1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Backlight driver for ArcticSand ARC_X_C_0N_0N Devices
4 *
5 * Copyright 2016 ArcticSand, Inc.
6 * Author : Brian Dodge <bdodge@arcticsand.com>
7 */
8
9#include <linux/backlight.h>
10#include <linux/err.h>
11#include <linux/i2c.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/slab.h>
15
16enum arcxcnn_chip_id {
17	ARC2C0608
18};
19
20/**
21 * struct arcxcnn_platform_data
22 * @name		: Backlight driver name (NULL will use default)
23 * @initial_brightness	: initial value of backlight brightness
24 * @leden		: initial LED string enables, upper bit is global on/off
25 * @led_config_0	: fading speed (period between intensity steps)
26 * @led_config_1	: misc settings, see datasheet
27 * @dim_freq		: pwm dimming frequency if in pwm mode
28 * @comp_config		: misc config, see datasheet
29 * @filter_config	: RC/PWM filter config, see datasheet
30 * @trim_config		: full scale current trim, see datasheet
31 */
32struct arcxcnn_platform_data {
33	const char *name;
34	u16 initial_brightness;
35	u8	leden;
36	u8	led_config_0;
37	u8	led_config_1;
38	u8	dim_freq;
39	u8	comp_config;
40	u8	filter_config;
41	u8	trim_config;
42};
43
44#define ARCXCNN_CMD		0x00	/* Command Register */
45#define ARCXCNN_CMD_STDBY	0x80	/*   I2C Standby */
46#define ARCXCNN_CMD_RESET	0x40	/*   Reset */
47#define ARCXCNN_CMD_BOOST	0x10	/*   Boost */
48#define ARCXCNN_CMD_OVP_MASK	0x0C	/*   --- Over Voltage Threshold */
49#define ARCXCNN_CMD_OVP_XXV	0x0C	/*   <rsvrd> Over Voltage Threshold */
50#define ARCXCNN_CMD_OVP_20V	0x08	/*   20v Over Voltage Threshold */
51#define ARCXCNN_CMD_OVP_24V	0x04	/*   24v Over Voltage Threshold */
52#define ARCXCNN_CMD_OVP_31V	0x00	/*   31.4v Over Voltage Threshold */
53#define ARCXCNN_CMD_EXT_COMP	0x01	/*   part (0) or full (1) ext. comp */
54
55#define ARCXCNN_CONFIG		0x01	/* Configuration */
56#define ARCXCNN_STATUS1		0x02	/* Status 1 */
57#define ARCXCNN_STATUS2		0x03	/* Status 2 */
58#define ARCXCNN_FADECTRL	0x04	/* Fading Control */
59#define ARCXCNN_ILED_CONFIG	0x05	/* ILED Configuration */
60#define ARCXCNN_ILED_DIM_PWM	0x00	/*   config dim mode pwm */
61#define ARCXCNN_ILED_DIM_INT	0x04	/*   config dim mode internal */
62#define ARCXCNN_LEDEN		0x06	/* LED Enable Register */
63#define ARCXCNN_LEDEN_ISETEXT	0x80	/*   Full-scale current set extern */
64#define ARCXCNN_LEDEN_MASK	0x3F	/*   LED string enables mask */
65#define ARCXCNN_LEDEN_BITS	0x06	/*   Bits of LED string enables */
66#define ARCXCNN_LEDEN_LED1	0x01
67#define ARCXCNN_LEDEN_LED2	0x02
68#define ARCXCNN_LEDEN_LED3	0x04
69#define ARCXCNN_LEDEN_LED4	0x08
70#define ARCXCNN_LEDEN_LED5	0x10
71#define ARCXCNN_LEDEN_LED6	0x20
72
73#define ARCXCNN_WLED_ISET_LSB	0x07	/* LED ISET LSB (in upper nibble) */
74#define ARCXCNN_WLED_ISET_LSB_SHIFT 0x04  /* ISET LSB Left Shift */
75#define ARCXCNN_WLED_ISET_MSB	0x08	/* LED ISET MSB (8 bits) */
76
77#define ARCXCNN_DIMFREQ		0x09
78#define ARCXCNN_COMP_CONFIG	0x0A
79#define ARCXCNN_FILT_CONFIG	0x0B
80#define ARCXCNN_IMAXTUNE	0x0C
81#define ARCXCNN_ID_MSB		0x1E
82#define ARCXCNN_ID_LSB		0x1F
83
84#define MAX_BRIGHTNESS		4095
85#define INIT_BRIGHT		60
86
87struct arcxcnn {
88	struct i2c_client *client;
89	struct backlight_device *bl;
90	struct device *dev;
91	struct arcxcnn_platform_data *pdata;
92};
93
94static int arcxcnn_update_field(struct arcxcnn *lp, u8 reg, u8 mask, u8 data)
95{
96	int ret;
97	u8 tmp;
98
99	ret = i2c_smbus_read_byte_data(lp->client, reg);
100	if (ret < 0) {
101		dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
102		return ret;
103	}
104
105	tmp = (u8)ret;
106	tmp &= ~mask;
107	tmp |= data & mask;
108
109	return i2c_smbus_write_byte_data(lp->client, reg, tmp);
110}
111
112static int arcxcnn_set_brightness(struct arcxcnn *lp, u32 brightness)
113{
114	int ret;
115	u8 val;
116
117	/* lower nibble of brightness goes in upper nibble of LSB register */
118	val = (brightness & 0xF) << ARCXCNN_WLED_ISET_LSB_SHIFT;
119	ret = i2c_smbus_write_byte_data(lp->client,
120		ARCXCNN_WLED_ISET_LSB, val);
121	if (ret < 0)
122		return ret;
123
124	/* remaining 8 bits of brightness go in MSB register */
125	val = (brightness >> 4);
126	return i2c_smbus_write_byte_data(lp->client,
127		ARCXCNN_WLED_ISET_MSB, val);
128}
129
130static int arcxcnn_bl_update_status(struct backlight_device *bl)
131{
132	struct arcxcnn *lp = bl_get_data(bl);
133	u32 brightness = bl->props.brightness;
134	int ret;
135
136	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
137		brightness = 0;
138
139	ret = arcxcnn_set_brightness(lp, brightness);
140	if (ret)
141		return ret;
142
143	/* set power-on/off/save modes */
144	return arcxcnn_update_field(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY,
145		(bl->props.power == 0) ? 0 : ARCXCNN_CMD_STDBY);
146}
147
148static const struct backlight_ops arcxcnn_bl_ops = {
149	.options = BL_CORE_SUSPENDRESUME,
150	.update_status = arcxcnn_bl_update_status,
151};
152
153static int arcxcnn_backlight_register(struct arcxcnn *lp)
154{
155	struct backlight_properties *props;
156	const char *name = lp->pdata->name ? : "arctic_bl";
157
158	props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL);
159	if (!props)
160		return -ENOMEM;
161
162	props->type = BACKLIGHT_PLATFORM;
163	props->max_brightness = MAX_BRIGHTNESS;
164
165	if (lp->pdata->initial_brightness > props->max_brightness)
166		lp->pdata->initial_brightness = props->max_brightness;
167
168	props->brightness = lp->pdata->initial_brightness;
169
170	lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
171				       &arcxcnn_bl_ops, props);
172	return PTR_ERR_OR_ZERO(lp->bl);
173}
174
175static void arcxcnn_parse_dt(struct arcxcnn *lp)
176{
177	struct device *dev = lp->dev;
178	struct device_node *node = dev->of_node;
179	u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS];
180	int ret;
181
182	/* device tree entry isn't required, defaults are OK */
183	if (!node)
184		return;
185
186	ret = of_property_read_string(node, "label", &lp->pdata->name);
187	if (ret < 0)
188		lp->pdata->name = NULL;
189
190	ret = of_property_read_u32(node, "default-brightness", &prog_val);
191	if (ret == 0)
192		lp->pdata->initial_brightness = prog_val;
193
194	ret = of_property_read_u32(node, "arc,led-config-0", &prog_val);
195	if (ret == 0)
196		lp->pdata->led_config_0 = (u8)prog_val;
197
198	ret = of_property_read_u32(node, "arc,led-config-1", &prog_val);
199	if (ret == 0)
200		lp->pdata->led_config_1 = (u8)prog_val;
201
202	ret = of_property_read_u32(node, "arc,dim-freq", &prog_val);
203	if (ret == 0)
204		lp->pdata->dim_freq = (u8)prog_val;
205
206	ret = of_property_read_u32(node, "arc,comp-config", &prog_val);
207	if (ret == 0)
208		lp->pdata->comp_config = (u8)prog_val;
209
210	ret = of_property_read_u32(node, "arc,filter-config", &prog_val);
211	if (ret == 0)
212		lp->pdata->filter_config = (u8)prog_val;
213
214	ret = of_property_read_u32(node, "arc,trim-config", &prog_val);
215	if (ret == 0)
216		lp->pdata->trim_config = (u8)prog_val;
217
218	ret = of_property_count_u32_elems(node, "led-sources");
219	if (ret < 0) {
220		lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */
221	} else {
222		num_entry = ret;
223		if (num_entry > ARCXCNN_LEDEN_BITS)
224			num_entry = ARCXCNN_LEDEN_BITS;
225
226		ret = of_property_read_u32_array(node, "led-sources", sources,
227					num_entry);
228		if (ret < 0) {
229			dev_err(dev, "led-sources node is invalid.\n");
230			return;
231		}
232
233		lp->pdata->leden = 0;
234
235		/* for each enable in source, set bit in led enable */
236		for (entry = 0; entry < num_entry; entry++) {
237			u8 onbit = 1 << sources[entry];
238
239			lp->pdata->leden |= onbit;
240		}
241	}
242}
243
244static int arcxcnn_probe(struct i2c_client *cl, const struct i2c_device_id *id)
245{
246	struct arcxcnn *lp;
247	int ret;
248
249	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
250		return -EIO;
251
252	lp = devm_kzalloc(&cl->dev, sizeof(*lp), GFP_KERNEL);
253	if (!lp)
254		return -ENOMEM;
255
256	lp->client = cl;
257	lp->dev = &cl->dev;
258	lp->pdata = dev_get_platdata(&cl->dev);
259
260	/* reset the device */
261	ret = i2c_smbus_write_byte_data(lp->client,
262		ARCXCNN_CMD, ARCXCNN_CMD_RESET);
263	if (ret)
264		goto probe_err;
265
266	if (!lp->pdata) {
267		lp->pdata = devm_kzalloc(lp->dev,
268				sizeof(*lp->pdata), GFP_KERNEL);
269		if (!lp->pdata)
270			return -ENOMEM;
271
272		/* Setup defaults based on power-on defaults */
273		lp->pdata->name = NULL;
274		lp->pdata->initial_brightness = INIT_BRIGHT;
275		lp->pdata->leden = ARCXCNN_LEDEN_MASK;
276
277		lp->pdata->led_config_0 = i2c_smbus_read_byte_data(
278			lp->client, ARCXCNN_FADECTRL);
279
280		lp->pdata->led_config_1 = i2c_smbus_read_byte_data(
281			lp->client, ARCXCNN_ILED_CONFIG);
282		/* insure dim mode is not default pwm */
283		lp->pdata->led_config_1 |= ARCXCNN_ILED_DIM_INT;
284
285		lp->pdata->dim_freq = i2c_smbus_read_byte_data(
286			lp->client, ARCXCNN_DIMFREQ);
287
288		lp->pdata->comp_config = i2c_smbus_read_byte_data(
289			lp->client, ARCXCNN_COMP_CONFIG);
290
291		lp->pdata->filter_config = i2c_smbus_read_byte_data(
292			lp->client, ARCXCNN_FILT_CONFIG);
293
294		lp->pdata->trim_config = i2c_smbus_read_byte_data(
295			lp->client, ARCXCNN_IMAXTUNE);
296
297		if (IS_ENABLED(CONFIG_OF))
298			arcxcnn_parse_dt(lp);
299	}
300
301	i2c_set_clientdata(cl, lp);
302
303	/* constrain settings to what is possible */
304	if (lp->pdata->initial_brightness > MAX_BRIGHTNESS)
305		lp->pdata->initial_brightness = MAX_BRIGHTNESS;
306
307	/* set initial brightness */
308	ret = arcxcnn_set_brightness(lp, lp->pdata->initial_brightness);
309	if (ret)
310		goto probe_err;
311
312	/* set other register values directly */
313	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FADECTRL,
314		lp->pdata->led_config_0);
315	if (ret)
316		goto probe_err;
317
318	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_ILED_CONFIG,
319		lp->pdata->led_config_1);
320	if (ret)
321		goto probe_err;
322
323	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_DIMFREQ,
324		lp->pdata->dim_freq);
325	if (ret)
326		goto probe_err;
327
328	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_COMP_CONFIG,
329		lp->pdata->comp_config);
330	if (ret)
331		goto probe_err;
332
333	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FILT_CONFIG,
334		lp->pdata->filter_config);
335	if (ret)
336		goto probe_err;
337
338	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_IMAXTUNE,
339		lp->pdata->trim_config);
340	if (ret)
341		goto probe_err;
342
343	/* set initial LED Enables */
344	arcxcnn_update_field(lp, ARCXCNN_LEDEN,
345		ARCXCNN_LEDEN_MASK, lp->pdata->leden);
346
347	ret = arcxcnn_backlight_register(lp);
348	if (ret)
349		goto probe_register_err;
350
351	backlight_update_status(lp->bl);
352
353	return 0;
354
355probe_register_err:
356	dev_err(lp->dev,
357		"failed to register backlight.\n");
358
359probe_err:
360	dev_err(lp->dev,
361		"failure ret: %d\n", ret);
362	return ret;
363}
364
365static int arcxcnn_remove(struct i2c_client *cl)
366{
367	struct arcxcnn *lp = i2c_get_clientdata(cl);
368
369	/* disable all strings (ignore errors) */
370	i2c_smbus_write_byte_data(lp->client,
371		ARCXCNN_LEDEN, 0x00);
372	/* reset the device (ignore errors) */
373	i2c_smbus_write_byte_data(lp->client,
374		ARCXCNN_CMD, ARCXCNN_CMD_RESET);
375
376	lp->bl->props.brightness = 0;
377
378	backlight_update_status(lp->bl);
379
380	return 0;
381}
382
383static const struct of_device_id arcxcnn_dt_ids[] = {
384	{ .compatible = "arc,arc2c0608" },
385	{ }
386};
387MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids);
388
389static const struct i2c_device_id arcxcnn_ids[] = {
390	{"arc2c0608", ARC2C0608},
391	{ }
392};
393MODULE_DEVICE_TABLE(i2c, arcxcnn_ids);
394
395static struct i2c_driver arcxcnn_driver = {
396	.driver = {
397		.name = "arcxcnn_bl",
398		.of_match_table = of_match_ptr(arcxcnn_dt_ids),
399	},
400	.probe = arcxcnn_probe,
401	.remove = arcxcnn_remove,
402	.id_table = arcxcnn_ids,
403};
404module_i2c_driver(arcxcnn_driver);
405
406MODULE_LICENSE("GPL v2");
407MODULE_AUTHOR("Brian Dodge <bdodge@arcticsand.com>");
408MODULE_DESCRIPTION("ARCXCNN Backlight driver");
409