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->dev.parent = ddev->dev;
158	adapter->nr = -1;
159
160	snprintf(adapter->name, sizeof(adapter->name), "lsdc-i2c%u", index);
161
162	i2c_set_adapdata(adapter, li2c);
163
164	ret = i2c_bit_add_bus(adapter);
165	if (ret) {
166		kfree(li2c);
167		return ret;
168	}
169
170	ret = drmm_add_action_or_reset(ddev, lsdc_destroy_i2c, li2c);
171	if (ret)
172		return ret;
173
174	drm_info(ddev, "%s(sda pin mask=%u, scl pin mask=%u) created\n",
175		 adapter->name, li2c->sda, li2c->scl);
176
177	return 0;
178}