From: Sunyun Yang <[email protected]> Add support for the Lontium LT7911EXC bridge chip, which converts eDP input to MIPI DSI output using an internal firmware-controlled pipeline.
The driver provides: - DRM bridge integration for eDP-to-DSI routing - MIPI DSI host interface for downstream panel attachment - Firmware upgrade mechanism over I2C (erase/program/verify) - GPIO-based reset and regulator management Display timing and MIPI DCS packet generation are handled by the chip firmware and are not configured by the driver. Signed-off-by: Sunyun Yang <[email protected]> --- drivers/gpu/drm/bridge/Kconfig | 17 + drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/lontium-lt7911exc.c | 784 +++++++++++++++++++++ 3 files changed, 802 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 4a57d49b4..ddf1143a6 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -132,6 +132,23 @@ config DRM_ITE_IT6505 help ITE IT6505 DisplayPort bridge chip driver. +config DRM_LONTIUM_LT7911EXC + tristate "Lontium LT7911EXC eDP/MIPI DSI bridge" + depends on OF + depends on I2C + select CRC32 + select DRM_PANEL_BRIDGE + select DRM_MIPI_DSI + select DRM_KMS_HELPER + select FW_LOADER + select REGMAP_I2C + select REGULATOR + help + DRM driver for the Lontium LT7911EXC bridge + chip. The LT7911EXC converts eDP input to 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 15cc821d8..e94def6c0 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 000000000..29df1183d --- /dev/null +++ b/drivers/gpu/drm/bridge/lontium-lt7911exc.c @@ -0,0 +1,784 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2026 Lontium Semiconductor, Inc. + */ +#include <linux/cleanup.h> +#include <linux/crc32.h> +#include <linux/delay.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/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/sizes.h> +#include <linux/slab.h> +#include <linux/sysfs.h> +#include <linux/workqueue.h> + +#include <drm/drm_atomic_helper.h> +#include <drm/drm_bridge.h> +#include <drm/drm_drv.h> +#include <drm/drm_mipi_dsi.h> +#include <drm/drm_of.h> +#include <drm/drm_probe_helper.h> +#include <video/mipi_display.h> + +#define FW_SIZE SZ_64K +#define LT_PAGE_SIZE 32 +#define FW_FILE "Lontium/lt7911exc_fw.bin" +#define LT7911EXC_PAGE_CONTROL 0xff + +struct lt7911exc { + struct device *dev; + struct regmap *regmap; + struct drm_bridge bridge; + struct work_struct work; + struct mipi_dsi_host dsi_host; + struct drm_bridge *output_bridge; + /* Fast lock: guards short register r/w and status checks */ + struct mutex ocm_lock; + /* Long lock: serializes firmware upgrade process to prevent DRM interference */ + struct mutex upgrade_lock; + struct gpio_desc *reset_gpio; + u32 fw_version; + bool upgrade; + bool removed; +}; + +static const struct regmap_range_cfg lt7911exc_range_cfg[] = { + { + .name = "lt7911exc_i2c", + .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_range_cfg, + .num_ranges = ARRAY_SIZE(lt7911exc_range_cfg), + .cache_type = REGCACHE_NONE, +}; + +static u32 cal_crc32_custom(const u8 *data, u64 length) +{ + u32 crc = 0xffffffff; + u8 buf[4]; + u64 i; + + if (!length || (length & 3)) + return 0; + + 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 inline struct lt7911exc *dsi_host_to_lt7911exc(struct mipi_dsi_host *host) +{ + return container_of(host, struct lt7911exc, dsi_host); +} + +static void lt7911exc_reset(struct lt7911exc *lt7911exc) +{ + /* Assert reset pin: logical 1 -> physical state low (Reset Active) */ + gpiod_set_value_cansleep(lt7911exc->reset_gpio, 1); + usleep_range(5000, 6000); + + /* Deassert reset pin: logical 0 -> physical state high (Run state) */ + gpiod_set_value_cansleep(lt7911exc->reset_gpio, 0); + msleep(400); +} + +static int lt7911exc_inside_mcu_stop(struct lt7911exc *lt7911exc) +{ + int ret = regmap_write(lt7911exc->regmap, 0xe0ee, 0x01); + + if (ret) + dev_err(lt7911exc->dev, "Failed to stop mcu\n"); + + return ret; +} + +static int lt7911exc_inside_mcu_run(struct lt7911exc *lt7911exc) +{ + int ret = regmap_write(lt7911exc->regmap, 0xe0ee, 0x00); + + if (ret) + dev_err(lt7911exc->dev, "Failed to run mcu\n"); + + return ret; +} + +static int lt7911exc_regulator_init(struct lt7911exc *lt7911exc) +{ + int ret; + + ret = devm_regulator_get_enable(lt7911exc->dev, "vcc"); + if (ret < 0) + return dev_err_probe(lt7911exc->dev, ret, "failed to enable vcc regulator\n"); + + usleep_range(5000, 6000); + + ret = devm_regulator_get_enable(lt7911exc->dev, "vdd"); + if (ret < 0) + return dev_err_probe(lt7911exc->dev, ret, "failed to enable vdd regulator\n"); + + return 0; +} + +static int lt7911exc_read_version(struct lt7911exc *lt7911exc, u32 *val) +{ + struct device *dev = lt7911exc->dev; + int ret; + u8 version[3]; + + /* version register is accessible without stopping MCU */ + ret = regmap_bulk_read(lt7911exc->regmap, 0xe081, version, ARRAY_SIZE(version)); + if (ret) { + dev_err(dev, "Failed to read version\n"); + return ret; + } + + *val = (u32)version[0] << 16 | (u32)version[1] << 8 | version[2]; + + return 0; +} + +/* after erase, all data in the flash is 0xff */ +static int lt7911exc_block_erase(struct lt7911exc *lt7911exc) +{ + struct device *dev = lt7911exc->dev; + const u32 addr = 0x00; + int ret; + + 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), + }; + + ret = regmap_multi_reg_write(lt7911exc->regmap, seq_write, ARRAY_SIZE(seq_write)); + if (ret) { + dev_err(dev, "Failed to erase flash.\n"); + return ret; + } + + /* hardware need delay 200ms */ + msleep(200); + + return 0; +} + +static int lt7911exc_prog_init(struct lt7911exc *lt7911exc, u64 addr) +{ + struct device *dev = lt7911exc->dev; + int ret; + + 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), + }; + + ret = regmap_multi_reg_write(lt7911exc->regmap, seq_write, ARRAY_SIZE(seq_write)); + if (ret) { + dev_err(dev, "Failed programe init.\n"); + return ret; + } + + return 0; +} + +/* + * Hardware Flash Erase Behavior Note: + * The LT7911EXC hardware erases the entire flash area into a default state of 0xff. + * When doing a partial page short write (where fw->size is not aligned to a 32-byte + * page boundary), the total unwritten residual bytes on the physical flash sector inherently + * retain their 0xff state. + * Therefore, raw physical short-write transmission is perfectly clean and matches the 0xff padded + * software calculated CRC32. No software-side buffer padding is required. + */ +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; + } + + for (num = 0; num < page; num++) { + offset = num * LT_PAGE_SIZE; + page_len = (offset + LT_PAGE_SIZE <= size) ? LT_PAGE_SIZE : (size - offset); + ret = lt7911exc_prog_init(lt7911exc, addr); + if (ret) + return ret; + + 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; + } + + /* write method for less than LT_PAGE_SIZE bytes */ + if (page_len < LT_PAGE_SIZE) { + ret = regmap_write(lt7911exc->regmap, 0xe05f, 0x05); + if (ret) + return ret; + + ret = regmap_write(lt7911exc->regmap, 0xe05f, 0x01); + if (ret) + return ret; + + /* hardware requires delay */ + usleep_range(1000, 2000); + } + + ret = regmap_write(lt7911exc->regmap, 0xe05f, 0x00); + if (ret) + return ret; + + addr += LT_PAGE_SIZE; + } + + return 0; +} + +static int lt7911exc_write_crc(struct lt7911exc *lt7911exc, u32 crc32, u64 addr) +{ + struct device *dev = lt7911exc->dev; + int ret; + + const struct reg_sequence seq_write[] = { + REG_SEQ0(0xe05f, 0x01), + REG_SEQ0(0xe05a, (addr >> 16) & 0xff), + REG_SEQ0(0xe05b, (addr >> 8) & 0xff), + REG_SEQ0(0xe05c, addr & 0xff), + REG_SEQ0(0xe05d, crc32 & 0xff), + REG_SEQ0(0xe05d, (crc32 >> 8) & 0xff), + REG_SEQ0(0xe05d, (crc32 >> 16) & 0xff), + REG_SEQ0(0xe05d, (crc32 >> 24) & 0xff), + REG_SEQ0(0xe05f, 0x05), + REG_SEQ(0xe05f, 0x01, 1000), /* hardware requires delay */ + REG_SEQ0(0xe05f, 0x00), + }; + + ret = regmap_multi_reg_write(lt7911exc->regmap, seq_write, ARRAY_SIZE(seq_write)); + if (ret) { + dev_err(dev, "Failed to write crc\n"); + return ret; + } + + return 0; +} + +static int lt7911exc_upgrade_result(struct lt7911exc *lt7911exc, u32 crc32) +{ + struct device *dev = lt7911exc->dev; + u32 read_hw_crc; + u8 crc_tmp[4]; + int ret; + + const struct reg_sequence seq_write[] = { + REG_SEQ0(0xe0ee, 0x01), + REG_SEQ0(0xe07b, 0x60), + REG_SEQ0(0xe07b, 0x40), + }; + + ret = regmap_multi_reg_write(lt7911exc->regmap, seq_write, ARRAY_SIZE(seq_write)); + if (ret) { + dev_err(dev, "Failed to setup CRC read\n"); + return ret; + } + + msleep(150); + + ret = regmap_bulk_read(lt7911exc->regmap, 0x22, crc_tmp, ARRAY_SIZE(crc_tmp)); + if (ret) { + dev_err(dev, "Failed to read CRC: %d\n", ret); + return ret; + } + + ret = regmap_write(lt7911exc->regmap, 0xe0ee, 0x00); + if (ret) { + dev_err(dev, "Failed to restore MCU state\n"); + return ret; + } + + read_hw_crc = ((u32)crc_tmp[0] << 24) | ((u32)crc_tmp[1] << 16) | + ((u32)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; + } + + return 0; +} + +static void lt7911exc_firmware_upgrade_work(struct work_struct *work) +{ + struct lt7911exc *lt7911exc = container_of(work, struct lt7911exc, work); + struct device *dev = lt7911exc->dev; + const struct firmware *fw; + u8 *buffer; + size_t total_size = FW_SIZE - 4; + u32 crc32, version; + int ret; + + mutex_lock(<7911exc->upgrade_lock); + if (lt7911exc->removed) + goto out_unlock_upgrade; + + ret = request_firmware(&fw, FW_FILE, dev); + if (ret) { + dev_err(dev, "failed to load '%s'\n", FW_FILE); + goto out_unlock_upgrade; + } + + if (fw->size > total_size) { + dev_err(dev, "firmware too large (%zu > %zu)\n", fw->size, total_size); + goto out_release_fw; + } + + buffer = kvmalloc(total_size, GFP_KERNEL); + if (!buffer) + goto out_release_fw; + + memset(buffer, 0xff, total_size); + memcpy(buffer, fw->data, fw->size); + crc32 = cal_crc32_custom(buffer, total_size); + kvfree(buffer); + + lt7911exc_reset(lt7911exc); + + scoped_guard(mutex, <7911exc->ocm_lock) { + ret = lt7911exc_inside_mcu_stop(lt7911exc); + } + if (ret) + goto out_release_fw; + + ret = lt7911exc_block_erase(lt7911exc); + if (ret) { + dev_err(dev, "failed to block erase.\n"); + goto out_mcu_run; + } + + ret = lt7911exc_write_data(lt7911exc, fw, 0); + if (ret < 0) { + dev_err(dev, "failed to write firmware data\n"); + goto out_mcu_run; + } + + ret = lt7911exc_write_crc(lt7911exc, crc32, FW_SIZE - 4); + if (ret < 0) { + dev_err(dev, "failed to write firmware crc\n"); + goto out_mcu_run; + } + + lt7911exc_reset(lt7911exc); + + ret = lt7911exc_upgrade_result(lt7911exc, crc32); + if (ret) + dev_err(dev, "firmware verification failed\n"); + + /* + * Always restore MCU to running state: flash is already erased, + * leaving MCU stopped would render the chip completely unusable. + */ + scoped_guard(mutex, <7911exc->ocm_lock) { + ret = lt7911exc_inside_mcu_run(lt7911exc); + if (!ret) { + ret = lt7911exc_read_version(lt7911exc, &version); + if (!ret) + lt7911exc->fw_version = version; + } + } + + if (ret) + dev_err(dev, "failed to read version after upgrade\n"); + + goto out_release_fw; + +out_mcu_run: + scoped_guard(mutex, <7911exc->ocm_lock) + lt7911exc_inside_mcu_run(lt7911exc); + +out_release_fw: + release_firmware(fw); + +out_unlock_upgrade: + scoped_guard(mutex, <7911exc->ocm_lock) { + if (!lt7911exc->removed) + lt7911exc->upgrade = false; + } + + /* Notify DRM to re-trigger modeset after firmware upgrade */ + if (!lt7911exc->removed && lt7911exc->bridge.dev) + drm_kms_helper_hotplug_event(lt7911exc->bridge.dev); + + mutex_unlock(<7911exc->upgrade_lock); +} + +static void lt7911exc_atomic_pre_enable(struct drm_bridge *bridge, struct drm_atomic_commit *state) +{ + struct lt7911exc *lt7911exc = bridge_to_lt7911exc(bridge); + struct device *dev = lt7911exc->dev; + int ret; + + guard(mutex)(<7911exc->ocm_lock); + + if (!lt7911exc->upgrade) { + ret = regmap_write(lt7911exc->regmap, 0xe0b0, 0x01); + if (ret) + dev_err(dev, "failed to enable mipi output stream\n"); + } +} + +static void lt7911exc_atomic_post_disable(struct drm_bridge *bridge, + struct drm_atomic_commit *state) +{ + struct lt7911exc *lt7911exc = bridge_to_lt7911exc(bridge); + struct device *dev = lt7911exc->dev; + int ret; + + guard(mutex)(<7911exc->ocm_lock); + + if (!lt7911exc->upgrade) { + ret = regmap_write(lt7911exc->regmap, 0xe0b0, 0x00); + if (ret) + dev_err(dev, "failed to disable mipi output stream\n"); + } +} + +static int lt7911exc_bridge_attach(struct drm_bridge *bridge, + struct drm_encoder *encoder, + enum drm_bridge_attach_flags flags) +{ + struct lt7911exc *lt7911exc = bridge_to_lt7911exc(bridge); + + if (!drm_core_check_feature(bridge->dev, DRIVER_ATOMIC)) { + dev_err(lt7911exc->dev, "needs atomic updates support\n"); + return -ENOTSUPP; + } + + return drm_bridge_attach(encoder, lt7911exc->output_bridge, bridge, flags); +} + +static const struct drm_bridge_funcs lt7911exc_bridge_funcs = { + .attach = lt7911exc_bridge_attach, + .atomic_pre_enable = lt7911exc_atomic_pre_enable, + .atomic_post_disable = lt7911exc_atomic_post_disable, + .atomic_reset = drm_atomic_helper_bridge_reset, + .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state, + .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state, +}; + +static int lt7911exc_dsi_host_attach(struct mipi_dsi_host *host, struct mipi_dsi_device *dev) +{ + struct lt7911exc *lt7911exc = dsi_host_to_lt7911exc(host); + struct drm_bridge *bridge; + + /* currently do not support connecting several DSI devices to the same host */ + if (lt7911exc->output_bridge) + return -EBUSY; + + if (dev->lanes > 4) { + dev_err(lt7911exc->dev, "unsupported number of data lanes(%u)\n", dev->lanes); + return -EINVAL; + } + + bridge = devm_drm_of_get_bridge(lt7911exc->dev, host->dev->of_node, 1, 0); + if (IS_ERR(bridge)) { + dev_err(lt7911exc->dev, "failed to add DSI device\n"); + return PTR_ERR(bridge); + } + + lt7911exc->output_bridge = bridge; + + /* + * Force panel-first enable order: the DSI output stream (0xe0b0) + * must not be enabled before the panel is powered on. + * This override is safe because LT7911EXC's transfer() is a stub — + * panel DCS commands are silently discarded and panel init is done + * by the chip's internal firmware. The panel driver's + * prepare_prev_first preference is therefore irrelevant here. + */ + lt7911exc->output_bridge->pre_enable_prev_first = false; + + drm_bridge_add(<7911exc->bridge); + + return 0; +} + +static int lt7911exc_dsi_host_detach(struct mipi_dsi_host *host, struct mipi_dsi_device *dev) +{ + struct lt7911exc *lt7911exc = dsi_host_to_lt7911exc(host); + + drm_bridge_remove(<7911exc->bridge); + + return 0; +} + +/* + * LT7911EXC's internal MCU owns the DSI link and handles all panel + * initialization. The host transfer() is a no-op sink: accept the + * message and report it as sent so the panel driver does not abort + * its init sequence. Actual DSI transmission is done by chip firmware. + */ +static ssize_t lt7911exc_dsi_host_transfer(struct mipi_dsi_host *host, + const struct mipi_dsi_msg *msg) +{ + struct lt7911exc *lt7911exc = dsi_host_to_lt7911exc(host); + + if (msg->rx_len) { + dev_warn(lt7911exc->dev, "MIPI rx is not supported\n"); + return -EOPNOTSUPP; + } + + switch (msg->type) { + case MIPI_DSI_DCS_SHORT_WRITE: + case MIPI_DSI_DCS_SHORT_WRITE_PARAM: + case MIPI_DSI_DCS_LONG_WRITE: + case MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM: + case MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM: + case MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM: + case MIPI_DSI_GENERIC_LONG_WRITE: + break; + default: + return -EOPNOTSUPP; + } + + guard(mutex)(<7911exc->ocm_lock); + + if (lt7911exc->upgrade) + return -EBUSY; + + return msg->tx_len; +} + +static const struct mipi_dsi_host_ops lt7911exc_dsi_host_ops = { + .attach = lt7911exc_dsi_host_attach, + .detach = lt7911exc_dsi_host_detach, + .transfer = lt7911exc_dsi_host_transfer, +}; + +static ssize_t lt7911exc_firmware_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct lt7911exc *lt7911exc = dev_get_drvdata(dev); + bool lt7911exc_busy = true; + + if (!lt7911exc) + return -ENODEV; + + if (!mutex_trylock(<7911exc->upgrade_lock)) + return -EBUSY; + + scoped_guard(mutex, <7911exc->ocm_lock) { + if (!lt7911exc->upgrade && !lt7911exc->removed) { + lt7911exc->upgrade = true; + lt7911exc_busy = false; + } + } + mutex_unlock(<7911exc->upgrade_lock); + + if (lt7911exc_busy) + return -EBUSY; + + schedule_work(<7911exc->work); + + return len; +} + +static ssize_t lt7911exc_firmware_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct lt7911exc *lt7911exc = dev_get_drvdata(dev); + u32 version; + + if (!lt7911exc) + return -ENODEV; + + guard(mutex)(<7911exc->ocm_lock); + version = lt7911exc->fw_version; + + return sysfs_emit(buf, "0x%04x\n", version); +} + +static DEVICE_ATTR_RW(lt7911exc_firmware); + +static struct attribute *lt7911exc_attrs[] = { + &dev_attr_lt7911exc_firmware.attr, + NULL, +}; + +static const struct attribute_group lt7911exc_attr_group = { + .attrs = lt7911exc_attrs, +}; + +static const struct attribute_group *lt7911exc_attr_groups[] = { + <7911exc_attr_group, + NULL, +}; + +static int lt7911exc_probe(struct i2c_client *client) +{ + struct lt7911exc *lt7911exc; + struct device *dev = &client->dev; + struct device_node *np = dev->of_node; + u32 version; + int ret; + + if (!np) + return -ENODEV; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return dev_err_probe(dev, -ENODEV, "device doesn't support I2C\n"); + + 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"); + + dev_set_drvdata(dev, lt7911exc); + + lt7911exc->dev = dev; + lt7911exc->upgrade = false; + lt7911exc->removed = false; + + ret = devm_mutex_init(dev, <7911exc->ocm_lock); + if (ret) + return dev_err_probe(dev, ret, "failed to init mutex\n"); + + ret = devm_mutex_init(dev, <7911exc->upgrade_lock); + if (ret) + return dev_err_probe(dev, ret, "failed to init upgrade_lock\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"); + + /* DT reset pin Active-low: assert (logical 1) to hold chip in reset */ + lt7911exc->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(lt7911exc->reset_gpio)) + return dev_err_probe(dev, PTR_ERR(lt7911exc->reset_gpio), + "failed to acquire reset gpio\n"); + + ret = lt7911exc_regulator_init(lt7911exc); + if (ret) + return ret; + + lt7911exc_reset(lt7911exc); + + scoped_guard(mutex, <7911exc->ocm_lock) + ret = lt7911exc_read_version(lt7911exc, &version); + + if (ret < 0) + return dev_err_probe(dev, ret, "failed read version of chip\n"); + + lt7911exc->fw_version = version; + + lt7911exc->dsi_host.dev = dev; + lt7911exc->dsi_host.ops = <7911exc_dsi_host_ops; + lt7911exc->bridge.of_node = np; + + INIT_WORK(<7911exc->work, lt7911exc_firmware_upgrade_work); + + ret = mipi_dsi_host_register(<7911exc->dsi_host); + if (ret) + return ret; + + return 0; +} + +static void lt7911exc_remove(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct lt7911exc *lt7911exc = dev_get_drvdata(dev); + + if (!lt7911exc) + return; + + scoped_guard(mutex, <7911exc->ocm_lock) { + lt7911exc->removed = true; + lt7911exc->upgrade = true; + } + + cancel_work_sync(<7911exc->work); + + dev_set_drvdata(dev, NULL); + + mipi_dsi_host_unregister(<7911exc->dsi_host); + + gpiod_set_value_cansleep(lt7911exc->reset_gpio, 1); +} + +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, + .remove = lt7911exc_remove, + .driver = { + .name = "lt7911exc", + .of_match_table = lt7911exc_devices, + .dev_groups = lt7911exc_attr_groups, + }, +}; +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
