drm/linux-core/nv50_i2c.c

401 lines
7.8 KiB
C

/*
* Copyright (C) 2008 Maarten Maathuis.
* All Rights Reserved.
*
* 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 COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS 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.
*
*/
/* This is largely a clone from xorg i2c functions, as i had serious trouble getting an i2c_bit_algo adaptor running. */
#include "nv50_i2c.h"
static uint32_t nv50_i2c_port(int index)
{
uint32_t port = 0;
switch (index) {
case 0:
port = NV50_PCONNECTOR_I2C_PORT_0;
break;
case 1:
port = NV50_PCONNECTOR_I2C_PORT_1;
break;
case 2:
port = NV50_PCONNECTOR_I2C_PORT_2;
break;
case 3:
port = NV50_PCONNECTOR_I2C_PORT_3;
break;
case 4:
port = NV50_PCONNECTOR_I2C_PORT_4;
break;
case 5:
port = NV50_PCONNECTOR_I2C_PORT_5;
break;
default:
break;
}
if (!port) {
DRM_ERROR("Invalid i2c port, returning 0.\n");
BUG();
}
return port;
}
static void nv50_i2c_set_bits(struct nv50_i2c_channel *chan, int clock_high, int data_high)
{
struct drm_nouveau_private *dev_priv = chan->dev->dev_private;
uint32_t port = nv50_i2c_port(chan->index);
if (!port)
return;
NV_WRITE(port, 4 | (data_high << 1) | clock_high);
}
static void nv50_i2c_get_bits(struct nv50_i2c_channel *chan, int *clock_high, int *data_high)
{
struct drm_nouveau_private *dev_priv = chan->dev->dev_private;
uint32_t port = nv50_i2c_port(chan->index);
uint32_t val;
if (!port)
return;
val = NV_READ(port);
if (val & 1)
*clock_high = 1;
else
*clock_high = 0;
if (val & 2)
*data_high = 1;
else
*data_high = 0;
}
static bool nv50_i2c_raise_clock(struct nv50_i2c_channel *chan, int data)
{
int i, clock;
nv50_i2c_set_bits(chan, 1, data);
udelay(2);
for (i = 2200; i > 0; i -= 2) {
nv50_i2c_get_bits(chan, &clock, &data);
if (clock)
return true;
udelay(2);
}
printk("a timeout occured in nv50_i2c_raise_clock\n");
return false;
}
static bool nv50_i2c_start(struct nv50_i2c_channel *chan)
{
if (!nv50_i2c_raise_clock(chan, 1))
return false;
nv50_i2c_set_bits(chan, 1, 0);
udelay(5);
nv50_i2c_set_bits(chan, 0, 0);
udelay(5);
return true;
}
static void nv50_i2c_stop(struct nv50_i2c_channel *chan)
{
nv50_i2c_set_bits(chan, 0, 0);
udelay(2);
nv50_i2c_set_bits(chan, 1, 0);
udelay(5);
nv50_i2c_set_bits(chan, 1, 1);
udelay(5);
}
static bool nv50_i2c_write_bit(struct nv50_i2c_channel *chan, int data)
{
bool rval;
nv50_i2c_set_bits(chan, 0, data);
udelay(2);
rval = nv50_i2c_raise_clock(chan, data);
udelay(5);
nv50_i2c_set_bits(chan, 0, data);
udelay(5);
return rval;
}
static bool nv50_i2c_read_bit(struct nv50_i2c_channel *chan, int *data)
{
bool rval;
int clock;
rval = nv50_i2c_raise_clock(chan, 1);
udelay(5);
nv50_i2c_get_bits(chan, &clock, data);
udelay(5);
nv50_i2c_set_bits(chan, 0, 1);
udelay(5);
return rval;
}
static bool nv50_i2c_write_byte(struct nv50_i2c_channel *chan, uint8_t byte)
{
bool rval;
int i, clock, data;
for (i = 7; i >= 0; i--)
if (!nv50_i2c_write_bit(chan, (byte >> i) & 1))
return false;
nv50_i2c_set_bits(chan, 0, 1);
udelay(5);
rval = nv50_i2c_raise_clock(chan, 1);
if (rval) {
for (i = 40; i > 0; i -= 2) {
udelay(2);
nv50_i2c_get_bits(chan, &clock, &data);
if (data == 0)
break;
}
if (i <= 0) {
printk("a timeout occured in nv50_i2c_write_byte\n");
rval = false;
}
}
nv50_i2c_set_bits(chan, 0, 1);
udelay(5);
return rval;
}
static bool nv50_i2c_read_byte(struct nv50_i2c_channel *chan, uint8_t *byte, bool last)
{
int i, bit;
nv50_i2c_set_bits(chan, 0, 1);
udelay(5);
*byte = 0;
for (i = 7; i >= 0; i--) {
if (nv50_i2c_read_bit(chan, &bit)) {
if (bit)
*byte |= (1 << i);
} else {
return false;
}
}
if (!nv50_i2c_write_bit(chan, last ? 1 : 0))
return false;
return true;
}
/* only 7 bits addresses. */
static bool nv50_i2c_address(struct nv50_i2c_channel *chan, uint8_t address, bool write)
{
if (nv50_i2c_start(chan)) {
uint8_t real_addr = (address << 1);
if (!write)
real_addr |= 1;
if (nv50_i2c_write_byte(chan, real_addr))
return true;
/* failure, so issue stop */
nv50_i2c_stop(chan);
}
return false;
}
static bool nv50_i2c_read(struct nv50_i2c_channel *chan, uint8_t address, uint8_t *buffer, uint32_t length)
{
int i, j;
bool rval, last;
/* retries */
for (i = 0; i < 4; i++) {
rval = nv50_i2c_address(chan, address, false);
if (!rval)
return false;
for (j = 0; j < length; j++) {
last = false;
if (j == (length - 1))
last = true;
rval = nv50_i2c_read_byte(chan, &buffer[j], last);
if (!rval) {
nv50_i2c_stop(chan);
break;
}
}
nv50_i2c_stop(chan);
/* done */
if (rval)
break;
}
if (!rval)
printk("nv50_i2c_read failed\n");
return rval;
}
static bool nv50_i2c_write(struct nv50_i2c_channel *chan, uint8_t address, uint8_t *buffer, uint32_t length)
{
int i, j;
bool rval;
/* retries */
for (i = 0; i < 4; i++) {
rval = nv50_i2c_address(chan, address, true);
if (!rval)
return false;
for (j = 0; j < length; j++) {
rval = nv50_i2c_write_byte(chan, buffer[j]);
if (!rval) {
break;
}
}
nv50_i2c_stop(chan);
/* done */
if (rval)
break;
}
if (!rval)
printk("nv50_i2c_write failed\n");
return rval;
}
static int nv50_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
{
struct nv50_i2c_channel *chan = i2c_get_adapdata(i2c_adap);
bool rval;
int i;
for (i = 0; i < num; i++) {
if (msgs[i].flags & I2C_M_RD) { /* read */
rval = nv50_i2c_read(chan, msgs[i].addr, msgs[i].buf, msgs[i].len);
} else { /* write */
rval = nv50_i2c_write(chan, msgs[i].addr, msgs[i].buf, msgs[i].len);
}
if (!rval)
break;
}
if (rval)
return i;
else
return -EINVAL;
}
static u32 nv50_i2c_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C;
}
static const struct i2c_algorithm nv50_i2c_algo = {
.master_xfer = nv50_i2c_xfer,
.functionality = nv50_i2c_functionality,
};
static int nv50_i2c_register_bus(struct i2c_adapter *adap)
{
adap->algo = &nv50_i2c_algo;
adap->timeout = 40;
adap->retries = 4;
return i2c_add_adapter(adap);
}
#define I2C_HW_B_NOUVEAU 0x010030
struct nv50_i2c_channel *nv50_i2c_channel_create(struct drm_device *dev, uint32_t index)
{
struct nv50_i2c_channel *chan;
chan = kzalloc(sizeof(struct nv50_i2c_channel), GFP_KERNEL);
if (!chan)
goto out;
DRM_INFO("Creating i2c bus with index %d\n", index);
chan->dev = dev;
chan->index = index;
snprintf(chan->adapter.name, I2C_NAME_SIZE, "nv50 i2c %d", index);
chan->adapter.owner = THIS_MODULE;
chan->adapter.id = I2C_HW_B_NOUVEAU;
chan->adapter.dev.parent = &dev->pdev->dev;
i2c_set_adapdata(&chan->adapter, chan);
if (nv50_i2c_register_bus(&chan->adapter))
goto out;
return chan;
out:
kfree(chan);
return NULL;
}
void nv50_i2c_channel_destroy(struct nv50_i2c_channel *chan)
{
if (!chan)
return;
i2c_del_adapter(&chan->adapter);
kfree(chan);
}