diff options
Diffstat (limited to 'drivers/spi/spi_mpc83xx.c')
| -rw-r--r-- | drivers/spi/spi_mpc83xx.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/drivers/spi/spi_mpc83xx.c b/drivers/spi/spi_mpc83xx.c new file mode 100644 index 00000000000..5d92a7e5cb4 --- /dev/null +++ b/drivers/spi/spi_mpc83xx.c @@ -0,0 +1,483 @@ +/* + * MPC83xx SPI controller driver. + * + * Maintainer: Kumar Gala + * + * Copyright (C) 2006 Polycom, Inc. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/completion.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/irq.h> +#include <linux/device.h> +#include <linux/spi/spi.h> +#include <linux/spi/spi_bitbang.h> +#include <linux/platform_device.h> +#include <linux/fsl_devices.h> + +#include <asm/irq.h> +#include <asm/io.h> + +/* SPI Controller registers */ +struct mpc83xx_spi_reg { + u8 res1[0x20]; + __be32 mode; + __be32 event; + __be32 mask; + __be32 command; + __be32 transmit; + __be32 receive; +}; + +/* SPI Controller mode register definitions */ +#define SPMODE_CI_INACTIVEHIGH (1 << 29) +#define SPMODE_CP_BEGIN_EDGECLK (1 << 28) +#define SPMODE_DIV16 (1 << 27) +#define SPMODE_REV (1 << 26) +#define SPMODE_MS (1 << 25) +#define SPMODE_ENABLE (1 << 24) +#define SPMODE_LEN(x) ((x) << 20) +#define SPMODE_PM(x) ((x) << 16) + +/* + * Default for SPI Mode: + * SPI MODE 0 (inactive low, phase middle, MSB, 8-bit length, slow clk + */ +#define SPMODE_INIT_VAL (SPMODE_CI_INACTIVEHIGH | SPMODE_DIV16 | SPMODE_REV | \ + SPMODE_MS | SPMODE_LEN(7) | SPMODE_PM(0xf)) + +/* SPIE register values */ +#define SPIE_NE 0x00000200 /* Not empty */ +#define SPIE_NF 0x00000100 /* Not full */ + +/* SPIM register values */ +#define SPIM_NE 0x00000200 /* Not empty */ +#define SPIM_NF 0x00000100 /* Not full */ + +/* SPI Controller driver's private data. */ +struct mpc83xx_spi { + /* bitbang has to be first */ + struct spi_bitbang bitbang; + struct completion done; + + struct mpc83xx_spi_reg __iomem *base; + + /* rx & tx bufs from the spi_transfer */ + const void *tx; + void *rx; + + /* functions to deal with different sized buffers */ + void (*get_rx) (u32 rx_data, struct mpc83xx_spi *); + u32(*get_tx) (struct mpc83xx_spi *); + + unsigned int count; + u32 irq; + + unsigned nsecs; /* (clock cycle time)/2 */ + + u32 sysclk; + void (*activate_cs) (u8 cs, u8 polarity); + void (*deactivate_cs) (u8 cs, u8 polarity); +}; + +static inline void mpc83xx_spi_write_reg(__be32 __iomem * reg, u32 val) +{ + out_be32(reg, val); +} + +static inline u32 mpc83xx_spi_read_reg(__be32 __iomem * reg) +{ + return in_be32(reg); +} + +#define MPC83XX_SPI_RX_BUF(type) \ +void mpc83xx_spi_rx_buf_##type(u32 data, struct mpc83xx_spi *mpc83xx_spi) \ +{ \ + type * rx = mpc83xx_spi->rx; \ + *rx++ = (type)data; \ + mpc83xx_spi->rx = rx; \ +} + +#define MPC83XX_SPI_TX_BUF(type) \ +u32 mpc83xx_spi_tx_buf_##type(struct mpc83xx_spi *mpc83xx_spi) \ +{ \ + u32 data; \ + const type * tx = mpc83xx_spi->tx; \ + data = *tx++; \ + mpc83xx_spi->tx = tx; \ + return data; \ +} + +MPC83XX_SPI_RX_BUF(u8) +MPC83XX_SPI_RX_BUF(u16) +MPC83XX_SPI_RX_BUF(u32) +MPC83XX_SPI_TX_BUF(u8) +MPC83XX_SPI_TX_BUF(u16) +MPC83XX_SPI_TX_BUF(u32) + +static void mpc83xx_spi_chipselect(struct spi_device *spi, int value) +{ + struct mpc83xx_spi *mpc83xx_spi; + u8 pol = spi->mode & SPI_CS_HIGH ? 1 : 0; + + mpc83xx_spi = spi_master_get_devdata(spi->master); + + if (value == BITBANG_CS_INACTIVE) { + if (mpc83xx_spi->deactivate_cs) + mpc83xx_spi->deactivate_cs(spi->chip_select, pol); + } + + if (value == BITBANG_CS_ACTIVE) { + u32 regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode); + u32 len = spi->bits_per_word; + if (len == 32) + len = 0; + else + len = len - 1; + + /* mask out bits we are going to set */ + regval &= ~0x38ff0000; + + if (spi->mode & SPI_CPHA) + regval |= SPMODE_CP_BEGIN_EDGECLK; + if (spi->mode & SPI_CPOL) + regval |= SPMODE_CI_INACTIVEHIGH; + + regval |= SPMODE_LEN(len); + + if ((mpc83xx_spi->sysclk / spi->max_speed_hz) >= 64) { + u8 pm = mpc83xx_spi->sysclk / (spi->max_speed_hz * 64); + regval |= SPMODE_PM(pm) | SPMODE_DIV16; + } else { + u8 pm = mpc83xx_spi->sysclk / (spi->max_speed_hz * 4); + regval |= SPMODE_PM(pm); + } + + mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval); + if (mpc83xx_spi->activate_cs) + mpc83xx_spi->activate_cs(spi->chip_select, pol); + } +} + +static +int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) +{ + struct mpc83xx_spi *mpc83xx_spi; + u32 regval; + u8 bits_per_word; + u32 hz; + + mpc83xx_spi = spi_master_get_devdata(spi->master); + + if (t) { + bits_per_word = t->bits_per_word; + hz = t->speed_hz; + } else { + bits_per_word = 0; + hz = 0; + } + + /* spi_transfer level calls that work per-word */ + if (!bits_per_word) + bits_per_word = spi->bits_per_word; + + /* Make sure its a bit width we support [4..16, 32] */ + if ((bits_per_word < 4) + || ((bits_per_word > 16) && (bits_per_word != 32))) + return -EINVAL; + + if (bits_per_word <= 8) { + mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u8; + mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u8; + } else if (bits_per_word <= 16) { + mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u16; + mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u16; + } else if (bits_per_word <= 32) { + mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u32; + mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u32; + } else + return -EINVAL; + + /* nsecs = (clock period)/2 */ + if (!hz) + hz = spi->max_speed_hz; + mpc83xx_spi->nsecs = (1000000000 / 2) / hz; + if (mpc83xx_spi->nsecs > MAX_UDELAY_MS * 1000) + return -EINVAL; + + if (bits_per_word == 32) + bits_per_word = 0; + else + bits_per_word = bits_per_word - 1; + + regval = mpc83xx_spi_read_reg(&mpc83xx_spi->base->mode); + + /* Mask out bits_per_wordgth */ + regval &= 0xff0fffff; + regval |= SPMODE_LEN(bits_per_word); + + mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval); + + return 0; +} + +static int mpc83xx_spi_setup(struct spi_device *spi) +{ + struct spi_bitbang *bitbang; + struct mpc83xx_spi *mpc83xx_spi; + int retval; + + if (!spi->max_speed_hz) + return -EINVAL; + + bitbang = spi_master_get_devdata(spi->master); + mpc83xx_spi = spi_master_get_devdata(spi->master); + + if (!spi->bits_per_word) + spi->bits_per_word = 8; + + retval = mpc83xx_spi_setup_transfer(spi, NULL); + if (retval < 0) + return retval; + + dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n", + __FUNCTION__, spi->mode & (SPI_CPOL | SPI_CPHA), + spi->bits_per_word, 2 * mpc83xx_spi->nsecs); + + /* NOTE we _need_ to call chipselect() early, ideally with adapter + * setup, unless the hardware defaults cooperate to avoid confusion + * between normal (active low) and inverted chipselects. + */ + + /* deselect chip (low or high) */ + spin_lock(&bitbang->lock); + if (!bitbang->busy) { + bitbang->chipselect(spi, BITBANG_CS_INACTIVE); + ndelay(mpc83xx_spi->nsecs); + } + spin_unlock(&bitbang->lock); + + return 0; +} + +static int mpc83xx_spi_bufs(struct spi_device *spi, struct spi_transfer *t) +{ + struct mpc83xx_spi *mpc83xx_spi; + u32 word; + + mpc83xx_spi = spi_master_get_devdata(spi->master); + + mpc83xx_spi->tx = t->tx_buf; + mpc83xx_spi->rx = t->rx_buf; + mpc83xx_spi->count = t->len; + INIT_COMPLETION(mpc83xx_spi->done); + + /* enable rx ints */ + mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, SPIM_NE); + + /* transmit word */ + word = mpc83xx_spi->get_tx(mpc83xx_spi); + mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit, word); + + wait_for_completion(&mpc83xx_spi->done); + + /* disable rx ints */ + mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, 0); + + return t->len - mpc83xx_spi->count; +} + +irqreturn_t mpc83xx_spi_irq(s32 irq, void *context_data, + struct pt_regs * ptregs) +{ + struct mpc83xx_spi *mpc83xx_spi = context_data; + u32 event; + irqreturn_t ret = IRQ_NONE; + + /* Get interrupt events(tx/rx) */ + event = mpc83xx_spi_read_reg(&mpc83xx_spi->base->event); + + /* We need handle RX first */ + if (event & SPIE_NE) { + u32 rx_data = mpc83xx_spi_read_reg(&mpc83xx_spi->base->receive); + + if (mpc83xx_spi->rx) + mpc83xx_spi->get_rx(rx_data, mpc83xx_spi); + + ret = IRQ_HANDLED; + } + + if ((event & SPIE_NF) == 0) + /* spin until TX is done */ + while (((event = + mpc83xx_spi_read_reg(&mpc83xx_spi->base->event)) & + SPIE_NF) == 0) + cpu_relax(); + + mpc83xx_spi->count -= 1; + if (mpc83xx_spi->count) { + if (mpc83xx_spi->tx) { + u32 word = mpc83xx_spi->get_tx(mpc83xx_spi); + mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit, + word); + } + } else { + complete(&mpc83xx_spi->done); + } + + /* Clear the events */ + mpc83xx_spi_write_reg(&mpc83xx_spi->base->event, event); + + return ret; +} + +static int __init mpc83xx_spi_probe(struct platform_device *dev) +{ + struct spi_master *master; + struct mpc83xx_spi *mpc83xx_spi; + struct fsl_spi_platform_data *pdata; + struct resource *r; + u32 regval; + int ret = 0; + + /* Get resources(memory, IRQ) associated with the device */ + master = spi_alloc_master(&dev->dev, sizeof(struct mpc83xx_spi)); + + if (master == NULL) { + ret = -ENOMEM; + goto err; + } + + platform_set_drvdata(dev, master); + pdata = dev->dev.platform_data; + + if (pdata == NULL) { + ret = -ENODEV; + goto free_master; + } + + r = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (r == NULL) { + ret = -ENODEV; + goto free_master; + } + + mpc83xx_spi = spi_master_get_devdata(master); + mpc83xx_spi->bitbang.master = spi_master_get(master); + mpc83xx_spi->bitbang.chipselect = mpc83xx_spi_chipselect; + mpc83xx_spi->bitbang.setup_transfer = mpc83xx_spi_setup_transfer; + mpc83xx_spi->bitbang.txrx_bufs = mpc83xx_spi_bufs; + mpc83xx_spi->sysclk = pdata->sysclk; + mpc83xx_spi->activate_cs = pdata->activate_cs; + mpc83xx_spi->deactivate_cs = pdata->deactivate_cs; + mpc83xx_spi->get_rx = mpc83xx_spi_rx_buf_u8; + mpc83xx_spi->get_tx = mpc83xx_spi_tx_buf_u8; + + mpc83xx_spi->bitbang.master->setup = mpc83xx_spi_setup; + init_completion(&mpc83xx_spi->done); + + mpc83xx_spi->base = ioremap(r->start, r->end - r->start + 1); + if (mpc83xx_spi->base == NULL) { + ret = -ENOMEM; + goto put_master; + } + + mpc83xx_spi->irq = platform_get_irq(dev, 0); + + if (mpc83xx_spi->irq < 0) { + ret = -ENXIO; + goto unmap_io; + } + + /* Register for SPI Interrupt */ + ret = request_irq(mpc83xx_spi->irq, mpc83xx_spi_irq, + 0, "mpc83xx_spi", mpc83xx_spi); + + if (ret != 0) + goto unmap_io; + + master->bus_num = pdata->bus_num; + master->num_chipselect = pdata->max_chipselect; + + /* SPI controller initializations */ + mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, 0); + mpc83xx_spi_write_reg(&mpc83xx_spi->base->mask, 0); + mpc83xx_spi_write_reg(&mpc83xx_spi->base->command, 0); + mpc83xx_spi_write_reg(&mpc83xx_spi->base->event, 0xffffffff); + + /* Enable SPI interface */ + regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE; + mpc83xx_spi_write_reg(&mpc83xx_spi->base->mode, regval); + + ret = spi_bitbang_start(&mpc83xx_spi->bitbang); + + if (ret != 0) + goto free_irq; + + printk(KERN_INFO + "%s: MPC83xx SPI Controller driver at 0x%p (irq = %d)\n", + dev->dev.bus_id, mpc83xx_spi->base, mpc83xx_spi->irq); + + return ret; + +free_irq: + free_irq(mpc83xx_spi->irq, mpc83xx_spi); +unmap_io: + iounmap(mpc83xx_spi->base); +put_master: + spi_master_put(master); +free_master: + kfree(master); +err: + return ret; +} + +static int __devexit mpc83xx_spi_remove(struct platform_device *dev) +{ + struct mpc83xx_spi *mpc83xx_spi; + struct spi_master *master; + + master = platform_get_drvdata(dev); + mpc83xx_spi = spi_master_get_devdata(master); + + spi_bitbang_stop(&mpc83xx_spi->bitbang); + free_irq(mpc83xx_spi->irq, mpc83xx_spi); + iounmap(mpc83xx_spi->base); + spi_master_put(mpc83xx_spi->bitbang.master); + + return 0; +} + +static struct platform_driver mpc83xx_spi_driver = { + .probe = mpc83xx_spi_probe, + .remove = __devexit_p(mpc83xx_spi_remove), + .driver = { + .name = "mpc83xx_spi", + }, +}; + +static int __init mpc83xx_spi_init(void) +{ + return platform_driver_register(&mpc83xx_spi_driver); +} + +static void __exit mpc83xx_spi_exit(void) +{ + platform_driver_unregister(&mpc83xx_spi_driver); +} + +module_init(mpc83xx_spi_init); +module_exit(mpc83xx_spi_exit); + +MODULE_AUTHOR("Kumar Gala"); +MODULE_DESCRIPTION("Simple MPC83xx SPI Driver"); +MODULE_LICENSE("GPL"); |