[PATCH V2 3/4] drm/bridge: Drivers for megachips-stdpxxxx-ge-b850v3-fw (LVDS-DP++)
Archit Taneja
architt at codeaurora.org
Tue Feb 28 20:08:48 PST 2017
On 02/28/2017 07:58 PM, Peter Senna Tschudin wrote:
> The video processing pipeline on the second output on the GE B850v3:
>
> Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
>
> Each bridge has a dedicated flash containing firmware for supporting the
> custom design. The result is that in this design neither the STDP4028
> nor the STDP2690 behave as the stock bridges would. The compatible
> strings include the suffix "-ge-b850v3-fw" to make it clear that the
> driver is for the bridges with the firmware which is specific for the GE
> B850v3.
>
> The driver is powerless to control the video processing pipeline, as the
> two bridges behaves as a single one. The driver is only needed for
> telling the host about EDID / HPD, and for giving the host powers to ack
> interrupts.
>
> This driver adds one i2c_device for each bridge, but only one
> drm_bridge. This design allows the creation of a functional connector
> that is capable of reading EDID from the STDP2690 while handling
> interrupts on the STDP4028.
>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Cc: Martyn Welch <martyn.welch at collabora.co.uk>
> Cc: Martin Donnelly <martin.donnelly at ge.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Enric Balletbo i Serra <enric.balletbo at collabora.com>
> Cc: Philipp Zabel <p.zabel at pengutronix.de>
> Cc: Rob Herring <robh at kernel.org>
> Cc: Fabio Estevam <fabio.estevam at nxp.com>
> Cc: David Airlie <airlied at linux.ie>
> Cc: Thierry Reding <treding at nvidia.com>
> Cc: Thierry Reding <thierry.reding at gmail.com>
> Cc: Archit Taneja <architt at codeaurora.org>
> Cc: Enric Balletbo <enric.balletbo at collabora.com>
> Signed-off-by: Peter Senna Tschudin <peter.senna at collabora.com>
> ---
> Changes from V1:
> - Updated copyright year
> - Fixed blank line issues
> - Updated ge_b850v3_lvds_remove() to not rely on ge_b850v3_lvds_ptr->edid and
> added a comment to explain the test.
> - Fixed checkpatch strict warnings about continuation lines. In one case
> fixing the warning would cause the continuation line to be over 80 chars and
> that strict warning remains.
>
> drivers/gpu/drm/bridge/Kconfig | 11 +
> drivers/gpu/drm/bridge/Makefile | 1 +
> .../drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c | 411 +++++++++++++++++++++
> 3 files changed, 423 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index eb8688e..4a937f1 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -48,6 +48,17 @@ config DRM_DW_HDMI_I2S_AUDIO
> Support the I2S Audio interface which is part of the Synopsis
> Designware HDMI block.
>
> +config DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW
> + tristate "MegaChips stdp4028-ge-b850v3-fw and stdp2690-ge-b850v3-fw"
> + depends on OF
> + select DRM_KMS_HELPER
> + select DRM_PANEL
> + ---help---
> + This is a driver for the display bridges of
> + GE B850v3 that convert dual channel LVDS
> + to DP++. This is used with the i.MX6 imx-ldb
> + driver. You are likely to say N here.
> +
> config DRM_NXP_PTN3460
> tristate "NXP PTN3460 DP/LVDS bridge"
> depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 2e83a785..af0b7cc 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o
> obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
> obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
> obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
> +obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
> obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
> obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
> obj-$(CONFIG_DRM_SIL_SII8620) += sil-sii8620.o
> diff --git a/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> new file mode 100644
> index 0000000..6f82a44
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
> @@ -0,0 +1,411 @@
> +/*
> + * Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP)
> + * Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++)
> +
> + * Copyright (c) 2017, Collabora Ltd.
> + * Copyright (c) 2017, General Electric Company
> +
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> +
> + * This program is distributed in the hope 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.
> +
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> +
> + * This driver creates a drm_bridge and a drm_connector for the LVDS to DP++
> + * display bridge of the GE B850v3. There are two physical bridges on the video
> + * signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The
> + * physical bridges are automatically configured by the input video signal, and
> + * the driver has no access to the video processing pipeline. The driver is
> + * only needed to read EDID from the STDP2690 and to handle HPD events from the
> + * STDP4028. The driver communicates with both bridges over i2c. The video
> + * signal pipeline is as follows:
> + *
> + * Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
> + *
> + */
> +
> +#include <linux/gpio.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_edid.h>
> +#include <drm/drmP.h>
> +
> +#define EDID_EXT_BLOCK_CNT 0x7E
> +
> +#define STDP4028_IRQ_OUT_CONF_REG 0x02
> +#define STDP4028_DPTX_IRQ_EN_REG 0x3C
> +#define STDP4028_DPTX_IRQ_STS_REG 0x3D
> +#define STDP4028_DPTX_STS_REG 0x3E
> +
> +#define STDP4028_DPTX_DP_IRQ_EN 0x1000
> +
> +#define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400
> +#define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000
> +#define STDP4028_DPTX_IRQ_CONFIG \
> + (STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN)
> +
> +#define STDP4028_DPTX_HOTPLUG_STS 0x0200
> +#define STDP4028_DPTX_LINK_STS 0x1000
> +#define STDP4028_CON_STATE_CONNECTED \
> + (STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS)
> +
> +#define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400
> +#define STDP4028_DPTX_LINK_CH_STS 0x2000
> +#define STDP4028_DPTX_IRQ_CLEAR \
> + (STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS)
> +
> +static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
> +
> +struct ge_b850v3_lvds {
> + struct drm_connector connector;
> + struct drm_bridge bridge;
> + struct i2c_client *stdp4028_i2c;
> + struct i2c_client *stdp2690_i2c;
> + struct edid *edid;
> +};
> +
> +static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
> +
> +u8 *stdp2690_get_edid(struct i2c_client *client)
> +{
> + struct i2c_adapter *adapter = client->adapter;
> + unsigned char start = 0x00;
> + unsigned int total_size;
> + u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL);
> +
> + struct i2c_msg msgs[] = {
> + {
> + .addr = client->addr,
> + .flags = 0,
> + .len = 1,
> + .buf = &start,
> + }, {
> + .addr = client->addr,
> + .flags = I2C_M_RD,
> + .len = EDID_LENGTH,
> + .buf = block,
> + }
> + };
> +
> + if (!block)
> + return NULL;
> +
> + if (i2c_transfer(adapter, msgs, 2) != 2) {
> + DRM_ERROR("Unable to read EDID.\n");
> + goto err;
> + }
> +
> + if (!drm_edid_block_valid(block, 0, false, NULL)) {
> + DRM_ERROR("Invalid EDID data\n");
> + goto err;
> + }
> +
> + total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
> + if (total_size > EDID_LENGTH) {
> + kfree(block);
> + block = kmalloc(total_size, GFP_KERNEL);
> + if (!block)
> + return NULL;
> +
> + /* Yes, read the entire buffer, and do not skip the first
> + * EDID_LENGTH bytes.
> + */
> + start = 0x00;
> + msgs[1].len = total_size;
> + msgs[1].buf = block;
> +
> + if (i2c_transfer(adapter, msgs, 2) != 2) {
> + DRM_ERROR("Unable to read EDID extension blocks.\n");
> + goto err;
> + }
> + if (!drm_edid_block_valid(block, 1, false, NULL)) {
> + DRM_ERROR("Invalid EDID data\n");
> + goto err;
> + }
> + }
> +
> + return block;
> +
> +err:
> + kfree(block);
> + return NULL;
> +}
> +
> +static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
> +{
> + struct i2c_client *client;
> + int num_modes = 0;
> +
> + client = ge_b850v3_lvds_ptr->stdp2690_i2c;
> +
> + kfree(ge_b850v3_lvds_ptr->edid);
> + ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client);
> +
> + if (ge_b850v3_lvds_ptr->edid) {
> + drm_mode_connector_update_edid_property(connector,
> + ge_b850v3_lvds_ptr->edid);
> + num_modes = drm_add_edid_modes(connector,
> + ge_b850v3_lvds_ptr->edid);
> + }
> +
> + return num_modes;
> +}
> +
> +static enum drm_mode_status ge_b850v3_lvds_mode_valid(
> + struct drm_connector *connector, struct drm_display_mode *mode)
> +{
> + return MODE_OK;
> +}
> +
> +static const struct
> +drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
> + .get_modes = ge_b850v3_lvds_get_modes,
> + .mode_valid = ge_b850v3_lvds_mode_valid,
> +};
> +
> +static enum drm_connector_status ge_b850v3_lvds_detect(
> + struct drm_connector *connector, bool force)
> +{
> + struct i2c_client *stdp4028_i2c =
> + ge_b850v3_lvds_ptr->stdp4028_i2c;
> + s32 link_state;
> +
> + link_state = i2c_smbus_read_word_data(stdp4028_i2c,
> + STDP4028_DPTX_STS_REG);
> +
> + if (link_state == STDP4028_CON_STATE_CONNECTED)
> + return connector_status_connected;
> +
> + if (link_state == 0)
> + return connector_status_disconnected;
> +
> + return connector_status_unknown;
> +}
> +
> +static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
> + .dpms = drm_atomic_helper_connector_dpms,
> + .fill_modes = drm_helper_probe_single_connector_modes,
> + .detect = ge_b850v3_lvds_detect,
> + .destroy = drm_connector_cleanup,
> + .reset = drm_atomic_helper_connector_reset,
> + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +};
> +
> +static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
> +{
> + struct i2c_client *stdp4028_i2c
> + = ge_b850v3_lvds_ptr->stdp4028_i2c;
> +
> + i2c_smbus_write_word_data(stdp4028_i2c,
> + STDP4028_DPTX_IRQ_STS_REG,
> + STDP4028_DPTX_IRQ_CLEAR);
> +
> + if (ge_b850v3_lvds_ptr->connector.dev)
> + drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->connector.dev);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int ge_b850v3_lvds_attach(struct drm_bridge *bridge)
> +{
> + struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
> + struct i2c_client *stdp4028_i2c
> + = ge_b850v3_lvds_ptr->stdp4028_i2c;
> + int ret;
> +
> + if (!bridge->encoder) {
> + DRM_ERROR("Parent encoder object not found");
> + return -ENODEV;
> + }
> +
> + connector->polled = DRM_CONNECTOR_POLL_HPD;
> +
> + drm_connector_helper_add(connector,
> + &ge_b850v3_lvds_connector_helper_funcs);
> +
> + ret = drm_connector_init(bridge->dev, connector,
> + &ge_b850v3_lvds_connector_funcs,
> + DRM_MODE_CONNECTOR_DisplayPort);
> + if (ret) {
> + DRM_ERROR("Failed to initialize connector with drm\n");
> + return ret;
> + }
> +
> + ret = drm_mode_connector_attach_encoder(connector, bridge->encoder);
> + if (ret)
> + return ret;
> +
> + /* Configures the bridge to re-enable interrupts after each ack. */
> + i2c_smbus_write_word_data(stdp4028_i2c,
> + STDP4028_IRQ_OUT_CONF_REG,
> + STDP4028_DPTX_DP_IRQ_EN);
> +
> + /* Enable interrupts */
> + i2c_smbus_write_word_data(stdp4028_i2c,
> + STDP4028_DPTX_IRQ_EN_REG,
> + STDP4028_DPTX_IRQ_CONFIG);
> +
> + return 0;
> +}
> +
> +static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
> + .attach = ge_b850v3_lvds_attach,
> +};
> +
> +static int ge_b850v3_lvds_init(struct device *dev)
> +{
> + mutex_lock(&ge_b850v3_lvds_dev_mutex);
> +
> + if (ge_b850v3_lvds_ptr)
> + goto success;
> +
> + ge_b850v3_lvds_ptr = devm_kzalloc(dev,
> + sizeof(*ge_b850v3_lvds_ptr),
> + GFP_KERNEL);
> +
> + if (!ge_b850v3_lvds_ptr) {
> + mutex_unlock(&ge_b850v3_lvds_dev_mutex);
> + return -ENOMEM;
> + }
> +
> + ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
> + ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
> + drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
> +
> +success:
> + mutex_unlock(&ge_b850v3_lvds_dev_mutex);
> + return 0;
> +}
> +
> +static void ge_b850v3_lvds_remove(void)
> +{
> + mutex_lock(&ge_b850v3_lvds_dev_mutex);
> + /*
> + * This check is to avoid both the drivers
> + * removing the bridge in their remove() function
> + */
> + if (!ge_b850v3_lvds_ptr)
> + goto out;
> +
> + drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
> +
> + kfree(ge_b850v3_lvds_ptr->edid);
> +
> + ge_b850v3_lvds_ptr = NULL;
> +out:
> + mutex_unlock(&ge_b850v3_lvds_dev_mutex);
> +}
> +
> +static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
> + const struct i2c_device_id *id)
> +{
> + struct device *dev = &stdp4028_i2c->dev;
> +
> + ge_b850v3_lvds_init(dev);
> +
> + ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
> + i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
> +
> + /* Clear pending interrupts since power up. */
> + i2c_smbus_write_word_data(stdp4028_i2c,
> + STDP4028_DPTX_IRQ_STS_REG,
> + STDP4028_DPTX_IRQ_CLEAR);
> +
> + if (!stdp4028_i2c->irq)
> + return 0;
> +
> + return devm_request_threaded_irq(&stdp4028_i2c->dev,
> + stdp4028_i2c->irq, NULL,
> + ge_b850v3_lvds_irq_handler,
> + IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> + "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
> +}
> +
> +static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
> +{
> + ge_b850v3_lvds_remove();
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
> + {"stdp4028_ge_fw", 0},
> + {},
> +};
> +MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
> +
> +static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
> + { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
> +
> +static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
> + .id_table = stdp4028_ge_b850v3_fw_i2c_table,
> + .probe = stdp4028_ge_b850v3_fw_probe,
> + .remove = stdp4028_ge_b850v3_fw_remove,
> + .driver = {
> + .name = "stdp4028-ge-b850v3-fw",
> + .of_match_table = stdp4028_ge_b850v3_fw_match,
> + },
> +};
> +module_i2c_driver(stdp4028_ge_b850v3_fw_driver);
> +
> +static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
> + const struct i2c_device_id *id)
> +{
> + struct device *dev = &stdp2690_i2c->dev;
> +
> + ge_b850v3_lvds_init(dev);
> +
> + ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
> + i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
> +
> + return 0;
> +}
> +
> +static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
> +{
> + ge_b850v3_lvds_remove();
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
> + {"stdp2690_ge_fw", 0},
> + {},
> +};
> +MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
> +
> +static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
> + { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
> +
> +static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
> + .id_table = stdp2690_ge_b850v3_fw_i2c_table,
> + .probe = stdp2690_ge_b850v3_fw_probe,
> + .remove = stdp2690_ge_b850v3_fw_remove,
> + .driver = {
> + .name = "stdp2690-ge-b850v3-fw",
> + .of_match_table = stdp2690_ge_b850v3_fw_match,
> + },
> +};
> +module_i2c_driver(stdp2690_ge_b850v3_fw_driver);
Didn't catch this in the last series, but there can only be one
module_init call per module. This breaks compilation when the
driver is built as a module.
You could do something like:
static int __init stdpxxxx_ge_b850v3_init(void)
{
int ret;
ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
if (ret)
return ret;
return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
}
module_init(stdpxxxx_ge_b850v3_init);
static void __exit stdpxxxx_ge_b850v3_exit(void)
{
i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
}
module_exit(stdpxxxx_ge_b850v3_exit);
Thanks,
Archit
> +
> +MODULE_AUTHOR("Peter Senna Tschudin <peter.senna at collabora.com>");
> +MODULE_AUTHOR("Martyn Welch <martyn.welch at collabora.co.uk>");
> +MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
> +MODULE_LICENSE("GPL v2");
>
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