1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Intel Medfield MSIC GPIO driver>
4 * Copyright (c) 2011, Intel Corporation.
5 *
6 * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
7 * Based on intel_pmic_gpio.c
8 */
9
10#include <linux/gpio/driver.h>
11#include <linux/init.h>
12#include <linux/interrupt.h>
13#include <linux/kernel.h>
14#include <linux/mfd/intel_msic.h>
15#include <linux/platform_device.h>
16#include <linux/slab.h>
17
18/* the offset for the mapping of global gpio pin to irq */
19#define MSIC_GPIO_IRQ_OFFSET	0x100
20
21#define MSIC_GPIO_DIR_IN	0
22#define MSIC_GPIO_DIR_OUT	BIT(5)
23#define MSIC_GPIO_TRIG_FALL	BIT(1)
24#define MSIC_GPIO_TRIG_RISE	BIT(2)
25
26/* masks for msic gpio output GPIOxxxxCTLO registers */
27#define MSIC_GPIO_DIR_MASK	BIT(5)
28#define MSIC_GPIO_DRV_MASK	BIT(4)
29#define MSIC_GPIO_REN_MASK	BIT(3)
30#define MSIC_GPIO_RVAL_MASK	(BIT(2) | BIT(1))
31#define MSIC_GPIO_DOUT_MASK	BIT(0)
32
33/* masks for msic gpio input GPIOxxxxCTLI registers */
34#define MSIC_GPIO_GLBYP_MASK	BIT(5)
35#define MSIC_GPIO_DBNC_MASK	(BIT(4) | BIT(3))
36#define MSIC_GPIO_INTCNT_MASK	(BIT(2) | BIT(1))
37#define MSIC_GPIO_DIN_MASK	BIT(0)
38
39#define MSIC_NUM_GPIO		24
40
41struct msic_gpio {
42	struct platform_device	*pdev;
43	struct mutex		buslock;
44	struct gpio_chip	chip;
45	int			irq;
46	unsigned		irq_base;
47	unsigned long		trig_change_mask;
48	unsigned		trig_type;
49};
50
51/*
52 * MSIC has 24 gpios, 16 low voltage (1.2-1.8v) and 8 high voltage (3v).
53 * Both the high and low voltage gpios are divided in two banks.
54 * GPIOs are numbered with GPIO0LV0 as gpio_base in the following order:
55 * GPIO0LV0..GPIO0LV7: low voltage, bank 0, gpio_base
56 * GPIO1LV0..GPIO1LV7: low voltage, bank 1,  gpio_base + 8
57 * GPIO0HV0..GPIO0HV3: high voltage, bank 0, gpio_base + 16
58 * GPIO1HV0..GPIO1HV3: high voltage, bank 1, gpio_base + 20
59 */
60
61static int msic_gpio_to_ireg(unsigned offset)
62{
63	if (offset >= MSIC_NUM_GPIO)
64		return -EINVAL;
65
66	if (offset < 8)
67		return INTEL_MSIC_GPIO0LV0CTLI - offset;
68	if (offset < 16)
69		return INTEL_MSIC_GPIO1LV0CTLI - offset + 8;
70	if (offset < 20)
71		return INTEL_MSIC_GPIO0HV0CTLI - offset + 16;
72
73	return INTEL_MSIC_GPIO1HV0CTLI - offset + 20;
74}
75
76static int msic_gpio_to_oreg(unsigned offset)
77{
78	if (offset >= MSIC_NUM_GPIO)
79		return -EINVAL;
80
81	if (offset < 8)
82		return INTEL_MSIC_GPIO0LV0CTLO - offset;
83	if (offset < 16)
84		return INTEL_MSIC_GPIO1LV0CTLO - offset + 8;
85	if (offset < 20)
86		return INTEL_MSIC_GPIO0HV0CTLO - offset + 16;
87
88	return INTEL_MSIC_GPIO1HV0CTLO - offset + 20;
89}
90
91static int msic_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
92{
93	int reg;
94
95	reg = msic_gpio_to_oreg(offset);
96	if (reg < 0)
97		return reg;
98
99	return intel_msic_reg_update(reg, MSIC_GPIO_DIR_IN, MSIC_GPIO_DIR_MASK);
100}
101
102static int msic_gpio_direction_output(struct gpio_chip *chip,
103			unsigned offset, int value)
104{
105	int reg;
106	unsigned mask;
107
108	value = (!!value) | MSIC_GPIO_DIR_OUT;
109	mask = MSIC_GPIO_DIR_MASK | MSIC_GPIO_DOUT_MASK;
110
111	reg = msic_gpio_to_oreg(offset);
112	if (reg < 0)
113		return reg;
114
115	return intel_msic_reg_update(reg, value, mask);
116}
117
118static int msic_gpio_get(struct gpio_chip *chip, unsigned offset)
119{
120	u8 r;
121	int ret;
122	int reg;
123
124	reg = msic_gpio_to_ireg(offset);
125	if (reg < 0)
126		return reg;
127
128	ret = intel_msic_reg_read(reg, &r);
129	if (ret < 0)
130		return ret;
131
132	return !!(r & MSIC_GPIO_DIN_MASK);
133}
134
135static void msic_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
136{
137	int reg;
138
139	reg = msic_gpio_to_oreg(offset);
140	if (reg < 0)
141		return;
142
143	intel_msic_reg_update(reg, !!value , MSIC_GPIO_DOUT_MASK);
144}
145
146/*
147 * This is called from genirq with mg->buslock locked and
148 * irq_desc->lock held. We can not access the scu bus here, so we
149 * store the change and update in the bus_sync_unlock() function below
150 */
151static int msic_irq_type(struct irq_data *data, unsigned type)
152{
153	struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
154	u32 gpio = data->irq - mg->irq_base;
155
156	if (gpio >= mg->chip.ngpio)
157		return -EINVAL;
158
159	/* mark for which gpio the trigger changed, protected by buslock */
160	mg->trig_change_mask |= (1 << gpio);
161	mg->trig_type = type;
162
163	return 0;
164}
165
166static int msic_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
167{
168	struct msic_gpio *mg = gpiochip_get_data(chip);
169	return mg->irq_base + offset;
170}
171
172static void msic_bus_lock(struct irq_data *data)
173{
174	struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
175	mutex_lock(&mg->buslock);
176}
177
178static void msic_bus_sync_unlock(struct irq_data *data)
179{
180	struct msic_gpio *mg = irq_data_get_irq_chip_data(data);
181	int offset;
182	int reg;
183	u8 trig = 0;
184
185	/* We can only get one change at a time as the buslock covers the
186	   entire transaction. The irq_desc->lock is dropped before we are
187	   called but that is fine */
188	if (mg->trig_change_mask) {
189		offset = __ffs(mg->trig_change_mask);
190
191		reg = msic_gpio_to_ireg(offset);
192		if (reg < 0)
193			goto out;
194
195		if (mg->trig_type & IRQ_TYPE_EDGE_RISING)
196			trig |= MSIC_GPIO_TRIG_RISE;
197		if (mg->trig_type & IRQ_TYPE_EDGE_FALLING)
198			trig |= MSIC_GPIO_TRIG_FALL;
199
200		intel_msic_reg_update(reg, trig, MSIC_GPIO_INTCNT_MASK);
201		mg->trig_change_mask = 0;
202	}
203out:
204	mutex_unlock(&mg->buslock);
205}
206
207/* Firmware does all the masking and unmasking for us, no masking here. */
208static void msic_irq_unmask(struct irq_data *data) { }
209
210static void msic_irq_mask(struct irq_data *data) { }
211
212static struct irq_chip msic_irqchip = {
213	.name			= "MSIC-GPIO",
214	.irq_mask		= msic_irq_mask,
215	.irq_unmask		= msic_irq_unmask,
216	.irq_set_type		= msic_irq_type,
217	.irq_bus_lock		= msic_bus_lock,
218	.irq_bus_sync_unlock	= msic_bus_sync_unlock,
219};
220
221static void msic_gpio_irq_handler(struct irq_desc *desc)
222{
223	struct irq_data *data = irq_desc_get_irq_data(desc);
224	struct msic_gpio *mg = irq_data_get_irq_handler_data(data);
225	struct irq_chip *chip = irq_data_get_irq_chip(data);
226	struct intel_msic *msic = pdev_to_intel_msic(mg->pdev);
227	unsigned long pending;
228	int i;
229	int bitnr;
230	u8 pin;
231
232	for (i = 0; i < (mg->chip.ngpio / BITS_PER_BYTE); i++) {
233		intel_msic_irq_read(msic, INTEL_MSIC_GPIO0LVIRQ + i, &pin);
234		pending = pin;
235
236		for_each_set_bit(bitnr, &pending, BITS_PER_BYTE)
237			generic_handle_irq(mg->irq_base + i * BITS_PER_BYTE + bitnr);
238	}
239	chip->irq_eoi(data);
240}
241
242static int platform_msic_gpio_probe(struct platform_device *pdev)
243{
244	struct device *dev = &pdev->dev;
245	struct intel_msic_gpio_pdata *pdata = dev_get_platdata(dev);
246	struct msic_gpio *mg;
247	int irq = platform_get_irq(pdev, 0);
248	int retval;
249	int i;
250
251	if (irq < 0) {
252		dev_err(dev, "no IRQ line: %d\n", irq);
253		return irq;
254	}
255
256	if (!pdata || !pdata->gpio_base) {
257		dev_err(dev, "incorrect or missing platform data\n");
258		return -EINVAL;
259	}
260
261	mg = kzalloc(sizeof(*mg), GFP_KERNEL);
262	if (!mg)
263		return -ENOMEM;
264
265	dev_set_drvdata(dev, mg);
266
267	mg->pdev = pdev;
268	mg->irq = irq;
269	mg->irq_base = pdata->gpio_base + MSIC_GPIO_IRQ_OFFSET;
270	mg->chip.label = "msic_gpio";
271	mg->chip.direction_input = msic_gpio_direction_input;
272	mg->chip.direction_output = msic_gpio_direction_output;
273	mg->chip.get = msic_gpio_get;
274	mg->chip.set = msic_gpio_set;
275	mg->chip.to_irq = msic_gpio_to_irq;
276	mg->chip.base = pdata->gpio_base;
277	mg->chip.ngpio = MSIC_NUM_GPIO;
278	mg->chip.can_sleep = true;
279	mg->chip.parent = dev;
280
281	mutex_init(&mg->buslock);
282
283	retval = gpiochip_add_data(&mg->chip, mg);
284	if (retval) {
285		dev_err(dev, "Adding MSIC gpio chip failed\n");
286		goto err;
287	}
288
289	for (i = 0; i < mg->chip.ngpio; i++) {
290		irq_set_chip_data(i + mg->irq_base, mg);
291		irq_set_chip_and_handler(i + mg->irq_base,
292					 &msic_irqchip,
293					 handle_simple_irq);
294	}
295	irq_set_chained_handler_and_data(mg->irq, msic_gpio_irq_handler, mg);
296
297	return 0;
298err:
299	kfree(mg);
300	return retval;
301}
302
303static struct platform_driver platform_msic_gpio_driver = {
304	.driver = {
305		.name		= "msic_gpio",
306	},
307	.probe		= platform_msic_gpio_probe,
308};
309
310static int __init platform_msic_gpio_init(void)
311{
312	return platform_driver_register(&platform_msic_gpio_driver);
313}
314subsys_initcall(platform_msic_gpio_init);
315