1 /*
2 * Intel Medfield MSIC GPIO driver>
3 * Copyright (c) 2011, Intel Corporation.
4 *
5 * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
6 * Based on intel_pmic_gpio.c
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions 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 it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 */
22
23 #include <linux/module.h>
24 #include <linux/kernel.h>
25 #include <linux/slab.h>
26 #include <linux/interrupt.h>
27 #include <linux/init.h>
28 #include <linux/gpio.h>
29 #include <linux/platform_device.h>
30 #include <linux/mfd/intel_msic.h>
31
32 /* the offset for the mapping of global gpio pin to irq */
33 #define MSIC_GPIO_IRQ_OFFSET 0x100
34
35 #define MSIC_GPIO_DIR_IN 0
36 #define MSIC_GPIO_DIR_OUT BIT(5)
37 #define MSIC_GPIO_TRIG_FALL BIT(1)
38 #define MSIC_GPIO_TRIG_RISE BIT(2)
39
40 /* masks for msic gpio output GPIOxxxxCTLO registers */
41 #define MSIC_GPIO_DIR_MASK BIT(5)
42 #define MSIC_GPIO_DRV_MASK BIT(4)
43 #define MSIC_GPIO_REN_MASK BIT(3)
44 #define MSIC_GPIO_RVAL_MASK (BIT(2) | BIT(1))
45 #define MSIC_GPIO_DOUT_MASK BIT(0)
46
47 /* masks for msic gpio input GPIOxxxxCTLI registers */
48 #define MSIC_GPIO_GLBYP_MASK BIT(5)
49 #define MSIC_GPIO_DBNC_MASK (BIT(4) | BIT(3))
50 #define MSIC_GPIO_INTCNT_MASK (BIT(2) | BIT(1))
51 #define MSIC_GPIO_DIN_MASK BIT(0)
52
53 #define MSIC_NUM_GPIO 24
54
55 struct msic_gpio {
56 struct platform_device *pdev;
57 struct mutex buslock;
58 struct gpio_chip chip;
59 int irq;
60 unsigned irq_base;
61 unsigned long trig_change_mask;
62 unsigned trig_type;
63 };
64
65 /*
66 * MSIC has 24 gpios, 16 low voltage (1.2-1.8v) and 8 high voltage (3v).
67 * Both the high and low voltage gpios are divided in two banks.
68 * GPIOs are numbered with GPIO0LV0 as gpio_base in the following order:
69 * GPIO0LV0..GPIO0LV7: low voltage, bank 0, gpio_base
70 * GPIO1LV0..GPIO1LV7: low voltage, bank 1, gpio_base + 8
71 * GPIO0HV0..GPIO0HV3: high voltage, bank 0, gpio_base + 16
72 * GPIO1HV0..GPIO1HV3: high voltage, bank 1, gpio_base + 20
73 */
74
msic_gpio_to_ireg(unsigned offset)75 static int msic_gpio_to_ireg(unsigned offset)
76 {
77 if (offset >= MSIC_NUM_GPIO)
78 return -EINVAL;
79
80 if (offset < 8)
81 return INTEL_MSIC_GPIO0LV0CTLI - offset;
82 if (offset < 16)
83 return INTEL_MSIC_GPIO1LV0CTLI - offset + 8;
84 if (offset < 20)
85 return INTEL_MSIC_GPIO0HV0CTLI - offset + 16;
86
87 return INTEL_MSIC_GPIO1HV0CTLI - offset + 20;
88 }
89
msic_gpio_to_oreg(unsigned offset)90 static int msic_gpio_to_oreg(unsigned offset)
91 {
92 if (offset >= MSIC_NUM_GPIO)
93 return -EINVAL;
94
95 if (offset < 8)
96 return INTEL_MSIC_GPIO0LV0CTLO - offset;
97 if (offset < 16)
98 return INTEL_MSIC_GPIO1LV0CTLO - offset + 8;
99 if (offset < 20)
100 return INTEL_MSIC_GPIO0HV0CTLO - offset + 16;
101
102 return INTEL_MSIC_GPIO1HV0CTLO - offset + 20;
103 }
104
msic_gpio_direction_input(struct gpio_chip * chip,unsigned offset)105 static int msic_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
106 {
107 int reg;
108
109 reg = msic_gpio_to_oreg(offset);
110 if (reg < 0)
111 return reg;
112
113 return intel_msic_reg_update(reg, MSIC_GPIO_DIR_IN, MSIC_GPIO_DIR_MASK);
114 }
115
msic_gpio_direction_output(struct gpio_chip * chip,unsigned offset,int value)116 static int msic_gpio_direction_output(struct gpio_chip *chip,
117 unsigned offset, int value)
118 {
119 int reg;
120 unsigned mask;
121
122 value = (!!value) | MSIC_GPIO_DIR_OUT;
123 mask = MSIC_GPIO_DIR_MASK | MSIC_GPIO_DOUT_MASK;
124
125 reg = msic_gpio_to_oreg(offset);
126 if (reg < 0)
127 return reg;
128
129 return intel_msic_reg_update(reg, value, mask);
130 }
131
msic_gpio_get(struct gpio_chip * chip,unsigned offset)132 static int msic_gpio_get(struct gpio_chip *chip, unsigned offset)
133 {
134 u8 r;
135 int ret;
136 int reg;
137
138 reg = msic_gpio_to_ireg(offset);
139 if (reg < 0)
140 return reg;
141
142 ret = intel_msic_reg_read(reg, &r);
143 if (ret < 0)
144 return ret;
145
146 return r & MSIC_GPIO_DIN_MASK;
147 }
148
msic_gpio_set(struct gpio_chip * chip,unsigned offset,int value)149 static void msic_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
150 {
151 int reg;
152
153 reg = msic_gpio_to_oreg(offset);
154 if (reg < 0)
155 return;
156
157 intel_msic_reg_update(reg, !!value , MSIC_GPIO_DOUT_MASK);
158 }
159
160 /*
161 * This is called from genirq with mg->buslock locked and
162 * irq_desc->lock held. We can not access the scu bus here, so we
163 * store the change and update in the bus_sync_unlock() function below
164 */
msic_irq_type(struct irq_data * data,unsigned type)165 static int msic_irq_type(struct irq_data *data, unsigned type)
166 {
167 struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
168 u32 gpio = data->irq - mg->irq_base;
169
170 if (gpio >= mg->chip.ngpio)
171 return -EINVAL;
172
173 /* mark for which gpio the trigger changed, protected by buslock */
174 mg->trig_change_mask |= (1 << gpio);
175 mg->trig_type = type;
176
177 return 0;
178 }
179
msic_gpio_to_irq(struct gpio_chip * chip,unsigned offset)180 static int msic_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
181 {
182 struct msic_gpio *mg = container_of(chip, struct msic_gpio, chip);
183 return mg->irq_base + offset;
184 }
185
msic_bus_lock(struct irq_data * data)186 static void msic_bus_lock(struct irq_data *data)
187 {
188 struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
189 mutex_lock(&mg->buslock);
190 }
191
msic_bus_sync_unlock(struct irq_data * data)192 static void msic_bus_sync_unlock(struct irq_data *data)
193 {
194 struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
195 int offset;
196 int reg;
197 u8 trig = 0;
198
199 /* We can only get one change at a time as the buslock covers the
200 entire transaction. The irq_desc->lock is dropped before we are
201 called but that is fine */
202 if (mg->trig_change_mask) {
203 offset = __ffs(mg->trig_change_mask);
204
205 reg = msic_gpio_to_ireg(offset);
206 if (reg < 0)
207 goto out;
208
209 if (mg->trig_type & IRQ_TYPE_EDGE_RISING)
210 trig |= MSIC_GPIO_TRIG_RISE;
211 if (mg->trig_type & IRQ_TYPE_EDGE_FALLING)
212 trig |= MSIC_GPIO_TRIG_FALL;
213
214 intel_msic_reg_update(reg, trig, MSIC_GPIO_INTCNT_MASK);
215 mg->trig_change_mask = 0;
216 }
217 out:
218 mutex_unlock(&mg->buslock);
219 }
220
221 /* Firmware does all the masking and unmasking for us, no masking here. */
msic_irq_unmask(struct irq_data * data)222 static void msic_irq_unmask(struct irq_data *data) { }
223
msic_irq_mask(struct irq_data * data)224 static void msic_irq_mask(struct irq_data *data) { }
225
226 static struct irq_chip msic_irqchip = {
227 .name = "MSIC-GPIO",
228 .irq_mask = msic_irq_mask,
229 .irq_unmask = msic_irq_unmask,
230 .irq_set_type = msic_irq_type,
231 .irq_bus_lock = msic_bus_lock,
232 .irq_bus_sync_unlock = msic_bus_sync_unlock,
233 };
234
msic_gpio_irq_handler(unsigned irq,struct irq_desc * desc)235 static void msic_gpio_irq_handler(unsigned irq, struct irq_desc *desc)
236 {
237 struct irq_data *data = irq_desc_get_irq_data(desc);
238 struct msic_gpio *mg = irq_data_get_irq_handler_data(data);
239 struct irq_chip *chip = irq_data_get_irq_chip(data);
240 struct intel_msic *msic = pdev_to_intel_msic(mg->pdev);
241 int i;
242 int bitnr;
243 u8 pin;
244 unsigned long pending = 0;
245
246 for (i = 0; i < (mg->chip.ngpio / BITS_PER_BYTE); i++) {
247 intel_msic_irq_read(msic, INTEL_MSIC_GPIO0LVIRQ + i, &pin);
248 pending = pin;
249
250 if (pending) {
251 for_each_set_bit(bitnr, &pending, BITS_PER_BYTE)
252 generic_handle_irq(mg->irq_base +
253 (i * BITS_PER_BYTE) + bitnr);
254 }
255 }
256 chip->irq_eoi(data);
257 }
258
platform_msic_gpio_probe(struct platform_device * pdev)259 static int platform_msic_gpio_probe(struct platform_device *pdev)
260 {
261 struct device *dev = &pdev->dev;
262 struct intel_msic_gpio_pdata *pdata = dev->platform_data;
263 struct msic_gpio *mg;
264 int irq = platform_get_irq(pdev, 0);
265 int retval;
266 int i;
267
268 if (irq < 0) {
269 dev_err(dev, "no IRQ line\n");
270 return -EINVAL;
271 }
272
273 if (!pdata || !pdata->gpio_base) {
274 dev_err(dev, "incorrect or missing platform data\n");
275 return -EINVAL;
276 }
277
278 mg = kzalloc(sizeof(*mg), GFP_KERNEL);
279 if (!mg)
280 return -ENOMEM;
281
282 dev_set_drvdata(dev, mg);
283
284 mg->pdev = pdev;
285 mg->irq = irq;
286 mg->irq_base = pdata->gpio_base + MSIC_GPIO_IRQ_OFFSET;
287 mg->chip.label = "msic_gpio";
288 mg->chip.direction_input = msic_gpio_direction_input;
289 mg->chip.direction_output = msic_gpio_direction_output;
290 mg->chip.get = msic_gpio_get;
291 mg->chip.set = msic_gpio_set;
292 mg->chip.to_irq = msic_gpio_to_irq;
293 mg->chip.base = pdata->gpio_base;
294 mg->chip.ngpio = MSIC_NUM_GPIO;
295 mg->chip.can_sleep = 1;
296 mg->chip.dev = dev;
297
298 mutex_init(&mg->buslock);
299
300 retval = gpiochip_add(&mg->chip);
301 if (retval) {
302 dev_err(dev, "Adding MSIC gpio chip failed\n");
303 goto err;
304 }
305
306 for (i = 0; i < mg->chip.ngpio; i++) {
307 irq_set_chip_data(i + mg->irq_base, mg);
308 irq_set_chip_and_handler_name(i + mg->irq_base,
309 &msic_irqchip,
310 handle_simple_irq,
311 "demux");
312 }
313 irq_set_chained_handler(mg->irq, msic_gpio_irq_handler);
314 irq_set_handler_data(mg->irq, mg);
315
316 return 0;
317 err:
318 kfree(mg);
319 return retval;
320 }
321
322 static struct platform_driver platform_msic_gpio_driver = {
323 .driver = {
324 .name = "msic_gpio",
325 .owner = THIS_MODULE,
326 },
327 .probe = platform_msic_gpio_probe,
328 };
329
platform_msic_gpio_init(void)330 static int __init platform_msic_gpio_init(void)
331 {
332 return platform_driver_register(&platform_msic_gpio_driver);
333 }
334
335 subsys_initcall(platform_msic_gpio_init);
336
337 MODULE_AUTHOR("Mathias Nyman <mathias.nyman@linux.intel.com>");
338 MODULE_DESCRIPTION("Intel Medfield MSIC GPIO driver");
339 MODULE_LICENSE("GPL v2");
340