spi: pxa2xx: Add slave mode support

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>

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index d46af11..a057c3b 100644 (file)
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -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;
        }

diff --git a/include/linux/spi/pxa2xx_spi.h b/include/linux/spi/pxa2xx_spi.h
index 9ec4c14..b0674e3 100644 (file)
--- a/include/linux/spi/pxa2xx_spi.h
+++ b/include/linux/spi/pxa2xx_spi.h
@@ -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);