linux-kernel - Re: [PATCH] i2c: amd-isp: Add ISP i2c-designware driver

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Message-ID: <0c714314-c5b0-4815-9e74-47d2402e8852@wanadoo.fr>
Date: Sat, 1 Mar 2025 09:32:30 +0100
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
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

Le 28/02/2025 à 17:45, Pratap Nirujogi a écrit :
> 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>

...

> 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 */

I think that this should be // comment style for SPDX-License-Identifier 
en c files.

> +/*
> + * Copyright 2024-2025 Advanced Micro Devices, Inc.
> + *

...

> +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(*isp_i2c_dev) maybe?

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

Just /*

> +	 * 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 dev_err_probe() would make code slightly simpler.

> +		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);
> +	}

Unneeded { } in both branches.

> +
> +	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);

dev_err_probe() would make code slightly simpler.

> +		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);

Is it needed? (there is apparently no reset_control_deassert() in this 
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");

MIT is stated in SPDX-License-Identifier

> +MODULE_IMPORT_NS("I2C_DW");
> +MODULE_IMPORT_NS("I2C_DW_COMMON");
> +MODULE_LICENSE("GPL and additional rights");

Is it allowed to have several MODULE_LICENSE?

...

CJ