diff options
Diffstat (limited to 'drivers/cpuidle/cpuidle-at91.c')
-rw-r--r-- | drivers/cpuidle/cpuidle-at91.c | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-at91.c b/drivers/cpuidle/cpuidle-at91.c new file mode 100644 index 000000000..f2446c78d --- /dev/null +++ b/drivers/cpuidle/cpuidle-at91.c @@ -0,0 +1,66 @@ +/* + * based on arch/arm/mach-kirkwood/cpuidle.c + * + * CPU idle support for AT91 SoC + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * The cpu idle uses wait-for-interrupt and RAM self refresh in order + * to implement two idle states - + * #1 wait-for-interrupt + * #2 wait-for-interrupt and RAM self refresh + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/cpuidle.h> +#include <linux/io.h> +#include <linux/export.h> +#include <asm/cpuidle.h> + +#define AT91_MAX_STATES 2 + +static void (*at91_standby)(void); + +/* Actual code that puts the SoC in different idle states */ +static int at91_enter_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, + int index) +{ + at91_standby(); + return index; +} + +static struct cpuidle_driver at91_idle_driver = { + .name = "at91_idle", + .owner = THIS_MODULE, + .states[0] = ARM_CPUIDLE_WFI_STATE, + .states[1] = { + .enter = at91_enter_idle, + .exit_latency = 10, + .target_residency = 10000, + .name = "RAM_SR", + .desc = "WFI and DDR Self Refresh", + }, + .state_count = AT91_MAX_STATES, +}; + +/* Initialize CPU idle by registering the idle states */ +static int at91_cpuidle_probe(struct platform_device *dev) +{ + at91_standby = (void *)(dev->dev.platform_data); + + return cpuidle_register(&at91_idle_driver, NULL); +} + +static struct platform_driver at91_cpuidle_driver = { + .driver = { + .name = "cpuidle-at91", + }, + .probe = at91_cpuidle_probe, +}; + +module_platform_driver(at91_cpuidle_driver); |