1 /* 2 * based on arch/arm/mach-kirkwood/cpuidle.c 3 * 4 * CPU idle support for AT91 SoC 5 * 6 * This file is licensed under the terms of the GNU General Public 7 * License version 2. This program is licensed "as is" without any 8 * warranty of any kind, whether express or implied. 9 * 10 * The cpu idle uses wait-for-interrupt and RAM self refresh in order 11 * to implement two idle states - 12 * #1 wait-for-interrupt 13 * #2 wait-for-interrupt and RAM self refresh 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/init.h> 18 #include <linux/platform_device.h> 19 #include <linux/cpuidle.h> 20 #include <linux/io.h> 21 #include <linux/export.h> 22 #include <asm/cpuidle.h> 23 24 #define AT91_MAX_STATES 2 25 26 static void (*at91_standby)(void); 27 28 /* Actual code that puts the SoC in different idle states */ 29 static int at91_enter_idle(struct cpuidle_device *dev, 30 struct cpuidle_driver *drv, 31 int index) 32 { 33 at91_standby(); 34 return index; 35 } 36 37 static struct cpuidle_driver at91_idle_driver = { 38 .name = "at91_idle", 39 .owner = THIS_MODULE, 40 .states[0] = ARM_CPUIDLE_WFI_STATE, 41 .states[1] = { 42 .enter = at91_enter_idle, 43 .exit_latency = 10, 44 .target_residency = 10000, 45 .name = "RAM_SR", 46 .desc = "WFI and DDR Self Refresh", 47 }, 48 .state_count = AT91_MAX_STATES, 49 }; 50 51 /* Initialize CPU idle by registering the idle states */ 52 static int at91_cpuidle_probe(struct platform_device *dev) 53 { 54 at91_standby = (void *)(dev->dev.platform_data); 55 56 return cpuidle_register(&at91_idle_driver, NULL); 57 } 58 59 static struct platform_driver at91_cpuidle_driver = { 60 .driver = { 61 .name = "cpuidle-at91", 62 }, 63 .probe = at91_cpuidle_probe, 64 }; 65 builtin_platform_driver(at91_cpuidle_driver); 66