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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright © 2006-2007 Intel Corporation
*
* Authors:
* Eric Anholt <eric@anholt.net>
*/
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/i2c-algo-bit.h>
#include <linux/i2c.h>
#include "psb_drv.h"
#include "psb_intel_reg.h"
/*
* Intel GPIO access functions
*/
#define I2C_RISEFALL_TIME 20
static int get_clock(void *data)
{
struct psb_intel_i2c_chan *chan = data;
struct drm_device *dev = chan->drm_dev;
u32 val;
val = REG_READ(chan->reg);
return (val & GPIO_CLOCK_VAL_IN) != 0;
}
static int get_data(void *data)
{
struct psb_intel_i2c_chan *chan = data;
struct drm_device *dev = chan->drm_dev;
u32 val;
val = REG_READ(chan->reg);
return (val & GPIO_DATA_VAL_IN) != 0;
}
static void set_clock(void *data, int state_high)
{
struct psb_intel_i2c_chan *chan = data;
struct drm_device *dev = chan->drm_dev;
u32 reserved = 0, clock_bits;
/* On most chips, these bits must be preserved in software. */
reserved =
REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
GPIO_CLOCK_PULLUP_DISABLE);
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;
REG_WRITE(chan->reg, reserved | clock_bits);
udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
}
static void set_data(void *data, int state_high)
{
struct psb_intel_i2c_chan *chan = data;
struct drm_device *dev = chan->drm_dev;
u32 reserved = 0, data_bits;
/* On most chips, these bits must be preserved in software. */
reserved =
REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
GPIO_CLOCK_PULLUP_DISABLE);
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;
REG_WRITE(chan->reg, reserved | data_bits);
udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
}
/**
* psb_intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
* @dev: DRM device
* @reg: GPIO reg to use
* @name: name for this bus
*
* Creates and registers a new i2c bus with the Linux i2c layer, for use
* in output probing and control (e.g. DDC or SDVO control functions).
*
* Possible values for @reg include:
* %GPIOA
* %GPIOB
* %GPIOC
* %GPIOD
* %GPIOE
* %GPIOF
* %GPIOG
* %GPIOH
* see PRM for details on how these different busses are used.
*/
struct psb_intel_i2c_chan *psb_intel_i2c_create(struct drm_device *dev,
const u32 reg, const char *name)
{
struct psb_intel_i2c_chan *chan;
chan = kzalloc(sizeof(struct psb_intel_i2c_chan), GFP_KERNEL);
if (!chan)
goto out_free;
chan->drm_dev = dev;
chan->reg = reg;
snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
chan->adapter.owner = THIS_MODULE;
chan->adapter.algo_data = &chan->algo;
chan->adapter.dev.parent = dev->dev;
chan->algo.setsda = set_data;
chan->algo.setscl = set_clock;
chan->algo.getsda = get_data;
chan->algo.getscl = get_clock;
chan->algo.udelay = 20;
chan->algo.timeout = usecs_to_jiffies(2200);
chan->algo.data = chan;
i2c_set_adapdata(&chan->adapter, chan);
if (i2c_bit_add_bus(&chan->adapter))
goto out_free;
/* JJJ: raise SCL and SDA? */
set_data(chan, 1);
set_clock(chan, 1);
udelay(20);
return chan;
out_free:
kfree(chan);
return NULL;
}
/**
* psb_intel_i2c_destroy - unregister and free i2c bus resources
* @chan: channel to free
*
* Unregister the adapter from the i2c layer, then free the structure.
*/
void psb_intel_i2c_destroy(struct psb_intel_i2c_chan *chan)
{
if (!chan)
return;
i2c_del_adapter(&chan->adapter);
kfree(chan);
}
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