Message-ID: <af881cfe-926a-451f-8f40-c7cb64c99693@amd.com>
Date: Fri, 28 Feb 2025 21:33:45 -0600
From: Mario Limonciello <mario.limonciello@....com>
To: Pratap Nirujogi <pratap.nirujogi@....com>, andi.shyti@...nel.org
Cc: linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
 benjamin.chan@....com
Subject: Re: [PATCH] i2c: amd-isp: Add ISP i2c-designware driver

On 2/28/2025 10:45, Pratap Nirujogi wrote:
> The camera sensor is connected via ISP I2C bus in AMD SOC
> architectures. Add new I2C designware driver to support
> new camera sensors on AMD HW.
> 
> Signed-off-by: Pratap Nirujogi <pratap.nirujogi@....com>
> ---
>   drivers/i2c/busses/Kconfig                 |  10 +
>   drivers/i2c/busses/Makefile                |   1 +
>   drivers/i2c/busses/i2c-designware-amdisp.c | 266 +++++++++++++++++++++
>   drivers/i2c/busses/i2c-designware-amdisp.h |  24 ++
>   4 files changed, 301 insertions(+)
>   create mode 100644 drivers/i2c/busses/i2c-designware-amdisp.c
>   create mode 100644 drivers/i2c/busses/i2c-designware-amdisp.h
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index fc438f445771..79448211baae 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -592,6 +592,16 @@ config I2C_DESIGNWARE_PLATFORM
>   	  This driver can also be built as a module.  If so, the module
>   	  will be called i2c-designware-platform.
>   
> +config I2C_DESIGNWARE_AMDISP
> +	tristate "Synopsys DesignWare Platform for AMDISP"
> +	depends on I2C_DESIGNWARE_CORE
> +	help
> +	  If you say yes to this option, support will be included for the
> +	  AMDISP Synopsys DesignWare I2C adapter.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called amd_isp_i2c_designware.
> +
>   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.
> + */
> +
> +#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>

Can you please audit this list for accuracy?  It seems like a very large 
number of headers.

Just off the bat for example I didn't see any DMI use, so dmi.h probably 
isn't needed.  I suspect there are others.

> +
> +#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))
> +
> +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),
> +				   GFP_KERNEL);
> +	if (!isp_i2c_dev)
> +		return -ENOMEM;
> +
> +	dev = &isp_i2c_dev->dw_dev;
> +	dev->dev = &pdev->dev;
> +
> +	/**
> +	 * 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);
> +		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;

Would it be better to allocate an IDA here?

> +
> +	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));
> +
> +	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);
> +		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);

I see 3 cases that isp_power_set(false) is called above:
* success
* failure exit probe
* failure exit

exit_probe falls through to exit, which means it's called twice.  That 
seems to be a mistake to me.

But since it's also called in the success flow this makes me wonder if 
it's better to use a macro like _free() which will automatically call 
isp_power_set(false) when the function exits.

Furthermore; are you missing a call to isp_power_set(true) in runtime 
resume and isp_power_set(false) in runtime suspend?  It would seem 
logical to me that when runtime suspended the tile is off and when on 
runtime resumed it's back on.

> +	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);
> +
> +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.
> + */
> +
> +int isp_power_set(int on);

Where does this symbol actually come from?  I didn't see it in this series.

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