V4L/DVB (9421): We must wait for the PLL to stabilize

Thanks to Peter for the in depth explanation

Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/media/dvb/ttpci/budget-ci.c b/drivers/media/dvb/ttpci/budget-ci.c
index 6b77b123f75c..21f5e2c6b4c0 100644
--- a/drivers/media/dvb/ttpci/budget-ci.c
+++ b/drivers/media/dvb/ttpci/budget-ci.c
@@ -1768,6 +1768,29 @@ static void frontend_init(struct budget_ci *budget_ci)
                 break;
 
         case 0x1019:            // TT S2-3200 PCI
+                /*
+                 * NOTE! on some STB0899 versions, the internal PLL takes a longer time
+                 * to settle, aka LOCK. On the older revisions of the chip, we don't see
+                 * this, as a result on the newer chips the entire clock tree, will not
+                 * be stable after a freshly POWER 'ed up situation.
+                 * In this case, we should RESET the STB0899 (Active LOW) and wait for
+                 * PLL stabilization.
+                 *
+                 * On the TT S2 3200 and clones, the STB0899 demodulator's RESETB is
+                 * connected to the SAA7146 GPIO, GPIO2, Pin 142
+                 */
+                /* Reset Demodulator */
+                saa7146_setgpio(budget->dev, 2, SAA7146_GPIO_OUTLO);
+                /* Wait for everything to die */
+                msleep(50);
+                /* Pull it up out of Reset state */
+                saa7146_setgpio(budget->dev, 2, SAA7146_GPIO_OUTHI);
+                /* Wait for PLL to stabilize */
+                msleep(250);
+                /*
+                 * PLL state should be stable now. Ideally, we should check
+                 * for PLL LOCK status. But well, never mind!
+                 */
                 budget_ci->budget.dvb_frontend = dvb_attach(stb0899_attach, &tt3200_config, &budget_ci->budget.i2c_adap);
                 if (budget_ci->budget.dvb_frontend) {
                         if (dvb_attach(stb6100_attach, budget_ci->budget.dvb_frontend, &tt3200_stb6100_config, &budget_ci->budget.i2c_adap)) {