diff options
Diffstat (limited to 'drivers/spi/spi-octeon.c')
| -rw-r--r-- | drivers/spi/spi-octeon.c | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/drivers/spi/spi-octeon.c b/drivers/spi/spi-octeon.c new file mode 100644 index 00000000000..ea8fb2efb0f --- /dev/null +++ b/drivers/spi/spi-octeon.c @@ -0,0 +1,362 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2011, 2012 Cavium, Inc. + */ + +#include <linux/platform_device.h> +#include <linux/interrupt.h> +#include <linux/spi/spi.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/of.h> + +#include <asm/octeon/octeon.h> +#include <asm/octeon/cvmx-mpi-defs.h> + +#define OCTEON_SPI_CFG 0 +#define OCTEON_SPI_STS 0x08 +#define OCTEON_SPI_TX 0x10 +#define OCTEON_SPI_DAT0 0x80 + +#define OCTEON_SPI_MAX_BYTES 9 + +#define OCTEON_SPI_MAX_CLOCK_HZ 16000000 + +struct octeon_spi { + struct spi_master *my_master; + u64 register_base; + u64 last_cfg; + u64 cs_enax; +}; + +struct octeon_spi_setup { + u32 max_speed_hz; + u8 chip_select; + u8 mode; + u8 bits_per_word; +}; + +static void octeon_spi_wait_ready(struct octeon_spi *p) +{ + union cvmx_mpi_sts mpi_sts; + unsigned int loops = 0; + + do { + if (loops++) + __delay(500); + mpi_sts.u64 = cvmx_read_csr(p->register_base + OCTEON_SPI_STS); + } while (mpi_sts.s.busy); +} + +static int octeon_spi_do_transfer(struct octeon_spi *p, + struct spi_message *msg, + struct spi_transfer *xfer, + bool last_xfer) +{ + union cvmx_mpi_cfg mpi_cfg; + union cvmx_mpi_tx mpi_tx; + unsigned int clkdiv; + unsigned int speed_hz; + int mode; + bool cpha, cpol; + int bits_per_word; + const u8 *tx_buf; + u8 *rx_buf; + int len; + int i; + + struct octeon_spi_setup *msg_setup = spi_get_ctldata(msg->spi); + + speed_hz = msg_setup->max_speed_hz; + mode = msg_setup->mode; + cpha = mode & SPI_CPHA; + cpol = mode & SPI_CPOL; + bits_per_word = msg_setup->bits_per_word; + + if (xfer->speed_hz) + speed_hz = xfer->speed_hz; + if (xfer->bits_per_word) + bits_per_word = xfer->bits_per_word; + + if (speed_hz > OCTEON_SPI_MAX_CLOCK_HZ) + speed_hz = OCTEON_SPI_MAX_CLOCK_HZ; + + clkdiv = octeon_get_io_clock_rate() / (2 * speed_hz); + + mpi_cfg.u64 = 0; + + mpi_cfg.s.clkdiv = clkdiv; + mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0; + mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0; + mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0; + mpi_cfg.s.idlelo = cpha != cpol; + mpi_cfg.s.cslate = cpha ? 1 : 0; + mpi_cfg.s.enable = 1; + + if (msg_setup->chip_select < 4) + p->cs_enax |= 1ull << (12 + msg_setup->chip_select); + mpi_cfg.u64 |= p->cs_enax; + + if (mpi_cfg.u64 != p->last_cfg) { + p->last_cfg = mpi_cfg.u64; + cvmx_write_csr(p->register_base + OCTEON_SPI_CFG, mpi_cfg.u64); + } + tx_buf = xfer->tx_buf; + rx_buf = xfer->rx_buf; + len = xfer->len; + while (len > OCTEON_SPI_MAX_BYTES) { + for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) { + u8 d; + if (tx_buf) + d = *tx_buf++; + else + d = 0; + cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d); + } + mpi_tx.u64 = 0; + mpi_tx.s.csid = msg_setup->chip_select; + mpi_tx.s.leavecs = 1; + mpi_tx.s.txnum = tx_buf ? OCTEON_SPI_MAX_BYTES : 0; + mpi_tx.s.totnum = OCTEON_SPI_MAX_BYTES; + cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64); + + octeon_spi_wait_ready(p); + if (rx_buf) + for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) { + u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i)); + *rx_buf++ = (u8)v; + } + len -= OCTEON_SPI_MAX_BYTES; + } + + for (i = 0; i < len; i++) { + u8 d; + if (tx_buf) + d = *tx_buf++; + else + d = 0; + cvmx_write_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i), d); + } + + mpi_tx.u64 = 0; + mpi_tx.s.csid = msg_setup->chip_select; + if (last_xfer) + mpi_tx.s.leavecs = xfer->cs_change; + else + mpi_tx.s.leavecs = !xfer->cs_change; + mpi_tx.s.txnum = tx_buf ? len : 0; + mpi_tx.s.totnum = len; + cvmx_write_csr(p->register_base + OCTEON_SPI_TX, mpi_tx.u64); + + octeon_spi_wait_ready(p); + if (rx_buf) + for (i = 0; i < len; i++) { + u64 v = cvmx_read_csr(p->register_base + OCTEON_SPI_DAT0 + (8 * i)); + *rx_buf++ = (u8)v; + } + + if (xfer->delay_usecs) + udelay(xfer->delay_usecs); + + return xfer->len; +} + +static int octeon_spi_validate_bpw(struct spi_device *spi, u32 speed) +{ + switch (speed) { + case 8: + break; + default: + dev_err(&spi->dev, "Error: %d bits per word not supported\n", + speed); + return -EINVAL; + } + return 0; +} + +static int octeon_spi_transfer_one_message(struct spi_master *master, + struct spi_message *msg) +{ + struct octeon_spi *p = spi_master_get_devdata(master); + unsigned int total_len = 0; + int status = 0; + struct spi_transfer *xfer; + + /* + * We better have set the configuration via a call to .setup + * before we get here. + */ + if (spi_get_ctldata(msg->spi) == NULL) { + status = -EINVAL; + goto err; + } + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if (xfer->bits_per_word) { + status = octeon_spi_validate_bpw(msg->spi, + xfer->bits_per_word); + if (status) + goto err; + } + } + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + bool last_xfer = &xfer->transfer_list == msg->transfers.prev; + int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer); + if (r < 0) { + status = r; + goto err; + } + total_len += r; + } +err: + msg->status = status; + msg->actual_length = total_len; + spi_finalize_current_message(master); + return status; +} + +static struct octeon_spi_setup *octeon_spi_new_setup(struct spi_device *spi) +{ + struct octeon_spi_setup *setup = kzalloc(sizeof(*setup), GFP_KERNEL); + if (!setup) + return NULL; + + setup->max_speed_hz = spi->max_speed_hz; + setup->chip_select = spi->chip_select; + setup->mode = spi->mode; + setup->bits_per_word = spi->bits_per_word; + return setup; +} + +static int octeon_spi_setup(struct spi_device *spi) +{ + int r; + struct octeon_spi_setup *new_setup; + struct octeon_spi_setup *old_setup = spi_get_ctldata(spi); + + r = octeon_spi_validate_bpw(spi, spi->bits_per_word); + if (r) + return r; + + new_setup = octeon_spi_new_setup(spi); + if (!new_setup) + return -ENOMEM; + + spi_set_ctldata(spi, new_setup); + kfree(old_setup); + + return 0; +} + +static void octeon_spi_cleanup(struct spi_device *spi) +{ + struct octeon_spi_setup *old_setup = spi_get_ctldata(spi); + spi_set_ctldata(spi, NULL); + kfree(old_setup); +} + +static int octeon_spi_nop_transfer_hardware(struct spi_master *master) +{ + return 0; +} + +static int __devinit octeon_spi_probe(struct platform_device *pdev) +{ + + struct resource *res_mem; + struct spi_master *master; + struct octeon_spi *p; + int err = -ENOENT; + + master = spi_alloc_master(&pdev->dev, sizeof(struct octeon_spi)); + if (!master) + return -ENOMEM; + p = spi_master_get_devdata(master); + platform_set_drvdata(pdev, p); + p->my_master = master; + + res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + if (res_mem == NULL) { + dev_err(&pdev->dev, "found no memory resource\n"); + err = -ENXIO; + goto fail; + } + if (!devm_request_mem_region(&pdev->dev, res_mem->start, + resource_size(res_mem), res_mem->name)) { + dev_err(&pdev->dev, "request_mem_region failed\n"); + goto fail; + } + p->register_base = (u64)devm_ioremap(&pdev->dev, res_mem->start, + resource_size(res_mem)); + + /* Dynamic bus numbering */ + master->bus_num = -1; + master->num_chipselect = 4; + master->mode_bits = SPI_CPHA | + SPI_CPOL | + SPI_CS_HIGH | + SPI_LSB_FIRST | + SPI_3WIRE; + + master->setup = octeon_spi_setup; + master->cleanup = octeon_spi_cleanup; + master->prepare_transfer_hardware = octeon_spi_nop_transfer_hardware; + master->transfer_one_message = octeon_spi_transfer_one_message; + master->unprepare_transfer_hardware = octeon_spi_nop_transfer_hardware; + + master->dev.of_node = pdev->dev.of_node; + err = spi_register_master(master); + if (err) { + dev_err(&pdev->dev, "register master failed: %d\n", err); + goto fail; + } + + dev_info(&pdev->dev, "OCTEON SPI bus driver\n"); + + return 0; +fail: + spi_master_put(master); + return err; +} + +static int __devexit octeon_spi_remove(struct platform_device *pdev) +{ + struct octeon_spi *p = platform_get_drvdata(pdev); + u64 register_base = p->register_base; + + spi_unregister_master(p->my_master); + + /* Clear the CSENA* and put everything in a known state. */ + cvmx_write_csr(register_base + OCTEON_SPI_CFG, 0); + + return 0; +} + +static struct of_device_id octeon_spi_match[] = { + { .compatible = "cavium,octeon-3010-spi", }, + {}, +}; +MODULE_DEVICE_TABLE(of, octeon_spi_match); + +static struct platform_driver octeon_spi_driver = { + .driver = { + .name = "spi-octeon", + .owner = THIS_MODULE, + .of_match_table = octeon_spi_match, + }, + .probe = octeon_spi_probe, + .remove = __devexit_p(octeon_spi_remove), +}; + +module_platform_driver(octeon_spi_driver); + +MODULE_DESCRIPTION("Cavium, Inc. OCTEON SPI bus driver"); +MODULE_AUTHOR("David Daney"); +MODULE_LICENSE("GPL"); |