i2c: amd-isp: Add ISP i2c-designware driver

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.

Co-developed-by: Venkata Narendra Kumar Gutta <vengutta@amd.com>
Signed-off-by: Venkata Narendra Kumar Gutta <vengutta@amd.com>
Co-developed-by: Bin Du <bin.du@amd.com>
Signed-off-by: Bin Du <bin.du@amd.com>
Signed-off-by: Pratap Nirujogi <pratap.nirujogi@amd.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20250424184952.1290019-1-pratap.nirujogi@amd.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

MAINTAINERS

@@ -23619,6 +23619,13 @@ L:	linux-i2c@vger.kernel.org
 S:	Supported
 F:	drivers/i2c/busses/i2c-designware-*
 
+SYNOPSYS DESIGNWARE I2C DRIVER - AMDISP
+M:	Nirujogi Pratap <pratap.nirujogi@amd.com>
+M:	Bin Du <bin.du@amd.com>
+L:	linux-i2c@vger.kernel.org
+S:	Maintained
+F:	drivers/i2c/busses/i2c-designware-amdisp.c
+
 SYNOPSYS DESIGNWARE MMC/SD/SDIO DRIVER
 M:	Jaehoon Chung <jh80.chung@samsung.com>
 L:	linux-mmc@vger.kernel.org

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

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

drivers/i2c/busses/i2c-designware-amdisp.c

@@ -0,0 +1,205 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Based on Synopsys DesignWare I2C adapter driver.
+ *
+ * Copyright (C) 2025 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include "i2c-designware-core.h"
+
+#define DRV_NAME		"amd_isp_i2c_designware"
+#define AMD_ISP_I2C_INPUT_CLK	100 /* Mhz */
+
+static void amd_isp_dw_i2c_plat_pm_cleanup(struct dw_i2c_dev *i2c_dev)
+{
+	pm_runtime_disable(i2c_dev->dev);
+
+	if (i2c_dev->shared_with_punit)
+		pm_runtime_put_noidle(i2c_dev->dev);
+}
+
+static inline u32 amd_isp_dw_i2c_get_clk_rate(struct dw_i2c_dev *i2c_dev)
+{
+	return AMD_ISP_I2C_INPUT_CLK * 1000;
+}
+
+static int amd_isp_dw_i2c_plat_probe(struct platform_device *pdev)
+{
+	struct dw_i2c_dev *isp_i2c_dev;
+	struct i2c_adapter *adap;
+	int ret;
+
+	isp_i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*isp_i2c_dev), GFP_KERNEL);
+	if (!isp_i2c_dev)
+		return -ENOMEM;
+	isp_i2c_dev->dev = &pdev->dev;
+
+	pdev->dev.init_name = DRV_NAME;
+
+	/*
+	 * Use the polling mode to send/receive the data, because
+	 * no IRQ connection from ISP I2C
+	 */
+	isp_i2c_dev->flags |= ACCESS_POLLING;
+	platform_set_drvdata(pdev, isp_i2c_dev);
+
+	isp_i2c_dev->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(isp_i2c_dev->base))
+		return dev_err_probe(&pdev->dev, PTR_ERR(isp_i2c_dev->base),
+				     "failed to get IOMEM resource\n");
+
+	isp_i2c_dev->get_clk_rate_khz = amd_isp_dw_i2c_get_clk_rate;
+	ret = i2c_dw_fw_parse_and_configure(isp_i2c_dev);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "failed to parse i2c dw fwnode and configure\n");
+
+	i2c_dw_configure(isp_i2c_dev);
+
+	adap = &isp_i2c_dev->adapter;
+	adap->owner = THIS_MODULE;
+	ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev));
+	adap->dev.of_node = pdev->dev.of_node;
+	/* use dynamically allocated adapter id */
+	adap->nr = -1;
+
+	if (isp_i2c_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);
+
+	if (isp_i2c_dev->shared_with_punit)
+		pm_runtime_get_noresume(&pdev->dev);
+
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+
+	ret = i2c_dw_probe(isp_i2c_dev);
+	if (ret) {
+		dev_err_probe(&pdev->dev, ret, "i2c_dw_probe failed\n");
+		goto error_release_rpm;
+	}
+
+	pm_runtime_put_sync(&pdev->dev);
+
+	return 0;
+
+error_release_rpm:
+	amd_isp_dw_i2c_plat_pm_cleanup(isp_i2c_dev);
+	pm_runtime_put_sync(&pdev->dev);
+	return ret;
+}
+
+static void amd_isp_dw_i2c_plat_remove(struct platform_device *pdev)
+{
+	struct dw_i2c_dev *isp_i2c_dev = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	i2c_del_adapter(&isp_i2c_dev->adapter);
+
+	i2c_dw_disable(isp_i2c_dev);
+
+	pm_runtime_put_sync(&pdev->dev);
+	amd_isp_dw_i2c_plat_pm_cleanup(isp_i2c_dev);
+}
+
+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);
+	int ret;
+
+	if (!i_dev)
+		return -ENODEV;
+
+	ret = amd_isp_dw_i2c_plat_runtime_suspend(dev);
+	if (!ret)
+		i2c_mark_adapter_suspended(&i_dev->adapter);
+
+	return ret;
+}
+
+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)
+		return -ENODEV;
+
+	if (!i_dev->shared_with_punit)
+		i2c_dw_prepare_clk(i_dev, true);
+	if (i_dev->init)
+		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	= DRV_NAME,
+		.pm	= pm_ptr(&amd_isp_dw_i2c_dev_pm_ops),
+	},
+};
+module_platform_driver(amd_isp_dw_i2c_driver);
+
+MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter in AMD ISP");
+MODULE_IMPORT_NS("I2C_DW");
+MODULE_IMPORT_NS("I2C_DW_COMMON");
+MODULE_AUTHOR("Venkata Narendra Kumar Gutta <vengutta@amd.com>");
+MODULE_AUTHOR("Pratap Nirujogi <pratap.nirujogi@amd.com>");
+MODULE_AUTHOR("Bin Du <bin.du@amd.com>");
+MODULE_LICENSE("GPL");