diff options
Diffstat (limited to 'drivers/input/touchscreen/cyttsp_spi.c')
| -rw-r--r-- | drivers/input/touchscreen/cyttsp_spi.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/drivers/input/touchscreen/cyttsp_spi.c b/drivers/input/touchscreen/cyttsp_spi.c new file mode 100644 index 0000000000..ada17f2dad --- /dev/null +++ b/drivers/input/touchscreen/cyttsp_spi.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Source for: + * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver. + * For use with Cypress Txx3xx parts. + * Supported parts include: + * CY8CTST341 + * CY8CTMA340 + * + * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc. + * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org> + * Copyright (C) 2013 Cypress Semiconductor + * + * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com> + */ + +#include "cyttsp_core.h" + +#include <linux/delay.h> +#include <linux/input.h> +#include <linux/spi/spi.h> + +#define CY_SPI_NAME "cyttsp-spi" + +#define CY_SPI_WR_OP 0x00 /* r/~w */ +#define CY_SPI_RD_OP 0x01 +#define CY_SPI_CMD_BYTES 4 +#define CY_SPI_SYNC_BYTE 2 +#define CY_SPI_SYNC_ACK1 0x62 /* from protocol v.2 */ +#define CY_SPI_SYNC_ACK2 0x9D /* from protocol v.2 */ +#define CY_SPI_DATA_SIZE 128 +#define CY_SPI_DATA_BUF_SIZE (CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE) +#define CY_SPI_BITS_PER_WORD 8 + +static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf, + u8 op, u16 reg, u8 *buf, int length) +{ + struct spi_device *spi = to_spi_device(dev); + struct spi_message msg; + struct spi_transfer xfer[2]; + u8 *wr_buf = &xfer_buf[0]; + u8 *rd_buf = &xfer_buf[CY_SPI_DATA_BUF_SIZE]; + int retval; + int i; + + if (length > CY_SPI_DATA_SIZE) { + dev_err(dev, "%s: length %d is too big.\n", + __func__, length); + return -EINVAL; + } + + memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE); + memset(rd_buf, 0, CY_SPI_DATA_BUF_SIZE); + + wr_buf[0] = 0x00; /* header byte 0 */ + wr_buf[1] = 0xFF; /* header byte 1 */ + wr_buf[2] = reg; /* reg index */ + wr_buf[3] = op; /* r/~w */ + if (op == CY_SPI_WR_OP) + memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length); + + memset(xfer, 0, sizeof(xfer)); + spi_message_init(&msg); + + /* + We set both TX and RX buffers because Cypress TTSP + requires full duplex operation. + */ + xfer[0].tx_buf = wr_buf; + xfer[0].rx_buf = rd_buf; + switch (op) { + case CY_SPI_WR_OP: + xfer[0].len = length + CY_SPI_CMD_BYTES; + spi_message_add_tail(&xfer[0], &msg); + break; + + case CY_SPI_RD_OP: + xfer[0].len = CY_SPI_CMD_BYTES; + spi_message_add_tail(&xfer[0], &msg); + + xfer[1].rx_buf = buf; + xfer[1].len = length; + spi_message_add_tail(&xfer[1], &msg); + break; + + default: + dev_err(dev, "%s: bad operation code=%d\n", __func__, op); + return -EINVAL; + } + + retval = spi_sync(spi, &msg); + if (retval < 0) { + dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n", + __func__, retval, xfer[1].len, op); + + /* + * do not return here since was a bad ACK sequence + * let the following ACK check handle any errors and + * allow silent retries + */ + } + + if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK1 || + rd_buf[CY_SPI_SYNC_BYTE + 1] != CY_SPI_SYNC_ACK2) { + dev_dbg(dev, "%s: operation %d failed\n", __func__, op); + + for (i = 0; i < CY_SPI_CMD_BYTES; i++) + dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n", + __func__, i, rd_buf[i]); + for (i = 0; i < length; i++) + dev_dbg(dev, "%s: test buf[%d]:0x%02x\n", + __func__, i, buf[i]); + + return -EIO; + } + + return 0; +} + +static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf, + u16 addr, u8 length, void *data) +{ + return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data, + length); +} + +static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf, + u16 addr, u8 length, const void *data) +{ + return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data, + length); +} + +static const struct cyttsp_bus_ops cyttsp_spi_bus_ops = { + .bustype = BUS_SPI, + .write = cyttsp_spi_write_block_data, + .read = cyttsp_spi_read_block_data, +}; + +static int cyttsp_spi_probe(struct spi_device *spi) +{ + struct cyttsp *ts; + int error; + + /* Set up SPI*/ + spi->bits_per_word = CY_SPI_BITS_PER_WORD; + spi->mode = SPI_MODE_0; + error = spi_setup(spi); + if (error < 0) { + dev_err(&spi->dev, "%s: SPI setup error %d\n", + __func__, error); + return error; + } + + ts = cyttsp_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq, + CY_SPI_DATA_BUF_SIZE * 2); + if (IS_ERR(ts)) + return PTR_ERR(ts); + + spi_set_drvdata(spi, ts); + + return 0; +} + +static const struct of_device_id cyttsp_of_spi_match[] = { + { .compatible = "cypress,cy8ctma340", }, + { .compatible = "cypress,cy8ctst341", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, cyttsp_of_spi_match); + +static struct spi_driver cyttsp_spi_driver = { + .driver = { + .name = CY_SPI_NAME, + .pm = pm_sleep_ptr(&cyttsp_pm_ops), + .of_match_table = cyttsp_of_spi_match, + }, + .probe = cyttsp_spi_probe, +}; + +module_spi_driver(cyttsp_spi_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver"); +MODULE_AUTHOR("Cypress"); +MODULE_ALIAS("spi:cyttsp"); |