[PATCH v2] mtd: m25p80: Add Power Management support

[Hou Zhiqiang <b48286@freescale.com>]

Add PM support using callback function suspend and resume in
.driver.pm of spi_driver.

Signed-off-by: Hou Zhiqiang <b48286@freescale.com>
---
v2:
 - Replace .driver.suspend and .driver.resume with .driver.pm
 - Use CONFIG_PM_SLEEP instead of CONFIG_PM

 drivers/mtd/devices/m25p80.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 7eda71d..eb558e8 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -66,6 +66,8 @@
 
 /* Used for Spansion flashes only. */
 #define	OPCODE_BRWR		0x17	/* Bank register write */
+#define	OPCODE_DP		0xb9	/* Enter deep power down mode */
+#define	OPCODE_RES		0xab	/* Exit deep power down mode */
 
 /* Status Register bits. */
 #define	SR_WIP			1	/* Write in progress */
@@ -1128,11 +1130,46 @@ static int m25p_remove(struct spi_device *spi)
 	return mtd_device_unregister(&flash->mtd);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int m25p_suspend(struct device *dev)
+{
+	struct m25p *flash = dev_get_drvdata(dev);
+	int ret;
+
+	flash->command[0] = OPCODE_DP;
+	mutex_lock(&flash->lock);
+	/* Wait until finished previous write/erase command. */
+	ret = wait_till_ready(flash);
+	if (ret) {
+		mutex_unlock(&flash->lock);
+		return ret;
+	}
+	ret = spi_write(flash->spi, flash->command, 1);
+	mutex_unlock(&flash->lock);
+
+	return ret;
+}
+
+static int m25p_resume(struct device *dev)
+{
+	struct m25p *flash = dev_get_drvdata(dev);
+	int ret;
+
+	flash->command[0] = OPCODE_RES;
+
+	return spi_write(flash->spi, flash->command, 1);
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops m25p_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(m25p_suspend, m25p_resume)
+};
 
 static struct spi_driver m25p80_driver = {
 	.driver = {
 		.name	= "m25p80",
 		.owner	= THIS_MODULE,
+		.pm	= &m25p_pm,
 	},
 	.id_table	= m25p_ids,
 	.probe	= m25p_probe,
-- 
1.8.4.1