mtd: docg3: add suspend and resume

Add functions to powerdown and powerup from suspend, in
order to save power.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Reviewed-by: Ivan Djelic <ivan.djelic@parrot.com>
Reviewed-by: Mike Dunn <mikedunn@newsguy.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

2 files changed, 80 insertions, 1 deletions

diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index 26cc17909b16..d94c759d3ea7 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -45,7 +45,6 @@
  * As no specification is available from M-Systems/Sandisk, this drivers lacks
  * several functions available on the chip, as :
  *  - IPL write
- *  - powerdown / powerup
  *
  * The bus data width (8bits versus 16bits) is not handled (if_cfg flag), and
  * the driver assumes a 16bits data bus.
@@ -1756,6 +1755,78 @@ static void doc_release_device(struct mtd_info *mtd)
 }
 
 /**
+ * docg3_resume - Awakens docg3 floor
+ * @pdev: platfrom device
+ *
+ * Returns 0 (always successfull)
+ */
+static int docg3_resume(struct platform_device *pdev)
+{
+        int i;
+        struct mtd_info **docg3_floors, *mtd;
+        struct docg3 *docg3;
+
+        docg3_floors = platform_get_drvdata(pdev);
+        mtd = docg3_floors[0];
+        docg3 = mtd->priv;
+
+        doc_dbg("docg3_resume()\n");
+        for (i = 0; i < 12; i++)
+                doc_readb(docg3, DOC_IOSPACE_IPL);
+        return 0;
+}
+
+/**
+ * docg3_suspend - Put in low power mode the docg3 floor
+ * @pdev: platform device
+ * @state: power state
+ *
+ * Shuts off most of docg3 circuitery to lower power consumption.
+ *
+ * Returns 0 if suspend succeeded, -EIO if chip refused suspend
+ */
+static int docg3_suspend(struct platform_device *pdev, pm_message_t state)
+{
+        int floor, i;
+        struct mtd_info **docg3_floors, *mtd;
+        struct docg3 *docg3;
+        u8 ctrl, pwr_down;
+
+        docg3_floors = platform_get_drvdata(pdev);
+        for (floor = 0; floor < DOC_MAX_NBFLOORS; floor++) {
+                mtd = docg3_floors[floor];
+                if (!mtd)
+                        continue;
+                docg3 = mtd->priv;
+
+                doc_writeb(docg3, floor, DOC_DEVICESELECT);
+                ctrl = doc_register_readb(docg3, DOC_FLASHCONTROL);
+                ctrl &= ~DOC_CTRL_VIOLATION & ~DOC_CTRL_CE;
+                doc_writeb(docg3, ctrl, DOC_FLASHCONTROL);
+
+                for (i = 0; i < 10; i++) {
+                        usleep_range(3000, 4000);
+                        pwr_down = doc_register_readb(docg3, DOC_POWERMODE);
+                        if (pwr_down & DOC_POWERDOWN_READY)
+                                break;
+                }
+                if (pwr_down & DOC_POWERDOWN_READY) {
+                        doc_dbg("docg3_suspend(): floor %d powerdown ok\n",
+                                floor);
+                } else {
+                        doc_err("docg3_suspend(): floor %d powerdown failed\n",
+                                floor);
+                        return -EIO;
+                }
+        }
+
+        mtd = docg3_floors[0];
+        docg3 = mtd->priv;
+        doc_set_asic_mode(docg3, DOC_ASICMODE_POWERDOWN);
+        return 0;
+}
+
+/**
  * doc_probe - Probe the IO space for a DiskOnChip G3 chip
  * @pdev: platform device
  *
@@ -1860,6 +1931,8 @@ static struct platform_driver g3_driver = {
                 .name   = "docg3",
                 .owner  = THIS_MODULE,
         },
+        .suspend        = docg3_suspend,
+        .resume         = docg3_resume,
         .remove         = __exit_p(docg3_release),
 };
 
diff --git a/drivers/mtd/devices/docg3.h b/drivers/mtd/devices/docg3.h
index 33db7272c460..cd70b181f797 100644
--- a/drivers/mtd/devices/docg3.h
+++ b/drivers/mtd/devices/docg3.h
@@ -127,6 +127,7 @@
 
 #define DOC_ASICMODECONFIRM             0x1072
 #define DOC_CHIPID_INV                  0x1074
+#define DOC_POWERMODE                   0x107c
 
 /*
  * Flash sequences
@@ -239,6 +240,11 @@
 #define DOC_READADDR_ADDR_MASK          0x1fff
 
 /*
+ * Flash register : DOC_POWERMODE
+ */
+#define DOC_POWERDOWN_READY             0x80
+
+/*
  * Status of erase and write operation
  */
 #define DOC_PLANES_STATUS_FAIL          0x01