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>

5 files changed, 47 insertions, 2 deletions

diff --git a/drivers/media/video/cx18/cx18-cards.c b/drivers/media/video/cx18/cx18-cards.c
index c18865b0d6cc..bbf23fa459d6 100644
--- a/drivers/media/video/cx18/cx18-cards.c
+++ b/drivers/media/video/cx18/cx18-cards.c
@@ -82,6 +82,11 @@ static const struct cx18_card cx18_card_hvr1600_esmt = {
         },
         .gpio_init.initial_value = 0x3001,
         .gpio_init.direction = 0x3001,
+        .gpio_i2c_slave_reset = {
+                .active_lo_mask = 0x3001,
+                .msecs_asserted = 10,
+                .msecs_recovery = 40,
+        },
         .i2c = &cx18_i2c_std,
 };
 
@@ -122,6 +127,11 @@ static const struct cx18_card cx18_card_hvr1600_samsung = {
         },
         .gpio_init.initial_value = 0x3001,
         .gpio_init.direction = 0x3001,
+        .gpio_i2c_slave_reset = {
+                .active_lo_mask = 0x3001,
+                .msecs_asserted = 10,
+                .msecs_recovery = 40,
+        },
         .i2c = &cx18_i2c_std,
 };
 
diff --git a/drivers/media/video/cx18/cx18-cards.h b/drivers/media/video/cx18/cx18-cards.h
index 3c2c0b92956c..dc2dd945d4c3 100644
--- a/drivers/media/video/cx18/cx18-cards.h
+++ b/drivers/media/video/cx18/cx18-cards.h
@@ -78,6 +78,13 @@ struct cx18_gpio_init { /* set initial GPIO DIR and OUT values */
         u32 initial_value;
 };
 
+struct cx18_gpio_i2c_slave_reset {
+        u32 active_lo_mask; /* GPIO outputs that reset i2c chips when low */
+        u32 active_hi_mask; /* GPIO outputs that reset i2c chips when high */
+        int msecs_asserted; /* time period reset must remain asserted */
+        int msecs_recovery; /* time after deassert for chips to be ready */
+};
+
 struct cx18_card_tuner {
         v4l2_std_id std;        /* standard for which the tuner is suitable */
         int         tuner;      /* tuner ID (from tuner.h) */
@@ -114,7 +121,8 @@ struct cx18_card {
 
         /* GPIO card-specific settings */
         u8 xceive_pin;          /* XCeive tuner GPIO reset pin */
-        struct cx18_gpio_init           gpio_init;
+        struct cx18_gpio_init            gpio_init;
+        struct cx18_gpio_i2c_slave_reset gpio_i2c_slave_reset;
 
         struct cx18_card_tuner tuners[CX18_CARD_MAX_TUNERS];
         struct cx18_card_tuner_i2c *i2c;
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;
diff --git a/drivers/media/video/cx18/cx18-gpio.h b/drivers/media/video/cx18/cx18-gpio.h
index 41bac8856b50..525c328f748a 100644
--- a/drivers/media/video/cx18/cx18-gpio.h
+++ b/drivers/media/video/cx18/cx18-gpio.h
@@ -21,4 +21,5 @@
  */
 
 void cx18_gpio_init(struct cx18 *cx);
+void cx18_reset_i2c_slaves_gpio(struct cx18 *cx);
 int cx18_reset_tuner_gpio(void *dev, int cmd, int value);
diff --git a/drivers/media/video/cx18/cx18-i2c.c b/drivers/media/video/cx18/cx18-i2c.c
index 1d6c51a75313..680bc4e35b79 100644
--- a/drivers/media/video/cx18/cx18-i2c.c
+++ b/drivers/media/video/cx18/cx18-i2c.c
@@ -405,6 +405,8 @@ int init_cx18_i2c(struct cx18 *cx)
         cx18_setscl(&cx->i2c_algo_cb_data[1], 1);
         cx18_setsda(&cx->i2c_algo_cb_data[1], 1);
 
+        cx18_reset_i2c_slaves_gpio(cx);
+
         return i2c_bit_add_bus(&cx->i2c_adap[0]) ||
                 i2c_bit_add_bus(&cx->i2c_adap[1]);
 }