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
55struct 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
75static 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
90static 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
105static 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
116static 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
132static 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
149static 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 */
165static 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
180static 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
186static 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
192static 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	}
217out:
218	mutex_unlock(&mg->buslock);
219}
220
221/* Firmware does all the masking and unmasking for us, no masking here. */
222static void msic_irq_unmask(struct irq_data *data) { }
223
224static void msic_irq_mask(struct irq_data *data) { }
225
226static 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
235static 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
259static int platform_msic_gpio_probe(struct platform_device *pdev)
260{
261	struct device *dev = &pdev->dev;
262	struct intel_msic_gpio_pdata *pdata = dev_get_platdata(dev);
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 = true;
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(i + mg->irq_base,
309					 &msic_irqchip,
310					 handle_simple_irq);
311	}
312	irq_set_chained_handler(mg->irq, msic_gpio_irq_handler);
313	irq_set_handler_data(mg->irq, mg);
314
315	return 0;
316err:
317	kfree(mg);
318	return retval;
319}
320
321static struct platform_driver platform_msic_gpio_driver = {
322	.driver = {
323		.name		= "msic_gpio",
324	},
325	.probe		= platform_msic_gpio_probe,
326};
327
328static int __init platform_msic_gpio_init(void)
329{
330	return platform_driver_register(&platform_msic_gpio_driver);
331}
332
333subsys_initcall(platform_msic_gpio_init);
334
335MODULE_AUTHOR("Mathias Nyman <mathias.nyman@linux.intel.com>");
336MODULE_DESCRIPTION("Intel Medfield MSIC GPIO driver");
337MODULE_LICENSE("GPL v2");
338