[PATCH V2 3/4] drm/bridge: Drivers for megachips-stdpxxxx-ge-b850v3-fw (LVDS-DP++)
Archit Taneja
architt at codeaurora.org
Thu Mar 2 01:29:40 PST 2017
Hi Peter,
On 3/1/2017 4:08 PM, Peter Senna Tschudin wrote:
> Hi Archit,
>
> Thank you for the review!
>
> On Wed, Mar 01, 2017 at 09:38:48AM +0530, Archit Taneja wrote:
>>
>>
>> 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.
>
> Unfortunately yes. Got loads of errors when trying to compile 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);
>
> Thank you! I was wondering if merging ge_b850v3_lvds_init() with
> stdpxxxx_ge_b850v3_init() and ge_b850v3_lvds_remove() with
> stdpxxxx_ge_b850v3_exit() make sense as it can probably eliminate the
> need for the mutex.
Doing anything apart from the driver registration/unregistration
in the module_init/exit calls is frowned upon. Nothing specific
to the device should ideally be added in them.
It would be nice to eventually get rid of the lvds_dev_mutex, but
I think we can live with it for now.
Regards,
Archit
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