cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cyttsp4_spi.c (4575B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Source for:
      4 * Cypress TrueTouch(TM) Standard Product (TTSP) SPI touchscreen driver.
      5 * For use with Cypress Txx4xx parts.
      6 * Supported parts include:
      7 * TMA4XX
      8 * TMA1036
      9 *
     10 * Copyright (C) 2009, 2010, 2011 Cypress Semiconductor, Inc.
     11 * Copyright (C) 2012 Javier Martinez Canillas <javier@dowhile0.org>
     12 * Copyright (C) 2013 Cypress Semiconductor
     13 *
     14 * Contact Cypress Semiconductor at www.cypress.com <ttdrivers@cypress.com>
     15 */
     16
     17#include "cyttsp4_core.h"
     18
     19#include <linux/delay.h>
     20#include <linux/input.h>
     21#include <linux/spi/spi.h>
     22
     23#define CY_SPI_WR_OP		0x00 /* r/~w */
     24#define CY_SPI_RD_OP		0x01
     25#define CY_SPI_BITS_PER_WORD	8
     26#define CY_SPI_A8_BIT		0x02
     27#define CY_SPI_WR_HEADER_BYTES	2
     28#define CY_SPI_RD_HEADER_BYTES	1
     29#define CY_SPI_CMD_BYTES	2
     30#define CY_SPI_SYNC_BYTE	0
     31#define CY_SPI_SYNC_ACK		0x62 /* from TRM *A protocol */
     32#define CY_SPI_DATA_SIZE	(2 * 256)
     33
     34#define CY_SPI_DATA_BUF_SIZE	(CY_SPI_CMD_BYTES + CY_SPI_DATA_SIZE)
     35
     36static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
     37			   u8 op, u16 reg, u8 *buf, int length)
     38{
     39	struct spi_device *spi = to_spi_device(dev);
     40	struct spi_message msg;
     41	struct spi_transfer xfer[2];
     42	u8 *wr_buf = &xfer_buf[0];
     43	u8 rd_buf[CY_SPI_CMD_BYTES];
     44	int retval;
     45	int i;
     46
     47	if (length > CY_SPI_DATA_SIZE) {
     48		dev_err(dev, "%s: length %d is too big.\n",
     49			__func__, length);
     50		return -EINVAL;
     51	}
     52
     53	memset(wr_buf, 0, CY_SPI_DATA_BUF_SIZE);
     54	memset(rd_buf, 0, CY_SPI_CMD_BYTES);
     55
     56	wr_buf[0] = op + (((reg >> 8) & 0x1) ? CY_SPI_A8_BIT : 0);
     57	if (op == CY_SPI_WR_OP) {
     58		wr_buf[1] = reg & 0xFF;
     59		if (length > 0)
     60			memcpy(wr_buf + CY_SPI_CMD_BYTES, buf, length);
     61	}
     62
     63	memset(xfer, 0, sizeof(xfer));
     64	spi_message_init(&msg);
     65
     66	/*
     67	  We set both TX and RX buffers because Cypress TTSP
     68	  requires full duplex operation.
     69	*/
     70	xfer[0].tx_buf = wr_buf;
     71	xfer[0].rx_buf = rd_buf;
     72	switch (op) {
     73	case CY_SPI_WR_OP:
     74		xfer[0].len = length + CY_SPI_CMD_BYTES;
     75		spi_message_add_tail(&xfer[0], &msg);
     76		break;
     77
     78	case CY_SPI_RD_OP:
     79		xfer[0].len = CY_SPI_RD_HEADER_BYTES;
     80		spi_message_add_tail(&xfer[0], &msg);
     81
     82		xfer[1].rx_buf = buf;
     83		xfer[1].len = length;
     84		spi_message_add_tail(&xfer[1], &msg);
     85		break;
     86
     87	default:
     88		dev_err(dev, "%s: bad operation code=%d\n", __func__, op);
     89		return -EINVAL;
     90	}
     91
     92	retval = spi_sync(spi, &msg);
     93	if (retval < 0) {
     94		dev_dbg(dev, "%s: spi_sync() error %d, len=%d, op=%d\n",
     95			__func__, retval, xfer[1].len, op);
     96
     97		/*
     98		 * do not return here since was a bad ACK sequence
     99		 * let the following ACK check handle any errors and
    100		 * allow silent retries
    101		 */
    102	}
    103
    104	if (rd_buf[CY_SPI_SYNC_BYTE] != CY_SPI_SYNC_ACK) {
    105		dev_dbg(dev, "%s: operation %d failed\n", __func__, op);
    106
    107		for (i = 0; i < CY_SPI_CMD_BYTES; i++)
    108			dev_dbg(dev, "%s: test rd_buf[%d]:0x%02x\n",
    109				__func__, i, rd_buf[i]);
    110		for (i = 0; i < length; i++)
    111			dev_dbg(dev, "%s: test buf[%d]:0x%02x\n",
    112				__func__, i, buf[i]);
    113
    114		return -EIO;
    115	}
    116
    117	return 0;
    118}
    119
    120static int cyttsp_spi_read_block_data(struct device *dev, u8 *xfer_buf,
    121				      u16 addr, u8 length, void *data)
    122{
    123	int rc;
    124
    125	rc = cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, NULL, 0);
    126	if (rc)
    127		return rc;
    128	else
    129		return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_RD_OP, addr, data,
    130				length);
    131}
    132
    133static int cyttsp_spi_write_block_data(struct device *dev, u8 *xfer_buf,
    134				       u16 addr, u8 length, const void *data)
    135{
    136	return cyttsp_spi_xfer(dev, xfer_buf, CY_SPI_WR_OP, addr, (void *)data,
    137			length);
    138}
    139
    140static const struct cyttsp4_bus_ops cyttsp_spi_bus_ops = {
    141	.bustype	= BUS_SPI,
    142	.write		= cyttsp_spi_write_block_data,
    143	.read		= cyttsp_spi_read_block_data,
    144};
    145
    146static int cyttsp4_spi_probe(struct spi_device *spi)
    147{
    148	struct cyttsp4 *ts;
    149	int error;
    150
    151	/* Set up SPI*/
    152	spi->bits_per_word = CY_SPI_BITS_PER_WORD;
    153	spi->mode = SPI_MODE_0;
    154	error = spi_setup(spi);
    155	if (error < 0) {
    156		dev_err(&spi->dev, "%s: SPI setup error %d\n",
    157			__func__, error);
    158		return error;
    159	}
    160
    161	ts = cyttsp4_probe(&cyttsp_spi_bus_ops, &spi->dev, spi->irq,
    162			  CY_SPI_DATA_BUF_SIZE);
    163
    164	return PTR_ERR_OR_ZERO(ts);
    165}
    166
    167static void cyttsp4_spi_remove(struct spi_device *spi)
    168{
    169	struct cyttsp4 *ts = spi_get_drvdata(spi);
    170	cyttsp4_remove(ts);
    171}
    172
    173static struct spi_driver cyttsp4_spi_driver = {
    174	.driver = {
    175		.name	= CYTTSP4_SPI_NAME,
    176		.pm	= &cyttsp4_pm_ops,
    177	},
    178	.probe  = cyttsp4_spi_probe,
    179	.remove = cyttsp4_spi_remove,
    180};
    181
    182module_spi_driver(cyttsp4_spi_driver);
    183
    184MODULE_LICENSE("GPL");
    185MODULE_DESCRIPTION("Cypress TrueTouch(R) Standard Product (TTSP) SPI driver");
    186MODULE_AUTHOR("Cypress");
    187MODULE_ALIAS("spi:cyttsp4");