1 /*
2  * nokia-modem.c
3  *
4  * HSI client driver for Nokia N900 modem.
5  *
6  * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * version 2 as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20  * 02110-1301 USA
21  */
22 
23 #include <linux/gpio/consumer.h>
24 #include <linux/hsi/hsi.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/of.h>
28 #include <linux/of_irq.h>
29 #include <linux/of_gpio.h>
30 #include <linux/hsi/ssi_protocol.h>
31 
32 static unsigned int pm = 1;
33 module_param(pm, int, 0400);
34 MODULE_PARM_DESC(pm,
35 	"Enable power management (0=disabled, 1=userland based [default])");
36 
37 struct nokia_modem_gpio {
38 	struct gpio_desc	*gpio;
39 	const char		*name;
40 };
41 
42 struct nokia_modem_device {
43 	struct tasklet_struct	nokia_modem_rst_ind_tasklet;
44 	int			nokia_modem_rst_ind_irq;
45 	struct device		*device;
46 	struct nokia_modem_gpio	*gpios;
47 	int			gpio_amount;
48 	struct hsi_client	*ssi_protocol;
49 	struct hsi_client	*cmt_speech;
50 };
51 
52 static void do_nokia_modem_rst_ind_tasklet(unsigned long data)
53 {
54 	struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
55 
56 	if (!modem)
57 		return;
58 
59 	dev_info(modem->device, "CMT rst line change detected\n");
60 
61 	if (modem->ssi_protocol)
62 		ssip_reset_event(modem->ssi_protocol);
63 }
64 
65 static irqreturn_t nokia_modem_rst_ind_isr(int irq, void *data)
66 {
67 	struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
68 
69 	tasklet_schedule(&modem->nokia_modem_rst_ind_tasklet);
70 
71 	return IRQ_HANDLED;
72 }
73 
74 static void nokia_modem_gpio_unexport(struct device *dev)
75 {
76 	struct nokia_modem_device *modem = dev_get_drvdata(dev);
77 	int i;
78 
79 	for (i = 0; i < modem->gpio_amount; i++) {
80 		sysfs_remove_link(&dev->kobj, modem->gpios[i].name);
81 		gpiod_unexport(modem->gpios[i].gpio);
82 	}
83 }
84 
85 static int nokia_modem_gpio_probe(struct device *dev)
86 {
87 	struct device_node *np = dev->of_node;
88 	struct nokia_modem_device *modem = dev_get_drvdata(dev);
89 	int gpio_count, gpio_name_count, i, err;
90 
91 	gpio_count = of_gpio_count(np);
92 
93 	if (gpio_count < 0) {
94 		dev_err(dev, "missing gpios: %d\n", gpio_count);
95 		return gpio_count;
96 	}
97 
98 	gpio_name_count = of_property_count_strings(np, "gpio-names");
99 
100 	if (gpio_count != gpio_name_count) {
101 		dev_err(dev, "number of gpios does not equal number of gpio names\n");
102 		return -EINVAL;
103 	}
104 
105 	modem->gpios = devm_kcalloc(dev, gpio_count, sizeof(*modem->gpios),
106 				    GFP_KERNEL);
107 	if (!modem->gpios)
108 		return -ENOMEM;
109 
110 	modem->gpio_amount = gpio_count;
111 
112 	for (i = 0; i < gpio_count; i++) {
113 		modem->gpios[i].gpio = devm_gpiod_get_index(dev, NULL, i,
114 							    GPIOD_OUT_LOW);
115 		if (IS_ERR(modem->gpios[i].gpio)) {
116 			dev_err(dev, "Could not get gpio %d\n", i);
117 			return PTR_ERR(modem->gpios[i].gpio);
118 		}
119 
120 		err = of_property_read_string_index(np, "gpio-names", i,
121 						&(modem->gpios[i].name));
122 		if (err) {
123 			dev_err(dev, "Could not get gpio name %d\n", i);
124 			return err;
125 		}
126 
127 		err = gpiod_export(modem->gpios[i].gpio, 0);
128 		if (err)
129 			return err;
130 
131 		err = gpiod_export_link(dev, modem->gpios[i].name,
132 							modem->gpios[i].gpio);
133 		if (err)
134 			return err;
135 	}
136 
137 	return 0;
138 }
139 
140 static int nokia_modem_probe(struct device *dev)
141 {
142 	struct device_node *np;
143 	struct nokia_modem_device *modem;
144 	struct hsi_client *cl = to_hsi_client(dev);
145 	struct hsi_port *port = hsi_get_port(cl);
146 	int irq, pflags, err;
147 	struct hsi_board_info ssip;
148 	struct hsi_board_info cmtspeech;
149 
150 	np = dev->of_node;
151 	if (!np) {
152 		dev_err(dev, "device tree node not found\n");
153 		return -ENXIO;
154 	}
155 
156 	modem = devm_kzalloc(dev, sizeof(*modem), GFP_KERNEL);
157 	if (!modem)
158 		return -ENOMEM;
159 
160 	dev_set_drvdata(dev, modem);
161 	modem->device = dev;
162 
163 	irq = irq_of_parse_and_map(np, 0);
164 	if (!irq) {
165 		dev_err(dev, "Invalid rst_ind interrupt (%d)\n", irq);
166 		return -EINVAL;
167 	}
168 	modem->nokia_modem_rst_ind_irq = irq;
169 	pflags = irq_get_trigger_type(irq);
170 
171 	tasklet_init(&modem->nokia_modem_rst_ind_tasklet,
172 			do_nokia_modem_rst_ind_tasklet, (unsigned long)modem);
173 	err = devm_request_irq(dev, irq, nokia_modem_rst_ind_isr,
174 				pflags, "modem_rst_ind", modem);
175 	if (err < 0) {
176 		dev_err(dev, "Request rst_ind irq(%d) failed (flags %d)\n",
177 								irq, pflags);
178 		return err;
179 	}
180 	enable_irq_wake(irq);
181 
182 	if (pm) {
183 		err = nokia_modem_gpio_probe(dev);
184 		if (err < 0) {
185 			dev_err(dev, "Could not probe GPIOs\n");
186 			goto error1;
187 		}
188 	}
189 
190 	ssip.name = "ssi-protocol";
191 	ssip.tx_cfg = cl->tx_cfg;
192 	ssip.rx_cfg = cl->rx_cfg;
193 	ssip.platform_data = NULL;
194 	ssip.archdata = NULL;
195 
196 	modem->ssi_protocol = hsi_new_client(port, &ssip);
197 	if (!modem->ssi_protocol) {
198 		dev_err(dev, "Could not register ssi-protocol device\n");
199 		err = -ENOMEM;
200 		goto error2;
201 	}
202 
203 	err = device_attach(&modem->ssi_protocol->device);
204 	if (err == 0) {
205 		dev_dbg(dev, "Missing ssi-protocol driver\n");
206 		err = -EPROBE_DEFER;
207 		goto error3;
208 	} else if (err < 0) {
209 		dev_err(dev, "Could not load ssi-protocol driver (%d)\n", err);
210 		goto error3;
211 	}
212 
213 	cmtspeech.name = "cmt-speech";
214 	cmtspeech.tx_cfg = cl->tx_cfg;
215 	cmtspeech.rx_cfg = cl->rx_cfg;
216 	cmtspeech.platform_data = NULL;
217 	cmtspeech.archdata = NULL;
218 
219 	modem->cmt_speech = hsi_new_client(port, &cmtspeech);
220 	if (!modem->cmt_speech) {
221 		dev_err(dev, "Could not register cmt-speech device\n");
222 		err = -ENOMEM;
223 		goto error3;
224 	}
225 
226 	err = device_attach(&modem->cmt_speech->device);
227 	if (err == 0) {
228 		dev_dbg(dev, "Missing cmt-speech driver\n");
229 		err = -EPROBE_DEFER;
230 		goto error4;
231 	} else if (err < 0) {
232 		dev_err(dev, "Could not load cmt-speech driver (%d)\n", err);
233 		goto error4;
234 	}
235 
236 	dev_info(dev, "Registered Nokia HSI modem\n");
237 
238 	return 0;
239 
240 error4:
241 	hsi_remove_client(&modem->cmt_speech->device, NULL);
242 error3:
243 	hsi_remove_client(&modem->ssi_protocol->device, NULL);
244 error2:
245 	nokia_modem_gpio_unexport(dev);
246 error1:
247 	disable_irq_wake(modem->nokia_modem_rst_ind_irq);
248 	tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
249 
250 	return err;
251 }
252 
253 static int nokia_modem_remove(struct device *dev)
254 {
255 	struct nokia_modem_device *modem = dev_get_drvdata(dev);
256 
257 	if (!modem)
258 		return 0;
259 
260 	if (modem->cmt_speech) {
261 		hsi_remove_client(&modem->cmt_speech->device, NULL);
262 		modem->cmt_speech = NULL;
263 	}
264 
265 	if (modem->ssi_protocol) {
266 		hsi_remove_client(&modem->ssi_protocol->device, NULL);
267 		modem->ssi_protocol = NULL;
268 	}
269 
270 	nokia_modem_gpio_unexport(dev);
271 	dev_set_drvdata(dev, NULL);
272 	disable_irq_wake(modem->nokia_modem_rst_ind_irq);
273 	tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
274 
275 	return 0;
276 }
277 
278 #ifdef CONFIG_OF
279 static const struct of_device_id nokia_modem_of_match[] = {
280 	{ .compatible = "nokia,n900-modem", },
281 	{ .compatible = "nokia,n950-modem", },
282 	{ .compatible = "nokia,n9-modem", },
283 	{},
284 };
285 MODULE_DEVICE_TABLE(of, nokia_modem_of_match);
286 #endif
287 
288 static struct hsi_client_driver nokia_modem_driver = {
289 	.driver = {
290 		.name	= "nokia-modem",
291 		.owner	= THIS_MODULE,
292 		.probe	= nokia_modem_probe,
293 		.remove	= nokia_modem_remove,
294 		.of_match_table = of_match_ptr(nokia_modem_of_match),
295 	},
296 };
297 
298 static int __init nokia_modem_init(void)
299 {
300 	return hsi_register_client_driver(&nokia_modem_driver);
301 }
302 module_init(nokia_modem_init);
303 
304 static void __exit nokia_modem_exit(void)
305 {
306 	hsi_unregister_client_driver(&nokia_modem_driver);
307 }
308 module_exit(nokia_modem_exit);
309 
310 MODULE_ALIAS("hsi:nokia-modem");
311 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
312 MODULE_DESCRIPTION("HSI driver module for Nokia N900 Modem");
313 MODULE_LICENSE("GPL");
314