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277 lines
6.8 KiB
277 lines
6.8 KiB
// 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 <[email protected]>"); |
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MODULE_DESCRIPTION("I2C Core interface for GSC"); |
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MODULE_LICENSE("GPL v2");
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