From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/drivers/spi/spi-xtensa-xtfpga.c | 170 +++++++++++++++++++++++++++++++++ 1 file changed, 170 insertions(+) create mode 100644 kernel/drivers/spi/spi-xtensa-xtfpga.c (limited to 'kernel/drivers/spi/spi-xtensa-xtfpga.c') diff --git a/kernel/drivers/spi/spi-xtensa-xtfpga.c b/kernel/drivers/spi/spi-xtensa-xtfpga.c new file mode 100644 index 000000000..2e32ea2f1 --- /dev/null +++ b/kernel/drivers/spi/spi-xtensa-xtfpga.c @@ -0,0 +1,170 @@ +/* + * Xtensa xtfpga SPI controller driver + * + * Copyright (c) 2014 Cadence Design Systems Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define XTFPGA_SPI_NAME "xtfpga_spi" + +#define XTFPGA_SPI_START 0x0 +#define XTFPGA_SPI_BUSY 0x4 +#define XTFPGA_SPI_DATA 0x8 + +#define BUSY_WAIT_US 100 + +struct xtfpga_spi { + struct spi_bitbang bitbang; + void __iomem *regs; + u32 data; + unsigned data_sz; +}; + +static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi, + unsigned addr, u32 val) +{ + iowrite32(val, spi->regs + addr); +} + +static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi, + unsigned addr) +{ + return ioread32(spi->regs + addr); +} + +static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi) +{ + unsigned i; + + for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) && + i < BUSY_WAIT_US; ++i) + udelay(1); + WARN_ON_ONCE(i == BUSY_WAIT_US); +} + +static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs, + u32 v, u8 bits) +{ + struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master); + + xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0)); + xspi->data_sz += bits; + if (xspi->data_sz >= 16) { + xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA, + xspi->data >> (xspi->data_sz - 16)); + xspi->data_sz -= 16; + xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1); + xtfpga_spi_wait_busy(xspi); + xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0); + } + + return 0; +} + +static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on) +{ + struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master); + + WARN_ON(xspi->data_sz != 0); + xspi->data_sz = 0; +} + +static int xtfpga_spi_probe(struct platform_device *pdev) +{ + struct xtfpga_spi *xspi; + struct resource *mem; + int ret; + struct spi_master *master; + + master = spi_alloc_master(&pdev->dev, sizeof(struct xtfpga_spi)); + if (!master) + return -ENOMEM; + + master->flags = SPI_MASTER_NO_RX; + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16); + master->bus_num = pdev->dev.id; + master->dev.of_node = pdev->dev.of_node; + + xspi = spi_master_get_devdata(master); + xspi->bitbang.master = master; + xspi->bitbang.chipselect = xtfpga_spi_chipselect; + xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word; + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!mem) { + dev_err(&pdev->dev, "No memory resource\n"); + ret = -ENODEV; + goto err; + } + xspi->regs = devm_ioremap_resource(&pdev->dev, mem); + if (IS_ERR(xspi->regs)) { + ret = PTR_ERR(xspi->regs); + goto err; + } + + xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0); + usleep_range(1000, 2000); + if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) { + dev_err(&pdev->dev, "Device stuck in busy state\n"); + ret = -EBUSY; + goto err; + } + + ret = spi_bitbang_start(&xspi->bitbang); + if (ret < 0) { + dev_err(&pdev->dev, "spi_bitbang_start failed\n"); + goto err; + } + + platform_set_drvdata(pdev, master); + return 0; +err: + spi_master_put(master); + return ret; +} + +static int xtfpga_spi_remove(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct xtfpga_spi *xspi = spi_master_get_devdata(master); + + spi_bitbang_stop(&xspi->bitbang); + spi_master_put(master); + + return 0; +} + +MODULE_ALIAS("platform:" XTFPGA_SPI_NAME); + +#ifdef CONFIG_OF +static const struct of_device_id xtfpga_spi_of_match[] = { + { .compatible = "cdns,xtfpga-spi", }, + {} +}; +MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match); +#endif + +static struct platform_driver xtfpga_spi_driver = { + .probe = xtfpga_spi_probe, + .remove = xtfpga_spi_remove, + .driver = { + .name = XTFPGA_SPI_NAME, + .of_match_table = of_match_ptr(xtfpga_spi_of_match), + }, +}; +module_platform_driver(xtfpga_spi_driver); + +MODULE_AUTHOR("Max Filippov "); +MODULE_DESCRIPTION("xtensa xtfpga SPI driver"); +MODULE_LICENSE("GPL"); -- cgit 1.2.3-korg