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Message-ID: <d492cbcb-3b13-82b8-8e5d-0f49320170a2@ideasonboard.com>
Date: Thu, 14 May 2020 12:47:02 +0100
From: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc: linux-renesas-soc@...r.kernel.org, linux-media@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Kieran Bingham <kieran.bingham@...asonboard.com>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Jacopo Mondi <jacopo@...ndi.org>,
Niklas Söderlund <niklas.soderlund@...natech.se>,
sakari.ailus@....fi, Hans Verkuil <hverkuil@...all.nl>,
Hyun Kwon <hyunk@...inx.com>, Rob Herring <robh+dt@...nel.org>,
Jacopo Mondi <jacopo+renesas@...ndi.org>,
Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
Niklas Söderlund
<niklas.soderlund+renesas@...natech.se>
Subject: Re: [PATCH v9 2/4] media: i2c: Add MAX9286 driver
Hi Mani,
On 14/05/2020 11:13, Manivannan Sadhasivam wrote:
> Hi Kieran,
>
> On Thu, May 14, 2020 at 11:02:53AM +0100, Kieran Bingham wrote:
>> Hi Mani,
>>
>> On 12/05/2020 19:17, Manivannan Sadhasivam wrote:
>>> On Tue, May 12, 2020 at 04:51:03PM +0100, Kieran Bingham wrote:
>>>> The MAX9286 is a 4-channel GMSL deserializer with coax or STP input and
>>>> CSI-2 output. The device supports multicamera streaming applications,
>>>> and features the ability to synchronise the attached cameras.
>>>>
>>>> CSI-2 output can be configured with 1 to 4 lanes, and a control channel
>>>> is supported over I2C, which implements an I2C mux to facilitate
>>>> communications with connected cameras across the reverse control
>>>> channel.
>>>>
>>>> Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
>>>> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
>>>> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
>>>> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
>>>>
>>>> --
>>>> v2:
>>>> - Fix MAINTAINERS entry
>>>>
>>>> This posting is released with the following modifications to work
>>>> without Sakari's VC developments:
>>>> - max9286_g_mbus_config() re-instated
>>>> - max9286_get_frame_desc() is not bus/csi aware
>>>> - max9286_{get,set}_routing() removed
>>>>
>>>> v3:
>>>> - Initialise notifier with v4l2_async_notifier_init
>>>> - Update for new mbus csi2 format V4L2_MBUS_CSI2_DPHY
>>>>
>>>> v4: - Re-introduce required code to function with the VC series.
>>>>
>>>> - Implement max9286_get_routing, max9286_set_routing
>>>> - Remove max9286_g_mbus_config
>>>>
>>>> v5: (internal release)
>>>> - Fix printk formatting for hex value
>>>> - max9286->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE (add |)
>>>> - MEDIA_ENT_F_PROC_VIDEO_PIXEL_FORMATTER -> MEDIA_ENT_F_VID_IF_BRIDGE
>>>> - Remove 'device is bound' workaround
>>>>
>>>> v6:
>>>> - v4l2_subdev_krouting instead of v4l2_subdev_routing separated
>>>> to allow integration without the VC/V4L2-Mux series.
>>>> - convert sd_to_max9286 to inline function
>>>> - rename max9286_device to max9286_priv
>>>> - Cleanup the v4l2_async_notifier
>>>> - Extend MODULE_AUTHOR
>>>> - Replace of_graph_get_endpoint_by_regs with fwnode_graph_get_endpoint_by_id
>>>> - Pass default bus type when parsing fwnode endpoint (Manivannan Sadhasivam)
>>>> - Use new YAML file reference in MAINTAINERS
>>>> - Parse new i2c-mux node in max9286_get_i2c_by_id
>>>> (This could/should be refactored to parse these separately first)
>>>> - Spelling and calculation fixes in the FSYNC_LOCKED check comments
>>>> - Identify each enabled i2c-mux channel in a single pass
>>>> - max9286: Improve mux-state readbility [v2]
>>>> - Fix frame sync lock durations
>>>> - Add comment to describe /why/ we must open the mux in s_stream
>>>> - use -EXDEV as return code for failed link synchronisation.
>>>> - Fix reference counting of the dt nodeS
>>>> - Convert to probe_new for I2C
>>>> - Remove redundant max9286_i2c_mux_state
>>>> - Provide optional enable-gpio (max9286-pwdn)
>>>>
>>>> v7:
>>>> [Kieran]
>>>> - Ensure powerdown lines are optional
>>>> - Add a 4ms power-up delay
>>>> - Add max9286_check_config_link() to core
>>>> - Add GPIO chip controller for GPIO0OUT and GPIO1OUT
>>>> - Fix GPIO registration
>>>> - max9286: Split out async registration
>>>> (fixes regulator -EPROBE_DEFERs failures)
>>>> - Collect all V4L2 registrations
>>>> - balance v4l2_async refcnting
>>>> - Rename max9286_v4l2_async_ => max9286_v4l2_notifier_
>>>>
>>>> [Jacopo]
>>>> - Remove redundanct MAXIM_I2C_SPEED macros
>>>> - Move notifiers operations
>>>> - Add delay after reverse channel reconfiguration
>>>> - Move link setup to completion
>>>> - Fix up max9286_check_config_link() implementation
>>>> - Remove redundant dual configuration of reverse channel
>>>>
>>>> v8:
>>>>
>>>> [Kieran]
>>>> - Update the bound_sources mask on unbind
>>>> - Convert probe kzalloc usage to devm_ variant
>>>> - Fix up cleanup path from GPIO PowerDown registration
>>>> - cleanup GPIO device registration fail path
>>>> - Convert to use devm_regulator_get()
>>>> - Fit max9286_parse_dt print on one line
>>>> - Move multi-device workarounds out of upstream driver
>>>> - Remove I2C mod-table
>>>> - Lock format changes
>>>> - Describe pad index usage
>>>> - Remove poc_enabled workaround
>>>> - Rename the max9286_gpio to be more explicit on it's actions.
>>>> - Move max9286_init_format call
>>>> - Rework probe sequence and simplify error paths.
>>>> - Simplify i2c comments
>>>> - Implement Pixelrate control
>>>> - Disable overlap window
>>>>
>>>> [Jacopo]
>>>> - Adapt Kconfig to latest upstream changes
>>>> - Put of node on error
>>>> - Calculate pixel rate
>>>> - Simplify overlap window disablement
>>>>
>>>> v9:
>>>>
>>>> [Kieran]
>>>> - Kconfig: Depend on OF
>>>> - Re-sort addition to Makefile
>>>> ---
>>>> MAINTAINERS | 10 +
>>>> drivers/media/i2c/Kconfig | 13 +
>>>> drivers/media/i2c/Makefile | 1 +
>>>> drivers/media/i2c/max9286.c | 1332 +++++++++++++++++++++++++++++++++++
>>>> 4 files changed, 1356 insertions(+)
>>>> create mode 100644 drivers/media/i2c/max9286.c
>>>>
>>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>>> index a7bb6e22d5da..99e3bf7760fd 100644
>>>> --- a/MAINTAINERS
>>>> +++ b/MAINTAINERS
>>>> @@ -10274,6 +10274,16 @@ F: Documentation/hwmon/max6697.rst
>>>> F: drivers/hwmon/max6697.c
>>>> F: include/linux/platform_data/max6697.h
>>>>
>>>> +MAX9286 QUAD GMSL DESERIALIZER DRIVER
>>>> +M: Jacopo Mondi <jacopo+renesas@...ndi.org>
>>>> +M: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
>>>> +M: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
>>>> +M: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
>>>> +L: linux-media@...r.kernel.org
>>>> +S: Maintained
>>>> +F: Documentation/devicetree/bindings/media/i2c/maxim,max9286.yaml
>>>> +F: drivers/media/i2c/max9286.c
>>>> +
>>>> MAX9860 MONO AUDIO VOICE CODEC DRIVER
>>>> M: Peter Rosin <peda@...ntia.se>
>>>> L: alsa-devel@...a-project.org (moderated for non-subscribers)
>>>> diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
>>>> index 3abc80373ec0..2e390f41f6da 100644
>>>> --- a/drivers/media/i2c/Kconfig
>>>> +++ b/drivers/media/i2c/Kconfig
>>>> @@ -464,6 +464,19 @@ config VIDEO_VPX3220
>>>> To compile this driver as a module, choose M here: the
>>>> module will be called vpx3220.
>>>>
>>>> +config VIDEO_MAX9286
>>>> + tristate "Maxim MAX9286 GMSL deserializer support"
>>>> + depends on I2C && I2C_MUX
>>>> + depends on OF
>>>> + select V4L2_FWNODE
>>>> + select VIDEO_V4L2_SUBDEV_API
>>>> + select MEDIA_CONTROLLER
>>>> + help
>>>> + This driver supports the Maxim MAX9286 GMSL deserializer.
>>>> +
>>>> + To compile this driver as a module, choose M here: the
>>>> + module will be called max9286.
>>>> +
>>>> comment "Video and audio decoders"
>>>>
>>>> config VIDEO_SAA717X
>>>> diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
>>>> index 77bf7d0b691f..f0b001ee4b05 100644
>>>> --- a/drivers/media/i2c/Makefile
>>>> +++ b/drivers/media/i2c/Makefile
>>>> @@ -117,6 +117,7 @@ obj-$(CONFIG_VIDEO_IMX274) += imx274.o
>>>> obj-$(CONFIG_VIDEO_IMX290) += imx290.o
>>>> obj-$(CONFIG_VIDEO_IMX319) += imx319.o
>>>> obj-$(CONFIG_VIDEO_IMX355) += imx355.o
>>>> +obj-$(CONFIG_VIDEO_MAX9286) += max9286.o
>>>> obj-$(CONFIG_VIDEO_ST_MIPID02) += st-mipid02.o
>>>>
>>>> obj-$(CONFIG_SDR_MAX2175) += max2175.o
>>>> diff --git a/drivers/media/i2c/max9286.c b/drivers/media/i2c/max9286.c
>>>> new file mode 100644
>>>> index 000000000000..481d65f2b51d
>>>> --- /dev/null
>>>> +++ b/drivers/media/i2c/max9286.c
>>>> @@ -0,0 +1,1332 @@
>>>> +// SPDX-License-Identifier: GPL-2.0+
>>>> +/*
>>>> + * Maxim MAX9286 GMSL Deserializer Driver
>>>> + *
>>>> + * Copyright (C) 2017-2019 Jacopo Mondi
>>>> + * Copyright (C) 2017-2019 Kieran Bingham
>>>> + * Copyright (C) 2017-2019 Laurent Pinchart
>>>> + * Copyright (C) 2017-2019 Niklas Söderlund
>>>> + * Copyright (C) 2016 Renesas Electronics Corporation
>>>> + * Copyright (C) 2015 Cogent Embedded, Inc.
>>>> + */
>>>> +
>>>> +#include <linux/delay.h>
>>>> +#include <linux/device.h>
>>>> +#include <linux/fwnode.h>
>>>> +#include <linux/gpio/consumer.h>
>>>> +#include <linux/gpio/driver.h>
>>>> +#include <linux/i2c.h>
>>>> +#include <linux/i2c-mux.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/mutex.h>
>>>> +#include <linux/of_graph.h>
>>>> +#include <linux/regulator/consumer.h>
>>>> +#include <linux/slab.h>
>>>> +
>>>> +#include <media/v4l2-async.h>
>>>> +#include <media/v4l2-ctrls.h>
>>>> +#include <media/v4l2-device.h>
>>>> +#include <media/v4l2-fwnode.h>
>>>> +#include <media/v4l2-subdev.h>
>>>> +
>>>> +/* Register 0x00 */
>>>> +#define MAX9286_MSTLINKSEL_AUTO (7 << 5)
>>>> +#define MAX9286_MSTLINKSEL(n) ((n) << 5)
>>>> +#define MAX9286_EN_VS_GEN BIT(4)
>>>> +#define MAX9286_LINKEN(n) (1 << (n))
>>>> +/* Register 0x01 */
>>>> +#define MAX9286_FSYNCMODE_ECU (3 << 6)
>>>> +#define MAX9286_FSYNCMODE_EXT (2 << 6)
>>>> +#define MAX9286_FSYNCMODE_INT_OUT (1 << 6)
>>>> +#define MAX9286_FSYNCMODE_INT_HIZ (0 << 6)
>>>> +#define MAX9286_GPIEN BIT(5)
>>>> +#define MAX9286_ENLMO_RSTFSYNC BIT(2)
>>>> +#define MAX9286_FSYNCMETH_AUTO (2 << 0)
>>>> +#define MAX9286_FSYNCMETH_SEMI_AUTO (1 << 0)
>>>> +#define MAX9286_FSYNCMETH_MANUAL (0 << 0)
>>>> +#define MAX9286_REG_FSYNC_PERIOD_L 0x06
>>>> +#define MAX9286_REG_FSYNC_PERIOD_M 0x07
>>>> +#define MAX9286_REG_FSYNC_PERIOD_H 0x08
>>>> +/* Register 0x0a */
>>>> +#define MAX9286_FWDCCEN(n) (1 << ((n) + 4))
>>>> +#define MAX9286_REVCCEN(n) (1 << (n))
>>>> +/* Register 0x0c */
>>>> +#define MAX9286_HVEN BIT(7)
>>>> +#define MAX9286_EDC_6BIT_HAMMING (2 << 5)
>>>> +#define MAX9286_EDC_6BIT_CRC (1 << 5)
>>>> +#define MAX9286_EDC_1BIT_PARITY (0 << 5)
>>>> +#define MAX9286_DESEL BIT(4)
>>>> +#define MAX9286_INVVS BIT(3)
>>>> +#define MAX9286_INVHS BIT(2)
>>>> +#define MAX9286_HVSRC_D0 (2 << 0)
>>>> +#define MAX9286_HVSRC_D14 (1 << 0)
>>>> +#define MAX9286_HVSRC_D18 (0 << 0)
>>>> +/* Register 0x0f */
>>>> +#define MAX9286_0X0F_RESERVED BIT(3)
>>>> +/* Register 0x12 */
>>>> +#define MAX9286_CSILANECNT(n) (((n) - 1) << 6)
>>>> +#define MAX9286_CSIDBL BIT(5)
>>>> +#define MAX9286_DBL BIT(4)
>>>> +#define MAX9286_DATATYPE_USER_8BIT (11 << 0)
>>>> +#define MAX9286_DATATYPE_USER_YUV_12BIT (10 << 0)
>>>> +#define MAX9286_DATATYPE_USER_24BIT (9 << 0)
>>>> +#define MAX9286_DATATYPE_RAW14 (8 << 0)
>>>> +#define MAX9286_DATATYPE_RAW11 (7 << 0)
>>>> +#define MAX9286_DATATYPE_RAW10 (6 << 0)
>>>> +#define MAX9286_DATATYPE_RAW8 (5 << 0)
>>>> +#define MAX9286_DATATYPE_YUV422_10BIT (4 << 0)
>>>> +#define MAX9286_DATATYPE_YUV422_8BIT (3 << 0)
>>>> +#define MAX9286_DATATYPE_RGB555 (2 << 0)
>>>> +#define MAX9286_DATATYPE_RGB565 (1 << 0)
>>>> +#define MAX9286_DATATYPE_RGB888 (0 << 0)
>>>> +/* Register 0x15 */
>>>> +#define MAX9286_VC(n) ((n) << 5)
>>>> +#define MAX9286_VCTYPE BIT(4)
>>>> +#define MAX9286_CSIOUTEN BIT(3)
>>>> +#define MAX9286_0X15_RESV (3 << 0)
>>>> +/* Register 0x1b */
>>>> +#define MAX9286_SWITCHIN(n) (1 << ((n) + 4))
>>>> +#define MAX9286_ENEQ(n) (1 << (n))
>>>> +/* Register 0x27 */
>>>> +#define MAX9286_LOCKED BIT(7)
>>>> +/* Register 0x31 */
>>>> +#define MAX9286_FSYNC_LOCKED BIT(6)
>>>> +/* Register 0x34 */
>>>> +#define MAX9286_I2CLOCACK BIT(7)
>>>> +#define MAX9286_I2CSLVSH_1046NS_469NS (3 << 5)
>>>> +#define MAX9286_I2CSLVSH_938NS_352NS (2 << 5)
>>>> +#define MAX9286_I2CSLVSH_469NS_234NS (1 << 5)
>>>> +#define MAX9286_I2CSLVSH_352NS_117NS (0 << 5)
>>>> +#define MAX9286_I2CMSTBT_837KBPS (7 << 2)
>>>> +#define MAX9286_I2CMSTBT_533KBPS (6 << 2)
>>>> +#define MAX9286_I2CMSTBT_339KBPS (5 << 2)
>>>> +#define MAX9286_I2CMSTBT_173KBPS (4 << 2)
>>>> +#define MAX9286_I2CMSTBT_105KBPS (3 << 2)
>>>> +#define MAX9286_I2CMSTBT_84KBPS (2 << 2)
>>>> +#define MAX9286_I2CMSTBT_28KBPS (1 << 2)
>>>> +#define MAX9286_I2CMSTBT_8KBPS (0 << 2)
>>>> +#define MAX9286_I2CSLVTO_NONE (3 << 0)
>>>> +#define MAX9286_I2CSLVTO_1024US (2 << 0)
>>>> +#define MAX9286_I2CSLVTO_256US (1 << 0)
>>>> +#define MAX9286_I2CSLVTO_64US (0 << 0)
>>>> +/* Register 0x3b */
>>>> +#define MAX9286_REV_TRF(n) ((n) << 4)
>>>> +#define MAX9286_REV_AMP(n) ((((n) - 30) / 10) << 1) /* in mV */
>>>> +#define MAX9286_REV_AMP_X BIT(0)
>>>> +/* Register 0x3f */
>>>> +#define MAX9286_EN_REV_CFG BIT(6)
>>>> +#define MAX9286_REV_FLEN(n) ((n) - 20)
>>>> +/* Register 0x49 */
>>>> +#define MAX9286_VIDEO_DETECT_MASK 0x0f
>>>> +/* Register 0x69 */
>>>> +#define MAX9286_LFLTBMONMASKED BIT(7)
>>>> +#define MAX9286_LOCKMONMASKED BIT(6)
>>>> +#define MAX9286_AUTOCOMBACKEN BIT(5)
>>>> +#define MAX9286_AUTOMASKEN BIT(4)
>>>> +#define MAX9286_MASKLINK(n) ((n) << 0)
>>>> +
>>>> +/*
>>>> + * The sink and source pads are created to match the OF graph port numbers so
>>>> + * that their indexes can be used interchangeably.
>>>> + */
>>>> +#define MAX9286_NUM_GMSL 4
>>>> +#define MAX9286_N_SINKS 4
>>>> +#define MAX9286_N_PADS 5
>>>> +#define MAX9286_SRC_PAD 4
>>>> +
>>>> +struct max9286_source {
>>>> + struct v4l2_async_subdev asd;
>>>> + struct v4l2_subdev *sd;
>>>> + struct fwnode_handle *fwnode;
>>>> +};
>>>> +
>>>> +#define asd_to_max9286_source(_asd) \
>>>> + container_of(_asd, struct max9286_source, asd)
>>>> +
>>>> +struct max9286_priv {
>>>> + struct i2c_client *client;
>>>> + struct gpio_desc *gpiod_pwdn;
>>>> + struct v4l2_subdev sd;
>>>> + struct media_pad pads[MAX9286_N_PADS];
>>>> + struct regulator *regulator;
>>>> +
>>>> + struct gpio_chip gpio;
>>>> + u8 gpio_state;
>>>> +
>>>> + struct i2c_mux_core *mux;
>>>> + unsigned int mux_channel;
>>>> + bool mux_open;
>>>> +
>>>> + struct v4l2_ctrl_handler ctrls;
>>>> + struct v4l2_ctrl *pixelrate;
>>>> +
>>>> + struct v4l2_mbus_framefmt fmt[MAX9286_N_SINKS];
>>>> +
>>>> + /* Protects controls and fmt structures */
>>>> + struct mutex mutex;
>>>> +
>>>> + unsigned int nsources;
>>>> + unsigned int source_mask;
>>>> + unsigned int route_mask;
>>>> + unsigned int bound_sources;
>>>> + unsigned int csi2_data_lanes;
>>>> + struct max9286_source sources[MAX9286_NUM_GMSL];
>>>> + struct v4l2_async_notifier notifier;
>>>> +};
>>>> +
>>>
>>> [...]
>>>
>>>> +static int max9286_register_gpio(struct max9286_priv *priv)
>>>> +{
>>>> + struct device *dev = &priv->client->dev;
>>>> + struct gpio_chip *gpio = &priv->gpio;
>>>> + int ret;
>>>> +
>>>> + static const char * const names[] = {
>>>> + "GPIO0OUT",
>>>> + "GPIO1OUT",
>>>> + };
>>>> +
>>>> + /* Configure the GPIO */
>>>> + gpio->label = dev_name(dev);
>>>
>>> So if you have more than one MAX9286 in a system, all gpiochips will appear
>>> with the same name. I'd recommend to append the index to distinguish properly.
>>
>> Ah yes, that's a good point, and I think I've even seen that.
>>
>> I'll fix it now.
Oh, in fact actually this doesn't.
gpiodetect prints:
gpiochip10 [4-004c] (2 lines)
gpiochip11 [4-006c] (2 lines)
and mostly references them as gpiochip10 and gpiochip11.
However,
> [ 2.318533] gpio gpiochip11: Detected name collision for GPIO name 'GPIO0OUT'
> [ 2.325739] gpio gpiochip11: Detected name collision for GPIO name 'GPIO1OUT'
That seems to be more of a problem for the gpio library, so I think I'll
just drop the const names. I don't think they add much value.
>>>> + gpio->parent = dev;
>>>> + gpio->owner = THIS_MODULE;
>>>> + gpio->of_node = dev->of_node;
>>>> + gpio->ngpio = 2;
>>>> + gpio->base = -1;
>>>> + gpio->set = max9286_gpio_set;
>>>> + gpio->get = max9286_gpio_get;
>>>> + gpio->can_sleep = true;
>>>> + gpio->names = names;
>>>> +
>>>> + /* GPIO values default to high */
>>>> + priv->gpio_state = BIT(0) | BIT(1);
>>>> +
>>>> + ret = devm_gpiochip_add_data(dev, gpio, priv);
>>>> + if (ret)
>>>> + dev_err(dev, "Unable to create gpio_chip\n");
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>
>>> [...]
>>>
>>>> +static int max9286_parse_dt(struct max9286_priv *priv)
>>>> +{
>>>> + struct device *dev = &priv->client->dev;
>>>> + struct device_node *i2c_mux;
>>>> + struct device_node *node = NULL;
>>>> + unsigned int i2c_mux_mask = 0;
>>>> +
>>>> + of_node_get(dev->of_node);
>>>
>>> Why this is needed?
>>
>> Hrm .. I recall adding it to solve dt reference balancing.
>>
>> I wish I'd added a comment at the time ... as I can't recall the details
>> now.
>>
>
> I understand that it is for the refcount balancing but I certainly don't see
> a need for it.
>
>>>> + i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
>>>> + if (!i2c_mux) {
>>>> + dev_err(dev, "Failed to find i2c-mux node\n");
>>>> + of_node_put(dev->of_node);
>>>> + return -EINVAL;
>>>> + }
>>>> +
> [...]
>>>
>>> [...]
>>>
>>>> +static int max9286_remove(struct i2c_client *client)
>>>> +{
>>>> + struct max9286_priv *priv = i2c_get_clientdata(client);
>>>> +
>>>> + i2c_mux_del_adapters(priv->mux);
>>>> +
>>>> + max9286_v4l2_unregister(priv);
>>>> +
>>>> + regulator_disable(priv->regulator);
>>>> +
>>>> + gpiod_set_value_cansleep(priv->gpiod_pwdn, 0);
>>>
>>> Usual power down sequence is to pull the power down gpio low and then turn off
>>> the regulators. This helps in clearing up the internal state machine properly.
>>
>> Do you mean usual, among drivers using regulators? or usual for the max9286?
>>
>
> Usual for devices exposing shutdown gpios and powered by an external regulator.
>
>> I have a platform which controls the regulators for the cameras
>> (priv->regulator) through one of the GPIOs provided by the MAX9286.
>>
>> If we powerdown the max9286 first, then we will not be able to change
>> the GPIO value on the gpio controlled regulator.
>>
>
> Hmm, I didn't think of this usecase. Let's keep it as it is.
>
> Thanks,
> Mani
>
>> (Currently it doesn't expose as a gpio regulator, but just a gpio-hog -
>> but thats a different matter)
>>
>> --
>> Kieran
>>
>>
>>>
>>> Thanks,
>>> Mani
>>>
>>>> +
>>>> + max9286_cleanup_dt(priv);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static const struct of_device_id max9286_dt_ids[] = {
>>>> + { .compatible = "maxim,max9286" },
>>>> + {},
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, max9286_dt_ids);
>>>> +
>>>> +static struct i2c_driver max9286_i2c_driver = {
>>>> + .driver = {
>>>> + .name = "max9286",
>>>> + .of_match_table = of_match_ptr(max9286_dt_ids),
>>>> + },
>>>> + .probe_new = max9286_probe,
>>>> + .remove = max9286_remove,
>>>> +};
>>>> +
>>>> +module_i2c_driver(max9286_i2c_driver);
>>>> +
>>>> +MODULE_DESCRIPTION("Maxim MAX9286 GMSL Deserializer Driver");
>>>> +MODULE_AUTHOR("Jacopo Mondi, Kieran Bingham, Laurent Pinchart, Niklas Söderlund, Vladimir Barinov");
>>>> +MODULE_LICENSE("GPL");
>>>> --
>>>> 2.25.1
>>>>
>>
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