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 <[email protected]>
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
hibmc_set_i2c_signal(void * data,u32 mask,int value)26 static void hibmc_set_i2c_signal(void *data, u32 mask, int value)
27 {
28 struct hibmc_vdac *vdac = data;
29 struct hibmc_drm_private *priv = to_hibmc_drm_private(vdac->connector.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
hibmc_get_i2c_signal(void * data,u32 mask)46 static int hibmc_get_i2c_signal(void *data, u32 mask)
47 {
48 struct hibmc_vdac *vdac = data;
49 struct hibmc_drm_private *priv = to_hibmc_drm_private(vdac->connector.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
hibmc_ddc_setsda(void * data,int state)60 static void hibmc_ddc_setsda(void *data, int state)
61 {
62 hibmc_set_i2c_signal(data, I2C_SDA_MASK, state);
63 }
64
hibmc_ddc_setscl(void * data,int state)65 static void hibmc_ddc_setscl(void *data, int state)
66 {
67 hibmc_set_i2c_signal(data, I2C_SCL_MASK, state);
68 }
69
hibmc_ddc_getsda(void * data)70 static int hibmc_ddc_getsda(void *data)
71 {
72 return hibmc_get_i2c_signal(data, I2C_SDA_MASK);
73 }
74
hibmc_ddc_getscl(void * data)75 static int hibmc_ddc_getscl(void *data)
76 {
77 return hibmc_get_i2c_signal(data, I2C_SCL_MASK);
78 }
79
hibmc_ddc_create(struct drm_device * drm_dev,struct hibmc_vdac * vdac)80 int hibmc_ddc_create(struct drm_device *drm_dev, struct hibmc_vdac *vdac)
81 {
82 vdac->adapter.owner = THIS_MODULE;
83 snprintf(vdac->adapter.name, I2C_NAME_SIZE, "HIS i2c bit bus");
84 vdac->adapter.dev.parent = drm_dev->dev;
85 i2c_set_adapdata(&vdac->adapter, vdac);
86 vdac->adapter.algo_data = &vdac->bit_data;
87
88 vdac->bit_data.udelay = 20;
89 vdac->bit_data.timeout = usecs_to_jiffies(2000);
90 vdac->bit_data.data = vdac;
91 vdac->bit_data.setsda = hibmc_ddc_setsda;
92 vdac->bit_data.setscl = hibmc_ddc_setscl;
93 vdac->bit_data.getsda = hibmc_ddc_getsda;
94 vdac->bit_data.getscl = hibmc_ddc_getscl;
95
96 return i2c_bit_add_bus(&vdac->adapter);
97 }
98