drivers/mfd/stmpe-spi.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * ST Microelectronics MFD: stmpe's spi client specific driver
0004  *
0005  * Copyright (C) ST Microelectronics SA 2011
0006  *
0007  * Author: Viresh Kumar <vireshk@kernel.org> for ST Microelectronics
0008  */
0009
0010 #include <linux/spi/spi.h>
0011 #include <linux/interrupt.h>
0012 #include <linux/kernel.h>
0013 #include <linux/module.h>
0014 #include <linux/of.h>
0015 #include <linux/types.h>
0016 #include "stmpe.h"
0017
0018 #define READ_CMD    (1 << 7)
0019
0020 static int spi_reg_read(struct stmpe *stmpe, u8 reg)
0021 {
0022     struct spi_device *spi = stmpe->client;
0023     int status = spi_w8r16(spi, reg | READ_CMD);
0024
0025     return (status < 0) ? status : status >> 8;
0026 }
0027
0028 static int spi_reg_write(struct stmpe *stmpe, u8 reg, u8 val)
0029 {
0030     struct spi_device *spi = stmpe->client;
0031     u16 cmd = (val << 8) | reg;
0032
0033     return spi_write(spi, (const u8 *)&cmd, 2);
0034 }
0035
0036 static int spi_block_read(struct stmpe *stmpe, u8 reg, u8 length, u8 *values)
0037 {
0038     int ret, i;
0039
0040     for (i = 0; i < length; i++) {
0041         ret = spi_reg_read(stmpe, reg + i);
0042         if (ret < 0)
0043             return ret;
0044         *(values + i) = ret;
0045     }
0046
0047     return 0;
0048 }
0049
0050 static int spi_block_write(struct stmpe *stmpe, u8 reg, u8 length,
0051         const u8 *values)
0052 {
0053     int ret = 0, i;
0054
0055     for (i = length; i > 0; i--, reg++) {
0056         ret = spi_reg_write(stmpe, reg, *(values + i - 1));
0057         if (ret < 0)
0058             return ret;
0059     }
0060
0061     return ret;
0062 }
0063
0064 static void spi_init(struct stmpe *stmpe)
0065 {
0066     struct spi_device *spi = stmpe->client;
0067
0068     spi->bits_per_word = 8;
0069
0070     /* This register is only present for stmpe811 */
0071     if (stmpe->variant->id_val == 0x0811)
0072         spi_reg_write(stmpe, STMPE811_REG_SPI_CFG, spi->mode);
0073
0074     if (spi_setup(spi) < 0)
0075         dev_dbg(&spi->dev, "spi_setup failed\n");
0076 }
0077
0078 static struct stmpe_client_info spi_ci = {
0079     .read_byte = spi_reg_read,
0080     .write_byte = spi_reg_write,
0081     .read_block = spi_block_read,
0082     .write_block = spi_block_write,
0083     .init = spi_init,
0084 };
0085
0086 static int
0087 stmpe_spi_probe(struct spi_device *spi)
0088 {
0089     const struct spi_device_id *id = spi_get_device_id(spi);
0090
0091     /* don't exceed max specified rate - 1MHz - Limitation of STMPE */
0092     if (spi->max_speed_hz > 1000000) {
0093         dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
0094                 (spi->max_speed_hz/1000));
0095         return -EINVAL;
0096     }
0097
0098     spi_ci.irq = spi->irq;
0099     spi_ci.client = spi;
0100     spi_ci.dev = &spi->dev;
0101
0102     return stmpe_probe(&spi_ci, id->driver_data);
0103 }
0104
0105 static void stmpe_spi_remove(struct spi_device *spi)
0106 {
0107     struct stmpe *stmpe = spi_get_drvdata(spi);
0108
0109     stmpe_remove(stmpe);
0110 }
0111
0112 static const struct of_device_id stmpe_spi_of_match[] = {
0113     { .compatible = "st,stmpe610", },
0114     { .compatible = "st,stmpe801", },
0115     { .compatible = "st,stmpe811", },
0116     { .compatible = "st,stmpe1601", },
0117     { .compatible = "st,stmpe2401", },
0118     { .compatible = "st,stmpe2403", },
0119     { /* sentinel */ },
0120 };
0121 MODULE_DEVICE_TABLE(of, stmpe_spi_of_match);
0122
0123 static const struct spi_device_id stmpe_spi_id[] = {
0124     { "stmpe610", STMPE610 },
0125     { "stmpe801", STMPE801 },
0126     { "stmpe811", STMPE811 },
0127     { "stmpe1601", STMPE1601 },
0128     { "stmpe2401", STMPE2401 },
0129     { "stmpe2403", STMPE2403 },
0130     { }
0131 };
0132 MODULE_DEVICE_TABLE(spi, stmpe_id);
0133
0134 static struct spi_driver stmpe_spi_driver = {
0135     .driver = {
0136         .name   = "stmpe-spi",
0137         .of_match_table = of_match_ptr(stmpe_spi_of_match),
0138 #ifdef CONFIG_PM
0139         .pm = &stmpe_dev_pm_ops,
0140 #endif
0141     },
0142     .probe      = stmpe_spi_probe,
0143     .remove     = stmpe_spi_remove,
0144     .id_table   = stmpe_spi_id,
0145 };
0146
0147 static int __init stmpe_init(void)
0148 {
0149     return spi_register_driver(&stmpe_spi_driver);
0150 }
0151 subsys_initcall(stmpe_init);
0152
0153 static void __exit stmpe_exit(void)
0154 {
0155     spi_unregister_driver(&stmpe_spi_driver);
0156 }
0157 module_exit(stmpe_exit);
0158
0159 MODULE_LICENSE("GPL v2");
0160 MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
0161 MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");