!ret)
ret = regmap_update_bits(as3711->regmap,
AS3711_STEPUP_CONTROL_2, 1, 1);
return ret;
}
/*
* Someone with less fragile or less expensive hardware could try to simplify
* the brightness adjustment procedure.
*/
static int as3711_bl_update_status(struct backlight_device *bl)
{
struct as3711_bl_data *data = bl_get_data(bl);
struct as3711_bl_supply *supply = to_supply(data);
struct as3711 *as3711 = supply->as3711;
int brightness;
int ret = 0;
brightness = backlight_get_brightness(bl);
if (data->type == AS3711_BL_SU1) {
ret = as3711_set_brightness_v(as3711, brightness,
AS3711_STEPUP_CONTROL_1);
} else {
const struct as3711_bl_pdata *pdata = supply->pdata;
switch (pdata->su2_feedback) {
case AS3711_SU2_VOLTAGE:
ret = as3711_set_brightness_v(as3711, brightness,
AS3711_STEPUP_CONTROL_2);
break;
case AS3711_SU2_CURR_AUTO:
ret = as3711_set_brightness_auto_i(data, brightness / 4);
if (ret < 0)
return ret;
if (brightness) {
ret = as3711_bl_su2_reset(supply);
if (ret < 0)
return ret;
udelay(500);
ret = as3711_set_brightness_auto_i(data, brightness);
} else {
ret = regmap_update_bits(as3711->regmap,
AS3711_STEPUP_CONTROL_2, 1, 0);
}
break;
/* Manual one current feedback pin below */
case AS3711_SU2_CURR1:
ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
brightness);
break;
case AS3711_SU2_CURR2:
ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
brightness);
break;
case AS3711_SU2_CURR3:
ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
brightness);
break;
default:
ret = -EINVAL;
}
}
if (!ret)
data->brightness = brightness;
return ret;
}
static int as3711_bl_get_brightness(struct backlight_device *bl)
{
struct as3711_bl_data *data = bl_get_data(bl);
return data->brightness;
}
static const struct backlight_ops as3711_bl_ops = {
.update_status = as3711_bl_update_status,
.get_brightness = as3711_bl_get_brightness,
};
static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
{
struct as3711 *as3711 = supply->as3711;
const struct as3711_bl_pdata *pdata = supply->pdata;
u8 ctl = 0;
int ret;
dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);
/* Turn SU2 off */
ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
if (ret < 0)
return ret;
switch (pdata->su2_feedback) {
case AS3711_SU2_VOLTAGE:
ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
break;
case AS3711_SU2_CURR1:
ctl = 1;
ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
break;
case AS3711_SU2_CURR2:
ctl = 4;
ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
break;
case AS3711_SU2_CURR3:
ctl = 0x10;
ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
break;
case AS3711_SU2_CURR_AUTO:
if (pdata->su2_auto_curr1)
ctl = 2;
if (pdata->su2_auto_curr2)
ctl |= 8;
if (pdata->su2_auto_curr3)
ctl |= 0x20;
ret = 0;
break;
default:
return -EINVAL;
}
if (!ret)
ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);
return ret;
}
static int as3711_bl_register(struct platform_device *pdev,
unsigned int max_brightness, struct as3711_bl_data *su)
{
struct backlight_properties props = {.type = BACKLIGHT_RAW,};
struct backlight_device *bl;
/* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
props.max_brightness = max_brightness;
bl = devm_backlight_device_register(&pdev->dev,
su->type == AS3711_BL_SU1 ?
"as3711-su1" : "as3711-su2",
&pdev->dev, su,
&as3711_bl_ops, &props);
if (IS_ERR(bl)) {
dev_err(&pdev->dev, "failed to register backlight\n");
return PTR_ERR(bl);
}
bl->props.brightness = props.max_brightness;
backlight_update_status(bl);
su->bl = bl;
return 0;
}
static int as3711_backlight_parse_dt(struct device *dev)
{
struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
struct device_node *bl, *fb;
int ret;
bl = of_get_child_by_name(dev->parent->of_node, "backlight");
if (!bl) {
dev_dbg(dev, "backlight node not found\n");
return -ENODEV;
}
fb = of_parse_phandle(bl, "su1-dev", 0);
if (fb) {
of_node_put(fb);
pdata->su1_fb = true;
ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
if (pdata->su1_max_uA <= 0)
ret = -EINVAL;
if (ret < 0)
goto err_put_bl;
}
fb = of_parse_phandle(bl, "su2-dev", 0);
if (fb) {
int count = 0;
of_node_put(fb);
pdata->su2_fb = true;
ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
if (pdata->su2_max_uA <= 0)
ret = -EINVAL;
if (ret < 0)
goto err_put_bl;
if (of_property_read_bool(bl, "su2-feedback-voltage")) {
pdata->su2_feedback = AS3711_SU2_VOLTAGE;
count++;
}
if (of_property_read_bool(bl, "su2-feedback-curr1")) {
pdata->su2_feedback = AS3711_SU2_CURR1;
count++;
}
if (of_property_read_bool(bl, "su2-feedback-curr2")) {
pdata->su2_feedback = AS3711_SU2_CURR2;
count++;
}
if (of_property_read_bool(bl, "su2-feedback-curr3")) {
pdata->su2_feedback = AS3711_SU2_CURR3;
count++;
}
if (of_property_read_bool(bl, "su2-feedback-curr-auto")) {
pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
count++;
}
if (count != 1) {
ret = -EINVAL;
goto err_put_bl;
}
count = 0;
if (of_property_read_bool(bl, "su2-fbprot-lx-sd4")) {
pdata->su2_fbprot = AS3711_SU2_LX_SD4;
count++;
}
if (of_property_read_bool(bl, "su2-fbprot-gpio2")) {
pdata->su2_fbprot = AS3711_SU2_GPIO2;
count++;
}
if (of_property_read_bool(bl, "su2-fbprot-gpio3")) {
pdata->su2_fbprot = AS3711_SU2_GPIO3;
count++;
}
if (of_property_read_bool(bl, "su2-fbprot-gpio4")) {
pdata->su2_fbprot = AS3711_SU2_GPIO4;
count++;
}
if (count != 1) {
ret = -EINVAL;
goto err_put_bl;
}
count = 0;
if (of_property_read_bool(bl, "su2-auto-curr1")) {
pdata->su2_auto_curr1 = true;
count++;
}
if (of_property_read_bool(bl, "su2-auto-curr2")) {
pdata->su2_auto_curr2 = true;
count++;
}
if (of_property_read_bool(bl, "su2-auto-curr3")) {
pdata->su2_auto_curr3 = true;
count++;
}
/*
* At least one su2-auto-curr* must be specified iff
* AS3711_SU2_CURR_AUTO is used
*/
if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO)) {
ret = -EINVAL;
goto err_put_bl;
}
}
of_node_put(bl);
return 0;
err_put_bl:
of_node_put(bl);
return ret;
}
static int as3711_backlight_probe(struct platform_device *pdev)
{
struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
struct as3711_bl_supply *supply;
struct as3711_bl_data *su;
unsigned int max_brightness;
int ret;
if (!pdata) {
dev_err(&pdev->dev, "No platform data, exiting...\n");
return -ENODEV;
}
if (pdev->dev.parent->of_node) {
ret = as3711_backlight_parse_dt(&pdev->dev);
if (ret < 0)
return dev_err_probe(&pdev->dev, ret, "DT parsing failed\n");
}
if (!pdata->su1_fb && !pdata->su2_fb) {
dev_err(&pdev->dev, "No framebuffer specified\n");
return -EINVAL;
}
/*
* Due to possible hardware damage I chose to block all modes,
* unsupported on my hardware. Anyone, wishing to use any of those modes
* will have to first review the code, then activate and test it.
*/
if (pdata->su1_fb ||
pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
dev_warn(&pdev->dev,
"Attention! An untested mode has been chosen!\n"
"Please, review the code, enable, test, and report success:-)\n");
return -EINVAL;
}
supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
if (!supply)
return -ENOMEM;
supply->as3711 = as3711;
supply->pdata = pdata;
if (pdata->su1_fb) {
su = &supply->su1;
su->type = AS3711_BL_SU1;
max_brightness = min(pdata->su1_max_uA, 31);
ret = as3711_bl_register(pdev, max_brightness, su);
if (ret < 0)
return ret;
}
if (pdata->su2_fb) {
su = &supply->su2;
su->type = AS3711_BL_SU2;
switch (pdata->su2_fbprot) {
case AS3711_SU2_GPIO2:
case AS3711_SU2_GPIO3:
case AS3711_SU2_GPIO4:
case AS3711_SU2_LX_SD4:
break;
default:
return -EINVAL;
}
switch (pdata->su2_feedback) {
case AS3711_SU2_VOLTAGE:
max_brightness = min(pdata->su2_max_uA, 31);
break;
case AS3711_SU2_CURR1:
case AS3711_SU2_CURR2:
case AS3711_SU2_CURR3:
case AS3711_SU2_CURR_AUTO:
max_brightness = min(pdata->su2_max_uA / 150, 255);
break;
default:
return -EINVAL;
}
ret = as3711_bl_init_su2(supply);
if (ret < 0)
return ret;
ret = as3711_bl_register(pdev, max_brightness, su);
if (ret < 0)
return ret;
}
platform_set_drvdata(pdev, supply);
return 0;
}
static struct platform_driver as3711_backlight_driver = {
.driver = {
.name = "as3711-backlight",
},
.probe = as3711_backlight_probe,
};
module_platform_driver(as3711_backlight_driver);
MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
MODULE_AUTHOR("Guennadi Liakhovetski <[email protected]");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:as3711-backlight");
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