arcxcnn_bl.c

  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 = backlight_get_brightness(bl);
134	int ret;
135
136	ret = arcxcnn_set_brightness(lp, brightness);
137	if (ret)
138		return ret;
139
140	/* set power-on/off/save modes */
141	return arcxcnn_update_field(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY,
142		(bl->props.power == 0) ? 0 : ARCXCNN_CMD_STDBY);
143}
144
145static const struct backlight_ops arcxcnn_bl_ops = {
146	.options = BL_CORE_SUSPENDRESUME,
147	.update_status = arcxcnn_bl_update_status,
148};
149
150static int arcxcnn_backlight_register(struct arcxcnn *lp)
151{
152	struct backlight_properties *props;
153	const char *name = lp->pdata->name ? : "arctic_bl";
154
155	props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL);
156	if (!props)
157		return -ENOMEM;
158
159	props->type = BACKLIGHT_PLATFORM;
160	props->max_brightness = MAX_BRIGHTNESS;
161
162	if (lp->pdata->initial_brightness > props->max_brightness)
163		lp->pdata->initial_brightness = props->max_brightness;
164
165	props->brightness = lp->pdata->initial_brightness;
166
167	lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
168				       &arcxcnn_bl_ops, props);
169	return PTR_ERR_OR_ZERO(lp->bl);
170}
171
172static void arcxcnn_parse_dt(struct arcxcnn *lp)
173{
174	struct device *dev = lp->dev;
175	struct device_node *node = dev->of_node;
176	u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS];
177	int ret;
178
179	/* device tree entry isn't required, defaults are OK */
180	if (!node)
181		return;
182
183	ret = of_property_read_string(node, "label", &lp->pdata->name);
184	if (ret < 0)
185		lp->pdata->name = NULL;
186
187	ret = of_property_read_u32(node, "default-brightness", &prog_val);
188	if (ret == 0)
189		lp->pdata->initial_brightness = prog_val;
190
191	ret = of_property_read_u32(node, "arc,led-config-0", &prog_val);
192	if (ret == 0)
193		lp->pdata->led_config_0 = (u8)prog_val;
194
195	ret = of_property_read_u32(node, "arc,led-config-1", &prog_val);
196	if (ret == 0)
197		lp->pdata->led_config_1 = (u8)prog_val;
198
199	ret = of_property_read_u32(node, "arc,dim-freq", &prog_val);
200	if (ret == 0)
201		lp->pdata->dim_freq = (u8)prog_val;
202
203	ret = of_property_read_u32(node, "arc,comp-config", &prog_val);
204	if (ret == 0)
205		lp->pdata->comp_config = (u8)prog_val;
206
207	ret = of_property_read_u32(node, "arc,filter-config", &prog_val);
208	if (ret == 0)
209		lp->pdata->filter_config = (u8)prog_val;
210
211	ret = of_property_read_u32(node, "arc,trim-config", &prog_val);
212	if (ret == 0)
213		lp->pdata->trim_config = (u8)prog_val;
214
215	ret = of_property_count_u32_elems(node, "led-sources");
216	if (ret < 0) {
217		lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */
218	} else {
219		num_entry = ret;
220		if (num_entry > ARCXCNN_LEDEN_BITS)
221			num_entry = ARCXCNN_LEDEN_BITS;
222
223		ret = of_property_read_u32_array(node, "led-sources", sources,
224					num_entry);
225		if (ret < 0) {
226			dev_err(dev, "led-sources node is invalid.\n");
227			return;
228		}
229
230		lp->pdata->leden = 0;
231
232		/* for each enable in source, set bit in led enable */
233		for (entry = 0; entry < num_entry; entry++) {
234			u8 onbit = 1 << sources[entry];
235
236			lp->pdata->leden |= onbit;
237		}
238	}
239}
240
241static int arcxcnn_probe(struct i2c_client *cl)
242{
243	struct arcxcnn *lp;
244	int ret;
245
246	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
247		return -EIO;
248
249	lp = devm_kzalloc(&cl->dev, sizeof(*lp), GFP_KERNEL);
250	if (!lp)
251		return -ENOMEM;
252
253	lp->client = cl;
254	lp->dev = &cl->dev;
255	lp->pdata = dev_get_platdata(&cl->dev);
256
257	/* reset the device */
258	ret = i2c_smbus_write_byte_data(lp->client,
259		ARCXCNN_CMD, ARCXCNN_CMD_RESET);
260	if (ret)
261		goto probe_err;
262
263	if (!lp->pdata) {
264		lp->pdata = devm_kzalloc(lp->dev,
265				sizeof(*lp->pdata), GFP_KERNEL);
266		if (!lp->pdata)
267			return -ENOMEM;
268
269		/* Setup defaults based on power-on defaults */
270		lp->pdata->name = NULL;
271		lp->pdata->initial_brightness = INIT_BRIGHT;
272		lp->pdata->leden = ARCXCNN_LEDEN_MASK;
273
274		lp->pdata->led_config_0 = i2c_smbus_read_byte_data(
275			lp->client, ARCXCNN_FADECTRL);
276
277		lp->pdata->led_config_1 = i2c_smbus_read_byte_data(
278			lp->client, ARCXCNN_ILED_CONFIG);
279		/* insure dim mode is not default pwm */
280		lp->pdata->led_config_1 |= ARCXCNN_ILED_DIM_INT;
281
282		lp->pdata->dim_freq = i2c_smbus_read_byte_data(
283			lp->client, ARCXCNN_DIMFREQ);
284
285		lp->pdata->comp_config = i2c_smbus_read_byte_data(
286			lp->client, ARCXCNN_COMP_CONFIG);
287
288		lp->pdata->filter_config = i2c_smbus_read_byte_data(
289			lp->client, ARCXCNN_FILT_CONFIG);
290
291		lp->pdata->trim_config = i2c_smbus_read_byte_data(
292			lp->client, ARCXCNN_IMAXTUNE);
293
294		if (IS_ENABLED(CONFIG_OF))
295			arcxcnn_parse_dt(lp);
296	}
297
298	i2c_set_clientdata(cl, lp);
299
300	/* constrain settings to what is possible */
301	if (lp->pdata->initial_brightness > MAX_BRIGHTNESS)
302		lp->pdata->initial_brightness = MAX_BRIGHTNESS;
303
304	/* set initial brightness */
305	ret = arcxcnn_set_brightness(lp, lp->pdata->initial_brightness);
306	if (ret)
307		goto probe_err;
308
309	/* set other register values directly */
310	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FADECTRL,
311		lp->pdata->led_config_0);
312	if (ret)
313		goto probe_err;
314
315	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_ILED_CONFIG,
316		lp->pdata->led_config_1);
317	if (ret)
318		goto probe_err;
319
320	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_DIMFREQ,
321		lp->pdata->dim_freq);
322	if (ret)
323		goto probe_err;
324
325	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_COMP_CONFIG,
326		lp->pdata->comp_config);
327	if (ret)
328		goto probe_err;
329
330	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FILT_CONFIG,
331		lp->pdata->filter_config);
332	if (ret)
333		goto probe_err;
334
335	ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_IMAXTUNE,
336		lp->pdata->trim_config);
337	if (ret)
338		goto probe_err;
339
340	/* set initial LED Enables */
341	arcxcnn_update_field(lp, ARCXCNN_LEDEN,
342		ARCXCNN_LEDEN_MASK, lp->pdata->leden);
343
344	ret = arcxcnn_backlight_register(lp);
345	if (ret)
346		goto probe_register_err;
347
348	backlight_update_status(lp->bl);
349
350	return 0;
351
352probe_register_err:
353	dev_err(lp->dev,
354		"failed to register backlight.\n");
355
356probe_err:
357	dev_err(lp->dev,
358		"failure ret: %d\n", ret);
359	return ret;
360}
361
362static void arcxcnn_remove(struct i2c_client *cl)
363{
364	struct arcxcnn *lp = i2c_get_clientdata(cl);
365
366	/* disable all strings (ignore errors) */
367	i2c_smbus_write_byte_data(lp->client,
368		ARCXCNN_LEDEN, 0x00);
369	/* reset the device (ignore errors) */
370	i2c_smbus_write_byte_data(lp->client,
371		ARCXCNN_CMD, ARCXCNN_CMD_RESET);
372
373	lp->bl->props.brightness = 0;
374
375	backlight_update_status(lp->bl);
376}
377
378static const struct of_device_id arcxcnn_dt_ids[] = {
379	{ .compatible = "arc,arc2c0608" },
380	{ }
381};
382MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids);
383
384static const struct i2c_device_id arcxcnn_ids[] = {
385	{"arc2c0608", ARC2C0608},
386	{ }
387};
388MODULE_DEVICE_TABLE(i2c, arcxcnn_ids);
389
390static struct i2c_driver arcxcnn_driver = {
391	.driver = {
392		.name = "arcxcnn_bl",
393		.of_match_table = arcxcnn_dt_ids,
394	},
395	.probe = arcxcnn_probe,
396	.remove = arcxcnn_remove,
397	.id_table = arcxcnn_ids,
398};
399module_i2c_driver(arcxcnn_driver);
400
401MODULE_LICENSE("GPL v2");
402MODULE_AUTHOR("Brian Dodge <bdodge@arcticsand.com>");
403MODULE_DESCRIPTION("ARCXCNN Backlight driver");