| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Intel BayTrail PMIC I2C bus semaphore implementation |
| * Copyright (c) 2014, Intel Corporation. |
| */ |
| #include <linux/device.h> |
| #include <linux/acpi.h> |
| #include <linux/i2c.h> |
| #include <linux/interrupt.h> |
| |
| #include <asm/iosf_mbi.h> |
| |
| #include "i2c-designware-core.h" |
| |
| int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev) |
| { |
| acpi_status status; |
| unsigned long long shared_host = 0; |
| acpi_handle handle; |
| |
| if (!dev || !dev->dev) |
| return 0; |
| |
| handle = ACPI_HANDLE(dev->dev); |
| if (!handle) |
| return 0; |
| |
| status = acpi_evaluate_integer(handle, "_SEM", NULL, &shared_host); |
| if (ACPI_FAILURE(status)) |
| return 0; |
| |
| if (!shared_host) |
| return 0; |
| |
| if (!iosf_mbi_available()) |
| return -EPROBE_DEFER; |
| |
| dev_info(dev->dev, "I2C bus managed by PUNIT\n"); |
| dev->acquire_lock = iosf_mbi_block_punit_i2c_access; |
| dev->release_lock = iosf_mbi_unblock_punit_i2c_access; |
| dev->shared_with_punit = true; |
| |
| return 0; |
| } |
