Root/drivers/gpio/gpio-msm-v2.c

1/* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
2 *
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License version 2 and
5 * only version 2 as published by the Free Software Foundation.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
15 * 02110-1301, USA.
16 *
17 */
18#define pr_fmt(fmt) "%s: " fmt, __func__
19
20#include <linux/bitmap.h>
21#include <linux/bitops.h>
22#include <linux/gpio.h>
23#include <linux/init.h>
24#include <linux/interrupt.h>
25#include <linux/io.h>
26#include <linux/irq.h>
27#include <linux/module.h>
28#include <linux/platform_device.h>
29#include <linux/spinlock.h>
30
31#include <asm/mach/irq.h>
32
33#include <mach/msm_gpiomux.h>
34#include <mach/msm_iomap.h>
35
36/* Bits of interest in the GPIO_IN_OUT register.
37 */
38enum {
39    GPIO_IN = 0,
40    GPIO_OUT = 1
41};
42
43/* Bits of interest in the GPIO_INTR_STATUS register.
44 */
45enum {
46    INTR_STATUS = 0,
47};
48
49/* Bits of interest in the GPIO_CFG register.
50 */
51enum {
52    GPIO_OE = 9,
53};
54
55/* Bits of interest in the GPIO_INTR_CFG register.
56 * When a GPIO triggers, two separate decisions are made, controlled
57 * by two separate flags.
58 *
59 * - First, INTR_RAW_STATUS_EN controls whether or not the GPIO_INTR_STATUS
60 * register for that GPIO will be updated to reflect the triggering of that
61 * gpio. If this bit is 0, this register will not be updated.
62 * - Second, INTR_ENABLE controls whether an interrupt is triggered.
63 *
64 * If INTR_ENABLE is set and INTR_RAW_STATUS_EN is NOT set, an interrupt
65 * can be triggered but the status register will not reflect it.
66 */
67enum {
68    INTR_ENABLE = 0,
69    INTR_POL_CTL = 1,
70    INTR_DECT_CTL = 2,
71    INTR_RAW_STATUS_EN = 3,
72};
73
74/* Codes of interest in GPIO_INTR_CFG_SU.
75 */
76enum {
77    TARGET_PROC_SCORPION = 4,
78    TARGET_PROC_NONE = 7,
79};
80
81
82#define GPIO_INTR_CFG_SU(gpio) (MSM_TLMM_BASE + 0x0400 + (0x04 * (gpio)))
83#define GPIO_CONFIG(gpio) (MSM_TLMM_BASE + 0x1000 + (0x10 * (gpio)))
84#define GPIO_IN_OUT(gpio) (MSM_TLMM_BASE + 0x1004 + (0x10 * (gpio)))
85#define GPIO_INTR_CFG(gpio) (MSM_TLMM_BASE + 0x1008 + (0x10 * (gpio)))
86#define GPIO_INTR_STATUS(gpio) (MSM_TLMM_BASE + 0x100c + (0x10 * (gpio)))
87
88/**
89 * struct msm_gpio_dev: the MSM8660 SoC GPIO device structure
90 *
91 * @enabled_irqs: a bitmap used to optimize the summary-irq handler. By
92 * keeping track of which gpios are unmasked as irq sources, we avoid
93 * having to do readl calls on hundreds of iomapped registers each time
94 * the summary interrupt fires in order to locate the active interrupts.
95 *
96 * @wake_irqs: a bitmap for tracking which interrupt lines are enabled
97 * as wakeup sources. When the device is suspended, interrupts which are
98 * not wakeup sources are disabled.
99 *
100 * @dual_edge_irqs: a bitmap used to track which irqs are configured
101 * as dual-edge, as this is not supported by the hardware and requires
102 * some special handling in the driver.
103 */
104struct msm_gpio_dev {
105    struct gpio_chip gpio_chip;
106    DECLARE_BITMAP(enabled_irqs, NR_GPIO_IRQS);
107    DECLARE_BITMAP(wake_irqs, NR_GPIO_IRQS);
108    DECLARE_BITMAP(dual_edge_irqs, NR_GPIO_IRQS);
109};
110
111static DEFINE_SPINLOCK(tlmm_lock);
112
113static inline struct msm_gpio_dev *to_msm_gpio_dev(struct gpio_chip *chip)
114{
115    return container_of(chip, struct msm_gpio_dev, gpio_chip);
116}
117
118static inline void set_gpio_bits(unsigned n, void __iomem *reg)
119{
120    writel(readl(reg) | n, reg);
121}
122
123static inline void clear_gpio_bits(unsigned n, void __iomem *reg)
124{
125    writel(readl(reg) & ~n, reg);
126}
127
128static int msm_gpio_get(struct gpio_chip *chip, unsigned offset)
129{
130    return readl(GPIO_IN_OUT(offset)) & BIT(GPIO_IN);
131}
132
133static void msm_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
134{
135    writel(val ? BIT(GPIO_OUT) : 0, GPIO_IN_OUT(offset));
136}
137
138static int msm_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
139{
140    unsigned long irq_flags;
141
142    spin_lock_irqsave(&tlmm_lock, irq_flags);
143    clear_gpio_bits(BIT(GPIO_OE), GPIO_CONFIG(offset));
144    spin_unlock_irqrestore(&tlmm_lock, irq_flags);
145    return 0;
146}
147
148static int msm_gpio_direction_output(struct gpio_chip *chip,
149                unsigned offset,
150                int val)
151{
152    unsigned long irq_flags;
153
154    spin_lock_irqsave(&tlmm_lock, irq_flags);
155    msm_gpio_set(chip, offset, val);
156    set_gpio_bits(BIT(GPIO_OE), GPIO_CONFIG(offset));
157    spin_unlock_irqrestore(&tlmm_lock, irq_flags);
158    return 0;
159}
160
161static int msm_gpio_request(struct gpio_chip *chip, unsigned offset)
162{
163    return msm_gpiomux_get(chip->base + offset);
164}
165
166static void msm_gpio_free(struct gpio_chip *chip, unsigned offset)
167{
168    msm_gpiomux_put(chip->base + offset);
169}
170
171static int msm_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
172{
173    return MSM_GPIO_TO_INT(chip->base + offset);
174}
175
176static inline int msm_irq_to_gpio(struct gpio_chip *chip, unsigned irq)
177{
178    return irq - MSM_GPIO_TO_INT(chip->base);
179}
180
181static struct msm_gpio_dev msm_gpio = {
182    .gpio_chip = {
183        .base = 0,
184        .ngpio = NR_GPIO_IRQS,
185        .direction_input = msm_gpio_direction_input,
186        .direction_output = msm_gpio_direction_output,
187        .get = msm_gpio_get,
188        .set = msm_gpio_set,
189        .to_irq = msm_gpio_to_irq,
190        .request = msm_gpio_request,
191        .free = msm_gpio_free,
192    },
193};
194
195/* For dual-edge interrupts in software, since the hardware has no
196 * such support:
197 *
198 * At appropriate moments, this function may be called to flip the polarity
199 * settings of both-edge irq lines to try and catch the next edge.
200 *
201 * The attempt is considered successful if:
202 * - the status bit goes high, indicating that an edge was caught, or
203 * - the input value of the gpio doesn't change during the attempt.
204 * If the value changes twice during the process, that would cause the first
205 * test to fail but would force the second, as two opposite
206 * transitions would cause a detection no matter the polarity setting.
207 *
208 * The do-loop tries to sledge-hammer closed the timing hole between
209 * the initial value-read and the polarity-write - if the line value changes
210 * during that window, an interrupt is lost, the new polarity setting is
211 * incorrect, and the first success test will fail, causing a retry.
212 *
213 * Algorithm comes from Google's msmgpio driver, see mach-msm/gpio.c.
214 */
215static void msm_gpio_update_dual_edge_pos(unsigned gpio)
216{
217    int loop_limit = 100;
218    unsigned val, val2, intstat;
219
220    do {
221        val = readl(GPIO_IN_OUT(gpio)) & BIT(GPIO_IN);
222        if (val)
223            clear_gpio_bits(BIT(INTR_POL_CTL), GPIO_INTR_CFG(gpio));
224        else
225            set_gpio_bits(BIT(INTR_POL_CTL), GPIO_INTR_CFG(gpio));
226        val2 = readl(GPIO_IN_OUT(gpio)) & BIT(GPIO_IN);
227        intstat = readl(GPIO_INTR_STATUS(gpio)) & BIT(INTR_STATUS);
228        if (intstat || val == val2)
229            return;
230    } while (loop_limit-- > 0);
231    pr_err("dual-edge irq failed to stabilize, "
232           "interrupts dropped. %#08x != %#08x\n",
233           val, val2);
234}
235
236static void msm_gpio_irq_ack(struct irq_data *d)
237{
238    int gpio = msm_irq_to_gpio(&msm_gpio.gpio_chip, d->irq);
239
240    writel(BIT(INTR_STATUS), GPIO_INTR_STATUS(gpio));
241    if (test_bit(gpio, msm_gpio.dual_edge_irqs))
242        msm_gpio_update_dual_edge_pos(gpio);
243}
244
245static void msm_gpio_irq_mask(struct irq_data *d)
246{
247    int gpio = msm_irq_to_gpio(&msm_gpio.gpio_chip, d->irq);
248    unsigned long irq_flags;
249
250    spin_lock_irqsave(&tlmm_lock, irq_flags);
251    writel(TARGET_PROC_NONE, GPIO_INTR_CFG_SU(gpio));
252    clear_gpio_bits(INTR_RAW_STATUS_EN | INTR_ENABLE, GPIO_INTR_CFG(gpio));
253    __clear_bit(gpio, msm_gpio.enabled_irqs);
254    spin_unlock_irqrestore(&tlmm_lock, irq_flags);
255}
256
257static void msm_gpio_irq_unmask(struct irq_data *d)
258{
259    int gpio = msm_irq_to_gpio(&msm_gpio.gpio_chip, d->irq);
260    unsigned long irq_flags;
261
262    spin_lock_irqsave(&tlmm_lock, irq_flags);
263    __set_bit(gpio, msm_gpio.enabled_irqs);
264    set_gpio_bits(INTR_RAW_STATUS_EN | INTR_ENABLE, GPIO_INTR_CFG(gpio));
265    writel(TARGET_PROC_SCORPION, GPIO_INTR_CFG_SU(gpio));
266    spin_unlock_irqrestore(&tlmm_lock, irq_flags);
267}
268
269static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int flow_type)
270{
271    int gpio = msm_irq_to_gpio(&msm_gpio.gpio_chip, d->irq);
272    unsigned long irq_flags;
273    uint32_t bits;
274
275    spin_lock_irqsave(&tlmm_lock, irq_flags);
276
277    bits = readl(GPIO_INTR_CFG(gpio));
278
279    if (flow_type & IRQ_TYPE_EDGE_BOTH) {
280        bits |= BIT(INTR_DECT_CTL);
281        __irq_set_handler_locked(d->irq, handle_edge_irq);
282        if ((flow_type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
283            __set_bit(gpio, msm_gpio.dual_edge_irqs);
284        else
285            __clear_bit(gpio, msm_gpio.dual_edge_irqs);
286    } else {
287        bits &= ~BIT(INTR_DECT_CTL);
288        __irq_set_handler_locked(d->irq, handle_level_irq);
289        __clear_bit(gpio, msm_gpio.dual_edge_irqs);
290    }
291
292    if (flow_type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_LEVEL_HIGH))
293        bits |= BIT(INTR_POL_CTL);
294    else
295        bits &= ~BIT(INTR_POL_CTL);
296
297    writel(bits, GPIO_INTR_CFG(gpio));
298
299    if ((flow_type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
300        msm_gpio_update_dual_edge_pos(gpio);
301
302    spin_unlock_irqrestore(&tlmm_lock, irq_flags);
303
304    return 0;
305}
306
307/*
308 * When the summary IRQ is raised, any number of GPIO lines may be high.
309 * It is the job of the summary handler to find all those GPIO lines
310 * which have been set as summary IRQ lines and which are triggered,
311 * and to call their interrupt handlers.
312 */
313static void msm_summary_irq_handler(unsigned int irq, struct irq_desc *desc)
314{
315    unsigned long i;
316    struct irq_chip *chip = irq_desc_get_chip(desc);
317
318    chained_irq_enter(chip, desc);
319
320    for (i = find_first_bit(msm_gpio.enabled_irqs, NR_GPIO_IRQS);
321         i < NR_GPIO_IRQS;
322         i = find_next_bit(msm_gpio.enabled_irqs, NR_GPIO_IRQS, i + 1)) {
323        if (readl(GPIO_INTR_STATUS(i)) & BIT(INTR_STATUS))
324            generic_handle_irq(msm_gpio_to_irq(&msm_gpio.gpio_chip,
325                               i));
326    }
327
328    chained_irq_exit(chip, desc);
329}
330
331static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
332{
333    int gpio = msm_irq_to_gpio(&msm_gpio.gpio_chip, d->irq);
334
335    if (on) {
336        if (bitmap_empty(msm_gpio.wake_irqs, NR_GPIO_IRQS))
337            irq_set_irq_wake(TLMM_SCSS_SUMMARY_IRQ, 1);
338        set_bit(gpio, msm_gpio.wake_irqs);
339    } else {
340        clear_bit(gpio, msm_gpio.wake_irqs);
341        if (bitmap_empty(msm_gpio.wake_irqs, NR_GPIO_IRQS))
342            irq_set_irq_wake(TLMM_SCSS_SUMMARY_IRQ, 0);
343    }
344
345    return 0;
346}
347
348static struct irq_chip msm_gpio_irq_chip = {
349    .name = "msmgpio",
350    .irq_mask = msm_gpio_irq_mask,
351    .irq_unmask = msm_gpio_irq_unmask,
352    .irq_ack = msm_gpio_irq_ack,
353    .irq_set_type = msm_gpio_irq_set_type,
354    .irq_set_wake = msm_gpio_irq_set_wake,
355};
356
357static int __devinit msm_gpio_probe(struct platform_device *dev)
358{
359    int i, irq, ret;
360
361    bitmap_zero(msm_gpio.enabled_irqs, NR_GPIO_IRQS);
362    bitmap_zero(msm_gpio.wake_irqs, NR_GPIO_IRQS);
363    bitmap_zero(msm_gpio.dual_edge_irqs, NR_GPIO_IRQS);
364    msm_gpio.gpio_chip.label = dev->name;
365    ret = gpiochip_add(&msm_gpio.gpio_chip);
366    if (ret < 0)
367        return ret;
368
369    for (i = 0; i < msm_gpio.gpio_chip.ngpio; ++i) {
370        irq = msm_gpio_to_irq(&msm_gpio.gpio_chip, i);
371        irq_set_chip_and_handler(irq, &msm_gpio_irq_chip,
372                     handle_level_irq);
373        set_irq_flags(irq, IRQF_VALID);
374    }
375
376    irq_set_chained_handler(TLMM_SCSS_SUMMARY_IRQ,
377                msm_summary_irq_handler);
378    return 0;
379}
380
381static int __devexit msm_gpio_remove(struct platform_device *dev)
382{
383    int ret = gpiochip_remove(&msm_gpio.gpio_chip);
384
385    if (ret < 0)
386        return ret;
387
388    irq_set_handler(TLMM_SCSS_SUMMARY_IRQ, NULL);
389
390    return 0;
391}
392
393static struct platform_driver msm_gpio_driver = {
394    .probe = msm_gpio_probe,
395    .remove = __devexit_p(msm_gpio_remove),
396    .driver = {
397        .name = "msmgpio",
398        .owner = THIS_MODULE,
399    },
400};
401
402static struct platform_device msm_device_gpio = {
403    .name = "msmgpio",
404    .id = -1,
405};
406
407static int __init msm_gpio_init(void)
408{
409    int rc;
410
411    rc = platform_driver_register(&msm_gpio_driver);
412    if (!rc) {
413        rc = platform_device_register(&msm_device_gpio);
414        if (rc)
415            platform_driver_unregister(&msm_gpio_driver);
416    }
417
418    return rc;
419}
420
421static void __exit msm_gpio_exit(void)
422{
423    platform_device_unregister(&msm_device_gpio);
424    platform_driver_unregister(&msm_gpio_driver);
425}
426
427postcore_initcall(msm_gpio_init);
428module_exit(msm_gpio_exit);
429
430MODULE_AUTHOR("Gregory Bean <gbean@codeaurora.org>");
431MODULE_DESCRIPTION("Driver for Qualcomm MSM TLMMv2 SoC GPIOs");
432MODULE_LICENSE("GPL v2");
433MODULE_ALIAS("platform:msmgpio");
434

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