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, "_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