/* * TXx9 SPI controller driver. * * Based on linux/arch/mips/tx4938/toshiba_rbtx4938/spi_txx9.c * Copyright (C) 2000-2001 Toshiba Corporation * * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the * terms of the GNU General Public License version 2. This program is * licensed "as is" without any warranty of any kind, whether express * or implied. * * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com) * * Convert to generic SPI framework - Atsushi Nemoto (anemo@mba.ocn.ne.jp) */ #include <linux/init.h> #include <linux/delay.h> #include <linux/errno.h> #include <linux/interrupt.h> #include <linux/platform_device.h> #include <linux/sched.h> #include <linux/spinlock.h> #include <linux/workqueue.h> #include <linux/spi/spi.h> #include <linux/err.h> #include <linux/clk.h> #include <linux/io.h> #include <linux/module.h> #include <linux/gpio.h> #define SPI_FIFO_SIZE 4 #define SPI_MAX_DIVIDER 0xff /* Max. value for SPCR1.SER */ #define SPI_MIN_DIVIDER 1 /* Min. value for SPCR1.SER */ #define TXx9_SPMCR 0x00 #define TXx9_SPCR0 0x04 #define TXx9_SPCR1 0x08 #define TXx9_SPFS 0x0c #define TXx9_SPSR 0x14 #define TXx9_SPDR 0x18 /* SPMCR : SPI Master Control */ #define TXx9_SPMCR_OPMODE 0xc0 #define TXx9_SPMCR_CONFIG 0x40 #define TXx9_SPMCR_ACTIVE 0x80 #define TXx9_SPMCR_SPSTP 0x02 #define TXx9_SPMCR_BCLR 0x01 /* SPCR0 : SPI Control 0 */ #define TXx9_SPCR0_TXIFL_MASK 0xc000 #define TXx9_SPCR0_RXIFL_MASK 0x3000 #define TXx9_SPCR0_SIDIE 0x0800 #define TXx9_SPCR0_SOEIE 0x0400 #define TXx9_SPCR0_RBSIE 0x0200 #define TXx9_SPCR0_TBSIE 0x0100 #define TXx9_SPCR0_IFSPSE 0x0010 #define TXx9_SPCR0_SBOS 0x0004 #define TXx9_SPCR0_SPHA 0x0002 #define TXx9_SPCR0_SPOL 0x0001 /* SPSR : SPI Status */ #define TXx9_SPSR_TBSI 0x8000 #define TXx9_SPSR_RBSI 0x4000 #define TXx9_SPSR_TBS_MASK 0x3800 #define TXx9_SPSR_RBS_MASK 0x0700 #define TXx9_SPSR_SPOE 0x0080 #define TXx9_SPSR_IFSD 0x0008 #define TXx9_SPSR_SIDLE 0x0004 #define TXx9_SPSR_STRDY 0x0002 #define TXx9_SPSR_SRRDY 0x0001 struct txx9spi { struct workqueue_struct *workqueue; struct work_struct work; spinlock_t lock; /* protect 'queue' */ struct list_head queue; wait_queue_head_t waitq; void __iomem *membase; int baseclk; struct clk *clk; int last_chipselect; int last_chipselect_val; }; static u32 txx9spi_rd(struct txx9spi *c, int reg) { return __raw_readl(c->membase + reg); } static void txx9spi_wr(struct txx9spi *c, u32 val, int reg) { __raw_writel(val, c->membase + reg); } static void txx9spi_cs_func(struct spi_device *spi, struct txx9spi *c, int on, unsigned int cs_delay) { int val = (spi->mode & SPI_CS_HIGH) ? on : !on; if (on) { /* deselect the chip with cs_change hint in last transfer */ if (c->last_chipselect >= 0) gpio_set_value(c->last_chipselect, !c->last_chipselect_val); c->last_chipselect = spi->chip_select; c->last_chipselect_val = val; } else { c->last_chipselect = -1; ndelay(cs_delay); /* CS Hold Time */ } gpio_set_value(spi->chip_select, val); ndelay(cs_delay); /* CS Setup Time / CS Recovery Time */ } static int txx9spi_setup(struct spi_device *spi) { struct txx9spi *c = spi_master_get_devdata(spi->master); if (!spi->max_speed_hz) return -EINVAL; if (gpio_direction_output(spi->chip_select, !(spi->mode & SPI_CS_HIGH))) { dev_err(&spi->dev, "Cannot setup GPIO for chipselect.\n"); return -EINVAL; } /* deselect chip */ spin_lock(&c->lock); txx9spi_cs_func(spi, c, 0, (NSEC_PER_SEC / 2) / spi->max_speed_hz); spin_unlock(&c->lock); return 0; } static irqreturn_t txx9spi_interrupt(int irq, void *dev_id) { struct txx9spi *c = dev_id; /* disable rx intr */ txx9spi_wr(c, txx9spi_rd(c, TXx9_SPCR0) & ~TXx9_SPCR0_RBSIE, TXx9_SPCR0); wake_up(&c->waitq); return IRQ_HANDLED; } static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m) { struct spi_device *spi = m->spi; struct spi_transfer *t; unsigned int cs_delay; unsigned int cs_change = 1; int status = 0; u32 mcr; u32 prev_speed_hz = 0; u8 prev_bits_per_word = 0; /* CS setup/hold/recovery time in nsec */ cs_delay = 100 + (NSEC_PER_SEC / 2) / spi->max_speed_hz; mcr = txx9spi_rd(c, TXx9_SPMCR); if (unlikely((mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE)) { dev_err(&spi->dev, "Bad mode.\n"); status = -EIO; goto exit; } mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR); /* enter config mode */ txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR); txx9spi_wr(c, TXx9_SPCR0_SBOS | ((spi->mode & SPI_CPOL) ? TXx9_SPCR0_SPOL : 0) | ((spi->mode & SPI_CPHA) ? TXx9_SPCR0_SPHA : 0) | 0x08, TXx9_SPCR0); list_for_each_entry(t, &m->transfers, transfer_list) { const void *txbuf = t->tx_buf; void *rxbuf = t->rx_buf; u32 data; unsigned int len = t->len; unsigned int wsize; u32 speed_hz = t->speed_hz; u8 bits_per_word = t->bits_per_word; wsize = bits_per_word >> 3; /* in bytes */ if (prev_speed_hz != speed_hz || prev_bits_per_word != bits_per_word) { int n = DIV_ROUND_UP(c->baseclk, speed_hz) - 1; n = clamp(n, SPI_MIN_DIVIDER, SPI_MAX_DIVIDER); /* enter config mode */ txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR); txx9spi_wr(c, (n << 8) | bits_per_word, TXx9_SPCR1); /* enter active mode */ txx9spi_wr(c, mcr | TXx9_SPMCR_ACTIVE, TXx9_SPMCR); prev_speed_hz = speed_hz; prev_bits_per_word = bits_per_word; } if (cs_change) txx9spi_cs_func(spi, c, 1, cs_delay); cs_change = t->cs_change; while (len) { unsigned int count = SPI_FIFO_SIZE; int i; u32 cr0; if (len < count * wsize) count = len / wsize; /* now tx must be idle... */ while (!(txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_SIDLE)) cpu_relax(); cr0 = txx9spi_rd(c, TXx9_SPCR0); cr0 &= ~TXx9_SPCR0_RXIFL_MASK; cr0 |= (count - 1) << 12; /* enable rx intr */ cr0 |= TXx9_SPCR0_RBSIE; txx9spi_wr(c, cr0, TXx9_SPCR0); /* send */ for (i = 0; i < count; i++) { if (txbuf) { data = (wsize == 1) ? *(const u8 *)txbuf : *(const u16 *)txbuf; txx9spi_wr(c, data, TXx9_SPDR); txbuf += wsize; } else txx9spi_wr(c, 0, TXx9_SPDR); } /* wait all rx data */ wait_event(c->waitq, txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_RBSI); /* receive */ for (i = 0; i < count; i++) { data = txx9spi_rd(c, TXx9_SPDR); if (rxbuf) { if (wsize == 1) *(u8 *)rxbuf = data; else *(u16 *)rxbuf = data; rxbuf += wsize; } } len -= count * wsize; } m->actual_length += t->len; if (t->delay_usecs) udelay(t->delay_usecs); if (!cs_change) continue; if (t->transfer_list.next == &m->transfers) break; /* sometimes a short mid-message deselect of the chip * may be needed to terminate a mode or command */ txx9spi_cs_func(spi, c, 0, cs_delay); } exit: m->status = status; if (m->complete) m->complete(m->context); /* normally deactivate chipselect ... unless no error and * cs_change has hinted that the next message will probably * be for this chip too. */ if (!(status == 0 && cs_change)) txx9spi_cs_func(spi, c, 0, cs_delay); /* enter config mode */ txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR); } static void txx9spi_work(struct work_struct *work) { struct txx9spi *c = container_of(work, struct txx9spi, work); unsigned long flags; spin_lock_irqsave(&c->lock, flags); while (!list_empty(&c->queue)) { struct spi_message *m; m = container_of(c->queue.next, struct spi_message, queue); list_del_init(&m->queue); spin_unlock_irqrestore(&c->lock, flags); txx9spi_work_one(c, m); spin_lock_irqsave(&c->lock, flags); } spin_unlock_irqrestore(&c->lock, flags); } static int txx9spi_transfer(struct spi_device *spi, struct spi_message *m) { struct spi_master *master = spi->master; struct txx9spi *c = spi_master_get_devdata(master); struct spi_transfer *t; unsigned long flags; m->actual_length = 0; /* check each transfer's parameters */ list_for_each_entry(t, &m->transfers, transfer_list) { if (!t->tx_buf && !t->rx_buf && t->len) return -EINVAL; } spin_lock_irqsave(&c->lock, flags); list_add_tail(&m->queue, &c->queue); queue_work(c->workqueue, &c->work); spin_unlock_irqrestore(&c->lock, flags); return 0; } static int txx9spi_probe(struct platform_device *dev) { struct spi_master *master; struct txx9spi *c; struct resource *res; int ret = -ENODEV; u32 mcr; int irq; master = spi_alloc_master(&dev->dev, sizeof(*c)); if (!master) return ret; c = spi_master_get_devdata(master); platform_set_drvdata(dev, master); INIT_WORK(&c->work, txx9spi_work); spin_lock_init(&c->lock); INIT_LIST_HEAD(&c->queue); init_waitqueue_head(&c->waitq); c->clk = devm_clk_get(&dev->dev, "spi-baseclk"); if (IS_ERR(c->clk)) { ret = PTR_ERR(c->clk); c->clk = NULL; goto exit; } ret = clk_enable(c->clk); if (ret) { c->clk = NULL; goto exit; } c->baseclk = clk_get_rate(c->clk); master->min_speed_hz = DIV_ROUND_UP(c->baseclk, SPI_MAX_DIVIDER + 1); master->max_speed_hz = c->baseclk / (SPI_MIN_DIVIDER + 1); res = platform_get_resource(dev, IORESOURCE_MEM, 0); c->membase = devm_ioremap_resource(&dev->dev, res); if (IS_ERR(c->membase)) goto exit_busy; /* enter config mode */ mcr = txx9spi_rd(c, TXx9_SPMCR); mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR); txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR); irq = platform_get_irq(dev, 0); if (irq < 0) goto exit_busy; ret = devm_request_irq(&dev->dev, irq, txx9spi_interrupt, 0, "spi_txx9", c); if (ret) goto exit; c->workqueue = create_singlethread_workqueue( dev_name(master->dev.parent)); if (!c->workqueue) goto exit_busy; c->last_chipselect = -1; dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n", (unsigned long long)res->start, irq, (c->baseclk + 500000) / 1000000); /* the spi->mode bits understood by this driver: */ master->mode_bits = SPI_CS_HIGH | SPI_CPOL | SPI_CPHA; master->bus_num = dev->id; master->setup = txx9spi_setup; master->transfer = txx9spi_transfer; master->num_chipselect = (u16)UINT_MAX; /* any GPIO numbers */ master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16); ret = devm_spi_register_master(&dev->dev, master); if (ret) goto exit; return 0; exit_busy: ret = -EBUSY; exit: if (c->workqueue) destroy_workqueue(c->workqueue); clk_disable(c->clk); spi_master_put(master); return ret; } static int txx9spi_remove(struct platform_device *dev) { struct spi_master *master = platform_get_drvdata(dev); struct txx9spi *c = spi_master_get_devdata(master); destroy_workqueue(c->workqueue); clk_disable(c->clk); return 0; } /* work with hotplug and coldplug */ MODULE_ALIAS("platform:spi_txx9"); static struct platform_driver txx9spi_driver = { .probe = txx9spi_probe, .remove = txx9spi_remove, .driver = { .name = "spi_txx9", }, }; static int __init txx9spi_init(void) { return platform_driver_register(&txx9spi_driver); } subsys_initcall(txx9spi_init); static void __exit txx9spi_exit(void) { platform_driver_unregister(&txx9spi_driver); } module_exit(txx9spi_exit); MODULE_DESCRIPTION("TXx9 SPI Driver"); MODULE_LICENSE("GPL");