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spi: pxa2xx: Add slave mode support

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Tested on an OLPC XO-1.75 machine, where the Embedded Controller happens
to be a SPI master.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Lubomir Rintel 2018-11-13 11:22:25 +01:00 • committed by Mark Brown
parent 810923f3bf
commit ec93cb6f82
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
2 changed files with 75 additions and 7 deletions
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81
drivers/spi/spi-pxa2xx.c
View file

@ -626,6 +626,11 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
return IRQ_HANDLED;
}
if (irq_status & SSSR_TUR) {
int_error_stop(drv_data, "interrupt_transfer: fifo underrun");
return IRQ_HANDLED;
}
if (irq_status & SSSR_TINT) {
pxa2xx_spi_write(drv_data, SSSR, SSSR_TINT);
if (drv_data->read(drv_data)) {
@ -1073,6 +1078,11 @@ static int pxa2xx_spi_transfer_one(struct spi_controller *master,
pxa2xx_spi_write(drv_data, SSTO, chip->timeout);
}
if (spi_controller_is_slave(master)) {
while (drv_data->write(drv_data))
;
}
/*
* Release the data by enabling service requests and interrupts,
* without changing any mode bits
@ -1082,6 +1092,27 @@ static int pxa2xx_spi_transfer_one(struct spi_controller *master,
return 1;
}
static int pxa2xx_spi_slave_abort(struct spi_master *master)
{
struct driver_data *drv_data = spi_controller_get_devdata(master);
/* Stop and reset SSP */
write_SSSR_CS(drv_data, drv_data->clear_sr);
reset_sccr1(drv_data);
if (!pxa25x_ssp_comp(drv_data))
pxa2xx_spi_write(drv_data, SSTO, 0);
pxa2xx_spi_flush(drv_data);
pxa2xx_spi_write(drv_data, SSCR0,
pxa2xx_spi_read(drv_data, SSCR0) & ~SSCR0_SSE);
dev_dbg(&drv_data->pdev->dev, "transfer aborted\n");
drv_data->master->cur_msg->status = -EINTR;
spi_finalize_current_transfer(drv_data->master);
return 0;
}
static void pxa2xx_spi_handle_err(struct spi_controller *master,
struct spi_message *msg)
{
@ -1209,9 +1240,14 @@ static int setup(struct spi_device *spi)
rx_thres = config->rx_threshold;
break;
default:
tx_thres = TX_THRESH_DFLT;
tx_hi_thres = 0;
rx_thres = RX_THRESH_DFLT;
if (spi_controller_is_slave(drv_data->master)) {
tx_thres = 1;
rx_thres = 2;
} else {
tx_thres = TX_THRESH_DFLT;
rx_thres = RX_THRESH_DFLT;
}
break;
}
@ -1255,6 +1291,12 @@ static int setup(struct spi_device *spi)
if (chip_info->enable_loopback)
chip->cr1 = SSCR1_LBM;
}
if (spi_controller_is_slave(drv_data->master)) {
chip->cr1 |= SSCR1_SCFR;
chip->cr1 |= SSCR1_SCLKDIR;
chip->cr1 |= SSCR1_SFRMDIR;
chip->cr1 |= SSCR1_SPH;
}
chip->lpss_rx_threshold = SSIRF_RxThresh(rx_thres);
chip->lpss_tx_threshold = SSITF_TxLoThresh(tx_thres)
@ -1494,6 +1536,13 @@ pxa2xx_spi_init_pdata(struct platform_device *pdev)
}
#endif
#if CONFIG_OF
if (of_id) {
pdata->is_slave = of_property_read_bool(pdev->dev.of_node,
"spi-slave");
}
#endif
ssp->clk = devm_clk_get(&pdev->dev, NULL);
ssp->irq = platform_get_irq(pdev, 0);
ssp->type = type;
@ -1559,7 +1608,11 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
return -ENODEV;
}
master = spi_alloc_master(dev, sizeof(struct driver_data));
if (platform_info->is_slave)
master = spi_alloc_slave(dev, sizeof(struct driver_data));
else
master = spi_alloc_master(dev, sizeof(struct driver_data));
if (!master) {
dev_err(&pdev->dev, "cannot alloc spi_master\n");
pxa_ssp_free(ssp);
@ -1581,6 +1634,7 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
master->setup = setup;
master->set_cs = pxa2xx_spi_set_cs;
master->transfer_one = pxa2xx_spi_transfer_one;
master->slave_abort = pxa2xx_spi_slave_abort;
master->handle_err = pxa2xx_spi_handle_err;
master->unprepare_transfer_hardware = pxa2xx_spi_unprepare_transfer;
master->fw_translate_cs = pxa2xx_spi_fw_translate_cs;
@ -1610,7 +1664,8 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
drv_data->int_cr1 = SSCR1_TIE | SSCR1_RIE | SSCR1_TINTE;
drv_data->dma_cr1 = DEFAULT_DMA_CR1;
drv_data->clear_sr = SSSR_ROR | SSSR_TINT;
drv_data->mask_sr = SSSR_TINT | SSSR_RFS | SSSR_TFS | SSSR_ROR;
drv_data->mask_sr = SSSR_TINT | SSSR_RFS | SSSR_TFS
| SSSR_ROR | SSSR_TUR;
}
status = request_irq(ssp->irq, ssp_int, IRQF_SHARED, dev_name(dev),
@ -1658,10 +1713,22 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
pxa2xx_spi_write(drv_data, SSCR0, tmp);
break;
default:
tmp = SSCR1_RxTresh(RX_THRESH_DFLT) |
SSCR1_TxTresh(TX_THRESH_DFLT);
if (spi_controller_is_slave(master)) {
tmp = SSCR1_SCFR |
SSCR1_SCLKDIR |
SSCR1_SFRMDIR |
SSCR1_RxTresh(2) |
SSCR1_TxTresh(1) |
SSCR1_SPH;
} else {
tmp = SSCR1_RxTresh(RX_THRESH_DFLT) |
SSCR1_TxTresh(TX_THRESH_DFLT);
}
pxa2xx_spi_write(drv_data, SSCR1, tmp);
tmp = SSCR0_SCR(2) | SSCR0_Motorola | SSCR0_DataSize(8);
tmp = SSCR0_Motorola | SSCR0_DataSize(8);
if (!spi_controller_is_slave(master))
tmp |= SSCR0_SCR(2);
pxa2xx_spi_write(drv_data, SSCR0, tmp);
break;
}

1
include/linux/spi/pxa2xx_spi.h
View file

@ -25,6 +25,7 @@ struct dma_chan;
struct pxa2xx_spi_master {
u16 num_chipselect;
u8 enable_dma;
bool is_slave;
/* DMA engine specific config */
bool (*dma_filter)(struct dma_chan *chan, void *param);