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 
i2c_dw_baytrail_probe_lock_support(struct dw_i2c_dev * dev)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, "_SEM", NULL, &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