V4L/DVB (8068): cx18: Add I2C slave reset via GPIO upon initialization

cx18: Add I2C slave reset via GPIO upon initialization.  One user,
Michael <msd4824@yahoo.com>, has reported this allows his HVR-1600 EEPROM to
be consistently recognized when using (long,) 100 msec delays.   The delays in
this commit are nominal (10 & 40 msec) and need testing/tuning on boards with
I2C problems to find the right values.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 25 insertions, 1 deletions

diff --git a/drivers/media/video/cx18/cx18-gpio.c b/drivers/media/video/cx18/cx18-gpio.c
index ceb63653c926..b302833f6f9d 100644
--- a/drivers/media/video/cx18/cx18-gpio.c
+++ b/drivers/media/video/cx18/cx18-gpio.c
@@ -53,10 +53,34 @@ static void gpio_write(struct cx18 *cx)
         write_reg(((dir & 0xffff) << 16) | (val & 0xffff),
                         CX18_REG_GPIO_OUT1);
         write_reg(dir & 0xffff0000, CX18_REG_GPIO_DIR2);
-        write_reg((dir & 0xffff0000) | ((val & 0xffff0000) >> 16),
+        write_reg_sync((dir & 0xffff0000) | ((val & 0xffff0000) >> 16),
                         CX18_REG_GPIO_OUT2);
 }
 
+void cx18_reset_i2c_slaves_gpio(struct cx18 *cx)
+{
+        const struct cx18_gpio_i2c_slave_reset *p;
+
+        p = &cx->card->gpio_i2c_slave_reset;
+
+        if ((p->active_lo_mask | p->active_hi_mask) == 0)
+                return;
+
+        /* Assuming that the masks are a subset of the bits in gpio_dir */
+
+        /* Assert */
+        cx->gpio_val =
+                (cx->gpio_val | p->active_hi_mask) & ~(p->active_lo_mask);
+        gpio_write(cx);
+        schedule_timeout_uninterruptible(msecs_to_jiffies(p->msecs_asserted));
+
+        /* Deassert */
+        cx->gpio_val =
+                (cx->gpio_val | p->active_lo_mask) & ~(p->active_hi_mask);
+        gpio_write(cx);
+        schedule_timeout_uninterruptible(msecs_to_jiffies(p->msecs_recovery));
+}
+
 void cx18_gpio_init(struct cx18 *cx)
 {
         cx->gpio_dir = cx->card->gpio_init.direction;