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 23 static void (*at91_standby)(void); 24 25 /* Actual code that puts the SoC in different idle states */ 26 static 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 34 static 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 */ 49 static 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 56 static struct platform_driver at91_cpuidle_driver = { 57 .driver = { 58 .name = "cpuidle-at91", 59 }, 60 .probe = at91_cpuidle_probe, 61 }; 62 builtin_platform_driver(at91_cpuidle_driver); 63