1d8523499STim Harvey // SPDX-License-Identifier: GPL-2.0
2d8523499STim Harvey /*
3d8523499STim Harvey * The Gateworks System Controller (GSC) is a multi-function
4d8523499STim Harvey * device designed for use in Gateworks Single Board Computers.
5d8523499STim Harvey * The control interface is I2C, with an interrupt. The device supports
6d8523499STim Harvey * system functions such as push-button monitoring, multiple ADC's for
7d8523499STim Harvey * voltage and temperature monitoring, fan controller and watchdog monitor.
8d8523499STim Harvey *
9d8523499STim Harvey * Copyright (C) 2020 Gateworks Corporation
10d8523499STim Harvey */
11d8523499STim Harvey
12d8523499STim Harvey #include <linux/device.h>
13d8523499STim Harvey #include <linux/i2c.h>
14d8523499STim Harvey #include <linux/interrupt.h>
15d8523499STim Harvey #include <linux/mfd/gsc.h>
16d8523499STim Harvey #include <linux/module.h>
17d8523499STim Harvey #include <linux/mutex.h>
18d8523499STim Harvey #include <linux/of.h>
19d8523499STim Harvey #include <linux/of_platform.h>
20d8523499STim Harvey #include <linux/platform_device.h>
21d8523499STim Harvey #include <linux/regmap.h>
22d8523499STim Harvey
23d8523499STim Harvey #include <asm/unaligned.h>
24d8523499STim Harvey
25d8523499STim Harvey /*
26d8523499STim Harvey * The GSC suffers from an errata where occasionally during
27d8523499STim Harvey * ADC cycles the chip can NAK I2C transactions. To ensure we have reliable
28d8523499STim Harvey * register access we place retries around register access.
29d8523499STim Harvey */
30d8523499STim Harvey #define I2C_RETRIES 3
31d8523499STim Harvey
gsc_write(void * context,unsigned int reg,unsigned int val)32d8523499STim Harvey int gsc_write(void *context, unsigned int reg, unsigned int val)
33d8523499STim Harvey {
34d8523499STim Harvey struct i2c_client *client = context;
35d8523499STim Harvey int retry, ret;
36d8523499STim Harvey
37d8523499STim Harvey for (retry = 0; retry < I2C_RETRIES; retry++) {
38d8523499STim Harvey ret = i2c_smbus_write_byte_data(client, reg, val);
39d8523499STim Harvey /*
40d8523499STim Harvey * -EAGAIN returned when the i2c host controller is busy
41d8523499STim Harvey * -EIO returned when i2c device is busy
42d8523499STim Harvey */
43d8523499STim Harvey if (ret != -EAGAIN && ret != -EIO)
44d8523499STim Harvey break;
45d8523499STim Harvey }
46d8523499STim Harvey
47d8523499STim Harvey return 0;
48d8523499STim Harvey }
49d8523499STim Harvey EXPORT_SYMBOL_GPL(gsc_write);
50d8523499STim Harvey
gsc_read(void * context,unsigned int reg,unsigned int * val)51d8523499STim Harvey int gsc_read(void *context, unsigned int reg, unsigned int *val)
52d8523499STim Harvey {
53d8523499STim Harvey struct i2c_client *client = context;
54d8523499STim Harvey int retry, ret;
55d8523499STim Harvey
56d8523499STim Harvey for (retry = 0; retry < I2C_RETRIES; retry++) {
57d8523499STim Harvey ret = i2c_smbus_read_byte_data(client, reg);
58d8523499STim Harvey /*
59d8523499STim Harvey * -EAGAIN returned when the i2c host controller is busy
60d8523499STim Harvey * -EIO returned when i2c device is busy
61d8523499STim Harvey */
62d8523499STim Harvey if (ret != -EAGAIN && ret != -EIO)
63d8523499STim Harvey break;
64d8523499STim Harvey }
65d8523499STim Harvey *val = ret & 0xff;
66d8523499STim Harvey
67d8523499STim Harvey return 0;
68d8523499STim Harvey }
69d8523499STim Harvey EXPORT_SYMBOL_GPL(gsc_read);
70d8523499STim Harvey
71d8523499STim Harvey /*
72d8523499STim Harvey * gsc_powerdown - API to use GSC to power down board for a specific time
73d8523499STim Harvey *
74d8523499STim Harvey * secs - number of seconds to remain powered off
75d8523499STim Harvey */
gsc_powerdown(struct gsc_dev * gsc,unsigned long secs)76d8523499STim Harvey static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs)
77d8523499STim Harvey {
78d8523499STim Harvey int ret;
79d8523499STim Harvey unsigned char regs[4];
80d8523499STim Harvey
81d8523499STim Harvey dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n",
82d8523499STim Harvey secs);
83d8523499STim Harvey
84d8523499STim Harvey put_unaligned_le32(secs, regs);
85d8523499STim Harvey ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4);
86d8523499STim Harvey if (ret)
87d8523499STim Harvey return ret;
88d8523499STim Harvey
89d8523499STim Harvey ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
90d8523499STim Harvey BIT(GSC_CTRL_1_SLEEP_ADD),
91d8523499STim Harvey BIT(GSC_CTRL_1_SLEEP_ADD));
92d8523499STim Harvey if (ret)
93d8523499STim Harvey return ret;
94d8523499STim Harvey
95d8523499STim Harvey ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
96d8523499STim Harvey BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
97d8523499STim Harvey BIT(GSC_CTRL_1_SLEEP_ENABLE),
98d8523499STim Harvey BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
99d8523499STim Harvey BIT(GSC_CTRL_1_SLEEP_ENABLE));
100d8523499STim Harvey
101d8523499STim Harvey
102d8523499STim Harvey return ret;
103d8523499STim Harvey }
104d8523499STim Harvey
gsc_show(struct device * dev,struct device_attribute * attr,char * buf)105d8523499STim Harvey static ssize_t gsc_show(struct device *dev, struct device_attribute *attr,
106d8523499STim Harvey char *buf)
107d8523499STim Harvey {
108d8523499STim Harvey struct gsc_dev *gsc = dev_get_drvdata(dev);
109d8523499STim Harvey const char *name = attr->attr.name;
110d8523499STim Harvey int rz = 0;
111d8523499STim Harvey
112d8523499STim Harvey if (strcasecmp(name, "fw_version") == 0)
113d8523499STim Harvey rz = sprintf(buf, "%d\n", gsc->fwver);
114d8523499STim Harvey else if (strcasecmp(name, "fw_crc") == 0)
115d8523499STim Harvey rz = sprintf(buf, "0x%04x\n", gsc->fwcrc);
116d8523499STim Harvey else
117d8523499STim Harvey dev_err(dev, "invalid command: '%s'\n", name);
118d8523499STim Harvey
119d8523499STim Harvey return rz;
120d8523499STim Harvey }
121d8523499STim Harvey
gsc_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)122d8523499STim Harvey static ssize_t gsc_store(struct device *dev, struct device_attribute *attr,
123d8523499STim Harvey const char *buf, size_t count)
124d8523499STim Harvey {
125d8523499STim Harvey struct gsc_dev *gsc = dev_get_drvdata(dev);
126d8523499STim Harvey const char *name = attr->attr.name;
127d8523499STim Harvey long value;
128d8523499STim Harvey
129d8523499STim Harvey if (strcasecmp(name, "powerdown") == 0) {
130d8523499STim Harvey if (kstrtol(buf, 0, &value) == 0)
131d8523499STim Harvey gsc_powerdown(gsc, value);
132d8523499STim Harvey } else {
133d8523499STim Harvey dev_err(dev, "invalid command: '%s\n", name);
134d8523499STim Harvey }
135d8523499STim Harvey
136d8523499STim Harvey return count;
137d8523499STim Harvey }
138d8523499STim Harvey
139d8523499STim Harvey static struct device_attribute attr_fwver =
140d8523499STim Harvey __ATTR(fw_version, 0440, gsc_show, NULL);
141d8523499STim Harvey static struct device_attribute attr_fwcrc =
142d8523499STim Harvey __ATTR(fw_crc, 0440, gsc_show, NULL);
143d8523499STim Harvey static struct device_attribute attr_pwrdown =
144d8523499STim Harvey __ATTR(powerdown, 0220, NULL, gsc_store);
145d8523499STim Harvey
146d8523499STim Harvey static struct attribute *gsc_attrs[] = {
147d8523499STim Harvey &attr_fwver.attr,
148d8523499STim Harvey &attr_fwcrc.attr,
149d8523499STim Harvey &attr_pwrdown.attr,
150d8523499STim Harvey NULL,
151d8523499STim Harvey };
152d8523499STim Harvey
153d8523499STim Harvey static struct attribute_group attr_group = {
154d8523499STim Harvey .attrs = gsc_attrs,
155d8523499STim Harvey };
156d8523499STim Harvey
157d8523499STim Harvey static const struct of_device_id gsc_of_match[] = {
158d8523499STim Harvey { .compatible = "gw,gsc", },
159d8523499STim Harvey { }
160d8523499STim Harvey };
161d8523499STim Harvey MODULE_DEVICE_TABLE(of, gsc_of_match);
162d8523499STim Harvey
163d8523499STim Harvey static struct regmap_bus gsc_regmap_bus = {
164d8523499STim Harvey .reg_read = gsc_read,
165d8523499STim Harvey .reg_write = gsc_write,
166d8523499STim Harvey };
167d8523499STim Harvey
168d8523499STim Harvey static const struct regmap_config gsc_regmap_config = {
169d8523499STim Harvey .reg_bits = 8,
170d8523499STim Harvey .val_bits = 8,
171d8523499STim Harvey .cache_type = REGCACHE_NONE,
172d8523499STim Harvey .max_register = GSC_WP,
173d8523499STim Harvey };
174d8523499STim Harvey
175d8523499STim Harvey static const struct regmap_irq gsc_irqs[] = {
176d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)),
177d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)),
178d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)),
179d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)),
180d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)),
181d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)),
182d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)),
183d8523499STim Harvey REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)),
184d8523499STim Harvey };
185d8523499STim Harvey
186d8523499STim Harvey static const struct regmap_irq_chip gsc_irq_chip = {
187d8523499STim Harvey .name = "gateworks-gsc",
188d8523499STim Harvey .irqs = gsc_irqs,
189d8523499STim Harvey .num_irqs = ARRAY_SIZE(gsc_irqs),
190d8523499STim Harvey .num_regs = 1,
191d8523499STim Harvey .status_base = GSC_IRQ_STATUS,
1923576fc04SAidan MacDonald .unmask_base = GSC_IRQ_ENABLE,
193d8523499STim Harvey .ack_base = GSC_IRQ_STATUS,
194d8523499STim Harvey .ack_invert = true,
195d8523499STim Harvey };
196d8523499STim Harvey
gsc_probe(struct i2c_client * client)197d8523499STim Harvey static int gsc_probe(struct i2c_client *client)
198d8523499STim Harvey {
199d8523499STim Harvey struct device *dev = &client->dev;
200d8523499STim Harvey struct gsc_dev *gsc;
201d8523499STim Harvey struct regmap_irq_chip_data *irq_data;
202d8523499STim Harvey int ret;
203d8523499STim Harvey unsigned int reg;
204d8523499STim Harvey
205d8523499STim Harvey gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
206d8523499STim Harvey if (!gsc)
207d8523499STim Harvey return -ENOMEM;
208d8523499STim Harvey
209d8523499STim Harvey gsc->dev = &client->dev;
210d8523499STim Harvey gsc->i2c = client;
211d8523499STim Harvey i2c_set_clientdata(client, gsc);
212d8523499STim Harvey
213d8523499STim Harvey gsc->regmap = devm_regmap_init(dev, &gsc_regmap_bus, client,
214d8523499STim Harvey &gsc_regmap_config);
215d8523499STim Harvey if (IS_ERR(gsc->regmap))
216d8523499STim Harvey return PTR_ERR(gsc->regmap);
217d8523499STim Harvey
218d8523499STim Harvey if (regmap_read(gsc->regmap, GSC_FW_VER, ®))
219d8523499STim Harvey return -EIO;
220d8523499STim Harvey gsc->fwver = reg;
221d8523499STim Harvey
222d8523499STim Harvey regmap_read(gsc->regmap, GSC_FW_CRC, ®);
223d8523499STim Harvey gsc->fwcrc = reg;
224d8523499STim Harvey regmap_read(gsc->regmap, GSC_FW_CRC + 1, ®);
225d8523499STim Harvey gsc->fwcrc |= reg << 8;
226d8523499STim Harvey
227d8523499STim Harvey gsc->i2c_hwmon = devm_i2c_new_dummy_device(dev, client->adapter,
228d8523499STim Harvey GSC_HWMON);
229d8523499STim Harvey if (IS_ERR(gsc->i2c_hwmon)) {
230d8523499STim Harvey dev_err(dev, "Failed to allocate I2C device for HWMON\n");
231d8523499STim Harvey return PTR_ERR(gsc->i2c_hwmon);
232d8523499STim Harvey }
233d8523499STim Harvey
234d8523499STim Harvey ret = devm_regmap_add_irq_chip(dev, gsc->regmap, client->irq,
235d8523499STim Harvey IRQF_ONESHOT | IRQF_SHARED |
2368d9bf3c3STim Harvey IRQF_TRIGGER_LOW, 0,
237d8523499STim Harvey &gsc_irq_chip, &irq_data);
238d8523499STim Harvey if (ret)
239d8523499STim Harvey return ret;
240d8523499STim Harvey
241d8523499STim Harvey dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n",
242d8523499STim Harvey gsc->fwver, gsc->fwcrc);
243d8523499STim Harvey
244d8523499STim Harvey ret = sysfs_create_group(&dev->kobj, &attr_group);
245d8523499STim Harvey if (ret)
246d8523499STim Harvey dev_err(dev, "failed to create sysfs attrs\n");
247d8523499STim Harvey
248d8523499STim Harvey ret = devm_of_platform_populate(dev);
249d8523499STim Harvey if (ret) {
250d8523499STim Harvey sysfs_remove_group(&dev->kobj, &attr_group);
251d8523499STim Harvey return ret;
252d8523499STim Harvey }
253d8523499STim Harvey
254d8523499STim Harvey return 0;
255d8523499STim Harvey }
256d8523499STim Harvey
gsc_remove(struct i2c_client * client)257ed5c2f5fSUwe Kleine-König static void gsc_remove(struct i2c_client *client)
258d8523499STim Harvey {
259d8523499STim Harvey sysfs_remove_group(&client->dev.kobj, &attr_group);
260d8523499STim Harvey }
261d8523499STim Harvey
262d8523499STim Harvey static struct i2c_driver gsc_driver = {
263d8523499STim Harvey .driver = {
264d8523499STim Harvey .name = "gateworks-gsc",
265d8523499STim Harvey .of_match_table = gsc_of_match,
266d8523499STim Harvey },
267*9816d859SUwe Kleine-König .probe = gsc_probe,
268d8523499STim Harvey .remove = gsc_remove,
269d8523499STim Harvey };
270d8523499STim Harvey module_i2c_driver(gsc_driver);
271d8523499STim Harvey
272d8523499STim Harvey MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
273d8523499STim Harvey MODULE_DESCRIPTION("I2C Core interface for GSC");
274d8523499STim Harvey MODULE_LICENSE("GPL v2");
275