[PATCH v2 3/4] mtd: devices: elm: Low power transition support

Philip Avinash
2013-02-07T12:36:57Z

In low power modes of AM335X platforms, peripherals power is cut off.
This patch supports low power sleep transition support for ELM driver.

Signed-off-by: Philip Avinash <avinashphilip@ti.com>
---
drivers/mtd/devices/elm.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)

diff --git a/drivers/mtd/devices/elm.c b/drivers/mtd/devices/elm.c
index f034239..a9ac8f2 100644
--- a/drivers/mtd/devices/elm.c
+++ b/drivers/mtd/devices/elm.c
@@ -20,6 +20,7 @@
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
+#include <linux/sched.h>
#include <linux/pm_runtime.h>
#include <linux/platform_data/elm.h>

@@ -62,6 +63,7 @@ struct elm_info {
struct completion elm_completion;
struct list_head list;
enum bch_ecc bch_type;
+ bool idle;
};

static LIST_HEAD(elm_devices);
@@ -86,9 +88,11 @@ void elm_config(struct device *dev, enum bch_ecc bch_type)
u32 reg_val;
struct elm_info *info = dev_get_drvdata(dev);

+ info->idle = true;
reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
info->bch_type = bch_type;
+ info->idle = false;
}
EXPORT_SYMBOL(elm_config);

@@ -280,6 +284,7 @@ void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
struct elm_info *info = dev_get_drvdata(dev);
u32 reg_val;

+ info->idle = true;
/* Enable page mode interrupt */
reg_val = elm_read_reg(info, ELM_IRQSTATUS);
elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
@@ -298,6 +303,7 @@ void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
reg_val = elm_read_reg(info, ELM_IRQENABLE);
elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
elm_error_correction(info, err_vec);
+ info->idle = false;
}
EXPORT_SYMBOL(elm_decode_bch_error_page);

@@ -368,6 +374,7 @@ static int elm_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&info->list);
list_add(&info->list, &elm_devices);
platform_set_drvdata(pdev, info);
+ info->idle = false;
return ret;
}

@@ -379,6 +386,38 @@ static int elm_remove(struct platform_device *pdev)
return 0;
}

+static int elm_suspend(struct device *dev)
+{
+ struct elm_info *info = dev_get_drvdata(dev);
+ wait_queue_head_t wq;
+ DECLARE_WAITQUEUE(wait, current);
+
+ init_waitqueue_head(&wq);
+ while (1) {
+ /* Make sure that ELM not running */
+ if (info->idle) {
+ add_wait_queue(&wq, &wait);
+ schedule();
+ remove_wait_queue(&wq, &wait);
+ } else {
+ break;
+ }
+ }
+ pm_runtime_put_sync(dev);
+ return 0;
+}
+
+static int elm_resume(struct device *dev)
+{
+ struct elm_info *info = dev_get_drvdata(dev);
+
+ pm_runtime_get_sync(dev);
+ elm_config(dev, info->bch_type);
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
+
#ifdef CONFIG_OF
static const struct of_device_id elm_of_match[] = {
{ .compatible = "ti,am3352-elm" },
@@ -392,6 +431,7 @@ static struct platform_driver elm_driver = {
.name = "elm",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(elm_of_match),
+ .pm = &elm_pm_ops,
},
.probe = elm_probe,
.remove = elm_remove,
--
1.7.9.5