/* * NXP SC18IS602/603 SPI driver * * Copyright (C) Guenter Roeck * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include enum chips { sc18is602, sc18is602b, sc18is603 }; #define SC18IS602_BUFSIZ 200 #define SC18IS602_CLOCK 7372000 #define SC18IS602_MODE_CPHA BIT(2) #define SC18IS602_MODE_CPOL BIT(3) #define SC18IS602_MODE_LSB_FIRST BIT(5) #define SC18IS602_MODE_CLOCK_DIV_4 0x0 #define SC18IS602_MODE_CLOCK_DIV_16 0x1 #define SC18IS602_MODE_CLOCK_DIV_64 0x2 #define SC18IS602_MODE_CLOCK_DIV_128 0x3 struct sc18is602 { struct spi_master *master; struct device *dev; u8 ctrl; u32 freq; u32 speed; /* I2C data */ struct i2c_client *client; enum chips id; u8 buffer[SC18IS602_BUFSIZ + 1]; int tlen; /* Data queued for tx in buffer */ int rindex; /* Receive data index in buffer */ }; static int sc18is602_wait_ready(struct sc18is602 *hw, int len) { int i, err; int usecs = 1000000 * len / hw->speed + 1; u8 dummy[1]; for (i = 0; i < 10; i++) { err = i2c_master_recv(hw->client, dummy, 1); if (err >= 0) return 0; usleep_range(usecs, usecs * 2); } return -ETIMEDOUT; } static int sc18is602_txrx(struct sc18is602 *hw, struct spi_message *msg, struct spi_transfer *t, bool do_transfer) { unsigned int len = t->len; int ret; if (hw->tlen == 0) { /* First byte (I2C command) is chip select */ hw->buffer[0] = 1 << msg->spi->chip_select; hw->tlen = 1; hw->rindex = 0; } /* * We can not immediately send data to the chip, since each I2C message * resembles a full SPI message (from CS active to CS inactive). * Enqueue messages up to the first read or until do_transfer is true. */ if (t->tx_buf) { memcpy(&hw->buffer[hw->tlen], t->tx_buf, len); hw->tlen += len; if (t->rx_buf) do_transfer = true; else hw->rindex = hw->tlen - 1; } else if (t->rx_buf) { /* * For receive-only transfers we still need to perform a dummy * write to receive data from the SPI chip. * Read data starts at the end of transmit data (minus 1 to * account for CS). */ hw->rindex = hw->tlen - 1; memset(&hw->buffer[hw->tlen], 0, len); hw->tlen += len; do_transfer = true; } if (do_transfer && hw->tlen > 1) { ret = sc18is602_wait_ready(hw, SC18IS602_BUFSIZ); if (ret < 0) return ret; ret = i2c_master_send(hw->client, hw->buffer, hw->tlen); if (ret < 0) return ret; if (ret != hw->tlen) return -EIO; if (t->rx_buf) { int rlen = hw->rindex + len; ret = sc18is602_wait_ready(hw, hw->tlen); if (ret < 0) return ret; ret = i2c_master_recv(hw->client, hw->buffer, rlen); if (ret < 0) return ret; if (ret != rlen) return -EIO; memcpy(t->rx_buf, &hw->buffer[hw->rindex], len); } hw->tlen = 0; } return len; } static int sc18is602_setup_transfer(struct sc18is602 *hw, u32 hz, u8 mode) { u8 ctrl = 0; int ret; if (mode & SPI_CPHA) ctrl |= SC18IS602_MODE_CPHA; if (mode & SPI_CPOL) ctrl |= SC18IS602_MODE_CPOL; if (mode & SPI_LSB_FIRST) ctrl |= SC18IS602_MODE_LSB_FIRST; /* Find the closest clock speed */ if (hz >= hw->freq / 4) { ctrl |= SC18IS602_MODE_CLOCK_DIV_4; hw->speed = hw->freq / 4; } else if (hz >= hw->freq / 16) { ctrl |= SC18IS602_MODE_CLOCK_DIV_16; hw->speed = hw->freq / 16; } else if (hz >= hw->freq / 64) { ctrl |= SC18IS602_MODE_CLOCK_DIV_64; hw->speed = hw->freq / 64; } else { ctrl |= SC18IS602_MODE_CLOCK_DIV_128; hw->speed = hw->freq / 128; } /* * Don't do anything if the control value did not change. The initial * value of 0xff for hw->ctrl ensures that the correct mode will be set * with the first call to this function. */ if (ctrl == hw->ctrl) return 0; ret = i2c_smbus_write_byte_data(hw->client, 0xf0, ctrl); if (ret < 0) return ret; hw->ctrl = ctrl; return 0; } static int sc18is602_check_transfer(struct spi_device *spi, struct spi_transfer *t, int tlen) { int bpw; uint32_t hz; if (t && t->len + tlen > SC18IS602_BUFSIZ) return -EINVAL; bpw = spi->bits_per_word; if (t && t->bits_per_word) bpw = t->bits_per_word; if (bpw != 8) return -EINVAL; hz = spi->max_speed_hz; if (t && t->speed_hz) hz = t->speed_hz; if (hz == 0) return -EINVAL; return 0; } static int sc18is602_transfer_one(struct spi_master *master, struct spi_message *m) { struct sc18is602 *hw = spi_master_get_devdata(master); struct spi_device *spi = m->spi; struct spi_transfer *t; int status = 0; /* SC18IS602 does not support CS2 */ if (hw->id == sc18is602 && spi->chip_select == 2) { status = -ENXIO; goto error; } hw->tlen = 0; list_for_each_entry(t, &m->transfers, transfer_list) { u32 hz = t->speed_hz ? : spi->max_speed_hz; bool do_transfer; status = sc18is602_check_transfer(spi, t, hw->tlen); if (status < 0) break; status = sc18is602_setup_transfer(hw, hz, spi->mode); if (status < 0) break; do_transfer = t->cs_change || list_is_last(&t->transfer_list, &m->transfers); if (t->len) { status = sc18is602_txrx(hw, m, t, do_transfer); if (status < 0) break; m->actual_length += status; } status = 0; if (t->delay_usecs) udelay(t->delay_usecs); } error: m->status = status; spi_finalize_current_message(master); return status; } static int sc18is602_setup(struct spi_device *spi) { if (!spi->bits_per_word) spi->bits_per_word = 8; if (spi->mode & ~(SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST)) return -EINVAL; return sc18is602_check_transfer(spi, NULL, 0); } static int sc18is602_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct device *dev = &client->dev; struct device_node *np = dev->of_node; struct sc18is602_platform_data *pdata = dev_get_platdata(dev); struct sc18is602 *hw; struct spi_master *master; int error; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) return -EINVAL; master = spi_alloc_master(dev, sizeof(struct sc18is602)); if (!master) return -ENOMEM; hw = spi_master_get_devdata(master); i2c_set_clientdata(client, hw); hw->master = master; hw->client = client; hw->dev = dev; hw->ctrl = 0xff; hw->id = id->driver_data; switch (hw->id) { case sc18is602: case sc18is602b: master->num_chipselect = 4; hw->freq = SC18IS602_CLOCK; break; case sc18is603: master->num_chipselect = 2; if (pdata) { hw->freq = pdata->clock_frequency; } else { const __be32 *val; int len; val = of_get_property(np, "clock-frequency", &len); if (val && len >= sizeof(__be32)) hw->freq = be32_to_cpup(val); } if (!hw->freq) hw->freq = SC18IS602_CLOCK; break; } master->bus_num = client->adapter->nr; master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST; master->setup = sc18is602_setup; master->transfer_one_message = sc18is602_transfer_one; master->dev.of_node = np; error = spi_register_master(master); if (error) goto error_reg; return 0; error_reg: spi_master_put(master); return error; } static int sc18is602_remove(struct i2c_client *client) { struct sc18is602 *hw = i2c_get_clientdata(client); struct spi_master *master = hw->master; spi_unregister_master(master); return 0; } static const struct i2c_device_id sc18is602_id[] = { { "sc18is602", sc18is602 }, { "sc18is602b", sc18is602b }, { "sc18is603", sc18is603 }, { } }; MODULE_DEVICE_TABLE(i2c, sc18is602_id); static struct i2c_driver sc18is602_driver = { .driver = { .name = "sc18is602", }, .probe = sc18is602_probe, .remove = sc18is602_remove, .id_table = sc18is602_id, }; module_i2c_driver(sc18is602_driver); MODULE_DESCRIPTION("SC18IC602/603 SPI Master Driver"); MODULE_AUTHOR("Guenter Roeck"); MODULE_LICENSE("GPL");