1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * based on arch/arm/mach-kirkwood/cpuidle.c
4 *
5 * CPU idle support for AT91 SoC
6 *
7 * The cpu idle uses wait-for-interrupt and RAM self refresh in order
8 * to implement two idle states -
9 * #1 wait-for-interrupt
10 * #2 wait-for-interrupt and RAM self refresh
11 */
12
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/platform_device.h>
16#include <linux/cpuidle.h>
17#include <linux/io.h>
18#include <linux/export.h>
19#include <asm/cpuidle.h>
20
21#define AT91_MAX_STATES	2
22
23static void (*at91_standby)(void);
24
25/* Actual code that puts the SoC in different idle states */
26static int at91_enter_idle(struct cpuidle_device *dev,
27			struct cpuidle_driver *drv,
28			       int index)
29{
30	at91_standby();
31	return index;
32}
33
34static struct cpuidle_driver at91_idle_driver = {
35	.name			= "at91_idle",
36	.owner			= THIS_MODULE,
37	.states[0]		= ARM_CPUIDLE_WFI_STATE,
38	.states[1]		= {
39		.enter			= at91_enter_idle,
40		.exit_latency		= 10,
41		.target_residency	= 10000,
42		.name			= "RAM_SR",
43		.desc			= "WFI and DDR Self Refresh",
44	},
45	.state_count = AT91_MAX_STATES,
46};
47
48/* Initialize CPU idle by registering the idle states */
49static int at91_cpuidle_probe(struct platform_device *dev)
50{
51	at91_standby = (void *)(dev->dev.platform_data);
52
53	return cpuidle_register(&at91_idle_driver, NULL);
54}
55
56static struct platform_driver at91_cpuidle_driver = {
57	.driver = {
58		.name = "cpuidle-at91",
59	},
60	.probe = at91_cpuidle_probe,
61};
62builtin_platform_driver(at91_cpuidle_driver);
63