[PATCH 06/14 v5] drm/i915/intel_i2c: gmbus disabled and reserved ports are invalid

Daniel Kurtz
2012-03-28T12:53:28Z

There is no GMBUS "disabled" port 0, nor "reserved" port 7.
For the other 6 ports there is a fixed 1:1 mapping between pin pairs and
gmbus ports, which means every real gmbus port has a gpio pin.

Given these realizations, clean up gmbus initialization.

Tested on Sandybridge (gen 6, PCH == CougarPoint) hardware.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
---
drivers/gpu/drm/i915/i915_drv.h | 3 +-
drivers/gpu/drm/i915/i915_reg.h | 2 +-
drivers/gpu/drm/i915/intel_i2c.c | 70 ++++++++++++++-----------------------
3 files changed, 29 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 44e6430..c5ad7b9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -303,7 +303,6 @@ struct intel_fbc_work;
struct intel_gmbus {
struct i2c_adapter adapter;
bool force_bit;
- bool has_gpio;
u32 reg0;
u32 gpio_reg;
struct i2c_algo_bit_data bit_algo;
@@ -1344,7 +1343,7 @@ extern int intel_setup_gmbus(struct drm_device *dev);
extern void intel_teardown_gmbus(struct drm_device *dev);
extern inline bool intel_gmbus_is_port_valid(unsigned port)
{
- return (port >= GMBUS_PORT_DISABLED && port <= GMBUS_PORT_RESERVED);
+ return (port >= GMBUS_PORT_SSC && port <= GMBUS_PORT_DPD);
}

extern struct i2c_adapter *intel_gmbus_get_adapter(
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index accd8ee..a8d218c 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -744,7 +744,7 @@
#define GMBUS_PORT_DPB 5 /* SDVO, HDMIB */
#define GMBUS_PORT_DPD 6 /* HDMID */
#define GMBUS_PORT_RESERVED 7 /* 7 reserved */
-#define GMBUS_NUM_PORTS 8
+#define GMBUS_NUM_PORTS (GMBUS_PORT_DPD - GMBUS_PORT_SSC + 1)
#define GMBUS1 0x5104 /* command/status */
#define GMBUS_SW_CLR_INT (1<<31)
#define GMBUS_SW_RDY (1<<30)
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index 2f65d01..dcde6f6 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -35,6 +35,20 @@
#include "i915_drm.h"
#include "i915_drv.h"

+struct gmbus_port {
+ const char *name;
+ int reg;
+};
+
+static const struct gmbus_port gmbus_ports[] = {
+ { "ssc", GPIOB },
+ { "vga", GPIOA },
+ { "panel", GPIOC },
+ { "dpc", GPIOD },
+ { "dpb", GPIOE },
+ { "dpd", GPIOF },
+};
+
/* Intel GPIO access functions */

#define I2C_RISEFALL_TIME 10
@@ -166,29 +180,16 @@ intel_gpio_post_xfer(struct i2c_adapter *adapter)
intel_i2c_quirk_set(dev_priv, false);
}

-static bool
+static void
intel_gpio_setup(struct intel_gmbus *bus, u32 pin)
{
struct drm_i915_private *dev_priv = bus->dev_priv;
- static const int map_pin_to_reg[] = {
- 0,
- GPIOB,
- GPIOA,
- GPIOC,
- GPIOD,
- GPIOE,
- GPIOF,
- 0,
- };
struct i2c_algo_bit_data *algo;

- if (pin >= ARRAY_SIZE(map_pin_to_reg) || !map_pin_to_reg[pin])
- return false;
-
algo = &bus->bit_algo;

- bus->gpio_reg = map_pin_to_reg[pin];
- bus->gpio_reg += dev_priv->gpio_mmio_base;
+ /* -1 to map pin pair to gmbus index */
+ bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_ports[pin - 1].reg;

bus->adapter.algo_data = algo;
algo->setsda = set_data;
@@ -200,8 +201,6 @@ intel_gpio_setup(struct intel_gmbus *bus, u32 pin)
algo->udelay = I2C_RISEFALL_TIME;
algo->timeout = usecs_to_jiffies(2200);
algo->data = bus;
-
- return true;
}

static int
@@ -351,15 +350,9 @@ timeout:
bus->adapter.name, bus->reg0 & 0xff);
I915_WRITE(GMBUS0 + reg_offset, 0);

- /* Hardware may not support GMBUS over these pins?
- * Try GPIO bitbanging instead.
- */
- if (!bus->has_gpio) {
- ret = -EIO;
- } else {
- bus->force_bit = true;
- ret = i2c_bit_algo.master_xfer(adapter, msgs, num);
- }
+ /* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
+ bus->force_bit = true;
+ ret = i2c_bit_algo.master_xfer(adapter, msgs, num);

out:
mutex_unlock(&dev_priv->gmbus_mutex);
@@ -386,16 +379,6 @@ static const struct i2c_algorithm gmbus_algorithm = {
*/
int intel_setup_gmbus(struct drm_device *dev)
{
- static const char *names[GMBUS_NUM_PORTS] = {
- "disabled",
- "ssc",
- "vga",
- "panel",
- "dpc",
- "dpb",
- "dpd",
- "reserved",
- };
struct drm_i915_private *dev_priv = dev->dev_private;
int ret, i;

@@ -413,13 +396,14 @@ int intel_setup_gmbus(struct drm_device *dev)

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 */

bus->adapter.owner = THIS_MODULE;
bus->adapter.class = I2C_CLASS_DDC;
snprintf(bus->adapter.name,
sizeof(bus->adapter.name),
"i915 gmbus %s",
- names[i]);
+ gmbus_ports[i].name);

bus->adapter.dev.parent = &dev->pdev->dev;
bus->dev_priv = dev_priv;
@@ -430,9 +414,9 @@ int intel_setup_gmbus(struct drm_device *dev)
goto err;

/* By default use a conservative clock rate */
- bus->reg0 = i | GMBUS_RATE_100KHZ;
+ bus->reg0 = port | GMBUS_RATE_100KHZ;

- bus->has_gpio = intel_gpio_setup(bus, i);
+ intel_gpio_setup(bus, port);
}

intel_i2c_reset(dev_priv->dev);
@@ -453,8 +437,9 @@ struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
unsigned port)
{
WARN_ON(!intel_gmbus_is_port_valid(port));
+ /* -1 to map pin pair to gmbus index */
return (intel_gmbus_is_port_valid(port)) ?
- &dev_priv->gmbus[port].adapter : NULL;
+ &dev_priv->gmbus[port - 1].adapter : NULL;
}

void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
@@ -468,8 +453,7 @@ void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
{
struct intel_gmbus *bus = to_intel_gmbus(adapter);

- if (bus->has_gpio)
- bus->force_bit = force_bit;
+ bus->force_bit = force_bit;
}

void intel_teardown_gmbus(struct drm_device *dev)
--
1.7.7.3