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159 lines
3.7 KiB
159 lines
3.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Xtensa xtfpga SPI controller driver |
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* |
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* Copyright (c) 2014 Cadence Design Systems Inc. |
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*/ |
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#include <linux/delay.h> |
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#include <linux/io.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/spi/spi.h> |
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#include <linux/spi/spi_bitbang.h> |
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#define XTFPGA_SPI_NAME "xtfpga_spi" |
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#define XTFPGA_SPI_START 0x0 |
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#define XTFPGA_SPI_BUSY 0x4 |
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#define XTFPGA_SPI_DATA 0x8 |
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#define BUSY_WAIT_US 100 |
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struct xtfpga_spi { |
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struct spi_bitbang bitbang; |
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void __iomem *regs; |
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u32 data; |
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unsigned data_sz; |
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}; |
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static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi, |
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unsigned addr, u32 val) |
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{ |
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__raw_writel(val, spi->regs + addr); |
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} |
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static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi, |
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unsigned addr) |
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{ |
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return __raw_readl(spi->regs + addr); |
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} |
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static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi) |
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{ |
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unsigned i; |
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for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) && |
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i < BUSY_WAIT_US; ++i) |
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udelay(1); |
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WARN_ON_ONCE(i == BUSY_WAIT_US); |
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} |
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static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs, |
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u32 v, u8 bits, unsigned flags) |
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{ |
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struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master); |
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xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0)); |
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xspi->data_sz += bits; |
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if (xspi->data_sz >= 16) { |
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xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA, |
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xspi->data >> (xspi->data_sz - 16)); |
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xspi->data_sz -= 16; |
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xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1); |
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xtfpga_spi_wait_busy(xspi); |
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xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0); |
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} |
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return 0; |
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} |
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static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on) |
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{ |
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struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master); |
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WARN_ON(xspi->data_sz != 0); |
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xspi->data_sz = 0; |
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} |
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static int xtfpga_spi_probe(struct platform_device *pdev) |
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{ |
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struct xtfpga_spi *xspi; |
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int ret; |
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struct spi_master *master; |
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master = spi_alloc_master(&pdev->dev, sizeof(struct xtfpga_spi)); |
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if (!master) |
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return -ENOMEM; |
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master->flags = SPI_MASTER_NO_RX; |
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master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16); |
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master->bus_num = pdev->dev.id; |
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master->dev.of_node = pdev->dev.of_node; |
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xspi = spi_master_get_devdata(master); |
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xspi->bitbang.master = master; |
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xspi->bitbang.chipselect = xtfpga_spi_chipselect; |
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xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word; |
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xspi->regs = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(xspi->regs)) { |
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ret = PTR_ERR(xspi->regs); |
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goto err; |
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} |
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xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0); |
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usleep_range(1000, 2000); |
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if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) { |
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dev_err(&pdev->dev, "Device stuck in busy state\n"); |
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ret = -EBUSY; |
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goto err; |
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} |
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ret = spi_bitbang_start(&xspi->bitbang); |
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if (ret < 0) { |
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dev_err(&pdev->dev, "spi_bitbang_start failed\n"); |
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goto err; |
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} |
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platform_set_drvdata(pdev, master); |
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return 0; |
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err: |
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spi_master_put(master); |
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return ret; |
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} |
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static int xtfpga_spi_remove(struct platform_device *pdev) |
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{ |
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struct spi_master *master = platform_get_drvdata(pdev); |
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struct xtfpga_spi *xspi = spi_master_get_devdata(master); |
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spi_bitbang_stop(&xspi->bitbang); |
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spi_master_put(master); |
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return 0; |
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} |
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MODULE_ALIAS("platform:" XTFPGA_SPI_NAME); |
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#ifdef CONFIG_OF |
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static const struct of_device_id xtfpga_spi_of_match[] = { |
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{ .compatible = "cdns,xtfpga-spi", }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match); |
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#endif |
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static struct platform_driver xtfpga_spi_driver = { |
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.probe = xtfpga_spi_probe, |
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.remove = xtfpga_spi_remove, |
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.driver = { |
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.name = XTFPGA_SPI_NAME, |
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.of_match_table = of_match_ptr(xtfpga_spi_of_match), |
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}, |
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}; |
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module_platform_driver(xtfpga_spi_driver); |
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MODULE_AUTHOR("Max Filippov <[email protected]>"); |
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MODULE_DESCRIPTION("xtensa xtfpga SPI driver"); |
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MODULE_LICENSE("GPL");
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