diff options
Diffstat (limited to 'drivers/spi/oc_tiny_spi.c')
| -rw-r--r-- | drivers/spi/oc_tiny_spi.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/drivers/spi/oc_tiny_spi.c b/drivers/spi/oc_tiny_spi.c new file mode 100644 index 0000000..fc01fb8 --- /dev/null +++ b/drivers/spi/oc_tiny_spi.c @@ -0,0 +1,248 @@ +/* + * Opencore tiny_spi driver + * + * http://opencores.org/project,tiny_spi + * + * based on bfin_spi.c + * Copyright (c) 2005-2008 Analog Devices Inc. + * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw> + * + * Licensed under the GPL-2 or later. + */ + +#include <common.h> +#include <asm/io.h> +#include <malloc.h> +#include <spi.h> +#include <asm/gpio.h> + +#define TINY_SPI_STATUS_TXE 0x1 +#define TINY_SPI_STATUS_TXR 0x2 + +struct tiny_spi_regs { + unsigned rxdata; /* Rx data reg */ + unsigned txdata; /* Tx data reg */ + unsigned status; /* Status reg */ + unsigned control; /* Control reg */ + unsigned baud; /* Baud reg */ +}; + +struct tiny_spi_host { + uint base; + uint freq; + uint baudwidth; +}; +static const struct tiny_spi_host tiny_spi_host_list[] = + CONFIG_SYS_TINY_SPI_LIST; + +struct tiny_spi_slave { + struct spi_slave slave; + const struct tiny_spi_host *host; + uint mode; + uint baud; + uint flg; +}; +#define to_tiny_spi_slave(s) container_of(s, struct tiny_spi_slave, slave) + +int spi_cs_is_valid(unsigned int bus, unsigned int cs) +{ + return bus < ARRAY_SIZE(tiny_spi_host_list) && gpio_is_valid(cs); +} + +void spi_cs_activate(struct spi_slave *slave) +{ + struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave); + unsigned int cs = slave->cs; + + gpio_set_value(cs, tiny_spi->flg); + debug("%s: SPI_CS_GPIO:%x\n", __func__, gpio_get_value(cs)); +} + +void spi_cs_deactivate(struct spi_slave *slave) +{ + struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave); + unsigned int cs = slave->cs; + + gpio_set_value(cs, !tiny_spi->flg); + debug("%s: SPI_CS_GPIO:%x\n", __func__, gpio_get_value(cs)); +} + +void spi_set_speed(struct spi_slave *slave, uint hz) +{ + struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave); + const struct tiny_spi_host *host = tiny_spi->host; + + tiny_spi->baud = min(DIV_ROUND_UP(host->freq, hz * 2), + (1 << host->baudwidth)) - 1; + debug("%s: speed %u actual %u\n", __func__, hz, + host->freq / ((tiny_spi->baud + 1) * 2)); +} + +void spi_init(void) +{ +} + +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, + unsigned int hz, unsigned int mode) +{ + struct tiny_spi_slave *tiny_spi; + + if (!spi_cs_is_valid(bus, cs) || gpio_request(cs, "tiny_spi")) + return NULL; + + tiny_spi = malloc(sizeof(*tiny_spi)); + if (!tiny_spi) + return NULL; + memset(tiny_spi, 0, sizeof(*tiny_spi)); + + tiny_spi->slave.bus = bus; + tiny_spi->slave.cs = cs; + tiny_spi->host = &tiny_spi_host_list[bus]; + tiny_spi->mode = mode & (SPI_CPOL | SPI_CPHA); + tiny_spi->flg = mode & SPI_CS_HIGH ? 1 : 0; + spi_set_speed(&tiny_spi->slave, hz); + + debug("%s: bus:%i cs:%i base:%lx\n", __func__, + bus, cs, tiny_spi->host->base); + return &tiny_spi->slave; +} + +void spi_free_slave(struct spi_slave *slave) +{ + struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave); + + gpio_free(slave->cs); + free(tiny_spi); +} + +int spi_claim_bus(struct spi_slave *slave) +{ + struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave); + struct tiny_spi_regs *regs = (void *)tiny_spi->host->base; + + debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs); + gpio_direction_output(slave->cs, !tiny_spi->flg); + writel(tiny_spi->mode, ®s->control); + writel(tiny_spi->baud, ®s->baud); + return 0; +} + +void spi_release_bus(struct spi_slave *slave) +{ + debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs); +} + +#ifndef CONFIG_TINY_SPI_IDLE_VAL +# define CONFIG_TINY_SPI_IDLE_VAL 0xff +#endif + +int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, + void *din, unsigned long flags) +{ + struct tiny_spi_slave *tiny_spi = to_tiny_spi_slave(slave); + struct tiny_spi_regs *regs = (void *)tiny_spi->host->base; + const u8 *txp = dout; + u8 *rxp = din; + uint bytes = bitlen / 8; + uint i; + + debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__, + slave->bus, slave->cs, bitlen, bytes, flags); + if (bitlen == 0) + goto done; + + /* assume to do 8 bits transfers */ + if (bitlen % 8) { + flags |= SPI_XFER_END; + goto done; + } + + if (flags & SPI_XFER_BEGIN) + spi_cs_activate(slave); + + /* we need to tighten the transfer loop */ + if (txp && rxp) { + writeb(*txp++, ®s->txdata); + if (bytes > 1) { + writeb(*txp++, ®s->txdata); + for (i = 2; i < bytes; i++) { + u8 rx, tx = *txp++; + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXR)) + ; + rx = readb(®s->txdata); + writeb(tx, ®s->txdata); + *rxp++ = rx; + } + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXR)) + ; + *rxp++ = readb(®s->txdata); + } + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXE)) + ; + *rxp++ = readb(®s->rxdata); + } else if (rxp) { + writeb(CONFIG_TINY_SPI_IDLE_VAL, ®s->txdata); + if (bytes > 1) { + writeb(CONFIG_TINY_SPI_IDLE_VAL, + ®s->txdata); + for (i = 2; i < bytes; i++) { + u8 rx; + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXR)) + ; + rx = readb(®s->txdata); + writeb(CONFIG_TINY_SPI_IDLE_VAL, + ®s->txdata); + *rxp++ = rx; + } + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXR)) + ; + *rxp++ = readb(®s->txdata); + } + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXE)) + ; + *rxp++ = readb(®s->rxdata); + } else if (txp) { + writeb(*txp++, ®s->txdata); + if (bytes > 1) { + writeb(*txp++, ®s->txdata); + for (i = 2; i < bytes; i++) { + u8 tx = *txp++; + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXR)) + ; + writeb(tx, ®s->txdata); + } + } + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXE)) + ; + } else { + writeb(CONFIG_TINY_SPI_IDLE_VAL, ®s->txdata); + if (bytes > 1) { + writeb(CONFIG_TINY_SPI_IDLE_VAL, + ®s->txdata); + for (i = 2; i < bytes; i++) { + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXR)) + ; + writeb(CONFIG_TINY_SPI_IDLE_VAL, + ®s->txdata); + } + } + while (!(readb(®s->status) & + TINY_SPI_STATUS_TXE)) + ; + } + + done: + if (flags & SPI_XFER_END) + spi_cs_deactivate(slave); + + return 0; +} |