278 lines
6.8 KiB
C
278 lines
6.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* The Gateworks System Controller (GSC) is a multi-function
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* device designed for use in Gateworks Single Board Computers.
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* The control interface is I2C, with an interrupt. The device supports
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* system functions such as push-button monitoring, multiple ADC's for
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* voltage and temperature monitoring, fan controller and watchdog monitor.
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*
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* Copyright (C) 2020 Gateworks Corporation
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*/
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#include <linux/device.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/mfd/gsc.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/regmap.h>
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#include <asm/unaligned.h>
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/*
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* The GSC suffers from an errata where occasionally during
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* ADC cycles the chip can NAK I2C transactions. To ensure we have reliable
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* register access we place retries around register access.
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*/
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#define I2C_RETRIES 3
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int gsc_write(void *context, unsigned int reg, unsigned int val)
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{
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struct i2c_client *client = context;
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int retry, ret;
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for (retry = 0; retry < I2C_RETRIES; retry++) {
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ret = i2c_smbus_write_byte_data(client, reg, val);
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/*
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* -EAGAIN returned when the i2c host controller is busy
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* -EIO returned when i2c device is busy
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*/
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if (ret != -EAGAIN && ret != -EIO)
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break;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(gsc_write);
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int gsc_read(void *context, unsigned int reg, unsigned int *val)
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{
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struct i2c_client *client = context;
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int retry, ret;
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for (retry = 0; retry < I2C_RETRIES; retry++) {
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ret = i2c_smbus_read_byte_data(client, reg);
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/*
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* -EAGAIN returned when the i2c host controller is busy
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* -EIO returned when i2c device is busy
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*/
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if (ret != -EAGAIN && ret != -EIO)
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break;
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}
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*val = ret & 0xff;
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return 0;
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}
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EXPORT_SYMBOL_GPL(gsc_read);
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/*
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* gsc_powerdown - API to use GSC to power down board for a specific time
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*
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* secs - number of seconds to remain powered off
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*/
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static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs)
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{
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int ret;
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unsigned char regs[4];
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dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n",
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secs);
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put_unaligned_le32(secs, regs);
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ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4);
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if (ret)
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return ret;
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ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
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BIT(GSC_CTRL_1_SLEEP_ADD),
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BIT(GSC_CTRL_1_SLEEP_ADD));
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if (ret)
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return ret;
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ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
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BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
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BIT(GSC_CTRL_1_SLEEP_ENABLE),
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BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
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BIT(GSC_CTRL_1_SLEEP_ENABLE));
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return ret;
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}
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static ssize_t gsc_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct gsc_dev *gsc = dev_get_drvdata(dev);
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const char *name = attr->attr.name;
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int rz = 0;
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if (strcasecmp(name, "fw_version") == 0)
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rz = sprintf(buf, "%d\n", gsc->fwver);
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else if (strcasecmp(name, "fw_crc") == 0)
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rz = sprintf(buf, "0x%04x\n", gsc->fwcrc);
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else
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dev_err(dev, "invalid command: '%s'\n", name);
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return rz;
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}
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static ssize_t gsc_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct gsc_dev *gsc = dev_get_drvdata(dev);
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const char *name = attr->attr.name;
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long value;
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if (strcasecmp(name, "powerdown") == 0) {
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if (kstrtol(buf, 0, &value) == 0)
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gsc_powerdown(gsc, value);
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} else {
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dev_err(dev, "invalid command: '%s\n", name);
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}
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return count;
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}
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static struct device_attribute attr_fwver =
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__ATTR(fw_version, 0440, gsc_show, NULL);
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static struct device_attribute attr_fwcrc =
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__ATTR(fw_crc, 0440, gsc_show, NULL);
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static struct device_attribute attr_pwrdown =
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__ATTR(powerdown, 0220, NULL, gsc_store);
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static struct attribute *gsc_attrs[] = {
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&attr_fwver.attr,
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&attr_fwcrc.attr,
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&attr_pwrdown.attr,
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NULL,
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};
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static struct attribute_group attr_group = {
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.attrs = gsc_attrs,
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};
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static const struct of_device_id gsc_of_match[] = {
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{ .compatible = "gw,gsc", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, gsc_of_match);
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static struct regmap_bus gsc_regmap_bus = {
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.reg_read = gsc_read,
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.reg_write = gsc_write,
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};
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static const struct regmap_config gsc_regmap_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.cache_type = REGCACHE_NONE,
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.max_register = GSC_WP,
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};
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static const struct regmap_irq gsc_irqs[] = {
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REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)),
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REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)),
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REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)),
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REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)),
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REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)),
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REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)),
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REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)),
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REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)),
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};
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static const struct regmap_irq_chip gsc_irq_chip = {
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.name = "gateworks-gsc",
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.irqs = gsc_irqs,
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.num_irqs = ARRAY_SIZE(gsc_irqs),
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.num_regs = 1,
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.status_base = GSC_IRQ_STATUS,
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.mask_base = GSC_IRQ_ENABLE,
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.mask_invert = true,
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.ack_base = GSC_IRQ_STATUS,
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.ack_invert = true,
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};
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static int gsc_probe(struct i2c_client *client)
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{
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struct device *dev = &client->dev;
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struct gsc_dev *gsc;
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struct regmap_irq_chip_data *irq_data;
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int ret;
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unsigned int reg;
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gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
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if (!gsc)
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return -ENOMEM;
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gsc->dev = &client->dev;
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gsc->i2c = client;
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i2c_set_clientdata(client, gsc);
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gsc->regmap = devm_regmap_init(dev, &gsc_regmap_bus, client,
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&gsc_regmap_config);
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if (IS_ERR(gsc->regmap))
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return PTR_ERR(gsc->regmap);
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if (regmap_read(gsc->regmap, GSC_FW_VER, ®))
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return -EIO;
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gsc->fwver = reg;
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regmap_read(gsc->regmap, GSC_FW_CRC, ®);
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gsc->fwcrc = reg;
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regmap_read(gsc->regmap, GSC_FW_CRC + 1, ®);
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gsc->fwcrc |= reg << 8;
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gsc->i2c_hwmon = devm_i2c_new_dummy_device(dev, client->adapter,
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GSC_HWMON);
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if (IS_ERR(gsc->i2c_hwmon)) {
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dev_err(dev, "Failed to allocate I2C device for HWMON\n");
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return PTR_ERR(gsc->i2c_hwmon);
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}
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ret = devm_regmap_add_irq_chip(dev, gsc->regmap, client->irq,
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IRQF_ONESHOT | IRQF_SHARED |
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IRQF_TRIGGER_LOW, 0,
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&gsc_irq_chip, &irq_data);
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if (ret)
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return ret;
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dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n",
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gsc->fwver, gsc->fwcrc);
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ret = sysfs_create_group(&dev->kobj, &attr_group);
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if (ret)
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dev_err(dev, "failed to create sysfs attrs\n");
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ret = devm_of_platform_populate(dev);
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if (ret) {
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sysfs_remove_group(&dev->kobj, &attr_group);
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return ret;
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}
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return 0;
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}
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static int gsc_remove(struct i2c_client *client)
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{
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sysfs_remove_group(&client->dev.kobj, &attr_group);
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return 0;
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}
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static struct i2c_driver gsc_driver = {
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.driver = {
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.name = "gateworks-gsc",
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.of_match_table = gsc_of_match,
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},
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.probe_new = gsc_probe,
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.remove = gsc_remove,
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};
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module_i2c_driver(gsc_driver);
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MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
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MODULE_DESCRIPTION("I2C Core interface for GSC");
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MODULE_LICENSE("GPL v2");
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