[Intel-gfx] [PATCH 5/5] drm/i915: add bxt gmbus support

[Jani Nikula]

From: "A.Sunil Kamath" <sunil.kamath at intel.com>

For BXT gmbus is pulled from GPU to CPU. From implementation point of
view only pin pair configuration will change. The existing
implementation supports all platforms previous to GEN8 and also SKL. But
for BXT pin pair configuration is completely different than SKL or other
previous GEN's. This patch introduces the new pin pair configuration
structure specific to BXT and also ensures every real gmbus port has a
gpio pin.

v3 by Jani: with the platform independent prep work in place, the bxt
enabling reduces to a fairly trivial patch. Credits are due Sunil for
giving me the ideas (with his patches) what the platform independent
parts should look like.

Issue: VIZ-3574
Signed-off-by: A.Sunil Kamath <sunil.kamath at intel.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h  |  3 +++
 drivers/gpu/drm/i915/intel_i2c.c | 29 +++++++++++++++++++++++------
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index cdc071cff001..b0dc506f2fd1 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1797,6 +1797,9 @@ enum skl_disp_power_wells {
 #define   GMBUS_PIN_DPB		5 /* SDVO, HDMIB */
 #define   GMBUS_PIN_DPD		6 /* HDMID */
 #define   GMBUS_PIN_RESERVED	7 /* 7 reserved */
+#define   GMBUS_PIN_1_BXT	1
+#define   GMBUS_PIN_2_BXT	2
+#define   GMBUS_PIN_3_BXT	3
 #define   GMBUS_PIN_MAX		7 /* not inclusive */
 #define GMBUS1			0x5104 /* command/status */
 #define   GMBUS_SW_CLR_INT	(1<<31)
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index ec9cc8cf642e..fd9cb6dcb84e 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -49,10 +49,20 @@ static const struct gmbus_pin gmbus_pins[] = {
 	[GMBUS_PIN_DPD] = { "dpd", GPIOF },
 };
 
+static const struct gmbus_pin gmbus_pins_bxt[] = {
+	[GMBUS_PIN_1_BXT] = { "dpb", PCH_GPIOB },
+	[GMBUS_PIN_2_BXT] = { "dpc", PCH_GPIOC },
+	[GMBUS_PIN_3_BXT] = { "misc", PCH_GPIOD },
+};
+
 bool intel_gmbus_is_valid_pin(struct drm_i915_private *dev_priv,
 			      unsigned int pin)
 {
-	return pin < ARRAY_SIZE(gmbus_pins) && gmbus_pins[pin].reg;
+	if (IS_BROXTON(dev_priv))
+		return pin < ARRAY_SIZE(gmbus_pins_bxt) &&
+			gmbus_pins_bxt[pin].reg;
+	else
+		return pin < ARRAY_SIZE(gmbus_pins) && gmbus_pins[pin].reg;
 }
 
 /* Intel GPIO access functions */
@@ -196,7 +206,10 @@ intel_gpio_setup(struct intel_gmbus *bus, unsigned int pin)
 
 	algo = &bus->bit_algo;
 
-	bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_pins[pin].reg;
+	if (IS_BROXTON(dev_priv))
+		bus->gpio_reg = gmbus_pins_bxt[pin].reg;
+	else
+		bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_pins[pin].reg;
 
 	bus->adapter.algo_data = algo;
 	algo->setsda = set_data;
@@ -540,6 +553,8 @@ int intel_setup_gmbus(struct drm_device *dev)
 	init_waitqueue_head(&dev_priv->gmbus_wait_queue);
 
 	for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
+		const char *name;
+
 		if (!intel_gmbus_is_valid_pin(dev_priv, pin))
 			continue;
 
@@ -547,10 +562,12 @@ int intel_setup_gmbus(struct drm_device *dev)
 
 		bus->adapter.owner = THIS_MODULE;
 		bus->adapter.class = I2C_CLASS_DDC;
-		snprintf(bus->adapter.name,
-			 sizeof(bus->adapter.name),
-			 "i915 gmbus %s",
-			 gmbus_pins[pin].name);
+		if (IS_BROXTON(dev_priv))
+			name = gmbus_pins_bxt[pin].name;
+		else
+			name = gmbus_pins[pin].name;
+		snprintf(bus->adapter.name, sizeof(bus->adapter.name),
+			 "i915 gmbus %s", name);
 
 		bus->adapter.dev.parent = &dev->pdev->dev;
 		bus->dev_priv = dev_priv;
-- 
2.1.4