[linux-2.6-block.git] / drivers / misc / arm-charlcd.c

/*
 * Driver for the on-board character LCD found on some ARM reference boards
 * This is basically an Hitachi HD44780 LCD with a custom IP block to drive it
 * http://en.wikipedia.org/wiki/HD44780_Character_LCD
 * Currently it will just display the text "ARM Linux" and the linux version
 *
 * License terms: GNU General Public License (GPL) version 2
 * Author: Linus Walleij <triad@df.lth.se>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <generated/utsrelease.h>

#define DRIVERNAME "arm-charlcd"
#define CHARLCD_TIMEOUT (msecs_to_jiffies(1000))

/* Offsets to registers */
#define CHAR_COM	0x00U
#define CHAR_DAT	0x04U
#define CHAR_RD		0x08U
#define CHAR_RAW	0x0CU
#define CHAR_MASK	0x10U
#define CHAR_STAT	0x14U

#define CHAR_RAW_CLEAR	0x00000000U
#define CHAR_RAW_VALID	0x00000100U

/* Hitachi HD44780 display commands */
#define HD_CLEAR			0x01U
#define HD_HOME				0x02U
#define HD_ENTRYMODE			0x04U
#define HD_ENTRYMODE_INCREMENT		0x02U
#define HD_ENTRYMODE_SHIFT		0x01U
#define HD_DISPCTRL			0x08U
#define HD_DISPCTRL_ON			0x04U
#define HD_DISPCTRL_CURSOR_ON		0x02U
#define HD_DISPCTRL_CURSOR_BLINK	0x01U
#define HD_CRSR_SHIFT			0x10U
#define HD_CRSR_SHIFT_DISPLAY		0x08U
#define HD_CRSR_SHIFT_DISPLAY_RIGHT	0x04U
#define HD_FUNCSET			0x20U
#define HD_FUNCSET_8BIT			0x10U
#define HD_FUNCSET_2_LINES		0x08U
#define HD_FUNCSET_FONT_5X10		0x04U
#define HD_SET_CGRAM			0x40U
#define HD_SET_DDRAM			0x80U
#define HD_BUSY_FLAG			0x80U

/**
 * @dev: a pointer back to containing device
 * @phybase: the offset to the controller in physical memory
 * @physize: the size of the physical page
 * @virtbase: the offset to the controller in virtual memory
 * @irq: reserved interrupt number
 * @complete: completion structure for the last LCD command
 */
struct charlcd {
	struct device *dev;
	u32 phybase;
	u32 physize;
	void __iomem *virtbase;
	int irq;
	struct completion complete;
	struct delayed_work init_work;
};

static irqreturn_t charlcd_interrupt(int irq, void *data)
{
	struct charlcd *lcd = data;
	u8 status;

	status = readl(lcd->virtbase + CHAR_STAT) & 0x01;
	/* Clear IRQ */
	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
	if (status)
		complete(&lcd->complete);
	else
		dev_info(lcd->dev, "Spurious IRQ (%02x)\n", status);
	return IRQ_HANDLED;
}


static void charlcd_wait_complete_irq(struct charlcd *lcd)
{
	int ret;

	ret = wait_for_completion_interruptible_timeout(&lcd->complete,
							CHARLCD_TIMEOUT);
	/* Disable IRQ after completion */
	writel(0x00, lcd->virtbase + CHAR_MASK);

	if (ret < 0) {
		dev_err(lcd->dev,
			"wait_for_completion_interruptible_timeout() "
			"returned %d waiting for ready\n", ret);
		return;
	}

	if (ret == 0) {
		dev_err(lcd->dev, "charlcd controller timed out "
			"waiting for ready\n");
		return;
	}
}

static u8 charlcd_4bit_read_char(struct charlcd *lcd)
{
	u8 data;
	u32 val;
	int i;

	/* If we can, use an IRQ to wait for the data, else poll */
	if (lcd->irq >= 0)
		charlcd_wait_complete_irq(lcd);
	else {
		i = 0;
		val = 0;
		while (!(val & CHAR_RAW_VALID) && i < 10) {
			udelay(100);
			val = readl(lcd->virtbase + CHAR_RAW);
			i++;
		}

		writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
	}
	msleep(1);

	/* Read the 4 high bits of the data */
	data = readl(lcd->virtbase + CHAR_RD) & 0xf0;

	/*
	 * The second read for the low bits does not trigger an IRQ
	 * so in this case we have to poll for the 4 lower bits
	 */
	i = 0;
	val = 0;
	while (!(val & CHAR_RAW_VALID) && i < 10) {
		udelay(100);
		val = readl(lcd->virtbase + CHAR_RAW);
		i++;
	}
	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
	msleep(1);

	/* Read the 4 low bits of the data */
	data |= (readl(lcd->virtbase + CHAR_RD) >> 4) & 0x0f;

	return data;
}

static bool charlcd_4bit_read_bf(struct charlcd *lcd)
{
	if (lcd->irq >= 0) {
		/*
		 * If we'll use IRQs to wait for the busyflag, clear any
		 * pending flag and enable IRQ
		 */
		writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
		init_completion(&lcd->complete);
		writel(0x01, lcd->virtbase + CHAR_MASK);
	}
	readl(lcd->virtbase + CHAR_COM);
	return charlcd_4bit_read_char(lcd) & HD_BUSY_FLAG ? true : false;
}

static void charlcd_4bit_wait_busy(struct charlcd *lcd)
{
	int retries = 50;

	udelay(100);
	while (charlcd_4bit_read_bf(lcd) && retries)
		retries--;
	if (!retries)
		dev_err(lcd->dev, "timeout waiting for busyflag\n");
}

static void charlcd_4bit_command(struct charlcd *lcd, u8 cmd)
{
	u32 cmdlo = (cmd << 4) & 0xf0;
	u32 cmdhi = (cmd & 0xf0);

	writel(cmdhi, lcd->virtbase + CHAR_COM);
	udelay(10);
	writel(cmdlo, lcd->virtbase + CHAR_COM);
	charlcd_4bit_wait_busy(lcd);
}

static void charlcd_4bit_char(struct charlcd *lcd, u8 ch)
{
	u32 chlo = (ch << 4) & 0xf0;
	u32 chhi = (ch & 0xf0);

	writel(chhi, lcd->virtbase + CHAR_DAT);
	udelay(10);
	writel(chlo, lcd->virtbase + CHAR_DAT);
	charlcd_4bit_wait_busy(lcd);
}

static void charlcd_4bit_print(struct charlcd *lcd, int line, const char *str)
{
	u8 offset;
	int i;

	/*
	 * We support line 0, 1
	 * Line 1 runs from 0x00..0x27
	 * Line 2 runs from 0x28..0x4f
	 */
	if (line == 0)
		offset = 0;
	else if (line == 1)
		offset = 0x28;
	else
		return;

	/* Set offset */
	charlcd_4bit_command(lcd, HD_SET_DDRAM | offset);

	/* Send string */
	for (i = 0; i < strlen(str) && i < 0x28; i++)
		charlcd_4bit_char(lcd, str[i]);
}

static void charlcd_4bit_init(struct charlcd *lcd)
{
	/* These commands cannot be checked with the busy flag */
	writel(HD_FUNCSET | HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
	msleep(5);
	writel(HD_FUNCSET | HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
	udelay(100);
	writel(HD_FUNCSET | HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
	udelay(100);
	/* Go to 4bit mode */
	writel(HD_FUNCSET, lcd->virtbase + CHAR_COM);
	udelay(100);
	/*
	 * 4bit mode, 2 lines, 5x8 font, after this the number of lines
	 * and the font cannot be changed until the next initialization sequence
	 */
	charlcd_4bit_command(lcd, HD_FUNCSET | HD_FUNCSET_2_LINES);
	charlcd_4bit_command(lcd, HD_DISPCTRL | HD_DISPCTRL_ON);
	charlcd_4bit_command(lcd, HD_ENTRYMODE | HD_ENTRYMODE_INCREMENT);
	charlcd_4bit_command(lcd, HD_CLEAR);
	charlcd_4bit_command(lcd, HD_HOME);
	/* Put something useful in the display */
	charlcd_4bit_print(lcd, 0, "ARM Linux");
	charlcd_4bit_print(lcd, 1, UTS_RELEASE);
}

static void charlcd_init_work(struct work_struct *work)
{
	struct charlcd *lcd =
		container_of(work, struct charlcd, init_work.work);

	charlcd_4bit_init(lcd);
}

static int __init charlcd_probe(struct platform_device *pdev)
{
	int ret;
	struct charlcd *lcd;
	struct resource *res;

	lcd = kzalloc(sizeof(struct charlcd), GFP_KERNEL);
	if (!lcd)
		return -ENOMEM;

	lcd->dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		ret = -ENOENT;
		goto out_no_resource;
	}
	lcd->phybase = res->start;
	lcd->physize = resource_size(res);

	if (request_mem_region(lcd->phybase, lcd->physize,
			       DRIVERNAME) == NULL) {
		ret = -EBUSY;
		goto out_no_memregion;
	}

	lcd->virtbase = ioremap(lcd->phybase, lcd->physize);
	if (!lcd->virtbase) {
		ret = -ENOMEM;
		goto out_no_memregion;
	}

	lcd->irq = platform_get_irq(pdev, 0);
	/* If no IRQ is supplied, we'll survive without it */
	if (lcd->irq >= 0) {
		if (request_irq(lcd->irq, charlcd_interrupt, 0,
				DRIVERNAME, lcd)) {
			ret = -EIO;
			goto out_no_irq;
		}
	}

	platform_set_drvdata(pdev, lcd);

	/*
	 * Initialize the display in a delayed work, because
	 * it is VERY slow and would slow down the boot of the system.
	 */
	INIT_DELAYED_WORK(&lcd->init_work, charlcd_init_work);
	schedule_delayed_work(&lcd->init_work, 0);

	dev_info(&pdev->dev, "initialized ARM character LCD at %08x\n",
		lcd->phybase);

	return 0;

out_no_irq:
	iounmap(lcd->virtbase);
out_no_memregion:
	release_mem_region(lcd->phybase, SZ_4K);
out_no_resource:
	kfree(lcd);
	return ret;
}

static int __exit charlcd_remove(struct platform_device *pdev)
{
	struct charlcd *lcd = platform_get_drvdata(pdev);

	if (lcd) {
		free_irq(lcd->irq, lcd);
		iounmap(lcd->virtbase);
		release_mem_region(lcd->phybase, lcd->physize);
		kfree(lcd);
	}

	return 0;
}

static int charlcd_suspend(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct charlcd *lcd = platform_get_drvdata(pdev);

	/* Power the display off */
	charlcd_4bit_command(lcd, HD_DISPCTRL);
	return 0;
}

static int charlcd_resume(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct charlcd *lcd = platform_get_drvdata(pdev);

	/* Turn the display back on */
	charlcd_4bit_command(lcd, HD_DISPCTRL | HD_DISPCTRL_ON);
	return 0;
}

static const struct dev_pm_ops charlcd_pm_ops = {
	.suspend = charlcd_suspend,
	.resume = charlcd_resume,
};

static const struct of_device_id charlcd_match[] = {
	{ .compatible = "arm,versatile-lcd", },
	{}
};

static struct platform_driver charlcd_driver = {
	.driver = {
		.name = DRIVERNAME,
		.pm = &charlcd_pm_ops,
		.of_match_table = of_match_ptr(charlcd_match),
	},
	.remove = __exit_p(charlcd_remove),
};

module_platform_driver_probe(charlcd_driver, charlcd_probe);

MODULE_AUTHOR("Linus Walleij <triad@df.lth.se>");
MODULE_DESCRIPTION("ARM Character LCD Driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
ce896245 LW	1	/*
	2	* Driver for the on-board character LCD found on some ARM reference boards
	3	* This is basically an Hitachi HD44780 LCD with a custom IP block to drive it
	4	* http://en.wikipedia.org/wiki/HD44780_Character_LCD
	5	* Currently it will just display the text "ARM Linux" and the linux version
	6	*
	7	* License terms: GNU General Public License (GPL) version 2
	8	* Author: Linus Walleij <triad@df.lth.se>
	9	*/
	10	#include <linux/init.h>
	11	#include <linux/module.h>
	12	#include <linux/interrupt.h>
	13	#include <linux/platform_device.h>
4f063810	14	#include <linux/of.h>
ce896245 LW	15	#include <linux/completion.h>
	16	#include <linux/delay.h>
	17	#include <linux/io.h>
	18	#include <linux/slab.h>
	19	#include <linux/workqueue.h>
	20	#include <generated/utsrelease.h>
	21
	22	#define DRIVERNAME "arm-charlcd"
	23	#define CHARLCD_TIMEOUT (msecs_to_jiffies(1000))
	24
	25	/* Offsets to registers */
	26	#define CHAR_COM 0x00U
	27	#define CHAR_DAT 0x04U
	28	#define CHAR_RD 0x08U
	29	#define CHAR_RAW 0x0CU
	30	#define CHAR_MASK 0x10U
	31	#define CHAR_STAT 0x14U
	32
	33	#define CHAR_RAW_CLEAR 0x00000000U
	34	#define CHAR_RAW_VALID 0x00000100U
	35
	36	/* Hitachi HD44780 display commands */
	37	#define HD_CLEAR 0x01U
	38	#define HD_HOME 0x02U
	39	#define HD_ENTRYMODE 0x04U
	40	#define HD_ENTRYMODE_INCREMENT 0x02U
	41	#define HD_ENTRYMODE_SHIFT 0x01U
	42	#define HD_DISPCTRL 0x08U
	43	#define HD_DISPCTRL_ON 0x04U
	44	#define HD_DISPCTRL_CURSOR_ON 0x02U
	45	#define HD_DISPCTRL_CURSOR_BLINK 0x01U
	46	#define HD_CRSR_SHIFT 0x10U
	47	#define HD_CRSR_SHIFT_DISPLAY 0x08U
	48	#define HD_CRSR_SHIFT_DISPLAY_RIGHT 0x04U
	49	#define HD_FUNCSET 0x20U
	50	#define HD_FUNCSET_8BIT 0x10U
	51	#define HD_FUNCSET_2_LINES 0x08U
	52	#define HD_FUNCSET_FONT_5X10 0x04U
	53	#define HD_SET_CGRAM 0x40U
	54	#define HD_SET_DDRAM 0x80U
	55	#define HD_BUSY_FLAG 0x80U
	56
	57	/**
	58	* @dev: a pointer back to containing device
	59	* @phybase: the offset to the controller in physical memory
	60	* @physize: the size of the physical page
	61	* @virtbase: the offset to the controller in virtual memory
	62	* @irq: reserved interrupt number
	63	* @complete: completion structure for the last LCD command
	64	*/
	65	struct charlcd {
	66	struct device *dev;
	67	u32 phybase;
	68	u32 physize;
	69	void __iomem *virtbase;
	70	int irq;
	71	struct completion complete;
	72	struct delayed_work init_work;
	73	};
	74
	75	static irqreturn_t charlcd_interrupt(int irq, void *data)
	76	{
	77	struct charlcd *lcd = data;
	78	u8 status;
79
80	status = readl(lcd->virtbase + CHAR_STAT) & 0x01;
81	/* Clear IRQ */
82	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
83	if (status)
84	complete(&lcd->complete);
85	else
86	dev_info(lcd->dev, "Spurious IRQ (%02x)\n", status);
87	return IRQ_HANDLED;
88	}
89
90
91	static void charlcd_wait_complete_irq(struct charlcd *lcd)
92	{
93	int ret;
94
95	ret = wait_for_completion_interruptible_timeout(&lcd->complete,
96	CHARLCD_TIMEOUT);
97	/* Disable IRQ after completion */
98	writel(0x00, lcd->virtbase + CHAR_MASK);
99
100	if (ret < 0) {
101	dev_err(lcd->dev,
102	"wait_for_completion_interruptible_timeout() "
103	"returned %d waiting for ready\n", ret);
104	return;
105	}
106
107	if (ret == 0) {
108	dev_err(lcd->dev, "charlcd controller timed out "
109	"waiting for ready\n");
110	return;
111	}
112	}
113
114	static u8 charlcd_4bit_read_char(struct charlcd *lcd)
115	{
116	u8 data;
117	u32 val;
118	int i;
119
120	/* If we can, use an IRQ to wait for the data, else poll */
121	if (lcd->irq >= 0)
122	charlcd_wait_complete_irq(lcd);
123	else {
124	i = 0;
125	val = 0;
126	while (!(val & CHAR_RAW_VALID) && i < 10) {
127	udelay(100);
128	val = readl(lcd->virtbase + CHAR_RAW);
129	i++;
130	}
131
132	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
133	}
134	msleep(1);
135
136	/* Read the 4 high bits of the data */
137	data = readl(lcd->virtbase + CHAR_RD) & 0xf0;
138
139	/*
140	* The second read for the low bits does not trigger an IRQ
141	* so in this case we have to poll for the 4 lower bits
142	*/
143	i = 0;
144	val = 0;
145	while (!(val & CHAR_RAW_VALID) && i < 10) {
146	udelay(100);
147	val = readl(lcd->virtbase + CHAR_RAW);
148	i++;
149	}
150	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
151	msleep(1);
152
153	/* Read the 4 low bits of the data */
154	data \|= (readl(lcd->virtbase + CHAR_RD) >> 4) & 0x0f;
155
156	return data;
157	}
158
159	static bool charlcd_4bit_read_bf(struct charlcd *lcd)
160	{
161	if (lcd->irq >= 0) {
162	/*
163	* If we'll use IRQs to wait for the busyflag, clear any
164	* pending flag and enable IRQ
165	*/
166	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
167	init_completion(&lcd->complete);
168	writel(0x01, lcd->virtbase + CHAR_MASK);
169	}
170	readl(lcd->virtbase + CHAR_COM);
171	return charlcd_4bit_read_char(lcd) & HD_BUSY_FLAG ? true : false;
172	}
173
174	static void charlcd_4bit_wait_busy(struct charlcd *lcd)
175	{
176	int retries = 50;
177
178	udelay(100);
179	while (charlcd_4bit_read_bf(lcd) && retries)
180	retries--;
181	if (!retries)
182	dev_err(lcd->dev, "timeout waiting for busyflag\n");
183	}
184
185	static void charlcd_4bit_command(struct charlcd *lcd, u8 cmd)
186	{
187	u32 cmdlo = (cmd << 4) & 0xf0;
188	u32 cmdhi = (cmd & 0xf0);
189
190	writel(cmdhi, lcd->virtbase + CHAR_COM);
191	udelay(10);
192	writel(cmdlo, lcd->virtbase + CHAR_COM);
193	charlcd_4bit_wait_busy(lcd);
194	}
195
196	static void charlcd_4bit_char(struct charlcd *lcd, u8 ch)
197	{
198	u32 chlo = (ch << 4) & 0xf0;
199	u32 chhi = (ch & 0xf0);
200
201	writel(chhi, lcd->virtbase + CHAR_DAT);
202	udelay(10);
203	writel(chlo, lcd->virtbase + CHAR_DAT);
204	charlcd_4bit_wait_busy(lcd);
205	}
206
207	static void charlcd_4bit_print(struct charlcd lcd, int line, const char str)
208	{
209	u8 offset;
210	int i;
211
212	/*
213	* We support line 0, 1
214	* Line 1 runs from 0x00..0x27
215	* Line 2 runs from 0x28..0x4f
216	*/
217	if (line == 0)
218	offset = 0;
219	else if (line == 1)
220	offset = 0x28;
221	else
222	return;
223
224	/* Set offset */
225	charlcd_4bit_command(lcd, HD_SET_DDRAM \| offset);
226
227	/* Send string */
228	for (i = 0; i < strlen(str) && i < 0x28; i++)
229	charlcd_4bit_char(lcd, str[i]);
230	}
231
232	static void charlcd_4bit_init(struct charlcd *lcd)
233	{
234	/* These commands cannot be checked with the busy flag */
235	writel(HD_FUNCSET \| HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
236	msleep(5);
237	writel(HD_FUNCSET \| HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
238	udelay(100);
239	writel(HD_FUNCSET \| HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
240	udelay(100);
241	/* Go to 4bit mode */
242	writel(HD_FUNCSET, lcd->virtbase + CHAR_COM);
243	udelay(100);
244	/*
245	* 4bit mode, 2 lines, 5x8 font, after this the number of lines
246	* and the font cannot be changed until the next initialization sequence
247	*/
248	charlcd_4bit_command(lcd, HD_FUNCSET \| HD_FUNCSET_2_LINES);
249	charlcd_4bit_command(lcd, HD_DISPCTRL \| HD_DISPCTRL_ON);
250	charlcd_4bit_command(lcd, HD_ENTRYMODE \| HD_ENTRYMODE_INCREMENT);
251	charlcd_4bit_command(lcd, HD_CLEAR);
252	charlcd_4bit_command(lcd, HD_HOME);
253	/* Put something useful in the display */
254	charlcd_4bit_print(lcd, 0, "ARM Linux");
255	charlcd_4bit_print(lcd, 1, UTS_RELEASE);
256	}
257
258	static void charlcd_init_work(struct work_struct *work)
259	{
260	struct charlcd *lcd =
261	container_of(work, struct charlcd, init_work.work);
262
263	charlcd_4bit_init(lcd);
264	}
265
266	static int __init charlcd_probe(struct platform_device *pdev)
267	{
268	int ret;
269	struct charlcd *lcd;
270	struct resource *res;
271
272	lcd = kzalloc(sizeof(struct charlcd), GFP_KERNEL);
273	if (!lcd)
274	return -ENOMEM;
275
276	lcd->dev = &pdev->dev;
277
278	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
279	if (!res) {
280	ret = -ENOENT;
281	goto out_no_resource;
282	}
283	lcd->phybase = res->start;
284	lcd->physize = resource_size(res);
285
286	if (request_mem_region(lcd->phybase, lcd->physize,
287	DRIVERNAME) == NULL) {
288	ret = -EBUSY;
289	goto out_no_memregion;
290	}
291
292	lcd->virtbase = ioremap(lcd->phybase, lcd->physize);
293	if (!lcd->virtbase) {
294	ret = -ENOMEM;
87f0a427	295	goto out_no_memregion;
ce896245 LW	296	}
	297
	298	lcd->irq = platform_get_irq(pdev, 0);
	299	/* If no IRQ is supplied, we'll survive without it */
	300	if (lcd->irq >= 0) {
b09534d3	301	if (request_irq(lcd->irq, charlcd_interrupt, 0,
ce896245 LW	302	DRIVERNAME, lcd)) {
	303	ret = -EIO;
	304	goto out_no_irq;
	305	}
	306	}
	307
	308	platform_set_drvdata(pdev, lcd);
	309
	310	/*
	311	* Initialize the display in a delayed work, because
	312	* it is VERY slow and would slow down the boot of the system.
	313	*/
	314	INIT_DELAYED_WORK(&lcd->init_work, charlcd_init_work);
	315	schedule_delayed_work(&lcd->init_work, 0);
	316
b595076a	317	dev_info(&pdev->dev, "initialized ARM character LCD at %08x\n",
ce896245 LW	318	lcd->phybase);
	319
	320	return 0;
	321
	322	out_no_irq:
	323	iounmap(lcd->virtbase);
ce896245 LW	324	out_no_memregion:
	325	release_mem_region(lcd->phybase, SZ_4K);
	326	out_no_resource:
	327	kfree(lcd);
	328	return ret;
	329	}
	330
	331	static int __exit charlcd_remove(struct platform_device *pdev)
	332	{
	333	struct charlcd *lcd = platform_get_drvdata(pdev);
	334
	335	if (lcd) {
	336	free_irq(lcd->irq, lcd);
	337	iounmap(lcd->virtbase);
	338	release_mem_region(lcd->phybase, lcd->physize);
ce896245 LW	339	kfree(lcd);
	340	}
	341
	342	return 0;
	343	}
	344
	345	static int charlcd_suspend(struct device *dev)
	346	{
	347	struct platform_device *pdev = to_platform_device(dev);
	348	struct charlcd *lcd = platform_get_drvdata(pdev);
	349
	350	/* Power the display off */
	351	charlcd_4bit_command(lcd, HD_DISPCTRL);
	352	return 0;
	353	}
	354
	355	static int charlcd_resume(struct device *dev)
	356	{
	357	struct platform_device *pdev = to_platform_device(dev);
	358	struct charlcd *lcd = platform_get_drvdata(pdev);
	359
	360	/* Turn the display back on */
	361	charlcd_4bit_command(lcd, HD_DISPCTRL \| HD_DISPCTRL_ON);
	362	return 0;
	363	}
	364
	365	static const struct dev_pm_ops charlcd_pm_ops = {
	366	.suspend = charlcd_suspend,
	367	.resume = charlcd_resume,
	368	};
	369
4f063810 RH	370	static const struct of_device_id charlcd_match[] = {
	371	{ .compatible = "arm,versatile-lcd", },
	372	{}
	373	};
	374
ce896245 LW	375	static struct platform_driver charlcd_driver = {
	376	.driver = {
	377	.name = DRIVERNAME,
ce896245	378	.pm = &charlcd_pm_ops,
4f063810	379	.of_match_table = of_match_ptr(charlcd_match),
ce896245 LW	380	},
	381	.remove = __exit_p(charlcd_remove),
	382	};
	383
0c759482	384	module_platform_driver_probe(charlcd_driver, charlcd_probe);
ce896245 LW	385
	386	MODULE_AUTHOR("Linus Walleij <triad@df.lth.se>");
	387	MODULE_DESCRIPTION("ARM Character LCD Driver");
	388	MODULE_LICENSE("GPL v2");