xref: /aosp_15_r20/external/coreboot/src/ec/lenovo/h8/sense.c (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 
3 #include <ec/acpi/ec.h>
4 
5 #include "h8.h"
6 
7 /**
8  * Return the EC sense status register state.
9  *
10  * Observations showed the sense registers are all zero until the EC populates
11  * them after some time. Likely the EC sets all bits to it's valid state at
12  * once, but there's no prove as the firmware isn't available.
13  *
14  * Wait for any register having at least one bit set.
15  * Unlikely that all register will be zero after booting has finished.
16  *
17  * @return 1 if the EC provides valid data in sense status registers
18  */
h8_get_sense_ready(void)19 int h8_get_sense_ready(void)
20 {
21 	static const u8 regs[] = { H8_STATUS0, H8_STATUS1, H8_STATUS2,
22 			H8_STATUS3};
23 
24 	for (size_t i = 0; i < ARRAY_SIZE(regs); i++) {
25 		if (ec_read(regs[i]))
26 			return 1;
27 	}
28 
29 	return 0;
30 }
31 
32 /**
33  * Return the state of Fn key.
34  * Only valid if h8_get_sense_ready (see above) returns true.
35  *
36  * @return 1 if the key is pressed.
37  */
h8_get_fn_key(void)38 int h8_get_fn_key(void)
39 {
40 	return ec_read(H8_STATUS0) & H8_STATUS0_FN_KEY_DOWN;
41 }
42