1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  i2c_pca_platform.c
4  *
5  *  Platform driver for the PCA9564 I2C controller.
6  *
7  *  Copyright (C) 2008 Pengutronix
8  *
9 
10  */
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/delay.h>
15 #include <linux/jiffies.h>
16 #include <linux/errno.h>
17 #include <linux/i2c.h>
18 #include <linux/interrupt.h>
19 #include <linux/platform_device.h>
20 #include <linux/i2c-algo-pca.h>
21 #include <linux/platform_data/i2c-pca-platform.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/io.h>
24 #include <linux/of.h>
25 #include <linux/of_device.h>
26 
27 #include <asm/irq.h>
28 
29 struct i2c_pca_pf_data {
30 	void __iomem			*reg_base;
31 	int				irq;	/* if 0, use polling */
32 	struct gpio_desc		*gpio;
33 	wait_queue_head_t		wait;
34 	struct i2c_adapter		adap;
35 	struct i2c_algo_pca_data	algo_data;
36 };
37 
38 /* Read/Write functions for different register alignments */
39 
40 static int i2c_pca_pf_readbyte8(void *pd, int reg)
41 {
42 	struct i2c_pca_pf_data *i2c = pd;
43 	return ioread8(i2c->reg_base + reg);
44 }
45 
46 static int i2c_pca_pf_readbyte16(void *pd, int reg)
47 {
48 	struct i2c_pca_pf_data *i2c = pd;
49 	return ioread8(i2c->reg_base + reg * 2);
50 }
51 
52 static int i2c_pca_pf_readbyte32(void *pd, int reg)
53 {
54 	struct i2c_pca_pf_data *i2c = pd;
55 	return ioread8(i2c->reg_base + reg * 4);
56 }
57 
58 static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
59 {
60 	struct i2c_pca_pf_data *i2c = pd;
61 	iowrite8(val, i2c->reg_base + reg);
62 }
63 
64 static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
65 {
66 	struct i2c_pca_pf_data *i2c = pd;
67 	iowrite8(val, i2c->reg_base + reg * 2);
68 }
69 
70 static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
71 {
72 	struct i2c_pca_pf_data *i2c = pd;
73 	iowrite8(val, i2c->reg_base + reg * 4);
74 }
75 
76 
77 static int i2c_pca_pf_waitforcompletion(void *pd)
78 {
79 	struct i2c_pca_pf_data *i2c = pd;
80 	unsigned long timeout;
81 	long ret;
82 
83 	if (i2c->irq) {
84 		ret = wait_event_timeout(i2c->wait,
85 			i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
86 			& I2C_PCA_CON_SI, i2c->adap.timeout);
87 	} else {
88 		/* Do polling */
89 		timeout = jiffies + i2c->adap.timeout;
90 		do {
91 			ret = time_before(jiffies, timeout);
92 			if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
93 					& I2C_PCA_CON_SI)
94 				break;
95 			udelay(100);
96 		} while (ret);
97 	}
98 
99 	return ret > 0;
100 }
101 
102 static void i2c_pca_pf_dummyreset(void *pd)
103 {
104 	struct i2c_pca_pf_data *i2c = pd;
105 
106 	dev_warn(&i2c->adap.dev, "No reset-pin found. Chip may get stuck!\n");
107 }
108 
109 static void i2c_pca_pf_resetchip(void *pd)
110 {
111 	struct i2c_pca_pf_data *i2c = pd;
112 
113 	gpiod_set_value(i2c->gpio, 1);
114 	ndelay(100);
115 	gpiod_set_value(i2c->gpio, 0);
116 }
117 
118 static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
119 {
120 	struct i2c_pca_pf_data *i2c = dev_id;
121 
122 	if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
123 		return IRQ_NONE;
124 
125 	wake_up(&i2c->wait);
126 
127 	return IRQ_HANDLED;
128 }
129 
130 
131 static int i2c_pca_pf_probe(struct platform_device *pdev)
132 {
133 	struct i2c_pca_pf_data *i2c;
134 	struct resource *res;
135 	struct i2c_pca9564_pf_platform_data *platform_data =
136 				dev_get_platdata(&pdev->dev);
137 	struct device_node *np = pdev->dev.of_node;
138 	int ret = 0;
139 	int irq;
140 
141 	irq = platform_get_irq_optional(pdev, 0);
142 	/* If irq is 0, we do polling. */
143 	if (irq < 0)
144 		irq = 0;
145 
146 	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
147 	if (!i2c)
148 		return -ENOMEM;
149 
150 	i2c->reg_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
151 	if (IS_ERR(i2c->reg_base))
152 		return PTR_ERR(i2c->reg_base);
153 
154 
155 	init_waitqueue_head(&i2c->wait);
156 
157 	i2c->irq = irq;
158 
159 	i2c->adap.nr = pdev->id;
160 	i2c->adap.owner = THIS_MODULE;
161 	snprintf(i2c->adap.name, sizeof(i2c->adap.name),
162 		 "PCA9564/PCA9665 at 0x%08lx",
163 		 (unsigned long) res->start);
164 	i2c->adap.algo_data = &i2c->algo_data;
165 	i2c->adap.dev.parent = &pdev->dev;
166 	i2c->adap.dev.of_node = np;
167 
168 	i2c->gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW);
169 	if (IS_ERR(i2c->gpio))
170 		return PTR_ERR(i2c->gpio);
171 
172 	i2c->adap.timeout = HZ;
173 	ret = device_property_read_u32(&pdev->dev, "clock-frequency",
174 				       &i2c->algo_data.i2c_clock);
175 	if (ret)
176 		i2c->algo_data.i2c_clock = 59000;
177 
178 	if (platform_data) {
179 		i2c->adap.timeout = platform_data->timeout;
180 		i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
181 	}
182 
183 	i2c->algo_data.data = i2c;
184 	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
185 	if (i2c->gpio)
186 		i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
187 	else
188 		i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
189 
190 	switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
191 	case IORESOURCE_MEM_32BIT:
192 		i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
193 		i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
194 		break;
195 	case IORESOURCE_MEM_16BIT:
196 		i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
197 		i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
198 		break;
199 	case IORESOURCE_MEM_8BIT:
200 	default:
201 		i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
202 		i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
203 		break;
204 	}
205 
206 	if (irq) {
207 		ret = devm_request_irq(&pdev->dev, irq, i2c_pca_pf_handler,
208 			IRQF_TRIGGER_FALLING, pdev->name, i2c);
209 		if (ret)
210 			return ret;
211 	}
212 
213 	ret = i2c_pca_add_numbered_bus(&i2c->adap);
214 	if (ret)
215 		return ret;
216 
217 	platform_set_drvdata(pdev, i2c);
218 
219 	dev_info(&pdev->dev, "registered.\n");
220 
221 	return 0;
222 }
223 
224 static int i2c_pca_pf_remove(struct platform_device *pdev)
225 {
226 	struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
227 
228 	i2c_del_adapter(&i2c->adap);
229 
230 	return 0;
231 }
232 
233 #ifdef CONFIG_OF
234 static const struct of_device_id i2c_pca_of_match_table[] = {
235 	{ .compatible = "nxp,pca9564" },
236 	{ .compatible = "nxp,pca9665" },
237 	{},
238 };
239 MODULE_DEVICE_TABLE(of, i2c_pca_of_match_table);
240 #endif
241 
242 static struct platform_driver i2c_pca_pf_driver = {
243 	.probe = i2c_pca_pf_probe,
244 	.remove = i2c_pca_pf_remove,
245 	.driver = {
246 		.name = "i2c-pca-platform",
247 		.of_match_table = of_match_ptr(i2c_pca_of_match_table),
248 	},
249 };
250 
251 module_platform_driver(i2c_pca_pf_driver);
252 
253 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
254 MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
255 MODULE_LICENSE("GPL");
256