linux/drivers/gpu/drm/panel/panel-olimex-lcd-olinuxino.c
Bernard Zhao c3ee8c65f6 drm/panel: remove return value of function drm_panel_add
The function "int drm_panel_add(struct drm_panel *panel)"
always returns 0, this return value is meaningless.
Also, there is no need to check return value which calls
"drm_panel_add and", error branch code will never run.

Signed-off-by: Bernard Zhao <bernard@vivo.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200801120216.8488-1-bernard@vivo.com
2020-08-02 08:59:06 +02:00

323 lines
7.2 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* LCD-OLinuXino support for panel driver
*
* Copyright (C) 2018 Olimex Ltd.
* Author: Stefan Mavrodiev <stefan@olimex.com>
*/
#include <linux/crc32.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <video/videomode.h>
#include <video/display_timing.h>
#include <drm/drm_device.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>
#define LCD_OLINUXINO_HEADER_MAGIC 0x4F4CB727
#define LCD_OLINUXINO_DATA_LEN 256
struct lcd_olinuxino_mode {
u32 pixelclock;
u32 hactive;
u32 hfp;
u32 hbp;
u32 hpw;
u32 vactive;
u32 vfp;
u32 vbp;
u32 vpw;
u32 refresh;
u32 flags;
};
struct lcd_olinuxino_info {
char name[32];
u32 width_mm;
u32 height_mm;
u32 bpc;
u32 bus_format;
u32 bus_flag;
} __attribute__((__packed__));
struct lcd_olinuxino_eeprom {
u32 header;
u32 id;
char revision[4];
u32 serial;
struct lcd_olinuxino_info info;
u32 num_modes;
u8 reserved[180];
u32 checksum;
} __attribute__((__packed__));
struct lcd_olinuxino {
struct drm_panel panel;
struct device *dev;
struct i2c_client *client;
struct mutex mutex;
bool prepared;
bool enabled;
struct regulator *supply;
struct gpio_desc *enable_gpio;
struct lcd_olinuxino_eeprom eeprom;
};
static inline struct lcd_olinuxino *to_lcd_olinuxino(struct drm_panel *panel)
{
return container_of(panel, struct lcd_olinuxino, panel);
}
static int lcd_olinuxino_disable(struct drm_panel *panel)
{
struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
if (!lcd->enabled)
return 0;
lcd->enabled = false;
return 0;
}
static int lcd_olinuxino_unprepare(struct drm_panel *panel)
{
struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
if (!lcd->prepared)
return 0;
gpiod_set_value_cansleep(lcd->enable_gpio, 0);
regulator_disable(lcd->supply);
lcd->prepared = false;
return 0;
}
static int lcd_olinuxino_prepare(struct drm_panel *panel)
{
struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
int ret;
if (lcd->prepared)
return 0;
ret = regulator_enable(lcd->supply);
if (ret < 0)
return ret;
gpiod_set_value_cansleep(lcd->enable_gpio, 1);
lcd->prepared = true;
return 0;
}
static int lcd_olinuxino_enable(struct drm_panel *panel)
{
struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
if (lcd->enabled)
return 0;
lcd->enabled = true;
return 0;
}
static int lcd_olinuxino_get_modes(struct drm_panel *panel,
struct drm_connector *connector)
{
struct lcd_olinuxino *lcd = to_lcd_olinuxino(panel);
struct lcd_olinuxino_info *lcd_info = &lcd->eeprom.info;
struct lcd_olinuxino_mode *lcd_mode;
struct drm_display_mode *mode;
u32 i, num = 0;
for (i = 0; i < lcd->eeprom.num_modes; i++) {
lcd_mode = (struct lcd_olinuxino_mode *)
&lcd->eeprom.reserved[i * sizeof(*lcd_mode)];
mode = drm_mode_create(connector->dev);
if (!mode) {
dev_err(panel->dev, "failed to add mode %ux%u@%u\n",
lcd_mode->hactive,
lcd_mode->vactive,
lcd_mode->refresh);
continue;
}
mode->clock = lcd_mode->pixelclock;
mode->hdisplay = lcd_mode->hactive;
mode->hsync_start = lcd_mode->hactive + lcd_mode->hfp;
mode->hsync_end = lcd_mode->hactive + lcd_mode->hfp +
lcd_mode->hpw;
mode->htotal = lcd_mode->hactive + lcd_mode->hfp +
lcd_mode->hpw + lcd_mode->hbp;
mode->vdisplay = lcd_mode->vactive;
mode->vsync_start = lcd_mode->vactive + lcd_mode->vfp;
mode->vsync_end = lcd_mode->vactive + lcd_mode->vfp +
lcd_mode->vpw;
mode->vtotal = lcd_mode->vactive + lcd_mode->vfp +
lcd_mode->vpw + lcd_mode->vbp;
/* Always make the first mode preferred */
if (i == 0)
mode->type |= DRM_MODE_TYPE_PREFERRED;
mode->type |= DRM_MODE_TYPE_DRIVER;
drm_mode_set_name(mode);
drm_mode_probed_add(connector, mode);
num++;
}
connector->display_info.width_mm = lcd_info->width_mm;
connector->display_info.height_mm = lcd_info->height_mm;
connector->display_info.bpc = lcd_info->bpc;
if (lcd_info->bus_format)
drm_display_info_set_bus_formats(&connector->display_info,
&lcd_info->bus_format, 1);
connector->display_info.bus_flags = lcd_info->bus_flag;
return num;
}
static const struct drm_panel_funcs lcd_olinuxino_funcs = {
.disable = lcd_olinuxino_disable,
.unprepare = lcd_olinuxino_unprepare,
.prepare = lcd_olinuxino_prepare,
.enable = lcd_olinuxino_enable,
.get_modes = lcd_olinuxino_get_modes,
};
static int lcd_olinuxino_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct lcd_olinuxino *lcd;
u32 checksum, i;
int ret = 0;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
I2C_FUNC_SMBUS_READ_I2C_BLOCK))
return -ENODEV;
lcd = devm_kzalloc(dev, sizeof(*lcd), GFP_KERNEL);
if (!lcd)
return -ENOMEM;
i2c_set_clientdata(client, lcd);
lcd->dev = dev;
lcd->client = client;
mutex_init(&lcd->mutex);
/* Copy data into buffer */
for (i = 0; i < LCD_OLINUXINO_DATA_LEN; i += I2C_SMBUS_BLOCK_MAX) {
mutex_lock(&lcd->mutex);
ret = i2c_smbus_read_i2c_block_data(client,
i,
I2C_SMBUS_BLOCK_MAX,
(u8 *)&lcd->eeprom + i);
mutex_unlock(&lcd->mutex);
if (ret < 0) {
dev_err(dev, "error reading from device at %02x\n", i);
return ret;
}
}
/* Check configuration checksum */
checksum = ~crc32(~0, (u8 *)&lcd->eeprom, 252);
if (checksum != lcd->eeprom.checksum) {
dev_err(dev, "configuration checksum does not match!\n");
return -EINVAL;
}
/* Check magic header */
if (lcd->eeprom.header != LCD_OLINUXINO_HEADER_MAGIC) {
dev_err(dev, "magic header does not match\n");
return -EINVAL;
}
dev_info(dev, "Detected %s, Rev. %s, Serial: %08x\n",
lcd->eeprom.info.name,
lcd->eeprom.revision,
lcd->eeprom.serial);
/*
* The eeprom can hold up to 4 modes.
* If the stored value is bigger, overwrite it.
*/
if (lcd->eeprom.num_modes > 4) {
dev_warn(dev, "invalid number of modes, falling back to 4\n");
lcd->eeprom.num_modes = 4;
}
lcd->enabled = false;
lcd->prepared = false;
lcd->supply = devm_regulator_get(dev, "power");
if (IS_ERR(lcd->supply))
return PTR_ERR(lcd->supply);
lcd->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
if (IS_ERR(lcd->enable_gpio))
return PTR_ERR(lcd->enable_gpio);
drm_panel_init(&lcd->panel, dev, &lcd_olinuxino_funcs,
DRM_MODE_CONNECTOR_DPI);
ret = drm_panel_of_backlight(&lcd->panel);
if (ret)
return ret;
drm_panel_add(&lcd->panel);
return 0;
}
static int lcd_olinuxino_remove(struct i2c_client *client)
{
struct lcd_olinuxino *panel = i2c_get_clientdata(client);
drm_panel_remove(&panel->panel);
drm_panel_disable(&panel->panel);
drm_panel_unprepare(&panel->panel);
return 0;
}
static const struct of_device_id lcd_olinuxino_of_ids[] = {
{ .compatible = "olimex,lcd-olinuxino" },
{ }
};
MODULE_DEVICE_TABLE(of, lcd_olinuxino_of_ids);
static struct i2c_driver lcd_olinuxino_driver = {
.driver = {
.name = "lcd_olinuxino",
.of_match_table = lcd_olinuxino_of_ids,
},
.probe = lcd_olinuxino_probe,
.remove = lcd_olinuxino_remove,
};
module_i2c_driver(lcd_olinuxino_driver);
MODULE_AUTHOR("Stefan Mavrodiev <stefan@olimex.com>");
MODULE_DESCRIPTION("LCD-OLinuXino driver");
MODULE_LICENSE("GPL");