drm/i915: index gmbus tables using the pin pair number

Index the gmbus tables directly using the pin instead of having a
confusing "port = i + 1" mapping. This finishes off removing the "gmbus
port" as a notion, and leaves us with just the "gmbus pin".

As pin 0 is invalid by definition and the gmbus tables will have a gap
at that index, add pin validity check to all the loops. This will be
benefitial for supporting platforms that have different numbers of pins,
or gaps.

v2: s/GMBUS_PIN_MAX/GMBUS_NUM_PINS/ (Ville, Daniel)

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 38 insertions, 27 deletions

diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index b0003a2bd854..ff47a8fdcb6d 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -34,18 +34,19 @@
 #include <drm/i915_drm.h>
 #include "i915_drv.h"
 
-struct gmbus_port {
+struct gmbus_pin {
         const char *name;
         int reg;
 };
 
-static const struct gmbus_port gmbus_ports[] = {
-        { "ssc", GPIOB },
-        { "vga", GPIOA },
-        { "panel", GPIOC },
-        { "dpc", GPIOD },
-        { "dpb", GPIOE },
-        { "dpd", GPIOF },
+/* Map gmbus pin pairs to names and registers. */
+static const struct gmbus_pin gmbus_pins[] = {
+        [GMBUS_PIN_SSC] = { "ssc", GPIOB },
+        [GMBUS_PIN_VGADDC] = { "vga", GPIOA },
+        [GMBUS_PIN_PANEL] = { "panel", GPIOC },
+        [GMBUS_PIN_DPC] = { "dpc", GPIOD },
+        [GMBUS_PIN_DPB] = { "dpb", GPIOE },
+        [GMBUS_PIN_DPD] = { "dpd", GPIOF },
 };
 
 /* Intel GPIO access functions */
@@ -182,15 +183,14 @@ intel_gpio_post_xfer(struct i2c_adapter *adapter)
 }
 
 static void
-intel_gpio_setup(struct intel_gmbus *bus, u32 pin)
+intel_gpio_setup(struct intel_gmbus *bus, unsigned int pin)
 {
         struct drm_i915_private *dev_priv = bus->dev_priv;
         struct i2c_algo_bit_data *algo;
 
         algo = &bus->bit_algo;
 
-        /* -1 to map pin pair to gmbus index */
-        bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_ports[pin - 1].reg;
+        bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_pins[pin].reg;
 
         bus->adapter.algo_data = algo;
         algo->setsda = set_data;
@@ -517,7 +517,9 @@ static const struct i2c_algorithm gmbus_algorithm = {
 int intel_setup_gmbus(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
-        int ret, i;
+        struct intel_gmbus *bus;
+        unsigned int pin;
+        int ret;
 
         if (HAS_PCH_NOP(dev))
                 return 0;
@@ -531,16 +533,18 @@ int intel_setup_gmbus(struct drm_device *dev)
         mutex_init(&dev_priv->gmbus_mutex);
         init_waitqueue_head(&dev_priv->gmbus_wait_queue);
 
-        for (i = 0; i < GMBUS_NUM_PORTS; i++) {
-                struct intel_gmbus *bus = &dev_priv->gmbus[i];
-                u32 port = i + 1; /* +1 to map gmbus index to pin pair */
+        for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
+                if (!intel_gmbus_is_valid_pin(pin))
+                        continue;
+
+                bus = &dev_priv->gmbus[pin];
 
                 bus->adapter.owner = THIS_MODULE;
                 bus->adapter.class = I2C_CLASS_DDC;
                 snprintf(bus->adapter.name,
                          sizeof(bus->adapter.name),
                          "i915 gmbus %s",
-                         gmbus_ports[i].name);
+                         gmbus_pins[pin].name);
 
                 bus->adapter.dev.parent = &dev->pdev->dev;
                 bus->dev_priv = dev_priv;
@@ -548,13 +552,13 @@ int intel_setup_gmbus(struct drm_device *dev)
                 bus->adapter.algo = &gmbus_algorithm;
 
                 /* By default use a conservative clock rate */
-                bus->reg0 = port | GMBUS_RATE_100KHZ;
+                bus->reg0 = pin | GMBUS_RATE_100KHZ;
 
                 /* gmbus seems to be broken on i830 */
                 if (IS_I830(dev))
                         bus->force_bit = 1;
 
-                intel_gpio_setup(bus, port);
+                intel_gpio_setup(bus, pin);
 
                 ret = i2c_add_adapter(&bus->adapter);
                 if (ret)
@@ -566,8 +570,11 @@ int intel_setup_gmbus(struct drm_device *dev)
         return 0;
 
 err:
-        while (--i) {
-                struct intel_gmbus *bus = &dev_priv->gmbus[i];
+        while (--pin) {
+                if (!intel_gmbus_is_valid_pin(pin))
+                        continue;
+
+                bus = &dev_priv->gmbus[pin];
                 i2c_del_adapter(&bus->adapter);
         }
         return ret;
@@ -576,10 +583,10 @@ err:
 struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
                                             unsigned int pin)
 {
-        WARN_ON(!intel_gmbus_is_valid_pin(pin));
-        /* -1 to map pin pair to gmbus index */
-        return (intel_gmbus_is_valid_pin(pin)) ?
-                &dev_priv->gmbus[pin - 1].adapter : NULL;
+        if (WARN_ON(!intel_gmbus_is_valid_pin(pin)))
+                return NULL;
+
+        return &dev_priv->gmbus[pin].adapter;
 }
 
 void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
@@ -602,10 +609,14 @@ void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
 void intel_teardown_gmbus(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
-        int i;
+        struct intel_gmbus *bus;
+        unsigned int pin;
+
+        for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
+                if (!intel_gmbus_is_valid_pin(pin))
+                        continue;
 
-        for (i = 0; i < GMBUS_NUM_PORTS; i++) {
-                struct intel_gmbus *bus = &dev_priv->gmbus[i];
+                bus = &dev_priv->gmbus[pin];
                 i2c_del_adapter(&bus->adapter);
         }
 }