// SPDX-License-Identifier: GPL-2.0
/*
* Panel driver for the TPO TPG110 400CH LTPS TFT LCD Single Chip
* Digital Driver.
*
* This chip drives a TFT LCD, so it does not know what kind of
* display is actually connected to it, so the width and height of that
* display needs to be supplied from the machine configuration.
*
* Author:
* Linus Walleij <[email protected]>
*/
#include <drm/drm_modes.h>
#include <drm/drm_panel.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#define TPG110_TEST 0x00
#define TPG110_CHIPID 0x01
#define TPG110_CTRL1 0x02
#define TPG110_RES_MASK GENMASK(2, 0)
#define TPG110_RES_800X480 0x07
#define TPG110_RES_640X480 0x06
#define TPG110_RES_480X272 0x05
#define TPG110_RES_480X640 0x04
#define TPG110_RES_480X272_D 0x01 /* Dual scan: outputs 800x480 */
#define TPG110_RES_400X240_D 0x00 /* Dual scan: outputs 800x480 */
#define TPG110_CTRL2 0x03
#define TPG110_CTRL2_PM BIT(0)
#define TPG110_CTRL2_RES_PM_CTRL BIT(7)
/**
* struct tpg110_panel_mode - lookup struct for the supported modes
*/
struct tpg110_panel_mode {
/**
* @name: the name of this panel
*/
const char *name;
/**
* @magic: the magic value from the detection register
*/
u32 magic;
/**
* @mode: the DRM display mode for this panel
*/
struct drm_display_mode mode;
/**
* @bus_flags: the DRM bus flags for this panel e.g. inverted clock
*/
u32 bus_flags;
};
/**
* struct tpg110 - state container for the TPG110 panel
*/
struct tpg110 {
/**
* @dev: the container device
*/
struct device *dev;
/**
* @spi: the corresponding SPI device
*/
struct spi_device *spi;
/**
* @panel: the DRM panel instance for this device
*/
struct drm_panel panel;
/**
* @panel_mode: the panel mode as detected
*/
const struct tpg110_panel_mode *panel_mode;
/**
* @width: the width of this panel in mm
*/
u32 width;
/**
* @height: the height of this panel in mm
*/
u32 height;
/**
* @grestb: reset GPIO line
*/
struct gpio_desc *grestb;
};
/*
* TPG110 modes, these are the simple modes, the dualscan modes that
* take 400x240 or 480x272 in and display as 800x480 are not listed.
*/
static const struct tpg110_panel_mode tpg110_modes[] = {
{
.name = "800x480 RGB",
.magic = TPG110_RES_800X480,
.mode = {
.clock = 33200,
.hdisplay = 800,
.hsync_start = 800 + 40,
.hsync_end = 800 + 40 + 1,
.htotal = 800 + 40 + 1 + 216,
.vdisplay = 480,
.vsync_start = 480 + 10,
.vsync_end = 480 + 10 + 1,
.vtotal = 480 + 10 + 1 + 35,
},
.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
},
{
.name = "640x480 RGB",
.magic = TPG110_RES_640X480,
.mode = {
.clock = 25200,
.hdisplay = 640,
.hsync_start = 640 + 24,
.hsync_end = 640 + 24 + 1,
.htotal = 640 + 24 + 1 + 136,
.vdisplay = 480,
.vsync_start = 480 + 18,
.vsync_end = 480 + 18 + 1,
.vtotal = 480 + 18 + 1 + 27,
},
.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
},
{
.name = "480x272 RGB",
.magic = TPG110_RES_480X272,
.mode = {
.clock = 9000,
.hdisplay = 480,
.hsync_start = 480 + 2,
.hsync_end = 480 + 2 + 1,
.htotal = 480 + 2 + 1 + 43,
.vdisplay = 272,
.vsync_start = 272 + 2,
.vsync_end = 272 + 2 + 1,
.vtotal = 272 + 2 + 1 + 12,
},
.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
},
{
.name = "480x640 RGB",
.magic = TPG110_RES_480X640,
.mode = {
.clock = 20500,
.hdisplay = 480,
.hsync_start = 480 + 2,
.hsync_end = 480 + 2 + 1,
.htotal = 480 + 2 + 1 + 43,
.vdisplay = 640,
.vsync_start = 640 + 4,
.vsync_end = 640 + 4 + 1,
.vtotal = 640 + 4 + 1 + 8,
},
.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
},
{
.name = "400x240 RGB",
.magic = TPG110_RES_400X240_D,
.mode = {
.clock = 8300,
.hdisplay = 400,
.hsync_start = 400 + 20,
.hsync_end = 400 + 20 + 1,
.htotal = 400 + 20 + 1 + 108,
.vdisplay = 240,
.vsync_start = 240 + 2,
.vsync_end = 240 + 2 + 1,
.vtotal = 240 + 2 + 1 + 20,
},
.bus_flags = DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE,
},
};
static inline struct tpg110 *
to_tpg110(struct drm_panel *panel)
{
return container_of(panel, struct tpg110, panel);
}
static u8 tpg110_readwrite_reg(struct tpg110 *tpg, bool write,
u8 address, u8 outval)
{
struct spi_message m;
struct spi_transfer t[2];
u8 buf[2];
int ret;
spi_message_init(&m);
memset(t, 0, sizeof(t));
if (write) {
/*
* Clear address bit 0, 1 when writing, just to be sure
* The actual bit indicating a write here is bit 1, bit
* 0 is just surplus to pad it up to 8 bits.
*/
buf[0] = address << 2;
buf[0] &= ~0x03;
buf[1] = outval;
t[0].bits_per_word = 8;
t[0].tx_buf = &buf[0];
t[0].len = 1;
t[1].tx_buf = &buf[1];
t[1].len = 1;
t[1].bits_per_word = 8;
} else {
/* Set address bit 0 to 1 to read */
buf[0] = address << 1;
buf[0] |= 0x01;
/*
* The last bit/clock is Hi-Z turnaround cycle, so we need
* to send only 7 bits here. The 8th bit is the high impedance
* turn-around cycle.
*/
t[0].bits_per_word = 7;
t[0].tx_buf = &buf[0];
t[0].len = 1;
t[1].rx_buf = &buf[1];
t[1].len = 1;
t[1].bits_per_word = 8;
}
spi_message_add_tail(&t[0], &m);
spi_message_add_tail(&t[1], &m);
ret = spi_sync(tpg->spi, &m);
if (ret) {
dev_err(tpg->dev, "SPI message error %d\n", ret);
return ret;
}
if (write)
return 0;
/* Read */
return buf[1];
}
static u8 tpg110_read_reg(struct tpg110 *tpg, u8 address)
{
return tpg110_readwrite_reg(tpg, false, address, 0);
}
static void tpg110_write_reg(struct tpg110 *tpg, u8 address, u8 outval)
{
tpg110_readwrite_reg(tpg, true, address, outval);
}
static int tpg110_startup(struct tpg110 *tpg)
{
u8 val;
int i;
/* De-assert the reset signal */
gpiod_set_value_cansleep(tpg->grestb, 0);
usleep_range(1000, 2000);
dev_dbg(tpg->dev, "de-asserted GRESTB\n");
/* Test display communication */
tpg110_write_reg(tpg, TPG110_TEST, 0x55);
val = tpg110_read_reg(tpg, TPG110_TEST);
if (val != 0x55) {
dev_err(tpg->dev, "failed communication test\n");
return -ENODEV;
}
val = tpg110_read_reg(tpg, TPG110_CHIPID);
dev_info(tpg->dev, "TPG110 chip ID: %d version: %d\n",
val >> 4, val & 0x0f);
/* Show display resolution */
val = tpg110_read_reg(tpg, TPG110_CTRL1);
val &= TPG110_RES_MASK;
switch (val) {
case TPG110_RES_400X240_D:
dev_info(tpg->dev, "IN 400x240 RGB -> OUT 800x480 RGB (dual scan)\n");
break;
case TPG110_RES_480X272_D:
dev_info(tpg->dev, "IN 480x272 RGB -> OUT 800x480 RGB (dual scan)\n");
break;
case TPG110_RES_480X640:
dev_info(tpg->dev, "480x640 RGB\n");
break;
case TPG110_RES_480X272:
dev_info(tpg->dev, "480x272 RGB\n");
break;
case TPG110_RES_640X480:
dev_info(tpg->dev, "640x480 RGB\n");
break;
case TPG110_RES_800X480:
dev_info(tpg->dev, "800x480 RGB\n");
break;
default:
dev_err(tpg->dev, "ILLEGAL RESOLUTION 0x%02x\n", val);
break;
}
/* From the producer side, this is the same resolution */
if (val == TPG110_RES_480X272_D)
val = TPG110_RES_480X272;
for (i = 0; i < ARRAY_SIZE(tpg110_modes); i++) {
const struct tpg110_panel_mode *pm;
pm = &tpg110_modes[i];
if (pm->magic == val) {
tpg->panel_mode = pm;
break;
}
}
if (i == ARRAY_SIZE(tpg110_modes)) {
dev_err(tpg->dev, "unsupported mode (%02x) detected\n", val);
return -ENODEV;
}
val = tpg110_read_reg(tpg, TPG110_CTRL2);
dev_info(tpg->dev, "resolution and standby is controlled by %s\n",
(val & TPG110_CTRL2_RES_PM_CTRL) ? "software" : "hardware");
/* Take control over resolution and standby */
val |= TPG110_CTRL2_RES_PM_CTRL;
tpg110_write_reg(tpg, TPG110_CTRL2, val);
return 0;
}
static int tpg110_disable(struct drm_panel *panel)
{
struct tpg110 *tpg = to_tpg110(panel);
u8 val;
/* Put chip into standby */
val = tpg110_read_reg(tpg, TPG110_CTRL2_PM);
val &= ~TPG110_CTRL2_PM;
tpg110_write_reg(tpg, TPG110_CTRL2_PM, val);
return 0;
}
static int tpg110_enable(struct drm_panel *panel)
{
struct tpg110 *tpg = to_tpg110(panel);
u8 val;
/* Take chip out of standby */
val = tpg110_read_reg(tpg, TPG110_CTRL2_PM);
val |= TPG110_CTRL2_PM;
tpg110_write_reg(tpg, TPG110_CTRL2_PM, val);
return 0;
}
/**
* tpg110_get_modes() - return the appropriate mode
* @panel: the panel to get the mode for
* @connector: reference to the central DRM connector control structure
*
* This currently does not present a forest of modes, instead it
* presents the mode that is configured for the system under use,
* and which is detected by reading the registers of the display.
*/
static int tpg110_get_modes(struct drm_panel *panel,
struct drm_connector *connector)
{
struct tpg110 *tpg = to_tpg110(panel);
struct drm_display_mode *mode;
connector->display_info.width_mm = tpg->width;
connector->display_info.height_mm = tpg->height;
connector->display_info.bus_flags = tpg->panel_mode->bus_flags;
mode = drm_mode_duplicate(connector->dev, &tpg->panel_mode->mode);
if (!mode)
return -ENOMEM;
drm_mode_set_name(mode);
mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
mode->width_mm = tpg->width;
mode->height_mm = tpg->height;
drm_mode_probed_add(connector, mode);
return 1;
}
static const struct drm_panel_funcs tpg110_drm_funcs = {
.disable = tpg110_disable,
.enable = tpg110_enable,
.get_modes = tpg110_get_modes,
};
static int tpg110_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct device_node *np = dev->of_node;
struct tpg110 *tpg;
int ret;
tpg = devm_kzalloc(dev, sizeof(*tpg), GFP_KERNEL);
if (!tpg)
return -ENOMEM;
tpg->dev = dev;
/* We get the physical display dimensions from the DT */
ret = of_property_read_u32(np, "width-mm", &tpg->width);
if (ret)
dev_err(dev, "no panel width specified\n");
ret = of_property_read_u32(np, "height-mm", &tpg->height);
if (ret)
dev_err(dev, "no panel height specified\n");
/* This asserts the GRESTB signal, putting the display into reset */
tpg->grestb = devm_gpiod_get(dev, "grestb", GPIOD_OUT_HIGH);
if (IS_ERR(tpg->grestb)) {
dev_err(dev, "no GRESTB GPIO\n");
return -ENODEV;
}
spi->bits_per_word = 8;
spi->mode |= SPI_3WIRE_HIZ;
ret = spi_setup(spi);
if (ret < 0) {
dev_err(dev, "spi setup failed.\n");
return ret;
}
tpg->spi = spi;
ret = tpg110_startup(tpg);
if (ret)
return ret;
drm_panel_init(&tpg->panel, dev, &tpg110_drm_funcs,
DRM_MODE_CONNECTOR_DPI);
ret = drm_panel_of_backlight(&tpg->panel);
if (ret)
return ret;
spi_set_drvdata(spi, tpg);
drm_panel_add(&tpg->panel);
return 0;
}
static void tpg110_remove(struct spi_device *spi)
{
struct tpg110 *tpg = spi_get_drvdata(spi);
drm_panel_remove(&tpg->panel);
}
static const struct of_device_id tpg110_match[] = {
{ .compatible = "tpo,tpg110", },
{},
};
MODULE_DEVICE_TABLE(of, tpg110_match);
static const struct spi_device_id tpg110_ids[] = {
{ "tpg110" },
{ },
};
MODULE_DEVICE_TABLE(spi, tpg110_ids);
static struct spi_driver tpg110_driver = {
.probe = tpg110_probe,
.remove = tpg110_remove,
.id_table = tpg110_ids,
.driver = {
.name = "tpo-tpg110-panel",
.of_match_table = tpg110_match,
},
};
module_spi_driver(tpg110_driver);
MODULE_AUTHOR("Linus Walleij <[email protected]>");
MODULE_DESCRIPTION("TPO TPG110 panel driver");
MODULE_LICENSE("GPL v2");
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