1/*
  2 * Copyright 2012 Red Hat Inc.
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the
  6 * "Software"), to deal in the Software without restriction, including
  7 * without limitation the rights to use, copy, modify, merge, publish,
  8 * distribute, sub license, and/or sell copies of the Software, and to
  9 * permit persons to whom the Software is furnished to do so, subject to
 10 * the following conditions:
 11 *
 12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 13 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 14 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 15 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 16 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 17 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 18 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 19 *
 20 * The above copyright notice and this permission notice (including the
 21 * next paragraph) shall be included in all copies or substantial portions
 22 * of the Software.
 23 *
 24 */
 25/*
 26 * Authors: Dave Airlie <airlied@redhat.com>
 27 */
 28
 29#include <linux/export.h>
 30#include <linux/i2c-algo-bit.h>
 31#include <linux/i2c.h>
 32#include <linux/pci.h>
 33
 34#include "mgag200_drv.h"
 35
 36static int mga_i2c_read_gpio(struct mga_device *mdev)
 37{
 38	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
 39	return RREG8(DAC_DATA);
 40}
 41
 42static void mga_i2c_set_gpio(struct mga_device *mdev, int mask, int val)
 43{
 44	int tmp;
 45
 46	WREG8(DAC_INDEX, MGA1064_GEN_IO_CTL);
 47	tmp = (RREG8(DAC_DATA) & mask) | val;
 48	WREG_DAC(MGA1064_GEN_IO_CTL, tmp);
 49	WREG_DAC(MGA1064_GEN_IO_DATA, 0);
 50}
 51
 52static inline void mga_i2c_set(struct mga_device *mdev, int mask, int state)
 53{
 54	if (state)
 55		state = 0;
 56	else
 57		state = mask;
 58	mga_i2c_set_gpio(mdev, ~mask, state);
 59}
 60
 61static void mga_gpio_setsda(void *data, int state)
 62{
 63	struct mga_i2c_chan *i2c = data;
 64	struct mga_device *mdev = to_mga_device(i2c->dev);
 65	mga_i2c_set(mdev, i2c->data, state);
 66}
 67
 68static void mga_gpio_setscl(void *data, int state)
 69{
 70	struct mga_i2c_chan *i2c = data;
 71	struct mga_device *mdev = to_mga_device(i2c->dev);
 72	mga_i2c_set(mdev, i2c->clock, state);
 73}
 74
 75static int mga_gpio_getsda(void *data)
 76{
 77	struct mga_i2c_chan *i2c = data;
 78	struct mga_device *mdev = to_mga_device(i2c->dev);
 79	return (mga_i2c_read_gpio(mdev) & i2c->data) ? 1 : 0;
 80}
 81
 82static int mga_gpio_getscl(void *data)
 83{
 84	struct mga_i2c_chan *i2c = data;
 85	struct mga_device *mdev = to_mga_device(i2c->dev);
 86	return (mga_i2c_read_gpio(mdev) & i2c->clock) ? 1 : 0;
 87}
 88
 89static void mgag200_i2c_release(void *res)
 90{
 91	struct mga_i2c_chan *i2c = res;
 92
 93	i2c_del_adapter(&i2c->adapter);
 94}
 95
 96int mgag200_i2c_init(struct mga_device *mdev, struct mga_i2c_chan *i2c)
 97{
 98	struct drm_device *dev = &mdev->base;
 99	const struct mgag200_device_info *info = mdev->info;
100	int ret;
101
102	WREG_DAC(MGA1064_GEN_IO_CTL2, 1);
103	WREG_DAC(MGA1064_GEN_IO_DATA, 0xff);
104	WREG_DAC(MGA1064_GEN_IO_CTL, 0);
105
106	i2c->data = BIT(info->i2c.data_bit);
107	i2c->clock = BIT(info->i2c.clock_bit);
108	i2c->adapter.owner = THIS_MODULE;
109	i2c->adapter.dev.parent = dev->dev;
110	i2c->dev = dev;
111	i2c_set_adapdata(&i2c->adapter, i2c);
112	snprintf(i2c->adapter.name, sizeof(i2c->adapter.name), "mga i2c");
113
114	i2c->adapter.algo_data = &i2c->bit;
115
116	i2c->bit.udelay = 10;
117	i2c->bit.timeout = 2;
118	i2c->bit.data = i2c;
119	i2c->bit.setsda		= mga_gpio_setsda;
120	i2c->bit.setscl		= mga_gpio_setscl;
121	i2c->bit.getsda		= mga_gpio_getsda;
122	i2c->bit.getscl		= mga_gpio_getscl;
123
124	ret = i2c_bit_add_bus(&i2c->adapter);
125	if (ret)
126		return ret;
127
128	return devm_add_action_or_reset(dev->dev, mgag200_i2c_release, i2c);
129}