[linux.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 <[email protected]>
 */
#include <linux/init.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 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,
		.suppress_bind_attrs = true,
		.of_match_table = of_match_ptr(charlcd_match),
	},
};
builtin_platform_driver_probe(charlcd_driver, charlcd_probe);
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 <[email protected]>
	9	*/
	10	#include <linux/init.h>
ce896245 LW	11	#include <linux/interrupt.h>
ce896245 LW	12	#include <linux/platform_device.h>
4f063810	13	#include <linux/of.h>
ce896245 LW	14	#include <linux/completion.h>
	15	#include <linux/delay.h>
	16	#include <linux/io.h>
	17	#include <linux/slab.h>
	18	#include <linux/workqueue.h>
	19	#include <generated/utsrelease.h>
	20
	21	#define DRIVERNAME "arm-charlcd"
	22	#define CHARLCD_TIMEOUT (msecs_to_jiffies(1000))
	23
	24	/* Offsets to registers */
	25	#define CHAR_COM 0x00U
	26	#define CHAR_DAT 0x04U
	27	#define CHAR_RD 0x08U
	28	#define CHAR_RAW 0x0CU
	29	#define CHAR_MASK 0x10U
	30	#define CHAR_STAT 0x14U
	31
	32	#define CHAR_RAW_CLEAR 0x00000000U
	33	#define CHAR_RAW_VALID 0x00000100U
	34
	35	/* Hitachi HD44780 display commands */
	36	#define HD_CLEAR 0x01U
	37	#define HD_HOME 0x02U
	38	#define HD_ENTRYMODE 0x04U
	39	#define HD_ENTRYMODE_INCREMENT 0x02U
	40	#define HD_ENTRYMODE_SHIFT 0x01U
	41	#define HD_DISPCTRL 0x08U
	42	#define HD_DISPCTRL_ON 0x04U
	43	#define HD_DISPCTRL_CURSOR_ON 0x02U
	44	#define HD_DISPCTRL_CURSOR_BLINK 0x01U
	45	#define HD_CRSR_SHIFT 0x10U
	46	#define HD_CRSR_SHIFT_DISPLAY 0x08U
	47	#define HD_CRSR_SHIFT_DISPLAY_RIGHT 0x04U
	48	#define HD_FUNCSET 0x20U
	49	#define HD_FUNCSET_8BIT 0x10U
	50	#define HD_FUNCSET_2_LINES 0x08U
	51	#define HD_FUNCSET_FONT_5X10 0x04U
	52	#define HD_SET_CGRAM 0x40U
	53	#define HD_SET_DDRAM 0x80U
	54	#define HD_BUSY_FLAG 0x80U
	55
	56	/**
	57	* @dev: a pointer back to containing device
	58	* @phybase: the offset to the controller in physical memory
	59	* @physize: the size of the physical page
	60	* @virtbase: the offset to the controller in virtual memory
	61	* @irq: reserved interrupt number
	62	* @complete: completion structure for the last LCD command
	63	*/
	64	struct charlcd {
	65	struct device *dev;
	66	u32 phybase;
	67	u32 physize;
	68	void __iomem *virtbase;
	69	int irq;
	70	struct completion complete;
	71	struct delayed_work init_work;
	72	};
	73
	74	static irqreturn_t charlcd_interrupt(int irq, void *data)
	75	{
	76	struct charlcd *lcd = data;
	77	u8 status;
78
79	status = readl(lcd->virtbase + CHAR_STAT) & 0x01;
80	/* Clear IRQ */
81	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
82	if (status)
83	complete(&lcd->complete);
84	else
85	dev_info(lcd->dev, "Spurious IRQ (%02x)\n", status);
86	return IRQ_HANDLED;
87	}
88
89
90	static void charlcd_wait_complete_irq(struct charlcd *lcd)
91	{
92	int ret;
93
94	ret = wait_for_completion_interruptible_timeout(&lcd->complete,
95	CHARLCD_TIMEOUT);
96	/* Disable IRQ after completion */
97	writel(0x00, lcd->virtbase + CHAR_MASK);
98
99	if (ret < 0) {
100	dev_err(lcd->dev,
101	"wait_for_completion_interruptible_timeout() "
102	"returned %d waiting for ready\n", ret);
103	return;
104	}
105
106	if (ret == 0) {
107	dev_err(lcd->dev, "charlcd controller timed out "
108	"waiting for ready\n");
109	return;
110	}
111	}
112
113	static u8 charlcd_4bit_read_char(struct charlcd *lcd)
114	{
115	u8 data;
116	u32 val;
117	int i;
118
119	/* If we can, use an IRQ to wait for the data, else poll */
120	if (lcd->irq >= 0)
121	charlcd_wait_complete_irq(lcd);
122	else {
123	i = 0;
124	val = 0;
125	while (!(val & CHAR_RAW_VALID) && i < 10) {
126	udelay(100);
127	val = readl(lcd->virtbase + CHAR_RAW);
128	i++;
129	}
130
131	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
132	}
133	msleep(1);
134
135	/* Read the 4 high bits of the data */
136	data = readl(lcd->virtbase + CHAR_RD) & 0xf0;
137
138	/*
139	* The second read for the low bits does not trigger an IRQ
140	* so in this case we have to poll for the 4 lower bits
141	*/
142	i = 0;
143	val = 0;
144	while (!(val & CHAR_RAW_VALID) && i < 10) {
145	udelay(100);
146	val = readl(lcd->virtbase + CHAR_RAW);
147	i++;
148	}
149	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
150	msleep(1);
151
152	/* Read the 4 low bits of the data */
153	data \|= (readl(lcd->virtbase + CHAR_RD) >> 4) & 0x0f;
154
155	return data;
156	}
157
158	static bool charlcd_4bit_read_bf(struct charlcd *lcd)
159	{
160	if (lcd->irq >= 0) {
161	/*
162	* If we'll use IRQs to wait for the busyflag, clear any
163	* pending flag and enable IRQ
164	*/
165	writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
166	init_completion(&lcd->complete);
167	writel(0x01, lcd->virtbase + CHAR_MASK);
168	}
169	readl(lcd->virtbase + CHAR_COM);
170	return charlcd_4bit_read_char(lcd) & HD_BUSY_FLAG ? true : false;
171	}
172
173	static void charlcd_4bit_wait_busy(struct charlcd *lcd)
174	{
175	int retries = 50;
176
177	udelay(100);
178	while (charlcd_4bit_read_bf(lcd) && retries)
179	retries--;
180	if (!retries)
181	dev_err(lcd->dev, "timeout waiting for busyflag\n");
182	}
183
184	static void charlcd_4bit_command(struct charlcd *lcd, u8 cmd)
185	{
186	u32 cmdlo = (cmd << 4) & 0xf0;
187	u32 cmdhi = (cmd & 0xf0);
188
189	writel(cmdhi, lcd->virtbase + CHAR_COM);
190	udelay(10);
191	writel(cmdlo, lcd->virtbase + CHAR_COM);
192	charlcd_4bit_wait_busy(lcd);
193	}
194
195	static void charlcd_4bit_char(struct charlcd *lcd, u8 ch)
196	{
197	u32 chlo = (ch << 4) & 0xf0;
198	u32 chhi = (ch & 0xf0);
199
200	writel(chhi, lcd->virtbase + CHAR_DAT);
201	udelay(10);
202	writel(chlo, lcd->virtbase + CHAR_DAT);
203	charlcd_4bit_wait_busy(lcd);
204	}
205
206	static void charlcd_4bit_print(struct charlcd lcd, int line, const char str)
207	{
208	u8 offset;
209	int i;
210
211	/*
212	* We support line 0, 1
213	* Line 1 runs from 0x00..0x27
214	* Line 2 runs from 0x28..0x4f
215	*/
216	if (line == 0)
217	offset = 0;
218	else if (line == 1)
219	offset = 0x28;
220	else
221	return;
222
223	/* Set offset */
224	charlcd_4bit_command(lcd, HD_SET_DDRAM \| offset);
225
226	/* Send string */
227	for (i = 0; i < strlen(str) && i < 0x28; i++)
228	charlcd_4bit_char(lcd, str[i]);
229	}
230
231	static void charlcd_4bit_init(struct charlcd *lcd)
232	{
233	/* These commands cannot be checked with the busy flag */
234	writel(HD_FUNCSET \| HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
235	msleep(5);
236	writel(HD_FUNCSET \| HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
237	udelay(100);
238	writel(HD_FUNCSET \| HD_FUNCSET_8BIT, lcd->virtbase + CHAR_COM);
239	udelay(100);
240	/* Go to 4bit mode */
241	writel(HD_FUNCSET, lcd->virtbase + CHAR_COM);
242	udelay(100);
243	/*
244	* 4bit mode, 2 lines, 5x8 font, after this the number of lines
245	* and the font cannot be changed until the next initialization sequence
246	*/
247	charlcd_4bit_command(lcd, HD_FUNCSET \| HD_FUNCSET_2_LINES);
248	charlcd_4bit_command(lcd, HD_DISPCTRL \| HD_DISPCTRL_ON);
249	charlcd_4bit_command(lcd, HD_ENTRYMODE \| HD_ENTRYMODE_INCREMENT);
250	charlcd_4bit_command(lcd, HD_CLEAR);
251	charlcd_4bit_command(lcd, HD_HOME);
252	/* Put something useful in the display */
253	charlcd_4bit_print(lcd, 0, "ARM Linux");
254	charlcd_4bit_print(lcd, 1, UTS_RELEASE);
255	}
256
257	static void charlcd_init_work(struct work_struct *work)
258	{
259	struct charlcd *lcd =
260	container_of(work, struct charlcd, init_work.work);
261
262	charlcd_4bit_init(lcd);
263	}
264
265	static int __init charlcd_probe(struct platform_device *pdev)
266	{
267	int ret;
268	struct charlcd *lcd;
269	struct resource *res;
270
271	lcd = kzalloc(sizeof(struct charlcd), GFP_KERNEL);
272	if (!lcd)
273	return -ENOMEM;
274
275	lcd->dev = &pdev->dev;
276
277	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
278	if (!res) {
279	ret = -ENOENT;
280	goto out_no_resource;
281	}
282	lcd->phybase = res->start;
283	lcd->physize = resource_size(res);
284
285	if (request_mem_region(lcd->phybase, lcd->physize,
286	DRIVERNAME) == NULL) {
287	ret = -EBUSY;
288	goto out_no_memregion;
289	}
290
291	lcd->virtbase = ioremap(lcd->phybase, lcd->physize);
292	if (!lcd->virtbase) {
293	ret = -ENOMEM;
87f0a427	294	goto out_no_memregion;
ce896245 LW	295	}
	296
	297	lcd->irq = platform_get_irq(pdev, 0);
	298	/* If no IRQ is supplied, we'll survive without it */
	299	if (lcd->irq >= 0) {
b09534d3	300	if (request_irq(lcd->irq, charlcd_interrupt, 0,
ce896245 LW	301	DRIVERNAME, lcd)) {
	302	ret = -EIO;
	303	goto out_no_irq;
	304	}
	305	}
	306
	307	platform_set_drvdata(pdev, lcd);
	308
	309	/*
	310	* Initialize the display in a delayed work, because
	311	* it is VERY slow and would slow down the boot of the system.
	312	*/
	313	INIT_DELAYED_WORK(&lcd->init_work, charlcd_init_work);
	314	schedule_delayed_work(&lcd->init_work, 0);
	315
b595076a	316	dev_info(&pdev->dev, "initialized ARM character LCD at %08x\n",
ce896245 LW	317	lcd->phybase);
	318
	319	return 0;
	320
	321	out_no_irq:
	322	iounmap(lcd->virtbase);
ce896245 LW	323	out_no_memregion:
	324	release_mem_region(lcd->phybase, SZ_4K);
	325	out_no_resource:
	326	kfree(lcd);
	327	return ret;
	328	}
	329
ce896245 LW	330	static int charlcd_suspend(struct device *dev)
	331	{
	332	struct platform_device *pdev = to_platform_device(dev);
	333	struct charlcd *lcd = platform_get_drvdata(pdev);
	334
	335	/* Power the display off */
	336	charlcd_4bit_command(lcd, HD_DISPCTRL);
	337	return 0;
	338	}
	339
	340	static int charlcd_resume(struct device *dev)
	341	{
	342	struct platform_device *pdev = to_platform_device(dev);
	343	struct charlcd *lcd = platform_get_drvdata(pdev);
	344
	345	/* Turn the display back on */
	346	charlcd_4bit_command(lcd, HD_DISPCTRL \| HD_DISPCTRL_ON);
	347	return 0;
	348	}
	349
	350	static const struct dev_pm_ops charlcd_pm_ops = {
	351	.suspend = charlcd_suspend,
	352	.resume = charlcd_resume,
	353	};
	354
4f063810 RH	355	static const struct of_device_id charlcd_match[] = {
	356	{ .compatible = "arm,versatile-lcd", },
	357	{}
	358	};
	359
ce896245 LW	360	static struct platform_driver charlcd_driver = {
	361	.driver = {
	362	.name = DRIVERNAME,
ce896245	363	.pm = &charlcd_pm_ops,
47312a4a	364	.suppress_bind_attrs = true,
4f063810	365	.of_match_table = of_match_ptr(charlcd_match),
ce896245	366	},
ce896245	367	};
47312a4a	368	builtin_platform_driver_probe(charlcd_driver, charlcd_probe);