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/proc-fns.h> 23 #include <asm/cpuidle.h> 24 25 #define AT91_MAX_STATES 2 26 27 static void (*at91_standby)(void); 28 29 /* Actual code that puts the SoC in different idle states */ 30 static int at91_enter_idle(struct cpuidle_device *dev, 31 struct cpuidle_driver *drv, 32 int index) 33 { 34 at91_standby(); 35 return index; 36 } 37 38 static struct cpuidle_driver at91_idle_driver = { 39 .name = "at91_idle", 40 .owner = THIS_MODULE, 41 .states[0] = ARM_CPUIDLE_WFI_STATE, 42 .states[1] = { 43 .enter = at91_enter_idle, 44 .exit_latency = 10, 45 .target_residency = 10000, 46 .name = "RAM_SR", 47 .desc = "WFI and DDR Self Refresh", 48 }, 49 .state_count = AT91_MAX_STATES, 50 }; 51 52 /* Initialize CPU idle by registering the idle states */ 53 static int at91_cpuidle_probe(struct platform_device *dev) 54 { 55 at91_standby = (void *)(dev->dev.platform_data); 56 57 return cpuidle_register(&at91_idle_driver, NULL); 58 } 59 60 static struct platform_driver at91_cpuidle_driver = { 61 .driver = { 62 .name = "cpuidle-at91", 63 }, 64 .probe = at91_cpuidle_probe, 65 }; 66 67 module_platform_driver(at91_cpuidle_driver); 68