Message-ID: <5db055e1-ef17-757f-f247-313caea60cc1@codeaurora.org>
Date:   Thu, 2 Mar 2017 14:59:40 +0530
From:   Archit Taneja <architt@...eaurora.org>
To:     Peter Senna Tschudin <peter.senna@...labora.com>
Cc:     airlied@...ux.ie, akpm@...ux-foundation.org,
        daniel.vetter@...ll.ch, davem@...emloft.net,
        devicetree@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        enric.balletbo@...labora.com, eballetbo@...il.com,
        galak@...eaurora.org, gregkh@...uxfoundation.org, heiko@...ech.de,
        ijc+devicetree@...lion.org.uk, javier@...hile0.org, jslaby@...e.cz,
        kernel@...gutronix.de, linux-arm-kernel@...ts.infradead.org,
        linux@...linux.org.uk, linux-kernel@...r.kernel.org,
        linux@...ck-us.net, mark.rutland@....com, martin.donnelly@...com,
        martyn.welch@...labora.co.uk, mchehab@....samsung.com,
        pawel.moll@....com, peter.senna@...il.com, p.zabel@...gutronix.de,
        thierry.reding@...il.com, rmk+kernel@...linux.org.uk,
        robh+dt@...nel.org, shawnguo@...nel.org, tiwai@...e.com,
        treding@...dia.com, ykk@...k-chips.com,
        laurent.pinchart@...asonboard.com, Rob Herring <robh@...nel.org>,
        Fabio Estevam <fabio.estevam@....com>
Subject: Re: [PATCH V2 3/4] drm/bridge: Drivers for
 megachips-stdpxxxx-ge-b850v3-fw (LVDS-DP++)

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@...asonboard.com>
>>> Cc: Martyn Welch <martyn.welch@...labora.co.uk>
>>> Cc: Martin Donnelly <martin.donnelly@...com>
>>> Cc: Daniel Vetter <daniel.vetter@...ll.ch>
>>> Cc: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>>> Cc: Philipp Zabel <p.zabel@...gutronix.de>
>>> Cc: Rob Herring <robh@...nel.org>
>>> Cc: Fabio Estevam <fabio.estevam@....com>
>>> Cc: David Airlie <airlied@...ux.ie>
>>> Cc: Thierry Reding <treding@...dia.com>
>>> Cc: Thierry Reding <thierry.reding@...il.com>
>>> Cc: Archit Taneja <architt@...eaurora.org>
>>> Cc: Enric Balletbo <enric.balletbo@...labora.com>
>>> Signed-off-by: Peter Senna Tschudin <peter.senna@...labora.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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