diff options
Diffstat (limited to 'drivers/fsi/fsi-master-gpio.c')
| -rw-r--r-- | drivers/fsi/fsi-master-gpio.c | 897 |
1 files changed, 897 insertions, 0 deletions
diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c new file mode 100644 index 000000000..7d5f29b4b --- /dev/null +++ b/drivers/fsi/fsi-master-gpio.c @@ -0,0 +1,897 @@ +// 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" }, + { }, +}; +MODULE_DEVICE_TABLE(of, fsi_master_gpio_match); + +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"); |