262 lines
6.1 KiB
C
262 lines
6.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* MCP23S08 SPI GPIO driver */
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/property.h>
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#include <linux/regmap.h>
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#include <linux/spi/spi.h>
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#include "pinctrl-mcp23s08.h"
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#define MCP_MAX_DEV_PER_CS 8
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/*
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* A given spi_device can represent up to eight mcp23sxx chips
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* sharing the same chipselect but using different addresses
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* (e.g. chips #0 and #3 might be populated, but not #1 or #2).
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* Driver data holds all the per-chip data.
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*/
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struct mcp23s08_driver_data {
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unsigned ngpio;
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struct mcp23s08 *mcp[8];
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struct mcp23s08 chip[];
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};
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static int mcp23sxx_spi_write(void *context, const void *data, size_t count)
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{
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struct mcp23s08 *mcp = context;
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struct spi_device *spi = to_spi_device(mcp->dev);
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struct spi_message m;
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struct spi_transfer t[2] = { { .tx_buf = &mcp->addr, .len = 1, },
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{ .tx_buf = data, .len = count, }, };
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spi_message_init(&m);
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spi_message_add_tail(&t[0], &m);
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spi_message_add_tail(&t[1], &m);
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return spi_sync(spi, &m);
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}
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static int mcp23sxx_spi_gather_write(void *context,
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const void *reg, size_t reg_size,
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const void *val, size_t val_size)
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{
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struct mcp23s08 *mcp = context;
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struct spi_device *spi = to_spi_device(mcp->dev);
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struct spi_message m;
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struct spi_transfer t[3] = { { .tx_buf = &mcp->addr, .len = 1, },
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{ .tx_buf = reg, .len = reg_size, },
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{ .tx_buf = val, .len = val_size, }, };
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spi_message_init(&m);
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spi_message_add_tail(&t[0], &m);
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spi_message_add_tail(&t[1], &m);
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spi_message_add_tail(&t[2], &m);
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return spi_sync(spi, &m);
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}
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static int mcp23sxx_spi_read(void *context, const void *reg, size_t reg_size,
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void *val, size_t val_size)
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{
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struct mcp23s08 *mcp = context;
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struct spi_device *spi = to_spi_device(mcp->dev);
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u8 tx[2];
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if (reg_size != 1)
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return -EINVAL;
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tx[0] = mcp->addr | 0x01;
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tx[1] = *((u8 *) reg);
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return spi_write_then_read(spi, tx, sizeof(tx), val, val_size);
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}
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static const struct regmap_bus mcp23sxx_spi_regmap = {
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.write = mcp23sxx_spi_write,
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.gather_write = mcp23sxx_spi_gather_write,
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.read = mcp23sxx_spi_read,
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};
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static int mcp23s08_spi_regmap_init(struct mcp23s08 *mcp, struct device *dev,
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unsigned int addr, unsigned int type)
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{
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const struct regmap_config *config;
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struct regmap_config *copy;
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const char *name;
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switch (type) {
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case MCP_TYPE_S08:
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mcp->reg_shift = 0;
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mcp->chip.ngpio = 8;
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mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s08.%d", addr);
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config = &mcp23x08_regmap;
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name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
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break;
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case MCP_TYPE_S17:
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mcp->reg_shift = 1;
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mcp->chip.ngpio = 16;
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mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s17.%d", addr);
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config = &mcp23x17_regmap;
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name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
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break;
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case MCP_TYPE_S18:
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mcp->reg_shift = 1;
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mcp->chip.ngpio = 16;
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mcp->chip.label = "mcp23s18";
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config = &mcp23x17_regmap;
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name = config->name;
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break;
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default:
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dev_err(dev, "invalid device type (%d)\n", type);
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return -EINVAL;
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}
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copy = devm_kmemdup(dev, config, sizeof(*config), GFP_KERNEL);
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if (!copy)
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return -ENOMEM;
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copy->name = name;
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mcp->regmap = devm_regmap_init(dev, &mcp23sxx_spi_regmap, mcp, copy);
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if (IS_ERR(mcp->regmap))
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dev_err(dev, "regmap init failed for %s\n", mcp->chip.label);
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return PTR_ERR_OR_ZERO(mcp->regmap);
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}
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static int mcp23s08_probe(struct spi_device *spi)
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{
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struct device *dev = &spi->dev;
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struct mcp23s08_driver_data *data;
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unsigned long spi_present_mask;
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const void *match;
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unsigned int addr;
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unsigned int ngpio = 0;
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int chips;
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int type;
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int ret;
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u32 v;
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match = device_get_match_data(dev);
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if (match)
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type = (int)(uintptr_t)match;
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else
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type = spi_get_device_id(spi)->driver_data;
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ret = device_property_read_u32(dev, "microchip,spi-present-mask", &v);
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if (ret) {
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ret = device_property_read_u32(dev, "mcp,spi-present-mask", &v);
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if (ret) {
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dev_err(dev, "missing spi-present-mask");
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return ret;
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}
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}
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spi_present_mask = v;
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if (!spi_present_mask || spi_present_mask >= BIT(MCP_MAX_DEV_PER_CS)) {
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dev_err(dev, "invalid spi-present-mask");
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return -ENODEV;
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}
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chips = hweight_long(spi_present_mask);
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data = devm_kzalloc(dev, struct_size(data, chip, chips), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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spi_set_drvdata(spi, data);
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for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
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data->mcp[addr] = &data->chip[--chips];
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data->mcp[addr]->irq = spi->irq;
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ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, type);
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if (ret)
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return ret;
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data->mcp[addr]->pinctrl_desc.name = devm_kasprintf(dev, GFP_KERNEL,
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"mcp23xxx-pinctrl.%d",
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addr);
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if (!data->mcp[addr]->pinctrl_desc.name)
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return -ENOMEM;
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ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1), type, -1);
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if (ret < 0)
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return ret;
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ngpio += data->mcp[addr]->chip.ngpio;
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}
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data->ngpio = ngpio;
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return 0;
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}
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static const struct spi_device_id mcp23s08_ids[] = {
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{ "mcp23s08", MCP_TYPE_S08 },
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{ "mcp23s17", MCP_TYPE_S17 },
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{ "mcp23s18", MCP_TYPE_S18 },
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{ }
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};
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MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
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static const struct of_device_id mcp23s08_spi_of_match[] = {
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{
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.compatible = "microchip,mcp23s08",
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.data = (void *) MCP_TYPE_S08,
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},
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{
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.compatible = "microchip,mcp23s17",
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.data = (void *) MCP_TYPE_S17,
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},
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{
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.compatible = "microchip,mcp23s18",
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.data = (void *) MCP_TYPE_S18,
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},
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/* NOTE: The use of the mcp prefix is deprecated and will be removed. */
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{
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.compatible = "mcp,mcp23s08",
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.data = (void *) MCP_TYPE_S08,
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},
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{
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.compatible = "mcp,mcp23s17",
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.data = (void *) MCP_TYPE_S17,
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},
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{ }
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};
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MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);
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static struct spi_driver mcp23s08_driver = {
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.probe = mcp23s08_probe,
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.id_table = mcp23s08_ids,
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.driver = {
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.name = "mcp23s08",
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.of_match_table = mcp23s08_spi_of_match,
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},
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};
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static int __init mcp23s08_spi_init(void)
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{
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return spi_register_driver(&mcp23s08_driver);
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}
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/*
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* Register after SPI postcore initcall and before
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* subsys initcalls that may rely on these GPIOs.
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*/
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subsys_initcall(mcp23s08_spi_init);
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static void mcp23s08_spi_exit(void)
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{
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spi_unregister_driver(&mcp23s08_driver);
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}
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module_exit(mcp23s08_spi_exit);
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MODULE_LICENSE("GPL");
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