diff options
Diffstat (limited to 'drivers/gpu/drm/panel/panel-tpo-tpg110.c')
| -rw-r--r-- | drivers/gpu/drm/panel/panel-tpo-tpg110.c | 480 |
1 files changed, 480 insertions, 0 deletions
diff --git a/drivers/gpu/drm/panel/panel-tpo-tpg110.c b/drivers/gpu/drm/panel/panel-tpo-tpg110.c new file mode 100644 index 000000000..735f1ea25 --- /dev/null +++ b/drivers/gpu/drm/panel/panel-tpo-tpg110.c @@ -0,0 +1,480 @@ +// 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 <linus.walleij@linaro.org> + */ +#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 struct spi_driver tpg110_driver = { + .probe = tpg110_probe, + .remove = tpg110_remove, + .driver = { + .name = "tpo-tpg110-panel", + .of_match_table = tpg110_match, + }, +}; +module_spi_driver(tpg110_driver); + +MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>"); +MODULE_DESCRIPTION("TPO TPG110 panel driver"); +MODULE_LICENSE("GPL v2"); |