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linux-sg2042/drivers/fsi/fsi-master-gpio.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* A FSI master controller, using a simple GPIO bit-banging interface
*/
#include <linux/crc4.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/fsi.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/irqflags.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include "fsi-master.h"
#define FSI_GPIO_STD_DLY 1 /* Standard pin delay in nS */
#define LAST_ADDR_INVALID 0x1
struct fsi_master_gpio {
struct fsi_master master;
struct device *dev;
struct mutex cmd_lock; /* mutex for command ordering */
struct gpio_desc *gpio_clk;
struct gpio_desc *gpio_data;
struct gpio_desc *gpio_trans; /* Voltage translator */
struct gpio_desc *gpio_enable; /* FSI enable */
struct gpio_desc *gpio_mux; /* Mux control */
bool external_mode;
bool no_delays;
uint32_t last_addr;
uint8_t t_send_delay;
uint8_t t_echo_delay;
};
#define CREATE_TRACE_POINTS
#include <trace/events/fsi_master_gpio.h>
#define to_fsi_master_gpio(m) container_of(m, struct fsi_master_gpio, master)
struct fsi_gpio_msg {
uint64_t msg;
uint8_t bits;
};
static void clock_toggle(struct fsi_master_gpio *master, int count)
{
int i;
for (i = 0; i < count; i++) {
if (!master->no_delays)
ndelay(FSI_GPIO_STD_DLY);
gpiod_set_value(master->gpio_clk, 0);
if (!master->no_delays)
ndelay(FSI_GPIO_STD_DLY);
gpiod_set_value(master->gpio_clk, 1);
}
}
static int sda_clock_in(struct fsi_master_gpio *master)
{
int in;
if (!master->no_delays)
ndelay(FSI_GPIO_STD_DLY);
gpiod_set_value(master->gpio_clk, 0);
/* Dummy read to feed the synchronizers */
gpiod_get_value(master->gpio_data);
/* Actual data read */
in = gpiod_get_value(master->gpio_data);
if (!master->no_delays)
ndelay(FSI_GPIO_STD_DLY);
gpiod_set_value(master->gpio_clk, 1);
return in ? 1 : 0;
}
static void sda_out(struct fsi_master_gpio *master, int value)
{
gpiod_set_value(master->gpio_data, value);
}
static void set_sda_input(struct fsi_master_gpio *master)
{
gpiod_direction_input(master->gpio_data);
gpiod_set_value(master->gpio_trans, 0);
}
static void set_sda_output(struct fsi_master_gpio *master, int value)
{
gpiod_set_value(master->gpio_trans, 1);
gpiod_direction_output(master->gpio_data, value);
}
static void clock_zeros(struct fsi_master_gpio *master, int count)
{
trace_fsi_master_gpio_clock_zeros(master, count);
set_sda_output(master, 1);
clock_toggle(master, count);
}
static void echo_delay(struct fsi_master_gpio *master)
{
clock_zeros(master, master->t_echo_delay);
}
static void serial_in(struct fsi_master_gpio *master, struct fsi_gpio_msg *msg,
uint8_t num_bits)
{
uint8_t bit, in_bit;
set_sda_input(master);
for (bit = 0; bit < num_bits; bit++) {
in_bit = sda_clock_in(master);
msg->msg <<= 1;
msg->msg |= ~in_bit & 0x1; /* Data is active low */
}
msg->bits += num_bits;
trace_fsi_master_gpio_in(master, num_bits, msg->msg);
}
static void serial_out(struct fsi_master_gpio *master,
const struct fsi_gpio_msg *cmd)
{
uint8_t bit;
uint64_t msg = ~cmd->msg; /* Data is active low */
uint64_t sda_mask = 0x1ULL << (cmd->bits - 1);
uint64_t last_bit = ~0;
int next_bit;
trace_fsi_master_gpio_out(master, cmd->bits, cmd->msg);
if (!cmd->bits) {
dev_warn(master->dev, "trying to output 0 bits\n");
return;
}
set_sda_output(master, 0);
/* Send the start bit */
sda_out(master, 0);
clock_toggle(master, 1);
/* Send the message */
for (bit = 0; bit < cmd->bits; bit++) {
next_bit = (msg & sda_mask) >> (cmd->bits - 1);
if (last_bit ^ next_bit) {
sda_out(master, next_bit);
last_bit = next_bit;
}
clock_toggle(master, 1);
msg <<= 1;
}
}
static void msg_push_bits(struct fsi_gpio_msg *msg, uint64_t data, int bits)
{
msg->msg <<= bits;
msg->msg |= data & ((1ull << bits) - 1);
msg->bits += bits;
}
static void msg_push_crc(struct fsi_gpio_msg *msg)
{
uint8_t crc;
int top;
top = msg->bits & 0x3;
/* start bit, and any non-aligned top bits */
crc = crc4(0, 1 << top | msg->msg >> (msg->bits - top), top + 1);
/* aligned bits */
crc = crc4(crc, msg->msg, msg->bits - top);
msg_push_bits(msg, crc, 4);
}
static bool check_same_address(struct fsi_master_gpio *master, int id,
uint32_t addr)
{
/* this will also handle LAST_ADDR_INVALID */
return master->last_addr == (((id & 0x3) << 21) | (addr & ~0x3));
}
static bool check_relative_address(struct fsi_master_gpio *master, int id,
uint32_t addr, uint32_t *rel_addrp)
{
uint32_t last_addr = master->last_addr;
int32_t rel_addr;
if (last_addr == LAST_ADDR_INVALID)
return false;
/* We may be in 23-bit addressing mode, which uses the id as the
* top two address bits. So, if we're referencing a different ID,
* use absolute addresses.
*/
if (((last_addr >> 21) & 0x3) != id)
return false;
/* remove the top two bits from any 23-bit addressing */
last_addr &= (1 << 21) - 1;
/* We know that the addresses are limited to 21 bits, so this won't
* overflow the signed rel_addr */
rel_addr = addr - last_addr;
if (rel_addr > 255 || rel_addr < -256)
return false;
*rel_addrp = (uint32_t)rel_addr;
return true;
}
static void last_address_update(struct fsi_master_gpio *master,
int id, bool valid, uint32_t addr)
{
if (!valid)
master->last_addr = LAST_ADDR_INVALID;
else
master->last_addr = ((id & 0x3) << 21) | (addr & ~0x3);
}
/*
* Encode an Absolute/Relative/Same Address command
*/
static void build_ar_command(struct fsi_master_gpio *master,
struct fsi_gpio_msg *cmd, uint8_t id,
uint32_t addr, size_t size, const void *data)
{
int i, addr_bits, opcode_bits;
bool write = !!data;
uint8_t ds, opcode;
uint32_t rel_addr;
cmd->bits = 0;
cmd->msg = 0;
/* we have 21 bits of address max */
addr &= ((1 << 21) - 1);
/* cmd opcodes are variable length - SAME_AR is only two bits */
opcode_bits = 3;
if (check_same_address(master, id, addr)) {
/* we still address the byte offset within the word */
addr_bits = 2;
opcode_bits = 2;
opcode = FSI_CMD_SAME_AR;
trace_fsi_master_gpio_cmd_same_addr(master);
} else if (check_relative_address(master, id, addr, &rel_addr)) {
/* 8 bits plus sign */
addr_bits = 9;
addr = rel_addr;
opcode = FSI_CMD_REL_AR;
trace_fsi_master_gpio_cmd_rel_addr(master, rel_addr);
} else {
addr_bits = 21;
opcode = FSI_CMD_ABS_AR;
trace_fsi_master_gpio_cmd_abs_addr(master, addr);
}
/*
* The read/write size is encoded in the lower bits of the address
* (as it must be naturally-aligned), and the following ds bit.
*
* size addr:1 addr:0 ds
* 1 x x 0
* 2 x 0 1
* 4 0 1 1
*
*/
ds = size > 1 ? 1 : 0;
addr &= ~(size - 1);
if (size == 4)
addr |= 1;
msg_push_bits(cmd, id, 2);
msg_push_bits(cmd, opcode, opcode_bits);
msg_push_bits(cmd, write ? 0 : 1, 1);
msg_push_bits(cmd, addr, addr_bits);
msg_push_bits(cmd, ds, 1);
for (i = 0; write && i < size; i++)
msg_push_bits(cmd, ((uint8_t *)data)[i], 8);
msg_push_crc(cmd);
}
static void build_dpoll_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
{
cmd->bits = 0;
cmd->msg = 0;
msg_push_bits(cmd, slave_id, 2);
msg_push_bits(cmd, FSI_CMD_DPOLL, 3);
msg_push_crc(cmd);
}
static void build_epoll_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
{
cmd->bits = 0;
cmd->msg = 0;
msg_push_bits(cmd, slave_id, 2);
msg_push_bits(cmd, FSI_CMD_EPOLL, 3);
msg_push_crc(cmd);
}
static void build_term_command(struct fsi_gpio_msg *cmd, uint8_t slave_id)
{
cmd->bits = 0;
cmd->msg = 0;
msg_push_bits(cmd, slave_id, 2);
msg_push_bits(cmd, FSI_CMD_TERM, 6);
msg_push_crc(cmd);
}
/*
* Note: callers rely specifically on this returning -EAGAIN for
* a CRC error detected in the response. Use other error code
* for other situations. It will be converted to something else
* higher up the stack before it reaches userspace.
*/
static int read_one_response(struct fsi_master_gpio *master,
uint8_t data_size, struct fsi_gpio_msg *msgp, uint8_t *tagp)
{
struct fsi_gpio_msg msg;
unsigned long flags;
uint32_t crc;
uint8_t tag;
int i;
local_irq_save(flags);
/* wait for the start bit */
for (i = 0; i < FSI_MASTER_MTOE_COUNT; i++) {
msg.bits = 0;
msg.msg = 0;
serial_in(master, &msg, 1);
if (msg.msg)
break;
}
if (i == FSI_MASTER_MTOE_COUNT) {
dev_dbg(master->dev,
"Master time out waiting for response\n");
local_irq_restore(flags);
return -ETIMEDOUT;
}
msg.bits = 0;
msg.msg = 0;
/* Read slave ID & response tag */
serial_in(master, &msg, 4);
tag = msg.msg & 0x3;
/* If we have an ACK and we're expecting data, clock the data in too */
if (tag == FSI_RESP_ACK && data_size)
serial_in(master, &msg, data_size * 8);
/* read CRC */
serial_in(master, &msg, FSI_CRC_SIZE);
local_irq_restore(flags);
/* we have a whole message now; check CRC */
crc = crc4(0, 1, 1);
crc = crc4(crc, msg.msg, msg.bits);
if (crc) {
/* Check if it's all 1's, that probably means the host is off */
if (((~msg.msg) & ((1ull << msg.bits) - 1)) == 0)
return -ENODEV;
dev_dbg(master->dev, "ERR response CRC msg: 0x%016llx (%d bits)\n",
msg.msg, msg.bits);
return -EAGAIN;
}
if (msgp)
*msgp = msg;
if (tagp)
*tagp = tag;
return 0;
}
static int issue_term(struct fsi_master_gpio *master, uint8_t slave)
{
struct fsi_gpio_msg cmd;
unsigned long flags;
uint8_t tag;
int rc;
build_term_command(&cmd, slave);
local_irq_save(flags);
serial_out(master, &cmd);
echo_delay(master);
local_irq_restore(flags);
rc = read_one_response(master, 0, NULL, &tag);
if (rc < 0) {
dev_err(master->dev,
"TERM failed; lost communication with slave\n");
return -EIO;
} else if (tag != FSI_RESP_ACK) {
dev_err(master->dev, "TERM failed; response %d\n", tag);
return -EIO;
}
return 0;
}
static int poll_for_response(struct fsi_master_gpio *master,
uint8_t slave, uint8_t size, void *data)
{
struct fsi_gpio_msg response, cmd;
int busy_count = 0, rc, i;
unsigned long flags;
uint8_t tag;
uint8_t *data_byte = data;
int crc_err_retries = 0;
retry:
rc = read_one_response(master, size, &response, &tag);
/* Handle retries on CRC errors */
if (rc == -EAGAIN) {
/* Too many retries ? */
if (crc_err_retries++ > FSI_CRC_ERR_RETRIES) {
/*
* Pass it up as a -EIO otherwise upper level will retry
* the whole command which isn't what we want here.
*/
rc = -EIO;
goto fail;
}
dev_dbg(master->dev,
"CRC error retry %d\n", crc_err_retries);
trace_fsi_master_gpio_crc_rsp_error(master);
build_epoll_command(&cmd, slave);
local_irq_save(flags);
clock_zeros(master, FSI_MASTER_EPOLL_CLOCKS);
serial_out(master, &cmd);
echo_delay(master);
local_irq_restore(flags);
goto retry;
} else if (rc)
goto fail;
switch (tag) {
case FSI_RESP_ACK:
if (size && data) {
uint64_t val = response.msg;
/* clear crc & mask */
val >>= 4;
val &= (1ull << (size * 8)) - 1;
for (i = 0; i < size; i++) {
data_byte[size-i-1] = val;
val >>= 8;
}
}
break;
case FSI_RESP_BUSY:
/*
* Its necessary to clock slave before issuing
* d-poll, not indicated in the hardware protocol
* spec. < 20 clocks causes slave to hang, 21 ok.
*/
if (busy_count++ < FSI_MASTER_MAX_BUSY) {
build_dpoll_command(&cmd, slave);
local_irq_save(flags);
clock_zeros(master, FSI_MASTER_DPOLL_CLOCKS);
serial_out(master, &cmd);
echo_delay(master);
local_irq_restore(flags);
goto retry;
}
dev_warn(master->dev,
"ERR slave is stuck in busy state, issuing TERM\n");
local_irq_save(flags);
clock_zeros(master, FSI_MASTER_DPOLL_CLOCKS);
local_irq_restore(flags);
issue_term(master, slave);
rc = -EIO;
break;
case FSI_RESP_ERRA:
dev_dbg(master->dev, "ERRA received: 0x%x\n", (int)response.msg);
rc = -EIO;
break;
case FSI_RESP_ERRC:
dev_dbg(master->dev, "ERRC received: 0x%x\n", (int)response.msg);
trace_fsi_master_gpio_crc_cmd_error(master);
rc = -EAGAIN;
break;
}
if (busy_count > 0)
trace_fsi_master_gpio_poll_response_busy(master, busy_count);
fail:
/*
* tSendDelay clocks, avoids signal reflections when switching
* from receive of response back to send of data.
*/
local_irq_save(flags);
clock_zeros(master, master->t_send_delay);
local_irq_restore(flags);
return rc;
}
static int send_request(struct fsi_master_gpio *master,
struct fsi_gpio_msg *cmd)
{
unsigned long flags;
if (master->external_mode)
return -EBUSY;
local_irq_save(flags);
serial_out(master, cmd);
echo_delay(master);
local_irq_restore(flags);
return 0;
}
static int fsi_master_gpio_xfer(struct fsi_master_gpio *master, uint8_t slave,
struct fsi_gpio_msg *cmd, size_t resp_len, void *resp)
{
int rc = -EAGAIN, retries = 0;
while ((retries++) < FSI_CRC_ERR_RETRIES) {
rc = send_request(master, cmd);
if (rc)
break;
rc = poll_for_response(master, slave, resp_len, resp);
if (rc != -EAGAIN)
break;
rc = -EIO;
dev_warn(master->dev, "ECRC retry %d\n", retries);
/* Pace it a bit before retry */
msleep(1);
}
return rc;
}
static int fsi_master_gpio_read(struct fsi_master *_master, int link,
uint8_t id, uint32_t addr, void *val, size_t size)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
struct fsi_gpio_msg cmd;
int rc;
if (link != 0)
return -ENODEV;
mutex_lock(&master->cmd_lock);
build_ar_command(master, &cmd, id, addr, size, NULL);
rc = fsi_master_gpio_xfer(master, id, &cmd, size, val);
last_address_update(master, id, rc == 0, addr);
mutex_unlock(&master->cmd_lock);
return rc;
}
static int fsi_master_gpio_write(struct fsi_master *_master, int link,
uint8_t id, uint32_t addr, const void *val, size_t size)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
struct fsi_gpio_msg cmd;
int rc;
if (link != 0)
return -ENODEV;
mutex_lock(&master->cmd_lock);
build_ar_command(master, &cmd, id, addr, size, val);
rc = fsi_master_gpio_xfer(master, id, &cmd, 0, NULL);
last_address_update(master, id, rc == 0, addr);
mutex_unlock(&master->cmd_lock);
return rc;
}
static int fsi_master_gpio_term(struct fsi_master *_master,
int link, uint8_t id)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
struct fsi_gpio_msg cmd;
int rc;
if (link != 0)
return -ENODEV;
mutex_lock(&master->cmd_lock);
build_term_command(&cmd, id);
rc = fsi_master_gpio_xfer(master, id, &cmd, 0, NULL);
last_address_update(master, id, false, 0);
mutex_unlock(&master->cmd_lock);
return rc;
}
static int fsi_master_gpio_break(struct fsi_master *_master, int link)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
unsigned long flags;
if (link != 0)
return -ENODEV;
trace_fsi_master_gpio_break(master);
mutex_lock(&master->cmd_lock);
if (master->external_mode) {
mutex_unlock(&master->cmd_lock);
return -EBUSY;
}
local_irq_save(flags);
set_sda_output(master, 1);
sda_out(master, 1);
clock_toggle(master, FSI_PRE_BREAK_CLOCKS);
sda_out(master, 0);
clock_toggle(master, FSI_BREAK_CLOCKS);
echo_delay(master);
sda_out(master, 1);
clock_toggle(master, FSI_POST_BREAK_CLOCKS);
local_irq_restore(flags);
last_address_update(master, 0, false, 0);
mutex_unlock(&master->cmd_lock);
/* Wait for logic reset to take effect */
udelay(200);
return 0;
}
static void fsi_master_gpio_init(struct fsi_master_gpio *master)
{
unsigned long flags;
gpiod_direction_output(master->gpio_mux, 1);
gpiod_direction_output(master->gpio_trans, 1);
gpiod_direction_output(master->gpio_enable, 1);
gpiod_direction_output(master->gpio_clk, 1);
gpiod_direction_output(master->gpio_data, 1);
/* todo: evaluate if clocks can be reduced */
local_irq_save(flags);
clock_zeros(master, FSI_INIT_CLOCKS);
local_irq_restore(flags);
}
static void fsi_master_gpio_init_external(struct fsi_master_gpio *master)
{
gpiod_direction_output(master->gpio_mux, 0);
gpiod_direction_output(master->gpio_trans, 0);
gpiod_direction_output(master->gpio_enable, 1);
gpiod_direction_input(master->gpio_clk);
gpiod_direction_input(master->gpio_data);
}
static int fsi_master_gpio_link_enable(struct fsi_master *_master, int link,
bool enable)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
int rc = -EBUSY;
if (link != 0)
return -ENODEV;
mutex_lock(&master->cmd_lock);
if (!master->external_mode) {
gpiod_set_value(master->gpio_enable, enable ? 1 : 0);
rc = 0;
}
mutex_unlock(&master->cmd_lock);
return rc;
}
static int fsi_master_gpio_link_config(struct fsi_master *_master, int link,
u8 t_send_delay, u8 t_echo_delay)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(_master);
if (link != 0)
return -ENODEV;
mutex_lock(&master->cmd_lock);
master->t_send_delay = t_send_delay;
master->t_echo_delay = t_echo_delay;
mutex_unlock(&master->cmd_lock);
return 0;
}
static ssize_t external_mode_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct fsi_master_gpio *master = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE - 1, "%u\n",
master->external_mode ? 1 : 0);
}
static ssize_t external_mode_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct fsi_master_gpio *master = dev_get_drvdata(dev);
unsigned long val;
bool external_mode;
int err;
err = kstrtoul(buf, 0, &val);
if (err)
return err;
external_mode = !!val;
mutex_lock(&master->cmd_lock);
if (external_mode == master->external_mode) {
mutex_unlock(&master->cmd_lock);
return count;
}
master->external_mode = external_mode;
if (master->external_mode)
fsi_master_gpio_init_external(master);
else
fsi_master_gpio_init(master);
mutex_unlock(&master->cmd_lock);
fsi_master_rescan(&master->master);
return count;
}
static DEVICE_ATTR(external_mode, 0664,
external_mode_show, external_mode_store);
static void fsi_master_gpio_release(struct device *dev)
{
struct fsi_master_gpio *master = to_fsi_master_gpio(dev_to_fsi_master(dev));
of_node_put(dev_of_node(master->dev));
kfree(master);
}
static int fsi_master_gpio_probe(struct platform_device *pdev)
{
struct fsi_master_gpio *master;
struct gpio_desc *gpio;
int rc;
master = kzalloc(sizeof(*master), GFP_KERNEL);
if (!master)
return -ENOMEM;
master->dev = &pdev->dev;
master->master.dev.parent = master->dev;
master->master.dev.of_node = of_node_get(dev_of_node(master->dev));
master->master.dev.release = fsi_master_gpio_release;
master->last_addr = LAST_ADDR_INVALID;
gpio = devm_gpiod_get(&pdev->dev, "clock", 0);
if (IS_ERR(gpio)) {
dev_err(&pdev->dev, "failed to get clock gpio\n");
rc = PTR_ERR(gpio);
goto err_free;
}
master->gpio_clk = gpio;
gpio = devm_gpiod_get(&pdev->dev, "data", 0);
if (IS_ERR(gpio)) {
dev_err(&pdev->dev, "failed to get data gpio\n");
rc = PTR_ERR(gpio);
goto err_free;
}
master->gpio_data = gpio;
/* Optional GPIOs */
gpio = devm_gpiod_get_optional(&pdev->dev, "trans", 0);
if (IS_ERR(gpio)) {
dev_err(&pdev->dev, "failed to get trans gpio\n");
rc = PTR_ERR(gpio);
goto err_free;
}
master->gpio_trans = gpio;
gpio = devm_gpiod_get_optional(&pdev->dev, "enable", 0);
if (IS_ERR(gpio)) {
dev_err(&pdev->dev, "failed to get enable gpio\n");
rc = PTR_ERR(gpio);
goto err_free;
}
master->gpio_enable = gpio;
gpio = devm_gpiod_get_optional(&pdev->dev, "mux", 0);
if (IS_ERR(gpio)) {
dev_err(&pdev->dev, "failed to get mux gpio\n");
rc = PTR_ERR(gpio);
goto err_free;
}
master->gpio_mux = gpio;
/*
* Check if GPIO block is slow enought that no extra delays
* are necessary. This improves performance on ast2500 by
* an order of magnitude.
*/
master->no_delays = device_property_present(&pdev->dev, "no-gpio-delays");
/* Default FSI command delays */
master->t_send_delay = FSI_SEND_DELAY_CLOCKS;
master->t_echo_delay = FSI_ECHO_DELAY_CLOCKS;
master->master.n_links = 1;
master->master.flags = FSI_MASTER_FLAG_SWCLOCK;
master->master.read = fsi_master_gpio_read;
master->master.write = fsi_master_gpio_write;
master->master.term = fsi_master_gpio_term;
master->master.send_break = fsi_master_gpio_break;
master->master.link_enable = fsi_master_gpio_link_enable;
master->master.link_config = fsi_master_gpio_link_config;
platform_set_drvdata(pdev, master);
mutex_init(&master->cmd_lock);
fsi_master_gpio_init(master);
rc = device_create_file(&pdev->dev, &dev_attr_external_mode);
if (rc)
goto err_free;
rc = fsi_master_register(&master->master);
if (rc) {
device_remove_file(&pdev->dev, &dev_attr_external_mode);
put_device(&master->master.dev);
return rc;
}
return 0;
err_free:
kfree(master);
return rc;
}
static int fsi_master_gpio_remove(struct platform_device *pdev)
{
struct fsi_master_gpio *master = platform_get_drvdata(pdev);
device_remove_file(&pdev->dev, &dev_attr_external_mode);
fsi_master_unregister(&master->master);
return 0;
}
static const struct of_device_id fsi_master_gpio_match[] = {
{ .compatible = "fsi-master-gpio" },
{ },
};
static struct platform_driver fsi_master_gpio_driver = {
.driver = {
.name = "fsi-master-gpio",
.of_match_table = fsi_master_gpio_match,
},
.probe = fsi_master_gpio_probe,
.remove = fsi_master_gpio_remove,
};
module_platform_driver(fsi_master_gpio_driver);
MODULE_LICENSE("GPL");
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