Message-ID: <cacba7c5-9e06-4471-91ed-ee0fd6d73daa@amd.com>
Date: Tue, 22 Apr 2025 12:12:08 -0400
From: "Nirujogi, Pratap" <pnirujog@....com>
To: Krzysztof Kozlowski <krzk@...nel.org>,
 Pratap Nirujogi <pratap.nirujogi@....com>, andi.shyti@...nel.org
Cc: linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
 benjamin.chan@....com, bin.du@....com, gjorgji.rosikopulos@....com,
 king.li@....com, dominic.antony@....com
Subject: Re: [PATCH] i2c: amd-isp: Add ISP i2c-designware driver

Hi Krzysztof,

Please accept my apologies for the delayed response to your review comments.

Thanks,
Pratap

On 3/1/2025 8:26 AM, Krzysztof Kozlowski wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
> 
> 
> On 28/02/2025 17:45, Pratap Nirujogi wrote:
>>   config I2C_DESIGNWARE_AMDPSP
>>        bool "AMD PSP I2C semaphore support"
>>        depends on ACPI
>> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
>> index 1c2a4510abe4..cfe53038df69 100644
>> --- a/drivers/i2c/busses/Makefile
>> +++ b/drivers/i2c/busses/Makefile
>> @@ -58,6 +58,7 @@ obj-$(CONFIG_I2C_DESIGNWARE_PLATFORM)                       += i2c-designware-platform.o
>>   i2c-designware-platform-y                            := i2c-designware-platdrv.o
>>   i2c-designware-platform-$(CONFIG_I2C_DESIGNWARE_AMDPSP)      += i2c-designware-amdpsp.o
>>   i2c-designware-platform-$(CONFIG_I2C_DESIGNWARE_BAYTRAIL) += i2c-designware-baytrail.o
>> +obj-$(CONFIG_I2C_DESIGNWARE_AMDISP) += i2c-designware-amdisp.o
>>   obj-$(CONFIG_I2C_DESIGNWARE_PCI)                     += i2c-designware-pci.o
>>   i2c-designware-pci-y                                 := i2c-designware-pcidrv.o
>>   obj-$(CONFIG_I2C_DIGICOLOR)  += i2c-digicolor.o
>> diff --git a/drivers/i2c/busses/i2c-designware-amdisp.c b/drivers/i2c/busses/i2c-designware-amdisp.c
>> new file mode 100644
>> index 000000000000..dc90510a440b
>> --- /dev/null
>> +++ b/drivers/i2c/busses/i2c-designware-amdisp.c
>> @@ -0,0 +1,266 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright 2024-2025 Advanced Micro Devices, Inc.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the "Software"),
>> + * to deal in the Software without restriction, including without limitation
>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> + * OTHER DEALINGS IN THE SOFTWARE.
> 
> Don't add custom license boilerplate.
> 
Thanks. Will remove it in V2.

> 
>> + */
>> +
>> +#include <linux/clk-provider.h>
>> +#include <linux/clk.h>
>> +#include <linux/delay.h>
>> +#include <linux/dmi.h>
>> +#include <linux/err.h>
>> +#include <linux/errno.h>
>> +#include <linux/i2c.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pm.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/property.h>
>> +#include <linux/regmap.h>
>> +#include <linux/reset.h>
>> +#include <linux/sched.h>
>> +#include <linux/slab.h>
>> +#include <linux/suspend.h>
>> +#include <linux/units.h>
>> +
>> +#include "i2c-designware-core.h"
>> +#include "i2c-designware-amdisp.h"
>> +
>> +#define AMD_ISP_I2C_INPUT_CLK                        100 //100 Mhz
>> +
>> +#define to_amd_isp_i2c_dev(dev) \
>> +     ((struct amd_isp_i2c_dev *)container_of(dev, struct amd_isp_i2c_dev, dw_dev))
> 
> Why do you need to cast? To drop const? That's poor coding.
> 
Thanks. Will remove it in V2.

>> +
>> +struct amd_isp_i2c_dev {
>> +     struct dw_i2c_dev       dw_dev;
>> +};
>> +
>> +static void amd_isp_dw_i2c_plat_pm_cleanup(struct dw_i2c_dev *dev)
>> +{
>> +     pm_runtime_disable(dev->dev);
>> +
>> +     if (dev->shared_with_punit)
>> +             pm_runtime_put_noidle(dev->dev);
>> +}
>> +
>> +static u32 amd_isp_dw_i2c_get_clk_rate(struct dw_i2c_dev *dev)
>> +{
>> +     return AMD_ISP_I2C_INPUT_CLK * 1000;
>> +}
>> +
>> +static int amd_isp_dw_i2c_plat_probe(struct platform_device *pdev)
>> +{
>> +     struct i2c_adapter *adap;
>> +     struct amd_isp_i2c_dev *isp_i2c_dev;
>> +     struct dw_i2c_dev *dev;
>> +     int ret;
>> +
>> +     isp_i2c_dev = devm_kzalloc(&pdev->dev, sizeof(struct amd_isp_i2c_dev),
> 
> sizeof(*)
> 
>> +                                GFP_KERNEL);
>> +     if (!isp_i2c_dev)
>> +             return -ENOMEM;
>> +
>> +     dev = &isp_i2c_dev->dw_dev;
>> +     dev->dev = &pdev->dev;
>> +
>> +     /**
> 
> Not a kerneldoc.
> 
> Please run standard kernel tools for static analysis, like coccinelle,
> smatch and sparse, and fix reported warnings. Also please check for
> warnings when building with W=1. Most of these commands (checks or W=1
> build) can build specific targets, like some directory, to narrow the
> scope to only your code. The code here looks like it needs a fix. Feel
> free to get in touch if the warning is not clear.
> 
Thanks. Will run the suggested tools and fix the warnings reported in V2.

>> +      * Use the polling mode to send/receive the data, because
>> +      * no IRQ connection from ISP I2C
>> +      */
>> +     dev->flags |= ACCESS_POLLING;
>> +     platform_set_drvdata(pdev, dev);
>> +
>> +     dev->base = devm_platform_ioremap_resource(pdev, 0);
>> +     if (IS_ERR(dev->base))
>> +             return PTR_ERR(dev->base);
>> +
>> +     ret = isp_power_set(true);
>> +     if (ret) {
>> +             dev_err(dev->dev, "unable to turn on the amdisp i2c power:%d\n", ret);
> 
> Syntax is return dev_err_probe()
> 
Thanks. Will update in V2.

>> +             return ret;
>> +     }
>> +
>> +     dev->get_clk_rate_khz = amd_isp_dw_i2c_get_clk_rate;
>> +     ret = i2c_dw_fw_parse_and_configure(dev);
>> +     if (ret)
>> +             goto exit;
>> +
>> +     i2c_dw_configure(dev);
>> +
>> +     adap = &dev->adapter;
>> +     adap->owner = THIS_MODULE;
>> +     ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
>> +     adap->dev.of_node = pdev->dev.of_node;
>> +     /* arbitrary large number to avoid any conflicts */
>> +     adap->nr = 99;
>> +
>> +     if (dev->flags & ACCESS_NO_IRQ_SUSPEND) {
>> +             dev_pm_set_driver_flags(&pdev->dev,
>> +                                     DPM_FLAG_SMART_PREPARE);
>> +     } else {
>> +             dev_pm_set_driver_flags(&pdev->dev,
>> +                                     DPM_FLAG_SMART_PREPARE |
>> +                                     DPM_FLAG_SMART_SUSPEND);
>> +     }
>> +
>> +     device_enable_async_suspend(&pdev->dev);
>> +
>> +     /* The code below assumes runtime PM to be disabled. */
>> +     WARN_ON(pm_runtime_enabled(&pdev->dev));
> 
> And how it could be enabled? Drop or fix your driver.
> 
Thanks. Will drop this in V2.

>> +
>> +     pm_runtime_dont_use_autosuspend(&pdev->dev);
>> +     pm_runtime_set_active(&pdev->dev);
>> +
>> +     if (dev->shared_with_punit)
>> +             pm_runtime_get_noresume(&pdev->dev);
>> +
>> +     pm_runtime_enable(&pdev->dev);
>> +
>> +     ret = i2c_dw_probe(dev);
>> +     if (ret) {
>> +             dev_err(dev->dev, "i2c_dw_probe failed %d\n", ret);
> 
> Use dev_err_probe()
> 
Thanks. Will update in V2.

>> +             goto exit_probe;
>> +     }
>> +
>> +     isp_power_set(false);
>> +     return ret;
>> +
>> +exit_probe:
>> +     amd_isp_dw_i2c_plat_pm_cleanup(dev);
>> +     isp_power_set(false);
>> +exit:
>> +     isp_power_set(false);
>> +     return ret;
>> +}
>> +
>> +static void amd_isp_dw_i2c_plat_remove(struct platform_device *pdev)
>> +{
>> +     struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
>> +
>> +     pm_runtime_get_sync(&pdev->dev);
>> +
>> +     i2c_del_adapter(&dev->adapter);
>> +
>> +     i2c_dw_disable(dev);
>> +
>> +     pm_runtime_dont_use_autosuspend(&pdev->dev);
>> +     pm_runtime_put_sync(&pdev->dev);
>> +     amd_isp_dw_i2c_plat_pm_cleanup(dev);
>> +
>> +     reset_control_assert(dev->rst);
>> +}
>> +
>> +static int amd_isp_dw_i2c_plat_prepare(struct device *dev)
>> +{
>> +     /*
>> +      * If the ACPI companion device object is present for this device, it
>> +      * may be accessed during suspend and resume of other devices via I2C
>> +      * operation regions, so tell the PM core and middle layers to avoid
>> +      * skipping system suspend/resume callbacks for it in that case.
>> +      */
>> +     return !has_acpi_companion(dev);
>> +}
>> +
>> +static int amd_isp_dw_i2c_plat_runtime_suspend(struct device *dev)
>> +{
>> +     struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
>> +
>> +     if (i_dev->shared_with_punit)
>> +             return 0;
>> +
>> +     i2c_dw_disable(i_dev);
>> +     i2c_dw_prepare_clk(i_dev, false);
>> +
>> +     return 0;
>> +}
>> +
>> +static int amd_isp_dw_i2c_plat_suspend(struct device *dev)
>> +{
>> +     struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
>> +
>> +     i2c_mark_adapter_suspended(&i_dev->adapter);
>> +
>> +     return amd_isp_dw_i2c_plat_runtime_suspend(dev);
>> +}
>> +
>> +static int amd_isp_dw_i2c_plat_runtime_resume(struct device *dev)
>> +{
>> +     struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
>> +
>> +     if (!i_dev->shared_with_punit)
>> +             i2c_dw_prepare_clk(i_dev, true);
>> +
>> +     i_dev->init(i_dev);
>> +
>> +     return 0;
>> +}
>> +
>> +static int amd_isp_dw_i2c_plat_resume(struct device *dev)
>> +{
>> +     struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
>> +
>> +     amd_isp_dw_i2c_plat_runtime_resume(dev);
>> +     i2c_mark_adapter_resumed(&i_dev->adapter);
>> +
>> +     return 0;
>> +}
>> +
>> +static const struct dev_pm_ops amd_isp_dw_i2c_dev_pm_ops = {
>> +     .prepare = pm_sleep_ptr(amd_isp_dw_i2c_plat_prepare),
>> +     LATE_SYSTEM_SLEEP_PM_OPS(amd_isp_dw_i2c_plat_suspend, amd_isp_dw_i2c_plat_resume)
>> +     RUNTIME_PM_OPS(amd_isp_dw_i2c_plat_runtime_suspend, amd_isp_dw_i2c_plat_runtime_resume, NULL)
>> +};
>> +
>> +/* Work with hotplug and coldplug */
>> +MODULE_ALIAS("platform:amd_isp_i2c_designware");
>> +
>> +static struct platform_driver amd_isp_dw_i2c_driver = {
>> +     .probe = amd_isp_dw_i2c_plat_probe,
>> +     .remove = amd_isp_dw_i2c_plat_remove,
>> +     .driver         = {
>> +             .name   = "amd_isp_i2c_designware",
>> +             .pm     = pm_ptr(&amd_isp_dw_i2c_dev_pm_ops),
>> +     },
>> +};
>> +
>> +static int __init amd_isp_dw_i2c_init_driver(void)
>> +{
>> +     return platform_driver_register(&amd_isp_dw_i2c_driver);
>> +}
>> +subsys_initcall(amd_isp_dw_i2c_init_driver);
> 
> Why this cannot be standard module initcall? This is ISP, not a critical
> boot component.
> 
Thanks. It need not be subsys_initcall. Will use module_init in V2.

>> +
>> +static void __exit amd_isp_dw_i2c_exit_driver(void)
>> +{
>> +     platform_driver_unregister(&amd_isp_dw_i2c_driver);
>> +}
>> +module_exit(amd_isp_dw_i2c_exit_driver);
>> +
>> +MODULE_AUTHOR("Venkata Narendra Kumar Gutta <vengutta@....com>");
>> +MODULE_AUTHOR("Pratap Nirujogi <pratap.nirujogi@....com>");
>> +MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter in AMD ISP");
>> +MODULE_LICENSE("GPL");
>> +MODULE_IMPORT_NS("I2C_DW");
>> +MODULE_IMPORT_NS("I2C_DW_COMMON");
>> +MODULE_LICENSE("GPL and additional rights");
>> diff --git a/drivers/i2c/busses/i2c-designware-amdisp.h b/drivers/i2c/busses/i2c-designware-amdisp.h
>> new file mode 100644
>> index 000000000000..f98661fdaedf
>> --- /dev/null
>> +++ b/drivers/i2c/busses/i2c-designware-amdisp.h
>> @@ -0,0 +1,24 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright 2024-2025 Advanced Micro Devices, Inc.
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> + * copy of this software and associated documentation files (the "Software"),
>> + * to deal in the Software without restriction, including without limitation
>> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
>> + * and/or sell copies of the Software, and to permit persons to whom the
>> + * Software is furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
>> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
>> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
>> + * OTHER DEALINGS IN THE SOFTWARE.
> 
> Don't add custom license boilerplate.
> 
Thanks. Will remove it in V2.

>> + */
>> +
>> +int isp_power_set(int on);
> 
> 
> Best regards,
> Krzysztof

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