1// SPDX-License-Identifier: GPL-2.0-or-later
 2/* Hisilicon Hibmc SoC drm driver
 3 *
 4 * Based on the bochs drm driver.
 5 *
 6 * Copyright (c) 2016 Huawei Limited.
 7 *
 8 * Author:
 9 *      Tian Tao <tiantao6@hisilicon.com>
10 */
11
12#include <linux/delay.h>
13#include <linux/pci.h>
14
15#include <drm/drm_atomic_helper.h>
16#include <drm/drm_probe_helper.h>
17
18#include "hibmc_drm_drv.h"
19
20#define GPIO_DATA		0x0802A0
21#define GPIO_DATA_DIRECTION	0x0802A4
22
23#define I2C_SCL_MASK		BIT(0)
24#define I2C_SDA_MASK		BIT(1)
25
26static void hibmc_set_i2c_signal(void *data, u32 mask, int value)
27{
28	struct hibmc_connector *hibmc_connector = data;
29	struct hibmc_drm_private *priv = to_hibmc_drm_private(hibmc_connector->base.dev);
30	u32 tmp_dir = readl(priv->mmio + GPIO_DATA_DIRECTION);
31
32	if (value) {
33		tmp_dir &= ~mask;
34		writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION);
35	} else {
36		u32 tmp_data = readl(priv->mmio + GPIO_DATA);
37
38		tmp_data &= ~mask;
39		writel(tmp_data, priv->mmio + GPIO_DATA);
40
41		tmp_dir |= mask;
42		writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION);
43	}
44}
45
46static int hibmc_get_i2c_signal(void *data, u32 mask)
47{
48	struct hibmc_connector *hibmc_connector = data;
49	struct hibmc_drm_private *priv = to_hibmc_drm_private(hibmc_connector->base.dev);
50	u32 tmp_dir = readl(priv->mmio + GPIO_DATA_DIRECTION);
51
52	if ((tmp_dir & mask) != mask) {
53		tmp_dir &= ~mask;
54		writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION);
55	}
56
57	return (readl(priv->mmio + GPIO_DATA) & mask) ? 1 : 0;
58}
59
60static void hibmc_ddc_setsda(void *data, int state)
61{
62	hibmc_set_i2c_signal(data, I2C_SDA_MASK, state);
63}
64
65static void hibmc_ddc_setscl(void *data, int state)
66{
67	hibmc_set_i2c_signal(data, I2C_SCL_MASK, state);
68}
69
70static int hibmc_ddc_getsda(void *data)
71{
72	return hibmc_get_i2c_signal(data, I2C_SDA_MASK);
73}
74
75static int hibmc_ddc_getscl(void *data)
76{
77	return hibmc_get_i2c_signal(data, I2C_SCL_MASK);
78}
79
80int hibmc_ddc_create(struct drm_device *drm_dev,
81		     struct hibmc_connector *connector)
82{
83	connector->adapter.owner = THIS_MODULE;
84	snprintf(connector->adapter.name, I2C_NAME_SIZE, "HIS i2c bit bus");
85	connector->adapter.dev.parent = drm_dev->dev;
86	i2c_set_adapdata(&connector->adapter, connector);
87	connector->adapter.algo_data = &connector->bit_data;
88
89	connector->bit_data.udelay = 20;
90	connector->bit_data.timeout = usecs_to_jiffies(2000);
91	connector->bit_data.data = connector;
92	connector->bit_data.setsda = hibmc_ddc_setsda;
93	connector->bit_data.setscl = hibmc_ddc_setscl;
94	connector->bit_data.getsda = hibmc_ddc_getsda;
95	connector->bit_data.getscl = hibmc_ddc_getscl;
96
97	return i2c_bit_add_bus(&connector->adapter);
98}