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// SPDX-License-Identifier: GPL-2.0
/*
* Novatek NT39016 TFT LCD panel driver
*
* Copyright (C) 2017, Maarten ter Huurne <maarten@treewalker.org>
* Copyright (C) 2019, Paul Cercueil <paul@crapouillou.net>
*/
#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>
enum nt39016_regs {
NT39016_REG_SYSTEM,
NT39016_REG_TIMING,
NT39016_REG_OP,
NT39016_REG_DATA_IN,
NT39016_REG_SRC_TIMING_DELAY,
NT39016_REG_GATE_TIMING_DELAY,
NT39016_REG_RESERVED,
NT39016_REG_INITIAL_FUNC,
NT39016_REG_CONTRAST,
NT39016_REG_BRIGHTNESS,
NT39016_REG_HUE_SATURATION,
NT39016_REG_RB_SUBCONTRAST,
NT39016_REG_R_SUBBRIGHTNESS,
NT39016_REG_B_SUBBRIGHTNESS,
NT39016_REG_VCOMDC,
NT39016_REG_VCOMAC,
NT39016_REG_VGAM2,
NT39016_REG_VGAM34,
NT39016_REG_VGAM56,
NT39016_REG_VCOMDC_TRIM = 0x1e,
NT39016_REG_DISPLAY_MODE = 0x20,
};
#define NT39016_SYSTEM_RESET_N BIT(0)
#define NT39016_SYSTEM_STANDBY BIT(1)
struct nt39016_panel_info {
struct drm_display_mode display_mode;
u16 width_mm, height_mm;
u32 bus_format, bus_flags;
};
struct nt39016 {
struct drm_panel drm_panel;
struct device *dev;
struct regmap *map;
struct regulator *supply;
const struct nt39016_panel_info *panel_info;
struct gpio_desc *reset_gpio;
struct backlight_device *backlight;
};
static inline struct nt39016 *to_nt39016(struct drm_panel *panel)
{
return container_of(panel, struct nt39016, drm_panel);
}
#define RV(REG, VAL) { .reg = (REG), .def = (VAL), .delay_us = 2 }
static const struct reg_sequence nt39016_panel_regs[] = {
RV(NT39016_REG_SYSTEM, 0x00),
RV(NT39016_REG_TIMING, 0x00),
RV(NT39016_REG_OP, 0x03),
RV(NT39016_REG_DATA_IN, 0xCC),
RV(NT39016_REG_SRC_TIMING_DELAY, 0x46),
RV(NT39016_REG_GATE_TIMING_DELAY, 0x05),
RV(NT39016_REG_RESERVED, 0x00),
RV(NT39016_REG_INITIAL_FUNC, 0x00),
RV(NT39016_REG_CONTRAST, 0x08),
RV(NT39016_REG_BRIGHTNESS, 0x40),
RV(NT39016_REG_HUE_SATURATION, 0x88),
RV(NT39016_REG_RB_SUBCONTRAST, 0x88),
RV(NT39016_REG_R_SUBBRIGHTNESS, 0x20),
RV(NT39016_REG_B_SUBBRIGHTNESS, 0x20),
RV(NT39016_REG_VCOMDC, 0x67),
RV(NT39016_REG_VCOMAC, 0xA4),
RV(NT39016_REG_VGAM2, 0x04),
RV(NT39016_REG_VGAM34, 0x24),
RV(NT39016_REG_VGAM56, 0x24),
RV(NT39016_REG_DISPLAY_MODE, 0x00),
};
#undef RV
static const struct regmap_range nt39016_regmap_no_ranges[] = {
regmap_reg_range(0x13, 0x1D),
regmap_reg_range(0x1F, 0x1F),
};
static const struct regmap_access_table nt39016_regmap_access_table = {
.no_ranges = nt39016_regmap_no_ranges,
.n_no_ranges = ARRAY_SIZE(nt39016_regmap_no_ranges),
};
static const struct regmap_config nt39016_regmap_config = {
.reg_bits = 6,
.pad_bits = 2,
.val_bits = 8,
.max_register = NT39016_REG_DISPLAY_MODE,
.wr_table = &nt39016_regmap_access_table,
.write_flag_mask = 0x02,
.cache_type = REGCACHE_FLAT,
};
static int nt39016_prepare(struct drm_panel *drm_panel)
{
struct nt39016 *panel = to_nt39016(drm_panel);
int err;
err = regulator_enable(panel->supply);
if (err) {
dev_err(panel->dev, "Failed to enable power supply: %d", err);
return err;
}
/*
* Reset the NT39016.
* The documentation says the reset pulse should be at least 40 us to
* pass the glitch filter, but when testing I see some resets fail and
* some succeed when using a 70 us delay, so we use 100 us instead.
*/
gpiod_set_value_cansleep(panel->reset_gpio, 1);
usleep_range(100, 1000);
gpiod_set_value_cansleep(panel->reset_gpio, 0);
udelay(2);
/* Init all registers. */
err = regmap_multi_reg_write(panel->map, nt39016_panel_regs,
ARRAY_SIZE(nt39016_panel_regs));
if (err) {
dev_err(panel->dev, "Failed to init registers: %d", err);
goto err_disable_regulator;
}
return 0;
err_disable_regulator:
regulator_disable(panel->supply);
return err;
}
static int nt39016_unprepare(struct drm_panel *drm_panel)
{
struct nt39016 *panel = to_nt39016(drm_panel);
gpiod_set_value_cansleep(panel->reset_gpio, 1);
regulator_disable(panel->supply);
return 0;
}
static int nt39016_enable(struct drm_panel *drm_panel)
{
struct nt39016 *panel = to_nt39016(drm_panel);
int ret;
ret = regmap_write(panel->map, NT39016_REG_SYSTEM,
NT39016_SYSTEM_RESET_N | NT39016_SYSTEM_STANDBY);
if (ret) {
dev_err(panel->dev, "Unable to enable panel: %d", ret);
return ret;
}
if (panel->backlight) {
/* Wait for the picture to be ready before enabling backlight */
msleep(150);
ret = backlight_enable(panel->backlight);
}
return ret;
}
static int nt39016_disable(struct drm_panel *drm_panel)
{
struct nt39016 *panel = to_nt39016(drm_panel);
int err;
backlight_disable(panel->backlight);
err = regmap_write(panel->map, NT39016_REG_SYSTEM,
NT39016_SYSTEM_RESET_N);
if (err) {
dev_err(panel->dev, "Unable to disable panel: %d", err);
return err;
}
return 0;
}
static int nt39016_get_modes(struct drm_panel *drm_panel)
{
struct nt39016 *panel = to_nt39016(drm_panel);
const struct nt39016_panel_info *panel_info = panel->panel_info;
struct drm_connector *connector = drm_panel->connector;
struct drm_display_mode *mode;
mode = drm_mode_duplicate(drm_panel->drm, &panel_info->display_mode);
if (!mode)
return -ENOMEM;
drm_mode_set_name(mode);
mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
drm_mode_probed_add(connector, mode);
connector->display_info.bpc = 8;
connector->display_info.width_mm = panel_info->width_mm;
connector->display_info.height_mm = panel_info->height_mm;
drm_display_info_set_bus_formats(&connector->display_info,
&panel_info->bus_format, 1);
connector->display_info.bus_flags = panel_info->bus_flags;
return 1;
}
static const struct drm_panel_funcs nt39016_funcs = {
.prepare = nt39016_prepare,
.unprepare = nt39016_unprepare,
.enable = nt39016_enable,
.disable = nt39016_disable,
.get_modes = nt39016_get_modes,
};
static int nt39016_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct nt39016 *panel;
int err;
panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
if (!panel)
return -ENOMEM;
panel->dev = dev;
spi_set_drvdata(spi, panel);
panel->panel_info = of_device_get_match_data(dev);
if (!panel->panel_info)
return -EINVAL;
panel->supply = devm_regulator_get(dev, "power");
if (IS_ERR(panel->supply)) {
dev_err(dev, "Failed to get power supply");
return PTR_ERR(panel->supply);
}
panel->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(panel->reset_gpio)) {
dev_err(dev, "Failed to get reset GPIO");
return PTR_ERR(panel->reset_gpio);
}
spi->bits_per_word = 8;
spi->mode = SPI_MODE_3 | SPI_3WIRE;
err = spi_setup(spi);
if (err) {
dev_err(dev, "Failed to setup SPI");
return err;
}
panel->map = devm_regmap_init_spi(spi, &nt39016_regmap_config);
if (IS_ERR(panel->map)) {
dev_err(dev, "Failed to init regmap");
return PTR_ERR(panel->map);
}
panel->backlight = devm_of_find_backlight(dev);
if (IS_ERR(panel->backlight)) {
err = PTR_ERR(panel->backlight);
if (err != -EPROBE_DEFER)
dev_err(dev, "Failed to get backlight handle");
return err;
}
drm_panel_init(&panel->drm_panel, dev, &nt39016_funcs,
DRM_MODE_CONNECTOR_DPI);
err = drm_panel_add(&panel->drm_panel);
if (err < 0) {
dev_err(dev, "Failed to register panel");
return err;
}
return 0;
}
static int nt39016_remove(struct spi_device *spi)
{
struct nt39016 *panel = spi_get_drvdata(spi);
drm_panel_remove(&panel->drm_panel);
nt39016_disable(&panel->drm_panel);
nt39016_unprepare(&panel->drm_panel);
return 0;
}
static const struct nt39016_panel_info kd035g6_info = {
.display_mode = {
.clock = 6000,
.hdisplay = 320,
.hsync_start = 320 + 10,
.hsync_end = 320 + 10 + 50,
.htotal = 320 + 10 + 50 + 20,
.vdisplay = 240,
.vsync_start = 240 + 5,
.vsync_end = 240 + 5 + 1,
.vtotal = 240 + 5 + 1 + 4,
.vrefresh = 60,
.flags = DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC,
},
.width_mm = 71,
.height_mm = 53,
.bus_format = MEDIA_BUS_FMT_RGB888_1X24,
.bus_flags = DRM_BUS_FLAG_PIXDATA_NEGEDGE,
};
static const struct of_device_id nt39016_of_match[] = {
{ .compatible = "kingdisplay,kd035g6-54nt", .data = &kd035g6_info },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, nt39016_of_match);
static struct spi_driver nt39016_driver = {
.driver = {
.name = "nt39016",
.of_match_table = nt39016_of_match,
},
.probe = nt39016_probe,
.remove = nt39016_remove,
};
module_spi_driver(nt39016_driver);
MODULE_AUTHOR("Maarten ter Huurne <maarten@treewalker.org>");
MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
MODULE_LICENSE("GPL v2");
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