V4L/DVB (5690): Cafe_ccic: Properly power down the sensor

The proper method for powering down the sensor on OLPC systems has
changed somewhat; in particular, the sensor must be powered down
completely (rather than simply told to power down) or the associated
"camera active" LED will stay on.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

2 files changed, 23 insertions, 1 deletions

diff --git a/drivers/media/video/cafe_ccic-regs.h b/drivers/media/video/cafe_ccic-regs.h
index b2c22a0d664..8e2a87cdc79 100644
--- a/drivers/media/video/cafe_ccic-regs.h
+++ b/drivers/media/video/cafe_ccic-regs.h
@@ -150,6 +150,12 @@
 #define REG_GL_IMASK   0x300c  /* Interrupt mask register */
 #define   GIMSK_CCIC_EN          0x00000004    /* CCIC Interrupt enable */
 
+#define REG_GL_FCR      0x3038  /* GPIO functional control register */
+#define   GFCR_GPIO_ON    0x08          /* Camera GPIO enabled */
+#define REG_GL_GPIOR    0x315c  /* GPIO register */
+#define   GGPIO_OUT             0x80000 /* GPIO output */
+#define   GGPIO_VAL             0x00008 /* Output pin value */
+
 #define REG_LEN                REG_GL_IMASK + 4
 
 
diff --git a/drivers/media/video/cafe_ccic.c b/drivers/media/video/cafe_ccic.c
index 96254dbaf62..c08f650df42 100644
--- a/drivers/media/video/cafe_ccic.c
+++ b/drivers/media/video/cafe_ccic.c
@@ -775,6 +775,12 @@ static void cafe_ctlr_power_up(struct cafe_camera *cam)
         spin_lock_irqsave(&cam->dev_lock, flags);
         cafe_reg_clear_bit(cam, REG_CTRL1, C1_PWRDWN);
         /*
+         * Part one of the sensor dance: turn the global
+         * GPIO signal on.
+         */
+        cafe_reg_write(cam, REG_GL_FCR, GFCR_GPIO_ON);
+        cafe_reg_write(cam, REG_GL_GPIOR, GGPIO_OUT|GGPIO_VAL);
+        /*
          * Put the sensor into operational mode (assumes OLPC-style
          * wiring).  Control 0 is reset - set to 1 to operate.
          * Control 1 is power down, set to 0 to operate.
@@ -784,6 +790,7 @@ static void cafe_ctlr_power_up(struct cafe_camera *cam)
         cafe_reg_write(cam, REG_GPR, GPR_C1EN|GPR_C0EN|GPR_C0);
 //      mdelay(1); /* Enough? */
         spin_unlock_irqrestore(&cam->dev_lock, flags);
+        msleep(5); /* Just to be sure */
 }
 
 static void cafe_ctlr_power_down(struct cafe_camera *cam)
@@ -792,6 +799,8 @@ static void cafe_ctlr_power_down(struct cafe_camera *cam)
 
         spin_lock_irqsave(&cam->dev_lock, flags);
         cafe_reg_write(cam, REG_GPR, GPR_C1EN|GPR_C0EN|GPR_C1);
+        cafe_reg_write(cam, REG_GL_FCR, GFCR_GPIO_ON);
+        cafe_reg_write(cam, REG_GL_GPIOR, GGPIO_OUT);
         cafe_reg_set_bit(cam, REG_CTRL1, C1_PWRDWN);
         spin_unlock_irqrestore(&cam->dev_lock, flags);
 }
@@ -851,6 +860,7 @@ static int cafe_cam_init(struct cafe_camera *cam)
         ret = 0;
         cam->state = S_IDLE;
   out:
+        cafe_ctlr_power_down(cam);
         mutex_unlock(&cam->s_mutex);
         return ret;
 }
@@ -2103,10 +2113,16 @@ static int cafe_pci_probe(struct pci_dev *pdev,
         ret = request_irq(pdev->irq, cafe_irq, IRQF_SHARED, "cafe-ccic", cam);
         if (ret)
                 goto out_iounmap;
+        /*
+         * Initialize the controller and leave it powered up.  It will
+         * stay that way until the sensor driver shows up.
+         */
         cafe_ctlr_init(cam);
         cafe_ctlr_power_up(cam);
         /*
-         * Set up I2C/SMBUS communications
+         * Set up I2C/SMBUS communications.  We have to drop the mutex here
+         * because the sensor could attach in this call chain, leading to
+         * unsightly deadlocks.
          */
         mutex_unlock(&cam->s_mutex);  /* attach can deadlock */
         ret = cafe_smbus_setup(cam);