Message-ID: <815f1029-fc0c-4211-ab47-c9ca985f52f1@gmx.de>
Date: Tue, 29 Apr 2025 22:52:38 +0200
From: Armin Wolf <W_Armin@....de>
To: "Nirujogi, Pratap" <pnirujog@....com>,
 Pratap Nirujogi <pratap.nirujogi@....com>, hdegoede@...hat.com,
 ilpo.jarvinen@...ux.intel.com, mario.limonciello@....com
Cc: platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
 benjamin.chan@....com, bin.du@....com, gjorgji.rosikopulos@....com,
 king.li@....com, dantony@....com
Subject: Re: [PATCH v7] platform/x86: Add AMD ISP platform config for OV05C10

Am 29.04.25 um 20:33 schrieb Nirujogi, Pratap:

> Hi Armin,
>
> On 4/26/2025 8:25 PM, Armin Wolf wrote:
>> Caution: This message originated from an External Source. Use proper 
>> caution when opening attachments, clicking links, or responding.
>>
>>
>> Am 17.04.25 um 20:28 schrieb Pratap Nirujogi:
>>
>>> ISP device specific configuration is not available in ACPI. Add
>>> swnode graph to configure the missing device properties for the
>>> OV05C10 camera device supported on amdisp platform.
>>>
>>> Add support to create i2c-client dynamically when amdisp i2c
>>> adapter is available.
>>>
>>> Co-developed-by: Benjamin Chan <benjamin.chan@....com>
>>> Signed-off-by: Benjamin Chan <benjamin.chan@....com>
>>> Signed-off-by: Pratap Nirujogi <pratap.nirujogi@....com>
>>> ---
>>> Changes v6 -> v7:
>>>
>>> * Use devm_kzalloc() inplace of kmemdup()
>>> * Use IS_ERR() inplace of i2c_client_has_driver()
>>> * Remove the extra cast
>>>
>>>   drivers/platform/x86/amd/Kconfig    |  11 ++
>>>   drivers/platform/x86/amd/Makefile   |   1 +
>>>   drivers/platform/x86/amd/amd_isp4.c | 269 
>>> ++++++++++++++++++++++++++++
>>>   3 files changed, 281 insertions(+)
>>>   create mode 100644 drivers/platform/x86/amd/amd_isp4.c
>>>
>>> diff --git a/drivers/platform/x86/amd/Kconfig 
>>> b/drivers/platform/x86/ amd/Kconfig
>>> index c3e086ea64fc..ec755b5fc93c 100644
>>> --- a/drivers/platform/x86/amd/Kconfig
>>> +++ b/drivers/platform/x86/amd/Kconfig
>>> @@ -32,3 +32,14 @@ config AMD_WBRF
>>>
>>>         This mechanism will only be activated on platforms that 
>>> advertise a
>>>         need for it.
>>> +
>>> +config AMD_ISP_PLATFORM
>>> +     tristate "AMD ISP4 platform driver"
>>> +     depends on I2C && X86_64 && ACPI && AMD_ISP4
>>
>> Hi,
>>
>> just a question: when will the CONFIG_AMD_ISP4 symbol be introduced?
>>
> CONFIG_AMD_ISP4 will be introduced in the V4L2 ISP driver patches. We 
> are working on isp driver patches and planning to submit once the 
> review for x86/platform and sensor driver patches completes.

Alright.

>
>>> +     help
>>> +       Platform driver for AMD platforms containing image signal 
>>> processor
>>> +       gen 4. Provides camera sensor module board information to allow
>>> +       sensor and V4L drivers to work properly.
>>> +
>>> +       This driver can also be built as a module.  If so, the module
>>> +       will be called amd_isp4.
>>> diff --git a/drivers/platform/x86/amd/Makefile 
>>> b/drivers/platform/x86/ amd/Makefile
>>> index c6c40bdcbded..b0e284b5d497 100644
>>> --- a/drivers/platform/x86/amd/Makefile
>>> +++ b/drivers/platform/x86/amd/Makefile
>>> @@ -10,3 +10,4 @@ obj-$(CONFIG_AMD_PMC)               += pmc/
>>>   obj-$(CONFIG_AMD_HSMP)              += hsmp/
>>>   obj-$(CONFIG_AMD_PMF)               += pmf/
>>>   obj-$(CONFIG_AMD_WBRF)              += wbrf.o
>>> +obj-$(CONFIG_AMD_ISP_PLATFORM)       += amd_isp4.o
>>> diff --git a/drivers/platform/x86/amd/amd_isp4.c b/drivers/platform/ 
>>> x86/amd/amd_isp4.c
>>> new file mode 100644
>>> index 000000000000..461a10be5ccd
>>> --- /dev/null
>>> +++ b/drivers/platform/x86/amd/amd_isp4.c
>>> @@ -0,0 +1,269 @@
>>> +// SPDX-License-Identifier: GPL-2.0+
>>> +/*
>>> + * AMD ISP platform driver for sensor i2-client instantiation
>>> + *
>>> + * Copyright 2025 Advanced Micro Devices, Inc.
>>> + */
>>> +
>>> +#include <linux/i2c.h>
>>> +#include <linux/module.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/property.h>
>>> +#include <linux/units.h>
>>> +
>>> +#define AMDISP_OV05C10_I2C_ADDR              0x10
>>> +#define AMDISP_OV05C10_PLAT_NAME "amdisp_ov05c10_platform"
>>> +#define AMDISP_OV05C10_HID           "OMNI5C10"
>>> +#define AMDISP_OV05C10_REMOTE_EP_NAME "ov05c10_isp_4_1_1"
>>> +#define AMD_ISP_PLAT_DRV_NAME                "amd-isp4"
>>> +
>>> +/*
>>> + * AMD ISP platform definition to configure the device properties
>>> + * missing in the ACPI table.
>>> + */
>>> +struct amdisp_platform {
>>> +     const char *name;
>>> +     u8 i2c_addr;
>>> +     u8 max_num_swnodes;
>>> +     struct i2c_board_info board_info;
>>> +     struct notifier_block i2c_nb;
>>> +     struct i2c_client *i2c_dev;
>>> +     const struct software_node **swnodes;
>>> +};
>>> +
>>> +/* Top-level OV05C10 camera node property table */
>>> +static const struct property_entry ov05c10_camera_props[] = {
>>> +     PROPERTY_ENTRY_U32("clock-frequency", 24 * HZ_PER_MHZ),
>>> +     { }
>>> +};
>>> +
>>> +/* Root AMD ISP OV05C10 camera node definition */
>>> +static const struct software_node camera_node = {
>>> +     .name = AMDISP_OV05C10_HID,
>>> +     .properties = ov05c10_camera_props,
>>> +};
>>> +
>>> +/*
>>> + * AMD ISP OV05C10 Ports node definition. No properties defined for
>>> + * ports node for OV05C10.
>>> + */
>>> +static const struct software_node ports = {
>>> +     .name = "ports",
>>> +     .parent = &camera_node,
>>> +};
>>> +
>>> +/*
>>> + * AMD ISP OV05C10 Port node definition. No properties defined for
>>> + * port node for OV05C10.
>>> + */
>>> +static const struct software_node port_node = {
>>> +     .name = "port@",
>>> +     .parent = &ports,
>>> +};
>>> +
>>> +/*
>>> + * Remote endpoint AMD ISP node definition. No properties defined for
>>> + * remote endpoint node for OV05C10.
>>> + */
>>> +static const struct software_node remote_ep_isp_node = {
>>> +     .name = AMDISP_OV05C10_REMOTE_EP_NAME,
>>> +};
>>> +
>>> +/*
>>> + * Remote endpoint reference for isp node included in the
>>> + * OV05C10 endpoint.
>>> + */
>>> +static const struct software_node_ref_args ov05c10_refs[] = {
>>> +     SOFTWARE_NODE_REFERENCE(&remote_ep_isp_node),
>>> +};
>>> +
>>> +/* OV05C supports one single link frequency */
>>> +static const u64 ov05c10_link_freqs[] = {
>>> +     925 * HZ_PER_MHZ,
>>> +};
>>> +
>>> +/* OV05C supports only 2-lane configuration */
>>> +static const u32 ov05c10_data_lanes[] = {
>>> +     1,
>>> +     2,
>>> +};
>>> +
>>> +/* OV05C10 endpoint node properties table */
>>> +static const struct property_entry ov05c10_endpoint_props[] = {
>>> +     PROPERTY_ENTRY_U32("bus-type", 4),
>>> +     PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes", ov05c10_data_lanes,
>>> + ARRAY_SIZE(ov05c10_data_lanes)),
>>> +     PROPERTY_ENTRY_U64_ARRAY_LEN("link-frequencies", 
>>> ov05c10_link_freqs,
>>> + ARRAY_SIZE(ov05c10_link_freqs)),
>>> +     PROPERTY_ENTRY_REF_ARRAY("remote-endpoint", ov05c10_refs),
>>> +     { }
>>> +};
>>> +
>>> +/* AMD ISP endpoint node definition */
>>> +static const struct software_node endpoint_node = {
>>> +     .name = "endpoint",
>>> +     .parent = &port_node,
>>> +     .properties = ov05c10_endpoint_props,
>>> +};
>>> +
>>> +/*
>>> + * AMD ISP swnode graph uses 5 nodes and also its relationship is
>>> + * fixed to align with the structure that v4l2 expects for successful
>>> + * endpoint fwnode parsing.
>>> + *
>>> + * It is only the node property_entries that will vary for each 
>>> platform
>>> + * supporting different sensor modules.
>>> + */
>>> +#define NUM_SW_NODES 5
>>> +
>>> +static const struct software_node *ov05c10_nodes[NUM_SW_NODES + 1] = {
>>> +     &camera_node,
>>> +     &ports,
>>> +     &port_node,
>>> +     &endpoint_node,
>>> +     &remote_ep_isp_node,
>>> +     NULL
>>> +};
>>> +
>>> +/* OV05C10 specific AMD ISP platform configuration */
>>> +static const struct amdisp_platform amdisp_ov05c10_platform_config = {
>>> +     .name = AMDISP_OV05C10_PLAT_NAME,
>>
>> Where is this field being used?
>>
>>> +     .board_info = {
>>> +             .dev_name = "ov05c10",
>>> +             I2C_BOARD_INFO("ov05c10", AMDISP_OV05C10_I2C_ADDR),
>>> +     },
>>> +     .i2c_addr = AMDISP_OV05C10_I2C_ADDR,
>>
>> Please reuse board_info->addr.
>>
>>> +     .max_num_swnodes = NUM_SW_NODES,
>>
>> Where is max_num_swnodes being used?
>>
>>> +     .swnodes = ov05c10_nodes,
>>
>> Why not drop .swnodes and referencing ov05c10_nodes directly?
>>
> Thanks. Some of the variables phased out with the ongoing development 
> and patching. I will take care of removing the unused and redudant 
> variables in 'struct amdisp_platform'.
>
>>> +};
>>> +
>>> +static const struct acpi_device_id amdisp_sensor_ids[] = {
>>> +     { AMDISP_OV05C10_HID },
>>> +     { }
>>> +};
>>> +MODULE_DEVICE_TABLE(acpi, amdisp_sensor_ids);
>>> +
>>> +static inline bool is_isp_i2c_adapter(struct i2c_adapter *adap)
>>> +{
>>> +     return !strcmp(adap->owner->name, "i2c_designware_amdisp");
>>> +}
>>> +
>>> +static void instantiate_isp_i2c_client(struct amdisp_platform 
>>> *ov05c10, struct i2c_adapter *adap)
>>> +{
>>> +     struct i2c_board_info *info = &ov05c10->board_info;
>>> +     struct i2c_client *i2c_dev;
>>> +
>>> +     if (ov05c10->i2c_dev)
>>> +             return;
>>> +
>>> +     if (!info->addr) {
>>> +             dev_err(&adap->dev, "invalid i2c_addr 0x%x 
>>> detected\n", ov05c10->i2c_addr);
>>> +             return;
>>> +     }
>>> +
>>> +     i2c_dev = i2c_new_client_device(adap, info);
>>> +     if (IS_ERR(i2c_dev)) {
>>> +             dev_err(&adap->dev, "error %pe registering isp 
>>> i2c_client\n", i2c_dev);
>>> +             return;
>>> +     }
>>> +     ov05c10->i2c_dev = i2c_dev;
>>> +}
>>> +
>>> +static int isp_i2c_bus_notify(struct notifier_block *nb,
>>> +                           unsigned long action, void *data)
>>> +{
>>> +     struct amdisp_platform *ov05c10 = container_of(nb, struct 
>>> amdisp_platform, i2c_nb);
>>> +     struct device *dev = data;
>>> +     struct i2c_client *client;
>>> +     struct i2c_adapter *adap;
>>> +
>>> +     switch (action) {
>>> +     case BUS_NOTIFY_ADD_DEVICE:
>>> +             adap = i2c_verify_adapter(dev);
>>> +             if (!adap)
>>> +                     break;
>>> +             if (is_isp_i2c_adapter(adap))
>>> +                     instantiate_isp_i2c_client(ov05c10, adap);
>>> +             break;
>>> +     case BUS_NOTIFY_REMOVED_DEVICE:
>>> +             client = i2c_verify_client(dev);
>>> +             if (!client)
>>> +                     break;
>>> +             if (ov05c10->i2c_dev == client) {
>>> +                     dev_dbg(&client->adapter->dev, "amdisp 
>>> i2c_client removed\n");
>>> +                     ov05c10->i2c_dev = NULL;
>>> +             }
>>> +             break;
>>> +     default:
>>> +             break;
>>> +     }
>>> +
>>> +     return NOTIFY_DONE;
>>
>> You still need to handle the situation where the AMD I2C adapter is 
>> already registered when
>> registering the bus notifier. In this case you will miss the 
>> BUS_NOTIFY_ADD_DEVICE event.
>>
> Thanks. I will cover this case using the below sequence.
>
> 1. bus_register_notifier()
> 2. i2c_for_each_dev()
>
> If at all i2c adapter is registered by the time 
> bus_register_notifier() is called, it should be detected in 
> i2c_for_each_dev(). I will add checks to avoid creation of duplicate 
> i2c_client devices when both notifier callback and i2c_for_each_dev() 
> passes especially when i2c adapter gets added between 1 and 2.
>
> Please suggest if there is an alternate better approach that I should 
> use to handle this case.
>
This approach seems good to me, i2c-dev uses something similar.

Thanks,
Armin Wolf

>>> +}
>>> +
>>> +static struct amdisp_platform *prepare_amdisp_platform(struct 
>>> device *dev,
>>> +                                                    const struct 
>>> amdisp_platform *src)
>>> +{
>>> +     struct amdisp_platform *isp_ov05c10;
>>> +     struct i2c_board_info *info;
>>> +     int ret;
>>> +
>>> +     isp_ov05c10 = devm_kzalloc(dev, sizeof(*isp_ov05c10), 
>>> GFP_KERNEL);
>>> +     if (!isp_ov05c10)
>>> +             return ERR_PTR(-ENOMEM);
>>> +     memcpy(isp_ov05c10, src, sizeof(*isp_ov05c10));
>>
>> This is not what i meant. I was complaining that 
>> amdisp_ov05c10_platform_config contains both
>> static data (swnodes) and data assigned during runtime (board_info- 
>>  >swnode, i2c_dev, ...).
>>
>> Please do not use a global instance of struct amdisp_platform for 
>> initialization. Instead initialize a
>> fresh instance of this struct inside prepare_amdisp_platform().
>>
> sure, will remove the global variable 
> 'amdisp_ov05c10_platform_config', and will take care of initializing 
> the amdisp_platform instance in the prepare_amdisp_platform().
>
>>> +
>>> +     info = &isp_ov05c10->board_info;
>>> +
>>> +     ret = software_node_register_node_group(src->swnodes);
>>> +     if (ret)
>>> +             return ERR_PTR(ret);
>>> +
>>> +     info->swnode = src->swnodes[0];
>>> +
>>> +     return isp_ov05c10;
>>> +}
>>> +
>>> +static int amd_isp_probe(struct platform_device *pdev)
>>> +{
>>> +     struct amdisp_platform *ov05c10;
>>> +     int ret;
>>> +
>>> +     ov05c10 = prepare_amdisp_platform(&pdev->dev, 
>>> &amdisp_ov05c10_platform_config);
>>> +     if (IS_ERR(ov05c10))
>>> +             return dev_err_probe(&pdev->dev, PTR_ERR(ov05c10),
>>> +                                  "failed to prepare AMD ISP 
>>> platform fwnode\n");
>>> +
>>> +     ov05c10->i2c_nb.notifier_call = isp_i2c_bus_notify;
>>> +     ret = bus_register_notifier(&i2c_bus_type, &ov05c10->i2c_nb);
>>> +     if (ret)
>>> +             return ret;
>>
>> You need to call software_node_unregister_node_group() here when 
>> bus_register_notifier() fails.
>>
> Thanks. I will fix this in the next V8 patch.
>
>> Thanks,
>> Armin Wolf>
> Thanks,
> Pratap
>
>>> +
>>> +     platform_set_drvdata(pdev, ov05c10);
>>> +     return 0;
>>> +}
>>> +
>>> +static void amd_isp_remove(struct platform_device *pdev)
>>> +{
>>> +     struct amdisp_platform *ov05c10 = platform_get_drvdata(pdev);
>>> +
>>> +     bus_unregister_notifier(&i2c_bus_type, &ov05c10->i2c_nb);
>>> +     i2c_unregister_device(ov05c10->i2c_dev);
>>> + software_node_unregister_node_group(ov05c10->swnodes);
>>> +}
>>> +
>>> +static struct platform_driver amd_isp_platform_driver = {
>>> +     .driver = {
>>> +             .name                   = AMD_ISP_PLAT_DRV_NAME,
>>> +             .acpi_match_table       = amdisp_sensor_ids,
>>> +     },
>>> +     .probe  = amd_isp_probe,
>>> +     .remove = amd_isp_remove,
>>> +};
>>> +
>>> +module_platform_driver(amd_isp_platform_driver);
>>> +
>>> +MODULE_AUTHOR("Benjamin Chan <benjamin.chan@....com>");
>>> +MODULE_AUTHOR("Pratap Nirujogi <pratap.nirujogi@....com>");
>>> +MODULE_DESCRIPTION("AMD ISP4 Platform Driver");
>>> +MODULE_LICENSE("GPL");
>
>

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