1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2023 Loongson Technology Corporation Limited
4 */
5
6#include <drm/drm_managed.h>
7
8#include "lsdc_drv.h"
9#include "lsdc_output.h"
10
11/*
12 * __lsdc_gpio_i2c_set - set the state of a gpio pin indicated by mask
13 * @mask: gpio pin mask
14 * @state: "0" for low, "1" for high
15 */
16static void __lsdc_gpio_i2c_set(struct lsdc_i2c * const li2c, int mask, int state)
17{
18	struct lsdc_device *ldev = to_lsdc(li2c->ddev);
19	unsigned long flags;
20	u8 val;
21
22	spin_lock_irqsave(&ldev->reglock, flags);
23
24	if (state) {
25		/*
26		 * Setting this pin as input directly, write 1 for input.
27		 * The external pull-up resistor will pull the level up
28		 */
29		val = readb(li2c->dir_reg);
30		val |= mask;
31		writeb(val, li2c->dir_reg);
32	} else {
33		/* First set this pin as output, write 0 for output */
34		val = readb(li2c->dir_reg);
35		val &= ~mask;
36		writeb(val, li2c->dir_reg);
37
38		/* Then, make this pin output 0 */
39		val = readb(li2c->dat_reg);
40		val &= ~mask;
41		writeb(val, li2c->dat_reg);
42	}
43
44	spin_unlock_irqrestore(&ldev->reglock, flags);
45}
46
47/*
48 * __lsdc_gpio_i2c_get - read value back from the gpio pin indicated by mask
49 * @mask: gpio pin mask
50 * return "0" for low, "1" for high
51 */
52static int __lsdc_gpio_i2c_get(struct lsdc_i2c * const li2c, int mask)
53{
54	struct lsdc_device *ldev = to_lsdc(li2c->ddev);
55	unsigned long flags;
56	u8 val;
57
58	spin_lock_irqsave(&ldev->reglock, flags);
59
60	/* First set this pin as input */
61	val = readb(li2c->dir_reg);
62	val |= mask;
63	writeb(val, li2c->dir_reg);
64
65	/* Then get level state from this pin */
66	val = readb(li2c->dat_reg);
67
68	spin_unlock_irqrestore(&ldev->reglock, flags);
69
70	return (val & mask) ? 1 : 0;
71}
72
73static void lsdc_gpio_i2c_set_sda(void *i2c, int state)
74{
75	struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
76	/* set state on the li2c->sda pin */
77	return __lsdc_gpio_i2c_set(li2c, li2c->sda, state);
78}
79
80static void lsdc_gpio_i2c_set_scl(void *i2c, int state)
81{
82	struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
83	/* set state on the li2c->scl pin */
84	return __lsdc_gpio_i2c_set(li2c, li2c->scl, state);
85}
86
87static int lsdc_gpio_i2c_get_sda(void *i2c)
88{
89	struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
90	/* read value from the li2c->sda pin */
91	return __lsdc_gpio_i2c_get(li2c, li2c->sda);
92}
93
94static int lsdc_gpio_i2c_get_scl(void *i2c)
95{
96	struct lsdc_i2c * const li2c = (struct lsdc_i2c *)i2c;
97	/* read the value from the li2c->scl pin */
98	return __lsdc_gpio_i2c_get(li2c, li2c->scl);
99}
100
101static void lsdc_destroy_i2c(struct drm_device *ddev, void *data)
102{
103	struct lsdc_i2c *li2c = (struct lsdc_i2c *)data;
104
105	if (li2c) {
106		i2c_del_adapter(&li2c->adapter);
107		kfree(li2c);
108	}
109}
110
111/*
112 * The DC in ls7a1000/ls7a2000/ls2k2000 has builtin gpio hardware
113 *
114 * @reg_base: gpio reg base
115 * @index: output channel index, 0 for PIPE0, 1 for PIPE1
116 */
117int lsdc_create_i2c_chan(struct drm_device *ddev,
118			 struct lsdc_display_pipe *dispipe,
119			 unsigned int index)
120{
121	struct lsdc_device *ldev = to_lsdc(ddev);
122	struct i2c_adapter *adapter;
123	struct lsdc_i2c *li2c;
124	int ret;
125
126	li2c = kzalloc(sizeof(*li2c), GFP_KERNEL);
127	if (!li2c)
128		return -ENOMEM;
129
130	dispipe->li2c = li2c;
131
132	if (index == 0) {
133		li2c->sda = 0x01;  /* pin 0 */
134		li2c->scl = 0x02;  /* pin 1 */
135	} else if (index == 1) {
136		li2c->sda = 0x04;  /* pin 2 */
137		li2c->scl = 0x08;  /* pin 3 */
138	} else {
139		return -ENOENT;
140	}
141
142	li2c->ddev = ddev;
143	li2c->dir_reg = ldev->reg_base + LS7A_DC_GPIO_DIR_REG;
144	li2c->dat_reg = ldev->reg_base + LS7A_DC_GPIO_DAT_REG;
145
146	li2c->bit.setsda = lsdc_gpio_i2c_set_sda;
147	li2c->bit.setscl = lsdc_gpio_i2c_set_scl;
148	li2c->bit.getsda = lsdc_gpio_i2c_get_sda;
149	li2c->bit.getscl = lsdc_gpio_i2c_get_scl;
150	li2c->bit.udelay = 5;
151	li2c->bit.timeout = usecs_to_jiffies(2200);
152	li2c->bit.data = li2c;
153
154	adapter = &li2c->adapter;
155	adapter->algo_data = &li2c->bit;
156	adapter->owner = THIS_MODULE;
157	adapter->class = I2C_CLASS_DDC;
158	adapter->dev.parent = ddev->dev;
159	adapter->nr = -1;
160
161	snprintf(adapter->name, sizeof(adapter->name), "lsdc-i2c%u", index);
162
163	i2c_set_adapdata(adapter, li2c);
164
165	ret = i2c_bit_add_bus(adapter);
166	if (ret) {
167		kfree(li2c);
168		return ret;
169	}
170
171	ret = drmm_add_action_or_reset(ddev, lsdc_destroy_i2c, li2c);
172	if (ret)
173		return ret;
174
175	drm_info(ddev, "%s(sda pin mask=%u, scl pin mask=%u) created\n",
176		 adapter->name, li2c->sda, li2c->scl);
177
178	return 0;
179}
180