1 /*
2 * (C) Copyright 2009-2010
3 * Nokia Siemens Networks, michael.lawnick.ext@nsn.com
4 *
5 * Portions Copyright (C) 2010 - 2016 Cavium, Inc.
6 *
7 * This is a driver for the i2c adapter in Cavium Networks' OCTEON processors.
8 *
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
12 */
13
14 #include <linux/atomic.h>
15 #include <linux/delay.h>
16 #include <linux/i2c.h>
17 #include <linux/interrupt.h>
18 #include <linux/io.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/platform_device.h>
23 #include <linux/sched.h>
24 #include <linux/slab.h>
25
26 #include <asm/octeon/octeon.h>
27 #include "i2c-octeon-core.h"
28
29 #define DRV_NAME "i2c-octeon"
30
31 /**
32 * octeon_i2c_int_enable - enable the CORE interrupt
33 * @i2c: The struct octeon_i2c
34 *
35 * The interrupt will be asserted when there is non-STAT_IDLE state in
36 * the SW_TWSI_EOP_TWSI_STAT register.
37 */
octeon_i2c_int_enable(struct octeon_i2c * i2c)38 static void octeon_i2c_int_enable(struct octeon_i2c *i2c)
39 {
40 octeon_i2c_write_int(i2c, TWSI_INT_CORE_EN);
41 }
42
43 /* disable the CORE interrupt */
octeon_i2c_int_disable(struct octeon_i2c * i2c)44 static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
45 {
46 /* clear TS/ST/IFLG events */
47 octeon_i2c_write_int(i2c, 0);
48 }
49
50 /**
51 * octeon_i2c_int_enable78 - enable the CORE interrupt
52 * @i2c: The struct octeon_i2c
53 *
54 * The interrupt will be asserted when there is non-STAT_IDLE state in the
55 * SW_TWSI_EOP_TWSI_STAT register.
56 */
octeon_i2c_int_enable78(struct octeon_i2c * i2c)57 static void octeon_i2c_int_enable78(struct octeon_i2c *i2c)
58 {
59 atomic_inc_return(&i2c->int_enable_cnt);
60 enable_irq(i2c->irq);
61 }
62
__octeon_i2c_irq_disable(atomic_t * cnt,int irq)63 static void __octeon_i2c_irq_disable(atomic_t *cnt, int irq)
64 {
65 int count;
66
67 /*
68 * The interrupt can be disabled in two places, but we only
69 * want to make the disable_irq_nosync() call once, so keep
70 * track with the atomic variable.
71 */
72 count = atomic_dec_if_positive(cnt);
73 if (count >= 0)
74 disable_irq_nosync(irq);
75 }
76
77 /* disable the CORE interrupt */
octeon_i2c_int_disable78(struct octeon_i2c * i2c)78 static void octeon_i2c_int_disable78(struct octeon_i2c *i2c)
79 {
80 __octeon_i2c_irq_disable(&i2c->int_enable_cnt, i2c->irq);
81 }
82
83 /**
84 * octeon_i2c_hlc_int_enable78 - enable the ST interrupt
85 * @i2c: The struct octeon_i2c
86 *
87 * The interrupt will be asserted when there is non-STAT_IDLE state in
88 * the SW_TWSI_EOP_TWSI_STAT register.
89 */
octeon_i2c_hlc_int_enable78(struct octeon_i2c * i2c)90 static void octeon_i2c_hlc_int_enable78(struct octeon_i2c *i2c)
91 {
92 atomic_inc_return(&i2c->hlc_int_enable_cnt);
93 enable_irq(i2c->hlc_irq);
94 }
95
96 /* disable the ST interrupt */
octeon_i2c_hlc_int_disable78(struct octeon_i2c * i2c)97 static void octeon_i2c_hlc_int_disable78(struct octeon_i2c *i2c)
98 {
99 __octeon_i2c_irq_disable(&i2c->hlc_int_enable_cnt, i2c->hlc_irq);
100 }
101
102 /* HLC interrupt service routine */
octeon_i2c_hlc_isr78(int irq,void * dev_id)103 static irqreturn_t octeon_i2c_hlc_isr78(int irq, void *dev_id)
104 {
105 struct octeon_i2c *i2c = dev_id;
106
107 i2c->hlc_int_disable(i2c);
108 wake_up(&i2c->queue);
109
110 return IRQ_HANDLED;
111 }
112
octeon_i2c_hlc_int_enable(struct octeon_i2c * i2c)113 static void octeon_i2c_hlc_int_enable(struct octeon_i2c *i2c)
114 {
115 octeon_i2c_write_int(i2c, TWSI_INT_ST_EN);
116 }
117
octeon_i2c_functionality(struct i2c_adapter * adap)118 static u32 octeon_i2c_functionality(struct i2c_adapter *adap)
119 {
120 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
121 I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_SMBUS_BLOCK_PROC_CALL;
122 }
123
124 static const struct i2c_algorithm octeon_i2c_algo = {
125 .master_xfer = octeon_i2c_xfer,
126 .functionality = octeon_i2c_functionality,
127 };
128
129 static const struct i2c_adapter octeon_i2c_ops = {
130 .owner = THIS_MODULE,
131 .name = "OCTEON adapter",
132 .algo = &octeon_i2c_algo,
133 };
134
octeon_i2c_probe(struct platform_device * pdev)135 static int octeon_i2c_probe(struct platform_device *pdev)
136 {
137 struct device_node *node = pdev->dev.of_node;
138 int irq, result = 0, hlc_irq = 0;
139 struct octeon_i2c *i2c;
140 bool cn78xx_style;
141
142 cn78xx_style = of_device_is_compatible(node, "cavium,octeon-7890-twsi");
143 if (cn78xx_style) {
144 hlc_irq = platform_get_irq(pdev, 0);
145 if (hlc_irq < 0)
146 return hlc_irq;
147
148 irq = platform_get_irq(pdev, 2);
149 if (irq < 0)
150 return irq;
151 } else {
152 /* All adaptors have an irq. */
153 irq = platform_get_irq(pdev, 0);
154 if (irq < 0)
155 return irq;
156 }
157
158 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
159 if (!i2c) {
160 result = -ENOMEM;
161 goto out;
162 }
163 i2c->dev = &pdev->dev;
164
165 i2c->roff.sw_twsi = 0x00;
166 i2c->roff.twsi_int = 0x10;
167 i2c->roff.sw_twsi_ext = 0x18;
168
169 i2c->twsi_base = devm_platform_ioremap_resource(pdev, 0);
170 if (IS_ERR(i2c->twsi_base)) {
171 result = PTR_ERR(i2c->twsi_base);
172 goto out;
173 }
174
175 /*
176 * "clock-rate" is a legacy binding, the official binding is
177 * "clock-frequency". Try the official one first and then
178 * fall back if it doesn't exist.
179 */
180 if (of_property_read_u32(node, "clock-frequency", &i2c->twsi_freq) &&
181 of_property_read_u32(node, "clock-rate", &i2c->twsi_freq)) {
182 dev_err(i2c->dev,
183 "no I2C 'clock-rate' or 'clock-frequency' property\n");
184 result = -ENXIO;
185 goto out;
186 }
187
188 i2c->sys_freq = octeon_get_io_clock_rate();
189
190 init_waitqueue_head(&i2c->queue);
191
192 i2c->irq = irq;
193
194 if (cn78xx_style) {
195 i2c->hlc_irq = hlc_irq;
196
197 i2c->int_enable = octeon_i2c_int_enable78;
198 i2c->int_disable = octeon_i2c_int_disable78;
199 i2c->hlc_int_enable = octeon_i2c_hlc_int_enable78;
200 i2c->hlc_int_disable = octeon_i2c_hlc_int_disable78;
201
202 irq_set_status_flags(i2c->irq, IRQ_NOAUTOEN);
203 irq_set_status_flags(i2c->hlc_irq, IRQ_NOAUTOEN);
204
205 result = devm_request_irq(&pdev->dev, i2c->hlc_irq,
206 octeon_i2c_hlc_isr78, 0,
207 DRV_NAME, i2c);
208 if (result < 0) {
209 dev_err(i2c->dev, "failed to attach interrupt\n");
210 goto out;
211 }
212 } else {
213 i2c->int_enable = octeon_i2c_int_enable;
214 i2c->int_disable = octeon_i2c_int_disable;
215 i2c->hlc_int_enable = octeon_i2c_hlc_int_enable;
216 i2c->hlc_int_disable = octeon_i2c_int_disable;
217 }
218
219 result = devm_request_irq(&pdev->dev, i2c->irq,
220 octeon_i2c_isr, 0, DRV_NAME, i2c);
221 if (result < 0) {
222 dev_err(i2c->dev, "failed to attach interrupt\n");
223 goto out;
224 }
225
226 if (OCTEON_IS_MODEL(OCTEON_CN38XX))
227 i2c->broken_irq_check = true;
228
229 result = octeon_i2c_init_lowlevel(i2c);
230 if (result) {
231 dev_err(i2c->dev, "init low level failed\n");
232 goto out;
233 }
234
235 octeon_i2c_set_clock(i2c);
236
237 i2c->adap = octeon_i2c_ops;
238 i2c->adap.timeout = msecs_to_jiffies(2);
239 i2c->adap.retries = 5;
240 i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info;
241 i2c->adap.dev.parent = &pdev->dev;
242 i2c->adap.dev.of_node = node;
243 i2c_set_adapdata(&i2c->adap, i2c);
244 platform_set_drvdata(pdev, i2c);
245
246 result = i2c_add_adapter(&i2c->adap);
247 if (result < 0)
248 goto out;
249 dev_info(i2c->dev, "probed\n");
250 return 0;
251
252 out:
253 return result;
254 };
255
octeon_i2c_remove(struct platform_device * pdev)256 static int octeon_i2c_remove(struct platform_device *pdev)
257 {
258 struct octeon_i2c *i2c = platform_get_drvdata(pdev);
259
260 i2c_del_adapter(&i2c->adap);
261 return 0;
262 };
263
264 static const struct of_device_id octeon_i2c_match[] = {
265 { .compatible = "cavium,octeon-3860-twsi", },
266 { .compatible = "cavium,octeon-7890-twsi", },
267 {},
268 };
269 MODULE_DEVICE_TABLE(of, octeon_i2c_match);
270
271 static struct platform_driver octeon_i2c_driver = {
272 .probe = octeon_i2c_probe,
273 .remove = octeon_i2c_remove,
274 .driver = {
275 .name = DRV_NAME,
276 .of_match_table = octeon_i2c_match,
277 },
278 };
279
280 module_platform_driver(octeon_i2c_driver);
281
282 MODULE_AUTHOR("Michael Lawnick <michael.lawnick.ext@nsn.com>");
283 MODULE_DESCRIPTION("I2C-Bus adapter for Cavium OCTEON processors");
284 MODULE_LICENSE("GPL");
285