linux/drivers/gpu/drm/i915/intel_i2c.c
Chris Wilson cb8ea7527b drm/i915: Use i2c bit banging instead of GMBUS
There are several reported instances of GMBUS failing to successfully
read the EDID, so revert back to bit banging until the issue is
resolved.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=30371
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
2010-09-28 13:35:47 +01:00

453 lines
11 KiB
C

/*
* Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
* Copyright © 2006-2008,2010 Intel Corporation
* Jesse Barnes <jesse.barnes@intel.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Authors:
* Eric Anholt <eric@anholt.net>
* Chris Wilson <chris@chris-wilson.co.uk>
*/
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include "drmP.h"
#include "drm.h"
#include "intel_drv.h"
#include "i915_drm.h"
#include "i915_drv.h"
/* Intel GPIO access functions */
#define I2C_RISEFALL_TIME 20
static inline struct intel_gmbus *
to_intel_gmbus(struct i2c_adapter *i2c)
{
return container_of(i2c, struct intel_gmbus, adapter);
}
struct intel_gpio {
struct i2c_adapter adapter;
struct i2c_algo_bit_data algo;
struct drm_i915_private *dev_priv;
u32 reg;
};
void
intel_i2c_reset(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
if (HAS_PCH_SPLIT(dev))
I915_WRITE(PCH_GMBUS0, 0);
else
I915_WRITE(GMBUS0, 0);
}
static void intel_i2c_quirk_set(struct drm_i915_private *dev_priv, bool enable)
{
u32 val;
/* When using bit bashing for I2C, this bit needs to be set to 1 */
if (!IS_PINEVIEW(dev_priv->dev))
return;
val = I915_READ(DSPCLK_GATE_D);
if (enable)
val |= DPCUNIT_CLOCK_GATE_DISABLE;
else
val &= ~DPCUNIT_CLOCK_GATE_DISABLE;
I915_WRITE(DSPCLK_GATE_D, val);
}
static u32 get_reserved(struct intel_gpio *gpio)
{
struct drm_i915_private *dev_priv = gpio->dev_priv;
struct drm_device *dev = dev_priv->dev;
u32 reserved = 0;
/* On most chips, these bits must be preserved in software. */
if (!IS_I830(dev) && !IS_845G(dev))
reserved = I915_READ(gpio->reg) & (GPIO_DATA_PULLUP_DISABLE |
GPIO_CLOCK_PULLUP_DISABLE);
return reserved;
}
static int get_clock(void *data)
{
struct intel_gpio *gpio = data;
struct drm_i915_private *dev_priv = gpio->dev_priv;
u32 reserved = get_reserved(gpio);
I915_WRITE(gpio->reg, reserved | GPIO_CLOCK_DIR_MASK);
I915_WRITE(gpio->reg, reserved);
return (I915_READ(gpio->reg) & GPIO_CLOCK_VAL_IN) != 0;
}
static int get_data(void *data)
{
struct intel_gpio *gpio = data;
struct drm_i915_private *dev_priv = gpio->dev_priv;
u32 reserved = get_reserved(gpio);
I915_WRITE(gpio->reg, reserved | GPIO_DATA_DIR_MASK);
I915_WRITE(gpio->reg, reserved);
return (I915_READ(gpio->reg) & GPIO_DATA_VAL_IN) != 0;
}
static void set_clock(void *data, int state_high)
{
struct intel_gpio *gpio = data;
struct drm_i915_private *dev_priv = gpio->dev_priv;
u32 reserved = get_reserved(gpio);
u32 clock_bits;
if (state_high)
clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
else
clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
GPIO_CLOCK_VAL_MASK;
I915_WRITE(gpio->reg, reserved | clock_bits);
POSTING_READ(gpio->reg);
}
static void set_data(void *data, int state_high)
{
struct intel_gpio *gpio = data;
struct drm_i915_private *dev_priv = gpio->dev_priv;
u32 reserved = get_reserved(gpio);
u32 data_bits;
if (state_high)
data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
else
data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
GPIO_DATA_VAL_MASK;
I915_WRITE(gpio->reg, reserved | data_bits);
POSTING_READ(gpio->reg);
}
static struct i2c_adapter *
intel_gpio_create(struct drm_i915_private *dev_priv, u32 pin)
{
static const int map_pin_to_reg[] = {
0,
GPIOB,
GPIOA,
GPIOC,
GPIOD,
GPIOE,
GPIOF,
};
struct intel_gpio *gpio;
if (pin < 1 || pin > 7)
return NULL;
gpio = kzalloc(sizeof(struct intel_gpio), GFP_KERNEL);
if (gpio == NULL)
return NULL;
gpio->reg = map_pin_to_reg[pin];
if (HAS_PCH_SPLIT(dev_priv->dev))
gpio->reg += PCH_GPIOA - GPIOA;
gpio->dev_priv = dev_priv;
snprintf(gpio->adapter.name, I2C_NAME_SIZE, "GPIO%c", "?BACDEF?"[pin]);
gpio->adapter.owner = THIS_MODULE;
gpio->adapter.algo_data = &gpio->algo;
gpio->adapter.dev.parent = &dev_priv->dev->pdev->dev;
gpio->algo.setsda = set_data;
gpio->algo.setscl = set_clock;
gpio->algo.getsda = get_data;
gpio->algo.getscl = get_clock;
gpio->algo.udelay = I2C_RISEFALL_TIME;
gpio->algo.timeout = usecs_to_jiffies(2200);
gpio->algo.data = gpio;
if (i2c_bit_add_bus(&gpio->adapter))
goto out_free;
return &gpio->adapter;
out_free:
kfree(gpio);
return NULL;
}
static int
intel_i2c_quirk_xfer(struct drm_i915_private *dev_priv,
struct i2c_adapter *adapter,
struct i2c_msg *msgs,
int num)
{
struct intel_gpio *gpio = container_of(adapter,
struct intel_gpio,
adapter);
int ret;
intel_i2c_reset(dev_priv->dev);
intel_i2c_quirk_set(dev_priv, true);
set_data(gpio, 1);
set_clock(gpio, 1);
udelay(I2C_RISEFALL_TIME);
ret = adapter->algo->master_xfer(adapter, msgs, num);
set_data(gpio, 1);
set_clock(gpio, 1);
intel_i2c_quirk_set(dev_priv, false);
return ret;
}
static int
gmbus_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs,
int num)
{
struct intel_gmbus *bus = container_of(adapter,
struct intel_gmbus,
adapter);
struct drm_i915_private *dev_priv = adapter->algo_data;
int i, reg_offset;
if (bus->force_bit)
return intel_i2c_quirk_xfer(dev_priv,
bus->force_bit, msgs, num);
reg_offset = HAS_PCH_SPLIT(dev_priv->dev) ? PCH_GMBUS0 - GMBUS0 : 0;
I915_WRITE(GMBUS0 + reg_offset, bus->reg0);
for (i = 0; i < num; i++) {
u16 len = msgs[i].len;
u8 *buf = msgs[i].buf;
if (msgs[i].flags & I2C_M_RD) {
I915_WRITE(GMBUS1 + reg_offset,
GMBUS_CYCLE_WAIT | (i + 1 == num ? GMBUS_CYCLE_STOP : 0) |
(len << GMBUS_BYTE_COUNT_SHIFT) |
(msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
GMBUS_SLAVE_READ | GMBUS_SW_RDY);
POSTING_READ(GMBUS2+reg_offset);
do {
u32 val, loop = 0;
if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
goto timeout;
if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
return 0;
val = I915_READ(GMBUS3 + reg_offset);
do {
*buf++ = val & 0xff;
val >>= 8;
} while (--len && ++loop < 4);
} while (len);
} else {
u32 val, loop;
val = loop = 0;
do {
val |= *buf++ << (8 * loop);
} while (--len && ++loop < 4);
I915_WRITE(GMBUS3 + reg_offset, val);
I915_WRITE(GMBUS1 + reg_offset,
(i + 1 == num ? GMBUS_CYCLE_STOP : GMBUS_CYCLE_WAIT) |
(msgs[i].len << GMBUS_BYTE_COUNT_SHIFT) |
(msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
POSTING_READ(GMBUS2+reg_offset);
while (len) {
if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
goto timeout;
if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
return 0;
val = loop = 0;
do {
val |= *buf++ << (8 * loop);
} while (--len && ++loop < 4);
I915_WRITE(GMBUS3 + reg_offset, val);
POSTING_READ(GMBUS2+reg_offset);
}
}
if (i + 1 < num && wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), 50))
goto timeout;
if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
return 0;
}
return num;
timeout:
DRM_INFO("GMBUS timed out, falling back to bit banging on pin %d [%s]\n",
bus->reg0 & 0xff, bus->adapter.name);
/* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */
bus->force_bit = intel_gpio_create(dev_priv, bus->reg0 & 0xff);
if (!bus->force_bit)
return -ENOMEM;
return intel_i2c_quirk_xfer(dev_priv, bus->force_bit, msgs, num);
}
static u32 gmbus_func(struct i2c_adapter *adapter)
{
struct intel_gmbus *bus = container_of(adapter,
struct intel_gmbus,
adapter);
if (bus->force_bit)
bus->force_bit->algo->functionality(bus->force_bit);
return (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
/* I2C_FUNC_10BIT_ADDR | */
I2C_FUNC_SMBUS_READ_BLOCK_DATA |
I2C_FUNC_SMBUS_BLOCK_PROC_CALL);
}
static const struct i2c_algorithm gmbus_algorithm = {
.master_xfer = gmbus_xfer,
.functionality = gmbus_func
};
/**
* intel_gmbus_setup - instantiate all Intel i2c GMBuses
* @dev: DRM device
*/
int intel_setup_gmbus(struct drm_device *dev)
{
static const char *names[GMBUS_NUM_PORTS] = {
"disabled",
"ssc",
"vga",
"panel",
"dpc",
"dpb",
"reserved"
"dpd",
};
struct drm_i915_private *dev_priv = dev->dev_private;
int ret, i;
dev_priv->gmbus = kcalloc(sizeof(struct intel_gmbus), GMBUS_NUM_PORTS,
GFP_KERNEL);
if (dev_priv->gmbus == NULL)
return -ENOMEM;
for (i = 0; i < GMBUS_NUM_PORTS; i++) {
struct intel_gmbus *bus = &dev_priv->gmbus[i];
bus->adapter.owner = THIS_MODULE;
bus->adapter.class = I2C_CLASS_DDC;
snprintf(bus->adapter.name,
I2C_NAME_SIZE,
"gmbus %s",
names[i]);
bus->adapter.dev.parent = &dev->pdev->dev;
bus->adapter.algo_data = dev_priv;
bus->adapter.algo = &gmbus_algorithm;
ret = i2c_add_adapter(&bus->adapter);
if (ret)
goto err;
/* By default use a conservative clock rate */
bus->reg0 = i | GMBUS_RATE_100KHZ;
/* XXX force bit banging until GMBUS is fully debugged */
bus->force_bit = intel_gpio_create(dev_priv, i);
}
intel_i2c_reset(dev_priv->dev);
return 0;
err:
while (--i) {
struct intel_gmbus *bus = &dev_priv->gmbus[i];
i2c_del_adapter(&bus->adapter);
}
kfree(dev_priv->gmbus);
dev_priv->gmbus = NULL;
return ret;
}
void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
{
struct intel_gmbus *bus = to_intel_gmbus(adapter);
/* speed:
* 0x0 = 100 KHz
* 0x1 = 50 KHz
* 0x2 = 400 KHz
* 0x3 = 1000 Khz
*/
bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | (speed << 8);
}
void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
{
struct intel_gmbus *bus = to_intel_gmbus(adapter);
if (force_bit) {
if (bus->force_bit == NULL) {
struct drm_i915_private *dev_priv = adapter->algo_data;
bus->force_bit = intel_gpio_create(dev_priv,
bus->reg0 & 0xff);
}
} else {
if (bus->force_bit) {
i2c_del_adapter(bus->force_bit);
kfree(bus->force_bit);
bus->force_bit = NULL;
}
}
}
void intel_teardown_gmbus(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
int i;
if (dev_priv->gmbus == NULL)
return;
for (i = 0; i < GMBUS_NUM_PORTS; i++) {
struct intel_gmbus *bus = &dev_priv->gmbus[i];
if (bus->force_bit) {
i2c_del_adapter(bus->force_bit);
kfree(bus->force_bit);
}
i2c_del_adapter(&bus->adapter);
}
kfree(dev_priv->gmbus);
dev_priv->gmbus = NULL;
}