1/*
  2 * STMicroelectronics ConneXt (STA2X11) GPIO driver
  3 *
  4 * Copyright 2012 ST Microelectronics (Alessandro Rubini)
  5 * Based on gpio-ml-ioh.c, Copyright 2010 OKI Semiconductors Ltd.
  6 * Also based on previous sta2x11 work, Copyright 2011 Wind River Systems, Inc.
  7 *
  8 * This program is free software; you can redistribute it and/or modify
  9 * it under the terms of the GNU General Public License version 2 as
 10 * published by the Free Software Foundation.
 11 *
 12 * This program is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 15 * See the GNU 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 20 *
 21 */
 22
 23#include <linux/module.h>
 24#include <linux/kernel.h>
 25#include <linux/slab.h>
 26#include <linux/gpio.h>
 27#include <linux/interrupt.h>
 28#include <linux/irq.h>
 29#include <linux/pci.h>
 30#include <linux/platform_device.h>
 31#include <linux/mfd/sta2x11-mfd.h>
 32
 33struct gsta_regs {
 34	u32 dat;		/* 0x00 */
 35	u32 dats;
 36	u32 datc;
 37	u32 pdis;
 38	u32 dir;		/* 0x10 */
 39	u32 dirs;
 40	u32 dirc;
 41	u32 unused_1c;
 42	u32 afsela;		/* 0x20 */
 43	u32 unused_24[7];
 44	u32 rimsc;		/* 0x40 */
 45	u32 fimsc;
 46	u32 is;
 47	u32 ic;
 48};
 49
 50struct gsta_gpio {
 51	spinlock_t			lock;
 52	struct device			*dev;
 53	void __iomem			*reg_base;
 54	struct gsta_regs __iomem	*regs[GSTA_NR_BLOCKS];
 55	struct gpio_chip		gpio;
 56	int				irq_base;
 57	/* FIXME: save the whole config here (AF, ...) */
 58	unsigned			irq_type[GSTA_NR_GPIO];
 59};
 60
 61static inline struct gsta_regs __iomem *__regs(struct gsta_gpio *chip, int nr)
 62{
 63	return chip->regs[nr / GSTA_GPIO_PER_BLOCK];
 64}
 65
 66static inline u32 __bit(int nr)
 67{
 68	return 1U << (nr % GSTA_GPIO_PER_BLOCK);
 69}
 70
 71/*
 72 * gpio methods
 73 */
 74
 75static void gsta_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
 76{
 77	struct gsta_gpio *chip = gpiochip_get_data(gpio);
 78	struct gsta_regs __iomem *regs = __regs(chip, nr);
 79	u32 bit = __bit(nr);
 80
 81	if (val)
 82		writel(bit, &regs->dats);
 83	else
 84		writel(bit, &regs->datc);
 85}
 86
 87static int gsta_gpio_get(struct gpio_chip *gpio, unsigned nr)
 88{
 89	struct gsta_gpio *chip = gpiochip_get_data(gpio);
 90	struct gsta_regs __iomem *regs = __regs(chip, nr);
 91	u32 bit = __bit(nr);
 92
 93	return !!(readl(&regs->dat) & bit);
 94}
 95
 96static int gsta_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
 97				      int val)
 98{
 99	struct gsta_gpio *chip = gpiochip_get_data(gpio);
100	struct gsta_regs __iomem *regs = __regs(chip, nr);
101	u32 bit = __bit(nr);
102
103	writel(bit, &regs->dirs);
104	/* Data register after direction, otherwise pullup/down is selected */
105	if (val)
106		writel(bit, &regs->dats);
107	else
108		writel(bit, &regs->datc);
109	return 0;
110}
111
112static int gsta_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
113{
114	struct gsta_gpio *chip = gpiochip_get_data(gpio);
115	struct gsta_regs __iomem *regs = __regs(chip, nr);
116	u32 bit = __bit(nr);
117
118	writel(bit, &regs->dirc);
119	return 0;
120}
121
122static int gsta_gpio_to_irq(struct gpio_chip *gpio, unsigned offset)
123{
124	struct gsta_gpio *chip = gpiochip_get_data(gpio);
125	return chip->irq_base + offset;
126}
127
128static void gsta_gpio_setup(struct gsta_gpio *chip) /* called from probe */
129{
130	struct gpio_chip *gpio = &chip->gpio;
131
132	/*
133	 * ARCH_NR_GPIOS is currently 256 and dynamic allocation starts
134	 * from the end. However, for compatibility, we need the first
135	 * ConneXt device to start from gpio 0: it's the main chipset
136	 * on most boards so documents and drivers assume gpio0..gpio127
137	 */
138	static int gpio_base;
139
140	gpio->label = dev_name(chip->dev);
141	gpio->owner = THIS_MODULE;
142	gpio->direction_input = gsta_gpio_direction_input;
143	gpio->get = gsta_gpio_get;
144	gpio->direction_output = gsta_gpio_direction_output;
145	gpio->set = gsta_gpio_set;
146	gpio->dbg_show = NULL;
147	gpio->base = gpio_base;
148	gpio->ngpio = GSTA_NR_GPIO;
149	gpio->can_sleep = false;
150	gpio->to_irq = gsta_gpio_to_irq;
151
152	/*
153	 * After the first device, turn to dynamic gpio numbers.
154	 * For example, with ARCH_NR_GPIOS = 256 we can fit two cards
155	 */
156	if (!gpio_base)
157		gpio_base = -1;
158}
159
160/*
161 * Special method: alternate functions and pullup/pulldown. This is only
162 * invoked on startup to configure gpio's according to platform data.
163 * FIXME : this functionality shall be managed (and exported to other drivers)
164 * via the pin control subsystem.
165 */
166static void gsta_set_config(struct gsta_gpio *chip, int nr, unsigned cfg)
167{
168	struct gsta_regs __iomem *regs = __regs(chip, nr);
169	unsigned long flags;
170	u32 bit = __bit(nr);
171	u32 val;
172	int err = 0;
173
174	pr_info("%s: %p %i %i\n", __func__, chip, nr, cfg);
175
176	if (cfg == PINMUX_TYPE_NONE)
177		return;
178
179	/* Alternate function or not? */
180	spin_lock_irqsave(&chip->lock, flags);
181	val = readl(&regs->afsela);
182	if (cfg == PINMUX_TYPE_FUNCTION)
183		val |= bit;
184	else
185		val &= ~bit;
186	writel(val | bit, &regs->afsela);
187	if (cfg == PINMUX_TYPE_FUNCTION) {
188		spin_unlock_irqrestore(&chip->lock, flags);
189		return;
190	}
191
192	/* not alternate function: set details */
193	switch (cfg) {
194	case PINMUX_TYPE_OUTPUT_LOW:
195		writel(bit, &regs->dirs);
196		writel(bit, &regs->datc);
197		break;
198	case PINMUX_TYPE_OUTPUT_HIGH:
199		writel(bit, &regs->dirs);
200		writel(bit, &regs->dats);
201		break;
202	case PINMUX_TYPE_INPUT:
203		writel(bit, &regs->dirc);
204		val = readl(&regs->pdis) | bit;
205		writel(val, &regs->pdis);
206		break;
207	case PINMUX_TYPE_INPUT_PULLUP:
208		writel(bit, &regs->dirc);
209		val = readl(&regs->pdis) & ~bit;
210		writel(val, &regs->pdis);
211		writel(bit, &regs->dats);
212		break;
213	case PINMUX_TYPE_INPUT_PULLDOWN:
214		writel(bit, &regs->dirc);
215		val = readl(&regs->pdis) & ~bit;
216		writel(val, &regs->pdis);
217		writel(bit, &regs->datc);
218		break;
219	default:
220		err = 1;
221	}
222	spin_unlock_irqrestore(&chip->lock, flags);
223	if (err)
224		pr_err("%s: chip %p, pin %i, cfg %i is invalid\n",
225		       __func__, chip, nr, cfg);
226}
227
228/*
229 * Irq methods
230 */
231
232static void gsta_irq_disable(struct irq_data *data)
233{
234	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
235	struct gsta_gpio *chip = gc->private;
236	int nr = data->irq - chip->irq_base;
237	struct gsta_regs __iomem *regs = __regs(chip, nr);
238	u32 bit = __bit(nr);
239	u32 val;
240	unsigned long flags;
241
242	spin_lock_irqsave(&chip->lock, flags);
243	if (chip->irq_type[nr] & IRQ_TYPE_EDGE_RISING) {
244		val = readl(&regs->rimsc) & ~bit;
245		writel(val, &regs->rimsc);
246	}
247	if (chip->irq_type[nr] & IRQ_TYPE_EDGE_FALLING) {
248		val = readl(&regs->fimsc) & ~bit;
249		writel(val, &regs->fimsc);
250	}
251	spin_unlock_irqrestore(&chip->lock, flags);
252	return;
253}
254
255static void gsta_irq_enable(struct irq_data *data)
256{
257	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
258	struct gsta_gpio *chip = gc->private;
259	int nr = data->irq - chip->irq_base;
260	struct gsta_regs __iomem *regs = __regs(chip, nr);
261	u32 bit = __bit(nr);
262	u32 val;
263	int type;
264	unsigned long flags;
265
266	type = chip->irq_type[nr];
267
268	spin_lock_irqsave(&chip->lock, flags);
269	val = readl(&regs->rimsc);
270	if (type & IRQ_TYPE_EDGE_RISING)
271		writel(val | bit, &regs->rimsc);
272	else
273		writel(val & ~bit, &regs->rimsc);
274	val = readl(&regs->rimsc);
275	if (type & IRQ_TYPE_EDGE_FALLING)
276		writel(val | bit, &regs->fimsc);
277	else
278		writel(val & ~bit, &regs->fimsc);
279	spin_unlock_irqrestore(&chip->lock, flags);
280	return;
281}
282
283static int gsta_irq_type(struct irq_data *d, unsigned int type)
284{
285	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
286	struct gsta_gpio *chip = gc->private;
287	int nr = d->irq - chip->irq_base;
288
289	/* We only support edge interrupts */
290	if (!(type & (IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING))) {
291		pr_debug("%s: unsupported type 0x%x\n", __func__, type);
292		return -EINVAL;
293	}
294
295	chip->irq_type[nr] = type; /* used for enable/disable */
296
297	gsta_irq_enable(d);
298	return 0;
299}
300
301static irqreturn_t gsta_gpio_handler(int irq, void *dev_id)
302{
303	struct gsta_gpio *chip = dev_id;
304	struct gsta_regs __iomem *regs;
305	u32 is;
306	int i, nr, base;
307	irqreturn_t ret = IRQ_NONE;
308
309	for (i = 0; i < GSTA_NR_BLOCKS; i++) {
310		regs = chip->regs[i];
311		base = chip->irq_base + i * GSTA_GPIO_PER_BLOCK;
312		while ((is = readl(&regs->is))) {
313			nr = __ffs(is);
314			irq = base + nr;
315			generic_handle_irq(irq);
316			writel(1 << nr, &regs->ic);
317			ret = IRQ_HANDLED;
318		}
319	}
320	return ret;
321}
322
323static void gsta_alloc_irq_chip(struct gsta_gpio *chip)
324{
325	struct irq_chip_generic *gc;
326	struct irq_chip_type *ct;
327
328	gc = irq_alloc_generic_chip(KBUILD_MODNAME, 1, chip->irq_base,
329				     chip->reg_base, handle_simple_irq);
330	gc->private = chip;
331	ct = gc->chip_types;
332
333	ct->chip.irq_set_type = gsta_irq_type;
334	ct->chip.irq_disable = gsta_irq_disable;
335	ct->chip.irq_enable = gsta_irq_enable;
336
337	/* FIXME: this makes at most 32 interrupts. Request 0 by now */
338	irq_setup_generic_chip(gc, 0 /* IRQ_MSK(GSTA_GPIO_PER_BLOCK) */, 0,
339			       IRQ_NOREQUEST | IRQ_NOPROBE, 0);
340
341	/* Set up all all 128 interrupts: code from setup_generic_chip */
342	{
343		struct irq_chip_type *ct = gc->chip_types;
344		int i, j;
345		for (j = 0; j < GSTA_NR_GPIO; j++) {
346			i = chip->irq_base + j;
347			irq_set_chip_and_handler(i, &ct->chip, ct->handler);
348			irq_set_chip_data(i, gc);
349			irq_clear_status_flags(i, IRQ_NOREQUEST | IRQ_NOPROBE);
350		}
351		gc->irq_cnt = i - gc->irq_base;
352	}
353}
354
355/* The platform device used here is instantiated by the MFD device */
356static int gsta_probe(struct platform_device *dev)
357{
358	int i, err;
359	struct pci_dev *pdev;
360	struct sta2x11_gpio_pdata *gpio_pdata;
361	struct gsta_gpio *chip;
362	struct resource *res;
363
364	pdev = *(struct pci_dev **)dev_get_platdata(&dev->dev);
365	gpio_pdata = dev_get_platdata(&pdev->dev);
366
367	if (gpio_pdata == NULL)
368		dev_err(&dev->dev, "no gpio config\n");
369	pr_debug("gpio config: %p\n", gpio_pdata);
370
371	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
372
373	chip = devm_kzalloc(&dev->dev, sizeof(*chip), GFP_KERNEL);
374	if (!chip)
375		return -ENOMEM;
376	chip->dev = &dev->dev;
377	chip->reg_base = devm_ioremap_resource(&dev->dev, res);
378	if (IS_ERR(chip->reg_base))
379		return PTR_ERR(chip->reg_base);
380
381	for (i = 0; i < GSTA_NR_BLOCKS; i++) {
382		chip->regs[i] = chip->reg_base + i * 4096;
383		/* disable all irqs */
384		writel(0, &chip->regs[i]->rimsc);
385		writel(0, &chip->regs[i]->fimsc);
386		writel(~0, &chip->regs[i]->ic);
387	}
388	spin_lock_init(&chip->lock);
389	gsta_gpio_setup(chip);
390	if (gpio_pdata)
391		for (i = 0; i < GSTA_NR_GPIO; i++)
392			gsta_set_config(chip, i, gpio_pdata->pinconfig[i]);
393
394	/* 384 was used in previous code: be compatible for other drivers */
395	err = irq_alloc_descs(-1, 384, GSTA_NR_GPIO, NUMA_NO_NODE);
396	if (err < 0) {
397		dev_warn(&dev->dev, "sta2x11 gpio: Can't get irq base (%i)\n",
398			 -err);
399		return err;
400	}
401	chip->irq_base = err;
402	gsta_alloc_irq_chip(chip);
403
404	err = request_irq(pdev->irq, gsta_gpio_handler,
405			     IRQF_SHARED, KBUILD_MODNAME, chip);
406	if (err < 0) {
407		dev_err(&dev->dev, "sta2x11 gpio: Can't request irq (%i)\n",
408			-err);
409		goto err_free_descs;
410	}
411
412	err = devm_gpiochip_add_data(&dev->dev, &chip->gpio, chip);
413	if (err < 0) {
414		dev_err(&dev->dev, "sta2x11 gpio: Can't register (%i)\n",
415			-err);
416		goto err_free_irq;
417	}
418
419	platform_set_drvdata(dev, chip);
420	return 0;
421
422err_free_irq:
423	free_irq(pdev->irq, chip);
424err_free_descs:
425	irq_free_descs(chip->irq_base, GSTA_NR_GPIO);
426	return err;
427}
428
429static struct platform_driver sta2x11_gpio_platform_driver = {
430	.driver = {
431		.name	= "sta2x11-gpio",
432	},
433	.probe = gsta_probe,
434};
435
436module_platform_driver(sta2x11_gpio_platform_driver);
437
438MODULE_LICENSE("GPL v2");
439MODULE_DESCRIPTION("sta2x11_gpio GPIO driver");