| 1 | // SPDX-License-Identifier: GPL-2.0 |
|---|---|
| 2 | /* |
| 3 | * Intel BayTrail PMIC I2C bus semaphore implementation |
| 4 | * Copyright (c) 2014, Intel Corporation. |
| 5 | */ |
| 6 | #include <linux/device.h> |
| 7 | #include <linux/acpi.h> |
| 8 | #include <linux/i2c.h> |
| 9 | #include <linux/interrupt.h> |
| 10 | |
| 11 | #include <asm/iosf_mbi.h> |
| 12 | |
| 13 | #include "i2c-designware-core.h" |
| 14 | |
| 15 | int i2c_dw_baytrail_probe_lock_support(struct dw_i2c_dev *dev) |
| 16 | { |
| 17 | acpi_status status; |
| 18 | unsigned long long shared_host = 0; |
| 19 | acpi_handle handle; |
| 20 | |
| 21 | if (!dev) |
| 22 | return -ENODEV; |
| 23 | |
| 24 | handle = ACPI_HANDLE(dev->dev); |
| 25 | if (!handle) |
| 26 | return -ENODEV; |
| 27 | |
| 28 | status = acpi_evaluate_integer(handle, pathname: "_SEM", NULL, data: &shared_host); |
| 29 | if (ACPI_FAILURE(status)) |
| 30 | return -ENODEV; |
| 31 | |
| 32 | if (!shared_host) |
| 33 | return -ENODEV; |
| 34 | |
| 35 | if (!iosf_mbi_available()) |
| 36 | return -EPROBE_DEFER; |
| 37 | |
| 38 | dev_info(dev->dev, "I2C bus managed by PUNIT\n"); |
| 39 | dev->acquire_lock = iosf_mbi_block_punit_i2c_access; |
| 40 | dev->release_lock = iosf_mbi_unblock_punit_i2c_access; |
| 41 | dev->shared_with_punit = true; |
| 42 | |
| 43 | return 0; |
| 44 | } |
| 45 |