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spi: spi-pxa2xx: SPI support for Intel Quark X1000
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There are two SPI controllers exported by PCI subsystem for Intel Quark X1000.
The SPI memory mapped I/O registers supported by Quark are different from
the current implementation, and Quark only supports the registers of 'SSCR0',
'SSCR1', 'SSSR', 'SSDR', and 'DDS_RATE'. This patch is to enable the SPI for
Intel Quark X1000.

This piece of work is derived from Dan O'Donovan's initial work for Intel Quark
X1000 SPI enabling.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Weike Chen <alvin.chen@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Weike Chen authored and Mark Brown committed Nov 26, 2014
1 parent 4fdb242 commit e5262d0
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Showing 4 changed files with 219 additions and 22 deletions.
8 changes: 8 additions & 0 deletions drivers/spi/spi-pxa2xx-pci.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ enum {
PORT_BSW0,
PORT_BSW1,
PORT_BSW2,
PORT_QUARK_X1000,
};

struct pxa_spi_info {
Expand Down Expand Up @@ -92,6 +93,12 @@ static struct pxa_spi_info spi_info_configs[] = {
.tx_param = &bsw2_tx_param,
.rx_param = &bsw2_rx_param,
},
[PORT_QUARK_X1000] = {
.type = QUARK_X1000_SSP,
.port_id = -1,
.num_chipselect = 1,
.max_clk_rate = 50000000,
},
};

static int pxa2xx_spi_pci_probe(struct pci_dev *dev,
Expand Down Expand Up @@ -191,6 +198,7 @@ static void pxa2xx_spi_pci_remove(struct pci_dev *dev)

static const struct pci_device_id pxa2xx_spi_pci_devices[] = {
{ PCI_VDEVICE(INTEL, 0x2e6a), PORT_CE4100 },
{ PCI_VDEVICE(INTEL, 0x0935), PORT_QUARK_X1000 },
{ PCI_VDEVICE(INTEL, 0x0f0e), PORT_BYT },
{ PCI_VDEVICE(INTEL, 0x228e), PORT_BSW0 },
{ PCI_VDEVICE(INTEL, 0x2290), PORT_BSW1 },
Expand Down
197 changes: 180 additions & 17 deletions drivers/spi/spi-pxa2xx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -63,10 +63,64 @@ MODULE_ALIAS("platform:pxa2xx-spi");
| SSCR1_RFT | SSCR1_TFT | SSCR1_MWDS \
| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)

#define QUARK_X1000_SSCR1_CHANGE_MASK (QUARK_X1000_SSCR1_STRF \
| QUARK_X1000_SSCR1_EFWR \
| QUARK_X1000_SSCR1_RFT \
| QUARK_X1000_SSCR1_TFT \
| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)

#define LPSS_RX_THRESH_DFLT 64
#define LPSS_TX_LOTHRESH_DFLT 160
#define LPSS_TX_HITHRESH_DFLT 224

struct quark_spi_rate {
u32 bitrate;
u32 dds_clk_rate;
u32 clk_div;
};

/*
* 'rate', 'dds', 'clk_div' lookup table, which is defined in
* the Quark SPI datasheet.
*/
static const struct quark_spi_rate quark_spi_rate_table[] = {
/* bitrate, dds_clk_rate, clk_div */
{50000000, 0x800000, 0},
{40000000, 0x666666, 0},
{25000000, 0x400000, 0},
{20000000, 0x666666, 1},
{16667000, 0x800000, 2},
{13333000, 0x666666, 2},
{12500000, 0x200000, 0},
{10000000, 0x800000, 4},
{8000000, 0x666666, 4},
{6250000, 0x400000, 3},
{5000000, 0x400000, 4},
{4000000, 0x666666, 9},
{3125000, 0x80000, 0},
{2500000, 0x400000, 9},
{2000000, 0x666666, 19},
{1563000, 0x40000, 0},
{1250000, 0x200000, 9},
{1000000, 0x400000, 24},
{800000, 0x666666, 49},
{781250, 0x20000, 0},
{625000, 0x200000, 19},
{500000, 0x400000, 49},
{400000, 0x666666, 99},
{390625, 0x10000, 0},
{250000, 0x400000, 99},
{200000, 0x666666, 199},
{195313, 0x8000, 0},
{125000, 0x100000, 49},
{100000, 0x200000, 124},
{50000, 0x100000, 124},
{25000, 0x80000, 124},
{10016, 0x20000, 77},
{5040, 0x20000, 154},
{1002, 0x8000, 194},
};

/* Offset from drv_data->lpss_base */
#define GENERAL_REG 0x08
#define GENERAL_REG_RXTO_HOLDOFF_DISABLE BIT(24)
Expand All @@ -80,9 +134,16 @@ static bool is_lpss_ssp(const struct driver_data *drv_data)
return drv_data->ssp_type == LPSS_SSP;
}

static bool is_quark_x1000_ssp(const struct driver_data *drv_data)
{
return drv_data->ssp_type == QUARK_X1000_SSP;
}

static u32 pxa2xx_spi_get_ssrc1_change_mask(const struct driver_data *drv_data)
{
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
return QUARK_X1000_SSCR1_CHANGE_MASK;
default:
return SSCR1_CHANGE_MASK;
}
Expand All @@ -92,6 +153,8 @@ static u32
pxa2xx_spi_get_rx_default_thre(const struct driver_data *drv_data)
{
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
return RX_THRESH_QUARK_X1000_DFLT;
default:
return RX_THRESH_DFLT;
}
Expand All @@ -103,6 +166,9 @@ static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
u32 mask;

switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
mask = QUARK_X1000_SSSR_TFL_MASK;
break;
default:
mask = SSSR_TFL_MASK;
break;
Expand All @@ -117,6 +183,9 @@ static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
u32 mask;

switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
mask = QUARK_X1000_SSCR1_RFT;
break;
default:
mask = SSCR1_RFT;
break;
Expand All @@ -128,6 +197,9 @@ static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
u32 *sccr1_reg, u32 threshold)
{
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
*sccr1_reg |= QUARK_X1000_SSCR1_RxTresh(threshold);
break;
default:
*sccr1_reg |= SSCR1_RxTresh(threshold);
break;
Expand All @@ -138,6 +210,11 @@ static u32 pxa2xx_configure_sscr0(const struct driver_data *drv_data,
u32 clk_div, u8 bits)
{
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
return clk_div
| QUARK_X1000_SSCR0_Motorola
| QUARK_X1000_SSCR0_DataSize(bits > 32 ? 8 : bits)
| SSCR0_SSE;
default:
return clk_div
| SSCR0_Motorola
Expand Down Expand Up @@ -654,6 +731,28 @@ static irqreturn_t ssp_int(int irq, void *dev_id)
return drv_data->transfer_handler(drv_data);
}

/*
* The Quark SPI data sheet gives a table, and for the given 'rate',
* the 'dds' and 'clk_div' can be found in the table.
*/
static u32 quark_x1000_set_clk_regvals(u32 rate, u32 *dds, u32 *clk_div)
{
unsigned int i;

for (i = 0; i < ARRAY_SIZE(quark_spi_rate_table); i++) {
if (rate >= quark_spi_rate_table[i].bitrate) {
*dds = quark_spi_rate_table[i].dds_clk_rate;
*clk_div = quark_spi_rate_table[i].clk_div;
return quark_spi_rate_table[i].bitrate;
}
}

*dds = quark_spi_rate_table[i-1].dds_clk_rate;
*clk_div = quark_spi_rate_table[i-1].clk_div;

return quark_spi_rate_table[i-1].bitrate;
}

static unsigned int ssp_get_clk_div(struct driver_data *drv_data, int rate)
{
unsigned long ssp_clk = drv_data->max_clk_rate;
Expand All @@ -667,6 +766,20 @@ static unsigned int ssp_get_clk_div(struct driver_data *drv_data, int rate)
return ((ssp_clk / rate - 1) & 0xfff) << 8;
}

static unsigned int pxa2xx_ssp_get_clk_div(struct driver_data *drv_data,
struct chip_data *chip, int rate)
{
u32 clk_div;

switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
quark_x1000_set_clk_regvals(rate, &chip->dds_rate, &clk_div);
return clk_div << 8;
default:
return ssp_get_clk_div(drv_data, rate);
}
}

static void pump_transfers(unsigned long data)
{
struct driver_data *drv_data = (struct driver_data *)data;
Expand Down Expand Up @@ -769,7 +882,7 @@ static void pump_transfers(unsigned long data)
if (transfer->bits_per_word)
bits = transfer->bits_per_word;

clk_div = ssp_get_clk_div(drv_data, speed);
clk_div = pxa2xx_ssp_get_clk_div(drv_data, chip, speed);

if (bits <= 8) {
drv_data->n_bytes = 1;
Expand Down Expand Up @@ -837,6 +950,10 @@ static void pump_transfers(unsigned long data)
write_SSITF(chip->lpss_tx_threshold, reg);
}

if (is_quark_x1000_ssp(drv_data) &&
(read_DDS_RATE(reg) != chip->dds_rate))
write_DDS_RATE(chip->dds_rate, reg);

/* see if we need to reload the config registers */
if ((read_SSCR0(reg) != cr0) ||
(read_SSCR1(reg) & change_mask) != (cr1 & change_mask)) {
Expand Down Expand Up @@ -940,14 +1057,22 @@ static int setup(struct spi_device *spi)
unsigned int clk_div;
uint tx_thres, tx_hi_thres, rx_thres;

if (is_lpss_ssp(drv_data)) {
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
tx_thres = TX_THRESH_QUARK_X1000_DFLT;
tx_hi_thres = 0;
rx_thres = RX_THRESH_QUARK_X1000_DFLT;
break;
case LPSS_SSP:
tx_thres = LPSS_TX_LOTHRESH_DFLT;
tx_hi_thres = LPSS_TX_HITHRESH_DFLT;
rx_thres = LPSS_RX_THRESH_DFLT;
} else {
break;
default:
tx_thres = TX_THRESH_DFLT;
tx_hi_thres = 0;
rx_thres = RX_THRESH_DFLT;
break;
}

/* Only alloc on first setup */
Expand Down Expand Up @@ -1000,9 +1125,6 @@ static int setup(struct spi_device *spi)
chip->enable_dma = drv_data->master_info->enable_dma;
}

chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
(SSCR1_TxTresh(tx_thres) & SSCR1_TFT);

chip->lpss_rx_threshold = SSIRF_RxThresh(rx_thres);
chip->lpss_tx_threshold = SSITF_TxLoThresh(tx_thres)
| SSITF_TxHiThresh(tx_hi_thres);
Expand All @@ -1021,11 +1143,24 @@ static int setup(struct spi_device *spi)
}
}

clk_div = ssp_get_clk_div(drv_data, spi->max_speed_hz);
clk_div = pxa2xx_ssp_get_clk_div(drv_data, chip, spi->max_speed_hz);
chip->speed_hz = spi->max_speed_hz;

chip->cr0 = pxa2xx_configure_sscr0(drv_data, clk_div,
spi->bits_per_word);
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
chip->threshold = (QUARK_X1000_SSCR1_RxTresh(rx_thres)
& QUARK_X1000_SSCR1_RFT)
| (QUARK_X1000_SSCR1_TxTresh(tx_thres)
& QUARK_X1000_SSCR1_TFT);
break;
default:
chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
(SSCR1_TxTresh(tx_thres) & SSCR1_TFT);
break;
}

chip->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
| (((spi->mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);
Expand Down Expand Up @@ -1054,7 +1189,8 @@ static int setup(struct spi_device *spi)
chip->read = u16_reader;
chip->write = u16_writer;
} else if (spi->bits_per_word <= 32) {
chip->cr0 |= SSCR0_EDSS;
if (!is_quark_x1000_ssp(drv_data))
chip->cr0 |= SSCR0_EDSS;
chip->n_bytes = 4;
chip->read = u32_reader;
chip->write = u32_writer;
Expand Down Expand Up @@ -1205,7 +1341,15 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
drv_data->ioaddr = ssp->mmio_base;
drv_data->ssdr_physical = ssp->phys_base + SSDR;
if (pxa25x_ssp_comp(drv_data)) {
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
break;
default:
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
break;
}

drv_data->int_cr1 = SSCR1_TIE | SSCR1_RIE;
drv_data->dma_cr1 = 0;
drv_data->clear_sr = SSSR_ROR;
Expand Down Expand Up @@ -1243,16 +1387,35 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)

/* Load default SSP configuration */
write_SSCR0(0, drv_data->ioaddr);
write_SSCR1(SSCR1_RxTresh(RX_THRESH_DFLT) |
SSCR1_TxTresh(TX_THRESH_DFLT),
drv_data->ioaddr);
write_SSCR0(SSCR0_SCR(2)
| SSCR0_Motorola
| SSCR0_DataSize(8),
drv_data->ioaddr);
switch (drv_data->ssp_type) {
case QUARK_X1000_SSP:
write_SSCR1(QUARK_X1000_SSCR1_RxTresh(
RX_THRESH_QUARK_X1000_DFLT) |
QUARK_X1000_SSCR1_TxTresh(
TX_THRESH_QUARK_X1000_DFLT),
drv_data->ioaddr);

/* using the Motorola SPI protocol and use 8 bit frame */
write_SSCR0(QUARK_X1000_SSCR0_Motorola
| QUARK_X1000_SSCR0_DataSize(8),
drv_data->ioaddr);
break;
default:
write_SSCR1(SSCR1_RxTresh(RX_THRESH_DFLT) |
SSCR1_TxTresh(TX_THRESH_DFLT),
drv_data->ioaddr);
write_SSCR0(SSCR0_SCR(2)
| SSCR0_Motorola
| SSCR0_DataSize(8),
drv_data->ioaddr);
break;
}

if (!pxa25x_ssp_comp(drv_data))
write_SSTO(0, drv_data->ioaddr);
write_SSPSP(0, drv_data->ioaddr);

if (!is_quark_x1000_ssp(drv_data))
write_SSPSP(0, drv_data->ioaddr);

lpss_ssp_setup(drv_data);

Expand Down
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