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drm/i915/intel_i2c: gmbus disabled and reserved ports are invalid
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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>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Daniel Kurtz authored and Daniel Vetter committed Mar 28, 2012
1 parent 3bd7d90 commit 2ed06c9
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Showing 3 changed files with 29 additions and 46 deletions.
3 changes: 1 addition & 2 deletions drivers/gpu/drm/i915/i915_drv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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(
Expand Down
2 changes: 1 addition & 1 deletion drivers/gpu/drm/i915/i915_reg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down
70 changes: 27 additions & 43 deletions drivers/gpu/drm/i915/intel_i2c.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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;
Expand All @@ -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
Expand Down Expand Up @@ -351,15 +350,9 @@ gmbus_xfer(struct i2c_adapter *adapter,
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);
Expand All @@ -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;

Expand All @@ -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;
Expand All @@ -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);
Expand All @@ -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)
Expand All @@ -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)
Expand Down

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