/* * 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; \ if (!tx) \ return 0; \ 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 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");