// SPDX-License-Identifier: GPL-2.0-only /* * SH SCI SPI interface * * Copyright (c) 2008 Magnus Damm * * Based on S3C24XX GPIO based SPI driver, which is: * Copyright (c) 2006 Ben Dooks * Copyright (c) 2006 Simtec Electronics */ #include <linux/kernel.h> #include <linux/delay.h> #include <linux/spinlock.h> #include <linux/platform_device.h> #include <linux/spi/spi.h> #include <linux/spi/spi_bitbang.h> #include <linux/module.h> #include <asm/spi.h> #include <asm/io.h> struct sh_sci_spi { struct spi_bitbang bitbang; void __iomem *membase; unsigned char val; struct sh_spi_info *info; struct platform_device *dev; }; #define SCSPTR(sp) (sp->membase + 0x1c) #define PIN_SCK (1 << 2) #define PIN_TXD (1 << 0) #define PIN_RXD PIN_TXD #define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD) static inline void setbits(struct sh_sci_spi *sp, int bits, int on) { /* * We are the only user of SCSPTR so no locking is required. * Reading bit 2 and 0 in SCSPTR gives pin state as input. * Writing the same bits sets the output value. * This makes regular read-modify-write difficult so we * use sp->val to keep track of the latest register value. */ if (on) sp->val |= bits; else sp->val &= ~bits; iowrite8(sp->val, SCSPTR(sp)); } static inline void setsck(struct spi_device *dev, int on) { setbits(spi_master_get_devdata(dev->master), PIN_SCK, on); } static inline void setmosi(struct spi_device *dev, int on) { setbits(spi_master_get_devdata(dev->master), PIN_TXD, on); } static inline u32 getmiso(struct spi_device *dev) { struct sh_sci_spi *sp = spi_master_get_devdata(dev->master); return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0; } #define spidelay(x) ndelay(x) #include "spi-bitbang-txrx.h" static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); } static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); } static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); } static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits, unsigned flags) { return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits); } static void sh_sci_spi_chipselect(struct spi_device *dev, int value) { struct sh_sci_spi *sp = spi_master_get_devdata(dev->master); if (sp->info->chip_select) (sp->info->chip_select)(sp->info, dev->chip_select, value); } static int sh_sci_spi_probe(struct platform_device *dev) { struct resource *r; struct spi_master *master; struct sh_sci_spi *sp; int ret; master = spi_alloc_master(&dev->dev, sizeof(struct sh_sci_spi)); if (master == NULL) { dev_err(&dev->dev, "failed to allocate spi master\n"); ret = -ENOMEM; goto err0; } sp = spi_master_get_devdata(master); platform_set_drvdata(dev, sp); sp->info = dev_get_platdata(&dev->dev); if (!sp->info) { dev_err(&dev->dev, "platform data is missing\n"); ret = -ENOENT; goto err1; } /* setup spi bitbang adaptor */ sp->bitbang.master = master; sp->bitbang.master->bus_num = sp->info->bus_num; sp->bitbang.master->num_chipselect = sp->info->num_chipselect; sp->bitbang.chipselect = sh_sci_spi_chipselect; sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0; sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1; sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2; sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3; r = platform_get_resource(dev, IORESOURCE_MEM, 0); if (r == NULL) { ret = -ENOENT; goto err1; } sp->membase = ioremap(r->start, resource_size(r)); if (!sp->membase) { ret = -ENXIO; goto err1; } sp->val = ioread8(SCSPTR(sp)); setbits(sp, PIN_INIT, 1); ret = spi_bitbang_start(&sp->bitbang); if (!ret) return 0; setbits(sp, PIN_INIT, 0); iounmap(sp->membase); err1: spi_master_put(sp->bitbang.master); err0: return ret; } static int sh_sci_spi_remove(struct platform_device *dev) { struct sh_sci_spi *sp = platform_get_drvdata(dev); spi_bitbang_stop(&sp->bitbang); setbits(sp, PIN_INIT, 0); iounmap(sp->membase); spi_master_put(sp->bitbang.master); return 0; } static struct platform_driver sh_sci_spi_drv = { .probe = sh_sci_spi_probe, .remove = sh_sci_spi_remove, .driver = { .name = "spi_sh_sci", }, }; module_platform_driver(sh_sci_spi_drv); MODULE_DESCRIPTION("SH SCI SPI Driver"); MODULE_AUTHOR("Magnus Damm <damm@opensource.se>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:spi_sh_sci");