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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Xtensa xtfpga SPI controller driver4 *5 * Copyright (c) 2014 Cadence Design Systems Inc.6 */7 8#include <linux/delay.h>9#include <linux/io.h>10#include <linux/module.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/spi/spi.h>14#include <linux/spi/spi_bitbang.h>15 16#define XTFPGA_SPI_NAME "xtfpga_spi"17 18#define XTFPGA_SPI_START 0x019#define XTFPGA_SPI_BUSY 0x420#define XTFPGA_SPI_DATA 0x821 22#define BUSY_WAIT_US 10023 24struct xtfpga_spi {25 struct spi_bitbang bitbang;26 void __iomem *regs;27 u32 data;28 unsigned data_sz;29};30 31static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi,32 unsigned addr, u32 val)33{34 __raw_writel(val, spi->regs + addr);35}36 37static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi,38 unsigned addr)39{40 return __raw_readl(spi->regs + addr);41}42 43static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi)44{45 unsigned i;46 47 for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) &&48 i < BUSY_WAIT_US; ++i)49 udelay(1);50 WARN_ON_ONCE(i == BUSY_WAIT_US);51}52 53static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs,54 u32 v, u8 bits, unsigned flags)55{56 struct xtfpga_spi *xspi = spi_controller_get_devdata(spi->controller);57 58 xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0));59 xspi->data_sz += bits;60 if (xspi->data_sz >= 16) {61 xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA,62 xspi->data >> (xspi->data_sz - 16));63 xspi->data_sz -= 16;64 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1);65 xtfpga_spi_wait_busy(xspi);66 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);67 }68 69 return 0;70}71 72static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on)73{74 struct xtfpga_spi *xspi = spi_controller_get_devdata(spi->controller);75 76 WARN_ON(xspi->data_sz != 0);77 xspi->data_sz = 0;78}79 80static int xtfpga_spi_probe(struct platform_device *pdev)81{82 struct xtfpga_spi *xspi;83 int ret;84 struct spi_controller *host;85 86 host = devm_spi_alloc_host(&pdev->dev, sizeof(struct xtfpga_spi));87 if (!host)88 return -ENOMEM;89 90 host->flags = SPI_CONTROLLER_NO_RX;91 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);92 host->bus_num = pdev->dev.id;93 host->dev.of_node = pdev->dev.of_node;94 95 xspi = spi_controller_get_devdata(host);96 xspi->bitbang.ctlr = host;97 xspi->bitbang.chipselect = xtfpga_spi_chipselect;98 xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word;99 xspi->regs = devm_platform_ioremap_resource(pdev, 0);100 if (IS_ERR(xspi->regs))101 return PTR_ERR(xspi->regs);102 103 xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);104 usleep_range(1000, 2000);105 if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) {106 dev_err(&pdev->dev, "Device stuck in busy state\n");107 return -EBUSY;108 }109 110 ret = spi_bitbang_start(&xspi->bitbang);111 if (ret < 0) {112 dev_err(&pdev->dev, "spi_bitbang_start failed\n");113 return ret;114 }115 116 platform_set_drvdata(pdev, host);117 return 0;118}119 120static void xtfpga_spi_remove(struct platform_device *pdev)121{122 struct spi_controller *host = platform_get_drvdata(pdev);123 struct xtfpga_spi *xspi = spi_controller_get_devdata(host);124 125 spi_bitbang_stop(&xspi->bitbang);126 spi_controller_put(host);127}128 129MODULE_ALIAS("platform:" XTFPGA_SPI_NAME);130 131#ifdef CONFIG_OF132static const struct of_device_id xtfpga_spi_of_match[] = {133 { .compatible = "cdns,xtfpga-spi", },134 {}135};136MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match);137#endif138 139static struct platform_driver xtfpga_spi_driver = {140 .probe = xtfpga_spi_probe,141 .remove_new = xtfpga_spi_remove,142 .driver = {143 .name = XTFPGA_SPI_NAME,144 .of_match_table = of_match_ptr(xtfpga_spi_of_match),145 },146};147module_platform_driver(xtfpga_spi_driver);148 149MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");150MODULE_DESCRIPTION("xtensa xtfpga SPI driver");151MODULE_LICENSE("GPL");152