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linux/drivers/spi/spi-davinci.c
Murali Karicheri e0b047bd8f spi: davinci: change the lower limit of pre-scale divider to 1 
SPI hardware spec for Keystone specify a lower value of 0 for pre-scale
divider which determine what max value of spi clock (spi-max-frequency)
the device can support. This translates to a clock divider of 2. So fix
the lower limit value used for the boundary check in
davinci_spi_get_prescale() function to 1 so that a maximum of spi device
clock rate / 2 is possible to be set for spi-max-frequency.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2015-06-10 18:28:04 +01:00

1127 lines
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/*
* Copyright (C) 2009 Texas Instruments.
* Copyright (C) 2010 EF Johnson Technologies
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/edma.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/slab.h>
#include <linux/platform_data/spi-davinci.h>
#define SPI_NO_RESOURCE ((resource_size_t)-1)
#define CS_DEFAULT 0xFF
#define SPIFMT_PHASE_MASK BIT(16)
#define SPIFMT_POLARITY_MASK BIT(17)
#define SPIFMT_DISTIMER_MASK BIT(18)
#define SPIFMT_SHIFTDIR_MASK BIT(20)
#define SPIFMT_WAITENA_MASK BIT(21)
#define SPIFMT_PARITYENA_MASK BIT(22)
#define SPIFMT_ODD_PARITY_MASK BIT(23)
#define SPIFMT_WDELAY_MASK 0x3f000000u
#define SPIFMT_WDELAY_SHIFT 24
#define SPIFMT_PRESCALE_SHIFT 8
/* SPIPC0 */
#define SPIPC0_DIFUN_MASK BIT(11) /* MISO */
#define SPIPC0_DOFUN_MASK BIT(10) /* MOSI */
#define SPIPC0_CLKFUN_MASK BIT(9) /* CLK */
#define SPIPC0_SPIENA_MASK BIT(8) /* nREADY */
#define SPIINT_MASKALL 0x0101035F
#define SPIINT_MASKINT 0x0000015F
#define SPI_INTLVL_1 0x000001FF
#define SPI_INTLVL_0 0x00000000
/* SPIDAT1 (upper 16 bit defines) */
#define SPIDAT1_CSHOLD_MASK BIT(12)
#define SPIDAT1_WDEL BIT(10)
/* SPIGCR1 */
#define SPIGCR1_CLKMOD_MASK BIT(1)
#define SPIGCR1_MASTER_MASK BIT(0)
#define SPIGCR1_POWERDOWN_MASK BIT(8)
#define SPIGCR1_LOOPBACK_MASK BIT(16)
#define SPIGCR1_SPIENA_MASK BIT(24)
/* SPIBUF */
#define SPIBUF_TXFULL_MASK BIT(29)
#define SPIBUF_RXEMPTY_MASK BIT(31)
/* SPIDELAY */
#define SPIDELAY_C2TDELAY_SHIFT 24
#define SPIDELAY_C2TDELAY_MASK (0xFF << SPIDELAY_C2TDELAY_SHIFT)
#define SPIDELAY_T2CDELAY_SHIFT 16
#define SPIDELAY_T2CDELAY_MASK (0xFF << SPIDELAY_T2CDELAY_SHIFT)
#define SPIDELAY_T2EDELAY_SHIFT 8
#define SPIDELAY_T2EDELAY_MASK (0xFF << SPIDELAY_T2EDELAY_SHIFT)
#define SPIDELAY_C2EDELAY_SHIFT 0
#define SPIDELAY_C2EDELAY_MASK 0xFF
/* Error Masks */
#define SPIFLG_DLEN_ERR_MASK BIT(0)
#define SPIFLG_TIMEOUT_MASK BIT(1)
#define SPIFLG_PARERR_MASK BIT(2)
#define SPIFLG_DESYNC_MASK BIT(3)
#define SPIFLG_BITERR_MASK BIT(4)
#define SPIFLG_OVRRUN_MASK BIT(6)
#define SPIFLG_BUF_INIT_ACTIVE_MASK BIT(24)
#define SPIFLG_ERROR_MASK (SPIFLG_DLEN_ERR_MASK \
| SPIFLG_TIMEOUT_MASK | SPIFLG_PARERR_MASK \
| SPIFLG_DESYNC_MASK | SPIFLG_BITERR_MASK \
| SPIFLG_OVRRUN_MASK)
#define SPIINT_DMA_REQ_EN BIT(16)
/* SPI Controller registers */
#define SPIGCR0 0x00
#define SPIGCR1 0x04
#define SPIINT 0x08
#define SPILVL 0x0c
#define SPIFLG 0x10
#define SPIPC0 0x14
#define SPIDAT1 0x3c
#define SPIBUF 0x40
#define SPIDELAY 0x48
#define SPIDEF 0x4c
#define SPIFMT0 0x50
/* SPI Controller driver's private data. */
struct davinci_spi {
struct spi_bitbang bitbang;
struct clk *clk;
u8 version;
resource_size_t pbase;
void __iomem *base;
u32 irq;
struct completion done;
const void *tx;
void *rx;
int rcount;
int wcount;
struct dma_chan *dma_rx;
struct dma_chan *dma_tx;
int dma_rx_chnum;
int dma_tx_chnum;
struct davinci_spi_platform_data pdata;
void (*get_rx)(u32 rx_data, struct davinci_spi *);
u32 (*get_tx)(struct davinci_spi *);
u8 *bytes_per_word;
};
static struct davinci_spi_config davinci_spi_default_cfg;
static void davinci_spi_rx_buf_u8(u32 data, struct davinci_spi *dspi)
{
if (dspi->rx) {
u8 *rx = dspi->rx;
*rx++ = (u8)data;
dspi->rx = rx;
}
}
static void davinci_spi_rx_buf_u16(u32 data, struct davinci_spi *dspi)
{
if (dspi->rx) {
u16 *rx = dspi->rx;
*rx++ = (u16)data;
dspi->rx = rx;
}
}
static u32 davinci_spi_tx_buf_u8(struct davinci_spi *dspi)
{
u32 data = 0;
if (dspi->tx) {
const u8 *tx = dspi->tx;
data = *tx++;
dspi->tx = tx;
}
return data;
}
static u32 davinci_spi_tx_buf_u16(struct davinci_spi *dspi)
{
u32 data = 0;
if (dspi->tx) {
const u16 *tx = dspi->tx;
data = *tx++;
dspi->tx = tx;
}
return data;
}
static inline void set_io_bits(void __iomem *addr, u32 bits)
{
u32 v = ioread32(addr);
v |= bits;
iowrite32(v, addr);
}
static inline void clear_io_bits(void __iomem *addr, u32 bits)
{
u32 v = ioread32(addr);
v &= ~bits;
iowrite32(v, addr);
}
/*
* Interface to control the chip select signal
*/
static void davinci_spi_chipselect(struct spi_device *spi, int value)
{
struct davinci_spi *dspi;
struct davinci_spi_platform_data *pdata;
struct davinci_spi_config *spicfg = spi->controller_data;
u8 chip_sel = spi->chip_select;
u16 spidat1 = CS_DEFAULT;
bool gpio_chipsel = false;
int gpio;
dspi = spi_master_get_devdata(spi->master);
pdata = &dspi->pdata;
if (spi->cs_gpio >= 0) {
/* SPI core parse and update master->cs_gpio */
gpio_chipsel = true;
gpio = spi->cs_gpio;
}
/* program delay transfers if tx_delay is non zero */
if (spicfg->wdelay)
spidat1 |= SPIDAT1_WDEL;
/*
* Board specific chip select logic decides the polarity and cs
* line for the controller
*/
if (gpio_chipsel) {
if (value == BITBANG_CS_ACTIVE)
gpio_set_value(gpio, spi->mode & SPI_CS_HIGH);
else
gpio_set_value(gpio, !(spi->mode & SPI_CS_HIGH));
} else {
if (value == BITBANG_CS_ACTIVE) {
spidat1 |= SPIDAT1_CSHOLD_MASK;
spidat1 &= ~(0x1 << chip_sel);
}
}
iowrite16(spidat1, dspi->base + SPIDAT1 + 2);
}
/**
* davinci_spi_get_prescale - Calculates the correct prescale value
* @maxspeed_hz: the maximum rate the SPI clock can run at
*
* This function calculates the prescale value that generates a clock rate
* less than or equal to the specified maximum.
*
* Returns: calculated prescale - 1 for easy programming into SPI registers
* or negative error number if valid prescalar cannot be updated.
*/
static inline int davinci_spi_get_prescale(struct davinci_spi *dspi,
u32 max_speed_hz)
{
int ret;
ret = DIV_ROUND_UP(clk_get_rate(dspi->clk), max_speed_hz);
if (ret < 1 || ret > 256)
return -EINVAL;
return ret - 1;
}
/**
* davinci_spi_setup_transfer - This functions will determine transfer method
* @spi: spi device on which data transfer to be done
* @t: spi transfer in which transfer info is filled
*
* This function determines data transfer method (8/16/32 bit transfer).
* It will also set the SPI Clock Control register according to
* SPI slave device freq.
*/
static int davinci_spi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
struct davinci_spi *dspi;
struct davinci_spi_config *spicfg;
u8 bits_per_word = 0;
u32 hz = 0, spifmt = 0;
int prescale;
dspi = spi_master_get_devdata(spi->master);
spicfg = spi->controller_data;
if (!spicfg)
spicfg = &davinci_spi_default_cfg;
if (t) {
bits_per_word = t->bits_per_word;
hz = t->speed_hz;
}
/* if bits_per_word is not set then set it default */
if (!bits_per_word)
bits_per_word = spi->bits_per_word;
/*
* Assign function pointer to appropriate transfer method
* 8bit, 16bit or 32bit transfer
*/
if (bits_per_word <= 8) {
dspi->get_rx = davinci_spi_rx_buf_u8;
dspi->get_tx = davinci_spi_tx_buf_u8;
dspi->bytes_per_word[spi->chip_select] = 1;
} else {
dspi->get_rx = davinci_spi_rx_buf_u16;
dspi->get_tx = davinci_spi_tx_buf_u16;
dspi->bytes_per_word[spi->chip_select] = 2;
}
if (!hz)
hz = spi->max_speed_hz;
/* Set up SPIFMTn register, unique to this chipselect. */
prescale = davinci_spi_get_prescale(dspi, hz);
if (prescale < 0)
return prescale;
spifmt = (prescale << SPIFMT_PRESCALE_SHIFT) | (bits_per_word & 0x1f);
if (spi->mode & SPI_LSB_FIRST)
spifmt |= SPIFMT_SHIFTDIR_MASK;
if (spi->mode & SPI_CPOL)
spifmt |= SPIFMT_POLARITY_MASK;
if (!(spi->mode & SPI_CPHA))
spifmt |= SPIFMT_PHASE_MASK;
/*
* Assume wdelay is used only on SPI peripherals that has this field
* in SPIFMTn register and when it's configured from board file or DT.
*/
if (spicfg->wdelay)
spifmt |= ((spicfg->wdelay << SPIFMT_WDELAY_SHIFT)
& SPIFMT_WDELAY_MASK);
/*
* Version 1 hardware supports two basic SPI modes:
* - Standard SPI mode uses 4 pins, with chipselect
* - 3 pin SPI is a 4 pin variant without CS (SPI_NO_CS)
* (distinct from SPI_3WIRE, with just one data wire;
* or similar variants without MOSI or without MISO)
*
* Version 2 hardware supports an optional handshaking signal,
* so it can support two more modes:
* - 5 pin SPI variant is standard SPI plus SPI_READY
* - 4 pin with enable is (SPI_READY | SPI_NO_CS)
*/
if (dspi->version == SPI_VERSION_2) {
u32 delay = 0;
if (spicfg->odd_parity)
spifmt |= SPIFMT_ODD_PARITY_MASK;
if (spicfg->parity_enable)
spifmt |= SPIFMT_PARITYENA_MASK;
if (spicfg->timer_disable) {
spifmt |= SPIFMT_DISTIMER_MASK;
} else {
delay |= (spicfg->c2tdelay << SPIDELAY_C2TDELAY_SHIFT)
& SPIDELAY_C2TDELAY_MASK;
delay |= (spicfg->t2cdelay << SPIDELAY_T2CDELAY_SHIFT)
& SPIDELAY_T2CDELAY_MASK;
}
if (spi->mode & SPI_READY) {
spifmt |= SPIFMT_WAITENA_MASK;
delay |= (spicfg->t2edelay << SPIDELAY_T2EDELAY_SHIFT)
& SPIDELAY_T2EDELAY_MASK;
delay |= (spicfg->c2edelay << SPIDELAY_C2EDELAY_SHIFT)
& SPIDELAY_C2EDELAY_MASK;
}
iowrite32(delay, dspi->base + SPIDELAY);
}
iowrite32(spifmt, dspi->base + SPIFMT0);
return 0;
}
static int davinci_spi_of_setup(struct spi_device *spi)
{
struct davinci_spi_config *spicfg = spi->controller_data;
struct device_node *np = spi->dev.of_node;
u32 prop;
if (spicfg == NULL && np) {
spicfg = kzalloc(sizeof(*spicfg), GFP_KERNEL);
if (!spicfg)
return -ENOMEM;
*spicfg = davinci_spi_default_cfg;
/* override with dt configured values */
if (!of_property_read_u32(np, "ti,spi-wdelay", &prop))
spicfg->wdelay = (u8)prop;
spi->controller_data = spicfg;
}
return 0;
}
/**
* davinci_spi_setup - This functions will set default transfer method
* @spi: spi device on which data transfer to be done
*
* This functions sets the default transfer method.
*/
static int davinci_spi_setup(struct spi_device *spi)
{
int retval = 0;
struct davinci_spi *dspi;
struct davinci_spi_platform_data *pdata;
struct spi_master *master = spi->master;
struct device_node *np = spi->dev.of_node;
bool internal_cs = true;
dspi = spi_master_get_devdata(spi->master);
pdata = &dspi->pdata;
if (!(spi->mode & SPI_NO_CS)) {
if (np && (master->cs_gpios != NULL) && (spi->cs_gpio >= 0)) {
retval = gpio_direction_output(
spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
internal_cs = false;
} else if (pdata->chip_sel &&
spi->chip_select < pdata->num_chipselect &&
pdata->chip_sel[spi->chip_select] != SPI_INTERN_CS) {
spi->cs_gpio = pdata->chip_sel[spi->chip_select];
retval = gpio_direction_output(
spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
internal_cs = false;
}
if (retval) {
dev_err(&spi->dev, "GPIO %d setup failed (%d)\n",
spi->cs_gpio, retval);
return retval;
}
if (internal_cs)
set_io_bits(dspi->base + SPIPC0, 1 << spi->chip_select);
}
if (spi->mode & SPI_READY)
set_io_bits(dspi->base + SPIPC0, SPIPC0_SPIENA_MASK);
if (spi->mode & SPI_LOOP)
set_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
else
clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_LOOPBACK_MASK);
return davinci_spi_of_setup(spi);
}
static void davinci_spi_cleanup(struct spi_device *spi)
{
struct davinci_spi_config *spicfg = spi->controller_data;
spi->controller_data = NULL;
if (spi->dev.of_node)
kfree(spicfg);
}
static int davinci_spi_check_error(struct davinci_spi *dspi, int int_status)
{
struct device *sdev = dspi->bitbang.master->dev.parent;
if (int_status & SPIFLG_TIMEOUT_MASK) {
dev_dbg(sdev, "SPI Time-out Error\n");
return -ETIMEDOUT;
}
if (int_status & SPIFLG_DESYNC_MASK) {
dev_dbg(sdev, "SPI Desynchronization Error\n");
return -EIO;
}
if (int_status & SPIFLG_BITERR_MASK) {
dev_dbg(sdev, "SPI Bit error\n");
return -EIO;
}
if (dspi->version == SPI_VERSION_2) {
if (int_status & SPIFLG_DLEN_ERR_MASK) {
dev_dbg(sdev, "SPI Data Length Error\n");
return -EIO;
}
if (int_status & SPIFLG_PARERR_MASK) {
dev_dbg(sdev, "SPI Parity Error\n");
return -EIO;
}
if (int_status & SPIFLG_OVRRUN_MASK) {
dev_dbg(sdev, "SPI Data Overrun error\n");
return -EIO;
}
if (int_status & SPIFLG_BUF_INIT_ACTIVE_MASK) {
dev_dbg(sdev, "SPI Buffer Init Active\n");
return -EBUSY;
}
}
return 0;
}
/**
* davinci_spi_process_events - check for and handle any SPI controller events
* @dspi: the controller data
*
* This function will check the SPIFLG register and handle any events that are
* detected there
*/
static int davinci_spi_process_events(struct davinci_spi *dspi)
{
u32 buf, status, errors = 0, spidat1;
buf = ioread32(dspi->base + SPIBUF);
if (dspi->rcount > 0 && !(buf & SPIBUF_RXEMPTY_MASK)) {
dspi->get_rx(buf & 0xFFFF, dspi);
dspi->rcount--;
}
status = ioread32(dspi->base + SPIFLG);
if (unlikely(status & SPIFLG_ERROR_MASK)) {
errors = status & SPIFLG_ERROR_MASK;
goto out;
}
if (dspi->wcount > 0 && !(buf & SPIBUF_TXFULL_MASK)) {
spidat1 = ioread32(dspi->base + SPIDAT1);
dspi->wcount--;
spidat1 &= ~0xFFFF;
spidat1 |= 0xFFFF & dspi->get_tx(dspi);
iowrite32(spidat1, dspi->base + SPIDAT1);
}
out:
return errors;
}
static void davinci_spi_dma_rx_callback(void *data)
{
struct davinci_spi *dspi = (struct davinci_spi *)data;
dspi->rcount = 0;
if (!dspi->wcount && !dspi->rcount)
complete(&dspi->done);
}
static void davinci_spi_dma_tx_callback(void *data)
{
struct davinci_spi *dspi = (struct davinci_spi *)data;
dspi->wcount = 0;
if (!dspi->wcount && !dspi->rcount)
complete(&dspi->done);
}
/**
* davinci_spi_bufs - functions which will handle transfer data
* @spi: spi device on which data transfer to be done
* @t: spi transfer in which transfer info is filled
*
* This function will put data to be transferred into data register
* of SPI controller and then wait until the completion will be marked
* by the IRQ Handler.
*/
static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct davinci_spi *dspi;
int data_type, ret = -ENOMEM;
u32 tx_data, spidat1;
u32 errors = 0;
struct davinci_spi_config *spicfg;
struct davinci_spi_platform_data *pdata;
unsigned uninitialized_var(rx_buf_count);
void *dummy_buf = NULL;
struct scatterlist sg_rx, sg_tx;
dspi = spi_master_get_devdata(spi->master);
pdata = &dspi->pdata;
spicfg = (struct davinci_spi_config *)spi->controller_data;
if (!spicfg)
spicfg = &davinci_spi_default_cfg;
/* convert len to words based on bits_per_word */
data_type = dspi->bytes_per_word[spi->chip_select];
dspi->tx = t->tx_buf;
dspi->rx = t->rx_buf;
dspi->wcount = t->len / data_type;
dspi->rcount = dspi->wcount;
spidat1 = ioread32(dspi->base + SPIDAT1);
clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
set_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
reinit_completion(&dspi->done);
if (spicfg->io_type == SPI_IO_TYPE_INTR)
set_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
if (spicfg->io_type != SPI_IO_TYPE_DMA) {
/* start the transfer */
dspi->wcount--;
tx_data = dspi->get_tx(dspi);
spidat1 &= 0xFFFF0000;
spidat1 |= tx_data & 0xFFFF;
iowrite32(spidat1, dspi->base + SPIDAT1);
} else {
struct dma_slave_config dma_rx_conf = {
.direction = DMA_DEV_TO_MEM,
.src_addr = (unsigned long)dspi->pbase + SPIBUF,
.src_addr_width = data_type,
.src_maxburst = 1,
};
struct dma_slave_config dma_tx_conf = {
.direction = DMA_MEM_TO_DEV,
.dst_addr = (unsigned long)dspi->pbase + SPIDAT1,
.dst_addr_width = data_type,
.dst_maxburst = 1,
};
struct dma_async_tx_descriptor *rxdesc;
struct dma_async_tx_descriptor *txdesc;
void *buf;
dummy_buf = kzalloc(t->len, GFP_KERNEL);
if (!dummy_buf)
goto err_alloc_dummy_buf;
dmaengine_slave_config(dspi->dma_rx, &dma_rx_conf);
dmaengine_slave_config(dspi->dma_tx, &dma_tx_conf);
sg_init_table(&sg_rx, 1);
if (!t->rx_buf)
buf = dummy_buf;
else
buf = t->rx_buf;
t->rx_dma = dma_map_single(&spi->dev, buf,
t->len, DMA_FROM_DEVICE);
if (!t->rx_dma) {
ret = -EFAULT;
goto err_rx_map;
}
sg_dma_address(&sg_rx) = t->rx_dma;
sg_dma_len(&sg_rx) = t->len;
sg_init_table(&sg_tx, 1);
if (!t->tx_buf)
buf = dummy_buf;
else
buf = (void *)t->tx_buf;
t->tx_dma = dma_map_single(&spi->dev, buf,
t->len, DMA_TO_DEVICE);
if (!t->tx_dma) {
ret = -EFAULT;
goto err_tx_map;
}
sg_dma_address(&sg_tx) = t->tx_dma;
sg_dma_len(&sg_tx) = t->len;
rxdesc = dmaengine_prep_slave_sg(dspi->dma_rx,
&sg_rx, 1, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!rxdesc)
goto err_desc;
txdesc = dmaengine_prep_slave_sg(dspi->dma_tx,
&sg_tx, 1, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!txdesc)
goto err_desc;
rxdesc->callback = davinci_spi_dma_rx_callback;
rxdesc->callback_param = (void *)dspi;
txdesc->callback = davinci_spi_dma_tx_callback;
txdesc->callback_param = (void *)dspi;
if (pdata->cshold_bug)
iowrite16(spidat1 >> 16, dspi->base + SPIDAT1 + 2);
dmaengine_submit(rxdesc);
dmaengine_submit(txdesc);
dma_async_issue_pending(dspi->dma_rx);
dma_async_issue_pending(dspi->dma_tx);
set_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
}
/* Wait for the transfer to complete */
if (spicfg->io_type != SPI_IO_TYPE_POLL) {
wait_for_completion_interruptible(&(dspi->done));
} else {
while (dspi->rcount > 0 || dspi->wcount > 0) {
errors = davinci_spi_process_events(dspi);
if (errors)
break;
cpu_relax();
}
}
clear_io_bits(dspi->base + SPIINT, SPIINT_MASKALL);
if (spicfg->io_type == SPI_IO_TYPE_DMA) {
clear_io_bits(dspi->base + SPIINT, SPIINT_DMA_REQ_EN);
dma_unmap_single(&spi->dev, t->rx_dma,
t->len, DMA_FROM_DEVICE);
dma_unmap_single(&spi->dev, t->tx_dma,
t->len, DMA_TO_DEVICE);
kfree(dummy_buf);
}
clear_io_bits(dspi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
/*
* Check for bit error, desync error,parity error,timeout error and
* receive overflow errors
*/
if (errors) {
ret = davinci_spi_check_error(dspi, errors);
WARN(!ret, "%s: error reported but no error found!\n",
dev_name(&spi->dev));
return ret;
}
if (dspi->rcount != 0 || dspi->wcount != 0) {
dev_err(&spi->dev, "SPI data transfer error\n");
return -EIO;
}
return t->len;
err_desc:
dma_unmap_single(&spi->dev, t->tx_dma, t->len, DMA_TO_DEVICE);
err_tx_map:
dma_unmap_single(&spi->dev, t->rx_dma, t->len, DMA_FROM_DEVICE);
err_rx_map:
kfree(dummy_buf);
err_alloc_dummy_buf:
return ret;
}
/**
* dummy_thread_fn - dummy thread function
* @irq: IRQ number for this SPI Master
* @context_data: structure for SPI Master controller davinci_spi
*
* This is to satisfy the request_threaded_irq() API so that the irq
* handler is called in interrupt context.
*/
static irqreturn_t dummy_thread_fn(s32 irq, void *data)
{
return IRQ_HANDLED;
}
/**
* davinci_spi_irq - Interrupt handler for SPI Master Controller
* @irq: IRQ number for this SPI Master
* @context_data: structure for SPI Master controller davinci_spi
*
* ISR will determine that interrupt arrives either for READ or WRITE command.
* According to command it will do the appropriate action. It will check
* transfer length and if it is not zero then dispatch transfer command again.
* If transfer length is zero then it will indicate the COMPLETION so that
* davinci_spi_bufs function can go ahead.
*/
static irqreturn_t davinci_spi_irq(s32 irq, void *data)
{
struct davinci_spi *dspi = data;
int status;
status = davinci_spi_process_events(dspi);
if (unlikely(status != 0))
clear_io_bits(dspi->base + SPIINT, SPIINT_MASKINT);
if ((!dspi->rcount && !dspi->wcount) || status)
complete(&dspi->done);
return IRQ_HANDLED;
}
static int davinci_spi_request_dma(struct davinci_spi *dspi)
{
dma_cap_mask_t mask;
struct device *sdev = dspi->bitbang.master->dev.parent;
int r;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
dspi->dma_rx = dma_request_channel(mask, edma_filter_fn,
&dspi->dma_rx_chnum);
if (!dspi->dma_rx) {
dev_err(sdev, "request RX DMA channel failed\n");
r = -ENODEV;
goto rx_dma_failed;
}
dspi->dma_tx = dma_request_channel(mask, edma_filter_fn,
&dspi->dma_tx_chnum);
if (!dspi->dma_tx) {
dev_err(sdev, "request TX DMA channel failed\n");
r = -ENODEV;
goto tx_dma_failed;
}
return 0;
tx_dma_failed:
dma_release_channel(dspi->dma_rx);
rx_dma_failed:
return r;
}
#if defined(CONFIG_OF)
static const struct of_device_id davinci_spi_of_match[] = {
{
.compatible = "ti,dm6441-spi",
},
{
.compatible = "ti,da830-spi",
.data = (void *)SPI_VERSION_2,
},
{ },
};
MODULE_DEVICE_TABLE(of, davinci_spi_of_match);
/**
* spi_davinci_get_pdata - Get platform data from DTS binding
* @pdev: ptr to platform data
* @dspi: ptr to driver data
*
* Parses and populates pdata in dspi from device tree bindings.
*
* NOTE: Not all platform data params are supported currently.
*/
static int spi_davinci_get_pdata(struct platform_device *pdev,
struct davinci_spi *dspi)
{
struct device_node *node = pdev->dev.of_node;
struct davinci_spi_platform_data *pdata;
unsigned int num_cs, intr_line = 0;
const struct of_device_id *match;
pdata = &dspi->pdata;
pdata->version = SPI_VERSION_1;
match = of_match_device(davinci_spi_of_match, &pdev->dev);
if (!match)
return -ENODEV;
/* match data has the SPI version number for SPI_VERSION_2 */
if (match->data == (void *)SPI_VERSION_2)
pdata->version = SPI_VERSION_2;
/*
* default num_cs is 1 and all chipsel are internal to the chip
* indicated by chip_sel being NULL or cs_gpios being NULL or
* set to -ENOENT. num-cs includes internal as well as gpios.
* indicated by chip_sel being NULL. GPIO based CS is not
* supported yet in DT bindings.
*/
num_cs = 1;
of_property_read_u32(node, "num-cs", &num_cs);
pdata->num_chipselect = num_cs;
of_property_read_u32(node, "ti,davinci-spi-intr-line", &intr_line);
pdata->intr_line = intr_line;
return 0;
}
#else
static struct davinci_spi_platform_data
*spi_davinci_get_pdata(struct platform_device *pdev,
struct davinci_spi *dspi)
{
return -ENODEV;
}
#endif
/**
* davinci_spi_probe - probe function for SPI Master Controller
* @pdev: platform_device structure which contains plateform specific data
*
* According to Linux Device Model this function will be invoked by Linux
* with platform_device struct which contains the device specific info.
* This function will map the SPI controller's memory, register IRQ,
* Reset SPI controller and setting its registers to default value.
* It will invoke spi_bitbang_start to create work queue so that client driver
* can register transfer method to work queue.
*/
static int davinci_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct davinci_spi *dspi;
struct davinci_spi_platform_data *pdata;
struct resource *r;
resource_size_t dma_rx_chan = SPI_NO_RESOURCE;
resource_size_t dma_tx_chan = SPI_NO_RESOURCE;
int ret = 0;
u32 spipc0;
master = spi_alloc_master(&pdev->dev, sizeof(struct davinci_spi));
if (master == NULL) {
ret = -ENOMEM;
goto err;
}
platform_set_drvdata(pdev, master);
dspi = spi_master_get_devdata(master);
if (dev_get_platdata(&pdev->dev)) {
pdata = dev_get_platdata(&pdev->dev);
dspi->pdata = *pdata;
} else {
/* update dspi pdata with that from the DT */
ret = spi_davinci_get_pdata(pdev, dspi);
if (ret < 0)
goto free_master;
}
/* pdata in dspi is now updated and point pdata to that */
pdata = &dspi->pdata;
dspi->bytes_per_word = devm_kzalloc(&pdev->dev,
sizeof(*dspi->bytes_per_word) *
pdata->num_chipselect, GFP_KERNEL);
if (dspi->bytes_per_word == NULL) {
ret = -ENOMEM;
goto free_master;
}
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (r == NULL) {
ret = -ENOENT;
goto free_master;
}
dspi->pbase = r->start;
dspi->base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(dspi->base)) {
ret = PTR_ERR(dspi->base);
goto free_master;
}
dspi->irq = platform_get_irq(pdev, 0);
if (dspi->irq <= 0) {
ret = -EINVAL;
goto free_master;
}
ret = devm_request_threaded_irq(&pdev->dev, dspi->irq, davinci_spi_irq,
dummy_thread_fn, 0, dev_name(&pdev->dev), dspi);
if (ret)
goto free_master;
dspi->bitbang.master = master;
dspi->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(dspi->clk)) {
ret = -ENODEV;
goto free_master;
}
clk_prepare_enable(dspi->clk);
master->dev.of_node = pdev->dev.of_node;
master->bus_num = pdev->id;
master->num_chipselect = pdata->num_chipselect;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 16);
master->setup = davinci_spi_setup;
master->cleanup = davinci_spi_cleanup;
dspi->bitbang.chipselect = davinci_spi_chipselect;
dspi->bitbang.setup_transfer = davinci_spi_setup_transfer;
dspi->version = pdata->version;
dspi->bitbang.flags = SPI_NO_CS | SPI_LSB_FIRST | SPI_LOOP;
if (dspi->version == SPI_VERSION_2)
dspi->bitbang.flags |= SPI_READY;
if (pdev->dev.of_node) {
int i;
for (i = 0; i < pdata->num_chipselect; i++) {
int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
"cs-gpios", i);
if (cs_gpio == -EPROBE_DEFER) {
ret = cs_gpio;
goto free_clk;
}
if (gpio_is_valid(cs_gpio)) {
ret = devm_gpio_request(&pdev->dev, cs_gpio,
dev_name(&pdev->dev));
if (ret)
goto free_clk;
}
}
}
r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (r)
dma_rx_chan = r->start;
r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
if (r)
dma_tx_chan = r->start;
dspi->bitbang.txrx_bufs = davinci_spi_bufs;
if (dma_rx_chan != SPI_NO_RESOURCE &&
dma_tx_chan != SPI_NO_RESOURCE) {
dspi->dma_rx_chnum = dma_rx_chan;
dspi->dma_tx_chnum = dma_tx_chan;
ret = davinci_spi_request_dma(dspi);
if (ret)
goto free_clk;
dev_info(&pdev->dev, "DMA: supported\n");
dev_info(&pdev->dev, "DMA: RX channel: %pa, TX channel: %pa, event queue: %d\n",
&dma_rx_chan, &dma_tx_chan,
pdata->dma_event_q);
}
dspi->get_rx = davinci_spi_rx_buf_u8;
dspi->get_tx = davinci_spi_tx_buf_u8;
init_completion(&dspi->done);
/* Reset In/OUT SPI module */
iowrite32(0, dspi->base + SPIGCR0);
udelay(100);
iowrite32(1, dspi->base + SPIGCR0);
/* Set up SPIPC0. CS and ENA init is done in davinci_spi_setup */
spipc0 = SPIPC0_DIFUN_MASK | SPIPC0_DOFUN_MASK | SPIPC0_CLKFUN_MASK;
iowrite32(spipc0, dspi->base + SPIPC0);
if (pdata->intr_line)
iowrite32(SPI_INTLVL_1, dspi->base + SPILVL);
else
iowrite32(SPI_INTLVL_0, dspi->base + SPILVL);
iowrite32(CS_DEFAULT, dspi->base + SPIDEF);
/* master mode default */
set_io_bits(dspi->base + SPIGCR1, SPIGCR1_CLKMOD_MASK);
set_io_bits(dspi->base + SPIGCR1, SPIGCR1_MASTER_MASK);
set_io_bits(dspi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
ret = spi_bitbang_start(&dspi->bitbang);
if (ret)
goto free_dma;
dev_info(&pdev->dev, "Controller at 0x%p\n", dspi->base);
return ret;
free_dma:
dma_release_channel(dspi->dma_rx);
dma_release_channel(dspi->dma_tx);
free_clk:
clk_disable_unprepare(dspi->clk);
free_master:
spi_master_put(master);
err:
return ret;
}
/**
* davinci_spi_remove - remove function for SPI Master Controller
* @pdev: platform_device structure which contains plateform specific data
*
* This function will do the reverse action of davinci_spi_probe function
* It will free the IRQ and SPI controller's memory region.
* It will also call spi_bitbang_stop to destroy the work queue which was
* created by spi_bitbang_start.
*/
static int davinci_spi_remove(struct platform_device *pdev)
{
struct davinci_spi *dspi;
struct spi_master *master;
master = platform_get_drvdata(pdev);
dspi = spi_master_get_devdata(master);
spi_bitbang_stop(&dspi->bitbang);
clk_disable_unprepare(dspi->clk);
spi_master_put(master);
return 0;
}
static struct platform_driver davinci_spi_driver = {
.driver = {
.name = "spi_davinci",
.of_match_table = of_match_ptr(davinci_spi_of_match),
},
.probe = davinci_spi_probe,
.remove = davinci_spi_remove,
};
module_platform_driver(davinci_spi_driver);
MODULE_DESCRIPTION("TI DaVinci SPI Master Controller Driver");
MODULE_LICENSE("GPL");
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