diff options
Diffstat (limited to 'drivers/spi/spi-txx9.c')
| -rw-r--r-- | drivers/spi/spi-txx9.c | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/drivers/spi/spi-txx9.c b/drivers/spi/spi-txx9.c new file mode 100644 index 000000000..3606232f1 --- /dev/null +++ b/drivers/spi/spi-txx9.c @@ -0,0 +1,477 @@ +/* + * 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/machine.h> +#include <linux/gpio/consumer.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 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; + struct gpio_desc *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) +{ + /* + * The GPIO descriptor will track polarity inversion inside + * gpiolib. + */ + if (on) { + /* deselect the chip with cs_change hint in last transfer */ + if (c->last_chipselect) + gpiod_set_value(c->last_chipselect, + !c->last_chipselect_val); + c->last_chipselect = spi->cs_gpiod; + c->last_chipselect_val = on; + } else { + c->last_chipselect = NULL; + ndelay(cs_delay); /* CS Hold Time */ + } + gpiod_set_value(spi->cs_gpiod, on); + 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; + + /* 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; + spi_transfer_delay_exec(t); + + 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); + schedule_work(&c->work); + spin_unlock_irqrestore(&c->lock, flags); + + return 0; +} + +/* + * Chip select uses GPIO only, further the driver is using the chip select + * numer (from the device tree "reg" property, and this can only come from + * device tree since this i MIPS and there is no way to pass platform data) as + * the GPIO number. As the platform has only one GPIO controller (the txx9 GPIO + * chip) it is thus using the chip select number as an offset into that chip. + * This chip has a maximum of 16 GPIOs 0..15 and this is what all platforms + * register. + * + * We modernized this behaviour by explicitly converting that offset to an + * offset on the GPIO chip using a GPIO descriptor machine table of the same + * size as the txx9 GPIO chip with a 1-to-1 mapping of chip select to GPIO + * offset. + * + * This is admittedly a hack, but it is countering the hack of using "reg" to + * contain a GPIO offset when it should be using "cs-gpios" as the SPI bindings + * state. + */ +static struct gpiod_lookup_table txx9spi_cs_gpio_table = { + .dev_id = "spi0", + .table = { + GPIO_LOOKUP_IDX("TXx9", 0, "cs", 0, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 1, "cs", 1, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 2, "cs", 2, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 3, "cs", 3, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 4, "cs", 4, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 5, "cs", 5, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 6, "cs", 6, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 7, "cs", 7, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 8, "cs", 8, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 9, "cs", 9, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 10, "cs", 10, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 11, "cs", 11, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 12, "cs", 12, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 13, "cs", 13, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 14, "cs", 14, GPIO_ACTIVE_LOW), + GPIO_LOOKUP_IDX("TXx9", 15, "cs", 15, GPIO_ACTIVE_LOW), + { }, + }, +}; + +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_prepare_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->last_chipselect = NULL; + + dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n", + (unsigned long long)res->start, irq, + (c->baseclk + 500000) / 1000000); + + gpiod_add_lookup_table(&txx9spi_cs_gpio_table); + + /* 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); + master->use_gpio_descriptors = true; + + ret = devm_spi_register_master(&dev->dev, master); + if (ret) + goto exit; + return 0; +exit_busy: + ret = -EBUSY; +exit: + clk_disable_unprepare(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); + + flush_work(&c->work); + clk_disable_unprepare(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"); |