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 <drm/drm_managed.h>
 35
 36#include "mgag200_ddc.h"
 37#include "mgag200_drv.h"
 38
 39struct mgag200_ddc {
 40	struct mga_device *mdev;
 41
 42	int data;
 43	int clock;
 44
 45	struct i2c_algo_bit_data bit;
 46	struct i2c_adapter adapter;
 47};
 48
 49static int mga_i2c_read_gpio(struct mga_device *mdev)
 50{
 51	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
 52	return RREG8(DAC_DATA);
 53}
 54
 55static void mga_i2c_set_gpio(struct mga_device *mdev, int mask, int val)
 56{
 57	int tmp;
 58
 59	WREG8(DAC_INDEX, MGA1064_GEN_IO_CTL);
 60	tmp = (RREG8(DAC_DATA) & mask) | val;
 61	WREG_DAC(MGA1064_GEN_IO_CTL, tmp);
 62	WREG_DAC(MGA1064_GEN_IO_DATA, 0);
 63}
 64
 65static inline void mga_i2c_set(struct mga_device *mdev, int mask, int state)
 66{
 67	if (state)
 68		state = 0;
 69	else
 70		state = mask;
 71	mga_i2c_set_gpio(mdev, ~mask, state);
 72}
 73
 74static void mgag200_ddc_algo_bit_data_setsda(void *data, int state)
 75{
 76	struct mgag200_ddc *ddc = data;
 77
 78	mga_i2c_set(ddc->mdev, ddc->data, state);
 79}
 80
 81static void mgag200_ddc_algo_bit_data_setscl(void *data, int state)
 82{
 83	struct mgag200_ddc *ddc = data;
 84
 85	mga_i2c_set(ddc->mdev, ddc->clock, state);
 86}
 87
 88static int mgag200_ddc_algo_bit_data_getsda(void *data)
 89{
 90	struct mgag200_ddc *ddc = data;
 91
 92	return (mga_i2c_read_gpio(ddc->mdev) & ddc->data) ? 1 : 0;
 93}
 94
 95static int mgag200_ddc_algo_bit_data_getscl(void *data)
 96{
 97	struct mgag200_ddc *ddc = data;
 98
 99	return (mga_i2c_read_gpio(ddc->mdev) & ddc->clock) ? 1 : 0;
100}
101
102static int mgag200_ddc_algo_bit_data_pre_xfer(struct i2c_adapter *adapter)
103{
104	struct mgag200_ddc *ddc = i2c_get_adapdata(adapter);
105	struct mga_device *mdev = ddc->mdev;
106
107	/*
108	 * Protect access to I/O registers from concurrent modesetting
109	 * by acquiring the I/O-register lock.
110	 */
111	mutex_lock(&mdev->rmmio_lock);
112
113	return 0;
114}
115
116static void mgag200_ddc_algo_bit_data_post_xfer(struct i2c_adapter *adapter)
117{
118	struct mgag200_ddc *ddc = i2c_get_adapdata(adapter);
119	struct mga_device *mdev = ddc->mdev;
120
121	mutex_unlock(&mdev->rmmio_lock);
122}
123
124static void mgag200_ddc_release(struct drm_device *dev, void *res)
125{
126	struct mgag200_ddc *ddc = res;
127
128	i2c_del_adapter(&ddc->adapter);
129}
130
131struct i2c_adapter *mgag200_ddc_create(struct mga_device *mdev)
132{
133	struct drm_device *dev = &mdev->base;
134	const struct mgag200_device_info *info = mdev->info;
135	struct mgag200_ddc *ddc;
136	struct i2c_algo_bit_data *bit;
137	struct i2c_adapter *adapter;
138	int ret;
139
140	ddc = drmm_kzalloc(dev, sizeof(*ddc), GFP_KERNEL);
141	if (!ddc)
142		return ERR_PTR(-ENOMEM);
143
144	WREG_DAC(MGA1064_GEN_IO_CTL2, 1);
145	WREG_DAC(MGA1064_GEN_IO_DATA, 0xff);
146	WREG_DAC(MGA1064_GEN_IO_CTL, 0);
147
148	ddc->mdev = mdev;
149	ddc->data = BIT(info->i2c.data_bit);
150	ddc->clock = BIT(info->i2c.clock_bit);
151
152	bit = &ddc->bit;
153	bit->data = ddc;
154	bit->setsda = mgag200_ddc_algo_bit_data_setsda;
155	bit->setscl = mgag200_ddc_algo_bit_data_setscl;
156	bit->getsda = mgag200_ddc_algo_bit_data_getsda;
157	bit->getscl = mgag200_ddc_algo_bit_data_getscl;
158	bit->pre_xfer = mgag200_ddc_algo_bit_data_pre_xfer;
159	bit->post_xfer = mgag200_ddc_algo_bit_data_post_xfer;
160	bit->udelay = 10;
161	bit->timeout = usecs_to_jiffies(2200);
162
163	adapter = &ddc->adapter;
164	adapter->owner = THIS_MODULE;
165	adapter->algo_data = bit;
166	adapter->dev.parent = dev->dev;
167	snprintf(adapter->name, sizeof(adapter->name), "Matrox DDC bus");
168	i2c_set_adapdata(adapter, ddc);
169
170	ret = i2c_bit_add_bus(adapter);
171	if (ret)
172		return ERR_PTR(ret);
173
174	ret = drmm_add_action_or_reset(dev, mgag200_ddc_release, ddc);
175	if (ret)
176		return ERR_PTR(ret);
177
178	return adapter;
179}