[RFC 05/11] drm/bridge: Analogix ANX7688 HDMI -> DP bridge driver
Ulrich Hecht
ulrich.hecht+renesas at gmail.com
Fri Sep 29 06:09:07 PDT 2017
Ported from chromeos-3.18.
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas at gmail.com>
---
drivers/gpu/drm/bridge/Kconfig | 9 ++
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/analogix-anx7688.c | 233 ++++++++++++++++++++++++++++++
3 files changed, 243 insertions(+)
create mode 100644 drivers/gpu/drm/bridge/analogix-anx7688.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index a1c0d95..712ac0a 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -38,6 +38,15 @@ config DRM_PARADE_PS8640
The PS8640 is a high-performance and low-power
MIPI DSI to eDP converter
+config DRM_ANALOGIX_ANX7688
+ tristate "Analogix ANX7688 bridge"
+ depends on DRM
+ select DRM_KMS_HELPER
+ ---help---
+ ANX7688 is a transmitter to support DisplayPort over USB-C for
+ smartphone and tablets.
+ This driver only supports the HDMI to DP component of the chip.
+
config DRM_ANALOGIX_ANX78XX
tristate "Analogix ANX78XX bridge"
select DRM_KMS_HELPER
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 6be8a9d..9cbf788 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -1,6 +1,7 @@
ccflags-y := -Iinclude/drm
obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
+obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o
obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
obj-$(CONFIG_DRM_GENERIC_GPIO_MUX) += generic-gpio-mux.o
obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
diff --git a/drivers/gpu/drm/bridge/analogix-anx7688.c b/drivers/gpu/drm/bridge/analogix-anx7688.c
new file mode 100644
index 0000000..cc995c8
--- /dev/null
+++ b/drivers/gpu/drm/bridge/analogix-anx7688.c
@@ -0,0 +1,233 @@
+/*
+ * ANX7688 HDMI->DP bridge driver
+ *
+ * Copyright (C) 2016 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <drm/drm_crtc.h>
+
+/* Register addresses */
+#define VENDOR_ID_REG 0x00
+#define DEVICE_ID_REG 0x02
+
+#define FW_VERSION_REG 0x80
+
+#define DP_BANDWIDTH_REG 0x85
+#define DP_LANE_COUNT_REG 0x86
+
+#define VENDOR_ID 0x1f29
+#define DEVICE_ID 0x7688
+
+/* First supported firmware version (0.85) */
+#define MINIMUM_FW_VERSION 0x0085
+
+struct anx7688 {
+ struct drm_bridge bridge;
+ struct i2c_client *client;
+
+ bool filter;
+};
+
+static int anx7688_read(struct i2c_client *client, u8 reg, u8 *data,
+ u16 data_len)
+{
+ int ret;
+ struct i2c_msg msgs[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = ®,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = data_len,
+ .buf = data,
+ }
+ };
+
+ ret = i2c_transfer(client->adapter, msgs, 2);
+
+ if (ret == 2)
+ return 0;
+ if (ret < 0)
+ return ret;
+ else
+ return -EIO;
+}
+
+static inline struct anx7688 *bridge_to_anx7688(struct drm_bridge *bridge)
+{
+ return container_of(bridge, struct anx7688, bridge);
+}
+
+static bool anx7688_bridge_mode_fixup(struct drm_bridge *bridge,
+ const struct drm_display_mode *mode,
+ struct drm_display_mode *adjusted_mode)
+{
+ struct anx7688 *anx7688 = bridge_to_anx7688(bridge);
+ u8 regs[2];
+ u8 dpbw, lanecount;
+ int totalbw, requiredbw;
+ int ret;
+
+ if (!anx7688->filter)
+ return true;
+
+ /* Read both regs 0x85 (bandwidth) and 0x86 (lane count). */
+ ret = anx7688_read(anx7688->client, DP_BANDWIDTH_REG, regs, 2);
+ if (ret < 0) {
+ dev_err(&anx7688->client->dev,
+ "Failed to read bandwidth/lane count\n");
+ return false;
+ }
+ dpbw = regs[0];
+ lanecount = regs[1];
+
+ /* Maximum 0x19 bandwidth (6.75 Gbps Turbo mode), 2 lanes */
+ if (dpbw > 0x19 || lanecount > 2) {
+ dev_err(&anx7688->client->dev,
+ "Invalid bandwidth/lane count (%02x/%d)\n",
+ dpbw, lanecount);
+ return false;
+ }
+
+ /* Compute available bandwidth (kHz) */
+ totalbw = dpbw * lanecount * 270000 * 8 / 10;
+
+ /* Required bandwidth (8 bpc, kHz) */
+ requiredbw = mode->clock * 8 * 3;
+
+ dev_dbg(&anx7688->client->dev,
+ "DP bandwidth: %d kHz (%02x/%d); mode requires %d Khz\n",
+ totalbw, dpbw, lanecount, requiredbw);
+
+ if (totalbw == 0) {
+ dev_warn(&anx7688->client->dev,
+ "Bandwidth/lane count are 0, not rejecting modes\n");
+ return true;
+ }
+
+ return totalbw >= requiredbw;
+}
+
+static const struct drm_bridge_funcs anx7688_bridge_funcs = {
+ .mode_fixup = anx7688_bridge_mode_fixup,
+};
+
+static int anx7688_i2c_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct anx7688 *anx7688;
+ int ret;
+ u8 buffer[4];
+ u16 vendor, device, fwversion;
+
+ anx7688 = devm_kzalloc(&client->dev, sizeof(*anx7688), GFP_KERNEL);
+ if (!anx7688)
+ return -ENOMEM;
+
+#if IS_ENABLED(CONFIG_OF)
+ anx7688->bridge.of_node = client->dev.of_node;
+#endif
+
+ anx7688->client = client;
+ i2c_set_clientdata(client, anx7688);
+
+ /* Read both vendor and device id (4 bytes). */
+ ret = anx7688_read(client, VENDOR_ID_REG, buffer, 4);
+ if (ret) {
+ dev_err(&client->dev, "Failed to read chip vendor/device id\n");
+ return ret;
+ }
+
+ vendor = (u16)buffer[1] << 8 | buffer[0];
+ device = (u16)buffer[3] << 8 | buffer[2];
+ if (vendor != VENDOR_ID || device != DEVICE_ID) {
+ dev_err(&client->dev,
+ "Invalid vendor/device id %04x/%04x\n",
+ vendor, device);
+ return -ENODEV;
+ }
+
+ ret = anx7688_read(client, FW_VERSION_REG, buffer, 2);
+ if (ret) {
+ dev_err(&client->dev, "Failed to read firmware version\n");
+ return ret;
+ }
+
+ fwversion = (u16)buffer[0] << 8 | buffer[1];
+ dev_info(&client->dev, "ANX7688 firwmare version %02x.%02x\n",
+ buffer[0], buffer[1]);
+
+ /* FW version >= 0.85 supports bandwidth/lane count registers */
+ if (fwversion >= MINIMUM_FW_VERSION) {
+ anx7688->filter = true;
+ } else {
+ /* Warn, but not fail, for backwards compatibility. */
+ dev_warn(&client->dev,
+ "Old ANX7688 FW version (%02x.%02x), not filtering\n",
+ buffer[0], buffer[1]);
+ }
+
+ anx7688->bridge.funcs = &anx7688_bridge_funcs;
+ ret = drm_bridge_add(&anx7688->bridge);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failed to add drm bridge\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int anx7688_i2c_remove(struct i2c_client *client)
+{
+ struct anx7688 *anx7688 = i2c_get_clientdata(client);
+
+ drm_bridge_remove(&anx7688->bridge);
+
+ return 0;
+}
+
+static const struct i2c_device_id anx7688_id[] = {
+ { "anx7688", 0 },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(i2c, anx7688_id);
+
+#if IS_ENABLED(CONFIG_OF)
+static const struct of_device_id anx7688_match_table[] = {
+ { .compatible = "analogix,anx7688", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, anx7688_match_table);
+#endif
+
+static struct i2c_driver anx7688_driver = {
+ .driver = {
+ .name = "anx7688",
+ .of_match_table = of_match_ptr(anx7688_match_table),
+ },
+ .probe = anx7688_i2c_probe,
+ .remove = anx7688_i2c_remove,
+ .id_table = anx7688_id,
+};
+
+module_i2c_driver(anx7688_driver);
+
+MODULE_DESCRIPTION("ANX7688 SlimPort Transmitter driver");
+MODULE_AUTHOR("Nicolas Boichat <drinkcat at chromium.org>");
+MODULE_LICENSE("GPL v2");
--
2.7.4
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