From: Sunyun Yang <[email protected]> The LT7911EXC is an I2C-controlled bridge that Receiver eDP1.4 and output signal/dual port mipi dsi.
Signed-off-by: Sunyun Yang <[email protected]> Reviewed-by: Dmitry Baryshkov <[email protected]> --- drivers/gpu/drm/bridge/Kconfig | 13 + drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/lontium-lt7911exc.c | 493 +++++++++++++++++++++ 3 files changed, 507 insertions(+) create mode 100644 drivers/gpu/drm/bridge/lontium-lt7911exc.c diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index c3209b0f4678..fe45a9052aa0 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -132,6 +132,19 @@ config DRM_ITE_IT6505 help ITE IT6505 DisplayPort bridge chip driver. +config DRM_LONTIUM_LT7911EXC + tristate "Lontium eDP/MIPI DSI bridge" + depends on OF + select CRC32 + select FW_LOADER + select DRM_PANEL + select DRM_KMS_HELPER + help + DRM driver for the Lontium LT7911EXC bridge chip. + The LT7911EXC converts eDP input to single/dual port + MIPI DSI output. + Please say Y if you have such hardware. + config DRM_LONTIUM_LT8912B tristate "Lontium LT8912B DSI/HDMI bridge" depends on OF diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index beab5b695a6e..70ddca75dd3a 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_DRM_I2C_NXP_TDA998X) += tda998x.o obj-$(CONFIG_DRM_INNO_HDMI) += inno-hdmi.o obj-$(CONFIG_DRM_ITE_IT6263) += ite-it6263.o obj-$(CONFIG_DRM_ITE_IT6505) += ite-it6505.o +obj-$(CONFIG_DRM_LONTIUM_LT7911EXC) += lontium-lt7911exc.o obj-$(CONFIG_DRM_LONTIUM_LT8912B) += lontium-lt8912b.o obj-$(CONFIG_DRM_LONTIUM_LT9211) += lontium-lt9211.o obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o diff --git a/drivers/gpu/drm/bridge/lontium-lt7911exc.c b/drivers/gpu/drm/bridge/lontium-lt7911exc.c new file mode 100644 index 000000000000..02648b396343 --- /dev/null +++ b/drivers/gpu/drm/bridge/lontium-lt7911exc.c @@ -0,0 +1,493 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2026 Lontium Semiconductor, Inc. + */ + +#include <linux/crc32.h> +#include <linux/firmware.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of_graph.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +#include <drm/drm_bridge.h> +#include <drm/drm_mipi_dsi.h> +#include <drm/drm_of.h> + +#define FW_SIZE (64 * 1024) +#define LT_PAGE_SIZE 32 +#define FW_FILE "lt7911exc_fw.bin" +#define LT7911EXC_PAGE_CONTROL 0xff + +struct lt7911exc { + struct device *dev; + struct i2c_client *client; + struct drm_bridge bridge; + struct regmap *regmap; + /* Protects all accesses to registers by stopping the on-chip MCU */ + struct mutex ocm_lock; + struct regulator_bulk_data supplies[2]; + struct gpio_desc *reset_gpio; + int fw_version; +}; + +static const struct regmap_range_cfg lt7911exc_ranges[] = { + { + .name = "register_range", + .range_min = 0, + .range_max = 0xe8ff, + .selector_reg = LT7911EXC_PAGE_CONTROL, + .selector_mask = 0xff, + .selector_shift = 0, + .window_start = 0, + .window_len = 0x100, + }, +}; + +static const struct regmap_config lt7911exc_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = 0xe8ff, + .ranges = lt7911exc_ranges, + .num_ranges = ARRAY_SIZE(lt7911exc_ranges), +}; + +static u32 cal_crc32_custom(const u8 *data, u64 length) +{ + u32 crc = 0xffffffff; + u8 buf[4]; + u64 i; + + for (i = 0; i < length; i += 4) { + buf[0] = data[i + 3]; + buf[1] = data[i + 2]; + buf[2] = data[i + 1]; + buf[3] = data[i + 0]; + crc = crc32_be(crc, buf, 4); + } + + return crc; +} + +static inline struct lt7911exc *bridge_to_lt7911exc(struct drm_bridge *bridge) +{ + return container_of(bridge, struct lt7911exc, bridge); +} + +static void lt7911exc_reset(struct lt7911exc *lt7911exc) +{ + gpiod_set_value_cansleep(lt7911exc->reset_gpio, 0); + msleep(20); + + gpiod_set_value_cansleep(lt7911exc->reset_gpio, 1); + msleep(20); + + gpiod_set_value_cansleep(lt7911exc->reset_gpio, 0); + msleep(400); + + dev_dbg(lt7911exc->dev, "lt7911exc reset.\n"); +} + +static int lt7911exc_parse_dt(struct lt7911exc *lt7911exc) +{ + struct device *dev = lt7911exc->dev; + int ret; + + lt7911exc->supplies[0].supply = "vcc"; + lt7911exc->supplies[1].supply = "vdd"; + + ret = devm_regulator_bulk_get(dev, 2, lt7911exc->supplies); + if (ret) + return dev_err_probe(dev, ret, "failed get regulator\n"); + + lt7911exc->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(lt7911exc->reset_gpio)) + return dev_err_probe(dev, PTR_ERR(lt7911exc->reset_gpio), + "failed to acquire reset gpio\n"); + + return 0; +} + +static int lt7911exc_read_version(struct lt7911exc *lt7911exc) +{ + u8 buf[3]; + int ret; + + ret = regmap_write(lt7911exc->regmap, 0xe0ee, 0x01); + if (ret) + return ret; + ret = regmap_bulk_read(lt7911exc->regmap, 0xe081, buf, sizeof(buf)); + if (ret) + return ret; + + return (buf[0] << 16) | (buf[1] << 8) | buf[2]; +} + +static void lt7911exc_lock(struct lt7911exc *lt7911exc) +{ + mutex_lock(<7911exc->ocm_lock); + regmap_write(lt7911exc->regmap, 0xe0ee, 0x01); +} + +static void lt7911exc_unlock(struct lt7911exc *lt7911exc) +{ + regmap_write(lt7911exc->regmap, 0xe0ee, 0x00); + mutex_unlock(<7911exc->ocm_lock); +} + +static void lt7911exc_block_erase(struct lt7911exc *lt7911exc) +{ + struct device *dev = lt7911exc->dev; + const u32 addr = 0x00; + + const struct reg_sequence seq_write[] = { + REG_SEQ0(0xe0ee, 0x01), + REG_SEQ0(0xe054, 0x01), + REG_SEQ0(0xe055, 0x06), + REG_SEQ0(0xe051, 0x01), + REG_SEQ0(0xe051, 0x00), + REG_SEQ0(0xe054, 0x05), + REG_SEQ0(0xe055, 0xd8), + REG_SEQ0(0xe05a, (addr >> 16) & 0xff), + REG_SEQ0(0xe05b, (addr >> 8) & 0xff), + REG_SEQ0(0xe05c, addr & 0xff), + REG_SEQ0(0xe051, 0x01), + REG_SEQ0(0xe050, 0x00), + }; + + regmap_multi_reg_write(lt7911exc->regmap, seq_write, ARRAY_SIZE(seq_write)); + + msleep(200); + dev_dbg(dev, "erase flash done.\n"); +} + +static void lt7911exc_prog_init(struct lt7911exc *lt7911exc, u64 addr) +{ + const struct reg_sequence seq_write[] = { + REG_SEQ0(0xe0ee, 0x01), + REG_SEQ0(0xe05f, 0x01), + REG_SEQ0(0xe05a, (addr >> 16) & 0xff), + REG_SEQ0(0xe05b, (addr >> 8) & 0xff), + REG_SEQ0(0xe05c, addr & 0xff), + }; + + regmap_multi_reg_write(lt7911exc->regmap, seq_write, ARRAY_SIZE(seq_write)); +} + +static int lt7911exc_write_data(struct lt7911exc *lt7911exc, const struct firmware *fw, u64 addr) +{ + struct device *dev = lt7911exc->dev; + int ret; + int page = 0, num = 0, page_len = 0; + u64 size, offset; + const u8 *data; + + data = fw->data; + size = fw->size; + page = (size + LT_PAGE_SIZE - 1) / LT_PAGE_SIZE; + if (page * LT_PAGE_SIZE > FW_SIZE) { + dev_err(dev, "firmware size out of range\n"); + return -EINVAL; + } + + dev_dbg(dev, "%u pages, total size %llu byte\n", page, size); + + for (num = 0; num < page; num++) { + offset = num * LT_PAGE_SIZE; + page_len = (offset + LT_PAGE_SIZE <= size) ? LT_PAGE_SIZE : (size - offset); + lt7911exc_prog_init(lt7911exc, addr); + + ret = regmap_raw_write(lt7911exc->regmap, 0xe05d, &data[offset], page_len); + if (ret) { + dev_err(dev, "write error at page %d\n", num); + return ret; + } + + if (page_len < LT_PAGE_SIZE) { + regmap_write(lt7911exc->regmap, 0xe05f, 0x05); + regmap_write(lt7911exc->regmap, 0xe05f, 0x01); + //hardware requires delay + usleep_range(1000, 2000); + } + + regmap_write(lt7911exc->regmap, 0xe05f, 0x00); + addr += LT_PAGE_SIZE; + } + + return 0; +} + +static int lt7911exc_write_crc(struct lt7911exc *lt7911exc, u32 crc32, u64 addr) +{ + u8 crc[4]; + int ret; + + crc[0] = crc32 & 0xff; + crc[1] = (crc32 >> 8) & 0xff; + crc[2] = (crc32 >> 16) & 0xff; + crc[3] = (crc32 >> 24) & 0xff; + + regmap_write(lt7911exc->regmap, 0xe05f, 0x01); + regmap_write(lt7911exc->regmap, 0xe05a, (addr >> 16) & 0xff); + regmap_write(lt7911exc->regmap, 0xe05b, (addr >> 8) & 0xff); + regmap_write(lt7911exc->regmap, 0xe05c, addr & 0xff); + + ret = regmap_raw_write(lt7911exc->regmap, 0xe05d, crc, 4); + if (ret) + return ret; + + regmap_write(lt7911exc->regmap, 0xe05f, 0x05); + regmap_write(lt7911exc->regmap, 0xe05f, 0x01); + usleep_range(1000, 2000); + regmap_write(lt7911exc->regmap, 0xe05f, 0x00); + + return 0; +} + +static int lt7911exc_upgrade_result(struct lt7911exc *lt7911exc, u32 crc32) +{ + struct device *dev = lt7911exc->dev; + u32 read_hw_crc = 0; + u8 crc_tmp[4]; + int ret; + + regmap_write(lt7911exc->regmap, 0xe0ee, 0x01); + regmap_write(lt7911exc->regmap, 0xe07b, 0x60); + regmap_write(lt7911exc->regmap, 0xe07b, 0x40); + msleep(150); + ret = regmap_bulk_read(lt7911exc->regmap, 0x22, crc_tmp, 4); + if (ret) { + dev_err(lt7911exc->dev, "Failed to read CRC: %d\n", ret); + return ret; + } + + read_hw_crc = crc_tmp[0] << 24 | crc_tmp[1] << 16 | + crc_tmp[2] << 8 | crc_tmp[3]; + + if (read_hw_crc != crc32) { + dev_err(dev, "lt7911exc firmware upgrade failed, expected CRC=0x%08x, read CRC=0x%08x\n", + crc32, read_hw_crc); + return -EIO; + } + + dev_dbg(dev, "lt7911exc firmware upgrade success, CRC=0x%08x\n", read_hw_crc); + return 0; +} + +static int lt7911exc_firmware_upgrade(struct lt7911exc *lt7911exc) +{ + struct device *dev = lt7911exc->dev; + const struct firmware *fw; + u8 *buffer; + size_t total_size = FW_SIZE - 4; + u32 crc32; + int ret; + + /*1. load firmware*/ + ret = request_firmware(&fw, FW_FILE, dev); + if (ret) + return dev_err_probe(dev, ret, "failed to load '%s'\n", FW_FILE); + + /*2. check size*/ + if (fw->size > total_size) { + dev_err(dev, "firmware too large (%zu > %zu)\n", fw->size, total_size); + ret = -EINVAL; + goto out_release_fw; + } + + /*3. calculate crc32 */ + buffer = kzalloc(total_size, GFP_KERNEL); + if (!buffer) { + ret = -ENOMEM; + goto out_release_fw; + } + memset(buffer, 0xff, total_size); + memcpy(buffer, fw->data, fw->size); + + crc32 = cal_crc32_custom(buffer, total_size); + kfree(buffer); + + /*4. firmware upgrade */ + dev_dbg(dev, "starting firmware upgrade, size: %zu bytes\n", fw->size); + + lt7911exc_block_erase(lt7911exc); + + ret = lt7911exc_write_data(lt7911exc, fw, 0); + if (ret < 0) { + dev_err(dev, "failed to write firmware data\n"); + goto out_release_fw; + } + + ret = lt7911exc_write_crc(lt7911exc, crc32, FW_SIZE - 4); + if (ret < 0) { + dev_err(dev, "failed to write firmware crc\n"); + goto out_release_fw; + } + + /*5. check upgrade of result*/ + lt7911exc_reset(lt7911exc); + + ret = lt7911exc_upgrade_result(lt7911exc, crc32); + +out_release_fw: + release_firmware(fw); + return ret; +} + +static void lt7911exc_atomic_pre_enable(struct drm_bridge *bridge, struct drm_atomic_state *state) +{ + struct lt7911exc *lt7911exc = bridge_to_lt7911exc(bridge); + int ret; + + ret = regulator_bulk_enable(ARRAY_SIZE(lt7911exc->supplies), lt7911exc->supplies); + if (ret) + return; + + lt7911exc_reset(lt7911exc); +} + +static void lt7911exc_atomic_disable(struct drm_bridge *bridge, struct drm_atomic_state *state) +{ + /* Delay after panel is disabled */ + msleep(20); +} + +static void lt7911exc_atomic_post_disable(struct drm_bridge *bridge, struct drm_atomic_state *state) +{ + struct lt7911exc *lt7911exc = bridge_to_lt7911exc(bridge); + int ret; + + ret = regulator_bulk_disable(ARRAY_SIZE(lt7911exc->supplies), lt7911exc->supplies); + if (ret) + return; + + gpiod_set_value_cansleep(lt7911exc->reset_gpio, 1); +} + +static int lt7911exc_attach(struct drm_bridge *bridge, + struct drm_encoder *encoder, + enum drm_bridge_attach_flags flags) +{ + struct lt7911exc *lt7911exc = bridge_to_lt7911exc(bridge); + + return drm_bridge_attach(lt7911exc->bridge.encoder, lt7911exc->bridge.next_bridge, + <7911exc->bridge, flags); +} + +static const struct drm_bridge_funcs lt7911exc_bridge_funcs = { + .attach = lt7911exc_attach, + .atomic_pre_enable = lt7911exc_atomic_pre_enable, + .atomic_disable = lt7911exc_atomic_disable, + .atomic_post_disable = lt7911exc_atomic_post_disable, +}; + +static int lt7911exc_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct lt7911exc *lt7911exc; + bool fw_updated = false; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { + dev_err(dev, "device doesn't support I2C\n"); + return -ENODEV; + } + + lt7911exc = devm_drm_bridge_alloc(dev, struct lt7911exc, bridge, + <7911exc_bridge_funcs); + if (IS_ERR(lt7911exc)) + return dev_err_probe(dev, PTR_ERR(lt7911exc), "drm bridge alloc failed.\n"); + + lt7911exc->bridge.next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0); + if (IS_ERR(lt7911exc->bridge.next_bridge)) + return PTR_ERR(lt7911exc->bridge.next_bridge); + + lt7911exc->client = client; + lt7911exc->dev = dev; + i2c_set_clientdata(client, lt7911exc); + + ret = devm_mutex_init(dev, <7911exc->ocm_lock); + if (ret) + return dev_err_probe(dev, ret, "failed to init mutex\n"); + + lt7911exc->regmap = devm_regmap_init_i2c(client, <7911exc_regmap_config); + if (IS_ERR(lt7911exc->regmap)) + return dev_err_probe(dev, PTR_ERR(lt7911exc->regmap), "regmap i2c init failed\n"); + + ret = lt7911exc_parse_dt(lt7911exc); + if (ret) + return ret; + + ret = regulator_bulk_enable(ARRAY_SIZE(lt7911exc->supplies), lt7911exc->supplies); + if (ret) + return ret; + + lt7911exc_reset(lt7911exc); + lt7911exc_lock(lt7911exc); + +retry: + lt7911exc->fw_version = lt7911exc_read_version(lt7911exc); + if (lt7911exc->fw_version < 0) { + dev_err(dev, "failed to read chip fw version\n"); + ret = -EOPNOTSUPP; + goto err_disable_regulators; + + } else if (lt7911exc->fw_version == 0) { + if (!fw_updated) { + fw_updated = true; + ret = lt7911exc_firmware_upgrade(lt7911exc); + if (ret < 0) + goto err_disable_regulators; + + goto retry; + + } else { + dev_err(dev, "fw version 0x%04x, update failed\n", lt7911exc->fw_version); + ret = -EOPNOTSUPP; + goto err_disable_regulators; + } + } + + lt7911exc_unlock(lt7911exc); + + lt7911exc->bridge.of_node = dev->of_node; + devm_drm_bridge_add(dev, <7911exc->bridge); + + return 0; + +err_disable_regulators: + lt7911exc_unlock(lt7911exc); + regulator_bulk_disable(ARRAY_SIZE(lt7911exc->supplies), lt7911exc->supplies); + return ret; +} + +static const struct i2c_device_id lt7911exc_i2c_table[] = { + {"lt7911exc"}, + {/* sentinel */} +}; + +MODULE_DEVICE_TABLE(i2c, lt7911exc_i2c_table); + +static const struct of_device_id lt7911exc_devices[] = { + {.compatible = "lontium,lt7911exc"}, + {/* sentinel */} +}; +MODULE_DEVICE_TABLE(of, lt7911exc_devices); + +static struct i2c_driver lt7911exc_driver = { + .id_table = lt7911exc_i2c_table, + .probe = lt7911exc_probe, + .driver = { + .name = "lt7911exc", + .of_match_table = lt7911exc_devices, + }, +}; +module_i2c_driver(lt7911exc_driver); + +MODULE_AUTHOR("SunYun Yang <[email protected]>"); +MODULE_DESCRIPTION("Lontium LT7911EXC EDP to MIPI DSI bridge driver"); +MODULE_LICENSE("GPL"); +MODULE_FIRMWARE(FW_FILE); -- 2.34.1
