spi: spi-rockchip: add support for spi slave mode

Add support for spi slave mode in spi-rockchip. The register map has an entry
for it. If spi-slave is set in dts, set this corresponding bit and add to
mode_bits the SPI_NO_CS, allow slave mode without explicit CS use.
Slave abort function had been added.

Signed-off-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Link: https://lore.kernel.org/r/20200511083022.23678-3-chris.ruehl@gtsys.com.hk
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index c501d8a84414bba3f9c394492a745556d4126d4f..f57a8faa6f31093ff2e7b29359cd114a94b5652a 100644 (file)
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -183,6 +183,8 @@ struct rockchip_spi {
        u8 rsd;
 
        bool cs_asserted[ROCKCHIP_SPI_MAX_CS_NUM];
+
+       bool slave_abort;
 };
 
 static inline void spi_enable_chip(struct rockchip_spi *rs, bool enable)
@@ -359,7 +361,7 @@ static void rockchip_spi_dma_rxcb(void *data)
        struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
        int state = atomic_fetch_andnot(RXDMA, &rs->state);
 
-       if (state & TXDMA)
+       if (state & TXDMA && !rs->slave_abort)
                return;
 
        spi_enable_chip(rs, false);
@@ -372,7 +374,7 @@ static void rockchip_spi_dma_txcb(void *data)
        struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
        int state = atomic_fetch_andnot(TXDMA, &rs->state);
 
-       if (state & RXDMA)
+       if (state & RXDMA && !rs->slave_abort)
                return;
 
        /* Wait until the FIFO data completely. */
@@ -457,7 +459,7 @@ static int rockchip_spi_prepare_dma(struct rockchip_spi *rs,
 
 static void rockchip_spi_config(struct rockchip_spi *rs,
                struct spi_device *spi, struct spi_transfer *xfer,
-               bool use_dma)
+               bool use_dma, bool slave_mode)
 {
        u32 cr0 = CR0_FRF_SPI  << CR0_FRF_OFFSET
                | CR0_BHT_8BIT << CR0_BHT_OFFSET
@@ -466,6 +468,10 @@ static void rockchip_spi_config(struct rockchip_spi *rs,
        u32 cr1;
        u32 dmacr = 0;
 
+       if (slave_mode)
+               cr0 |= CR0_OPM_SLAVE << CR0_OPM_OFFSET;
+       rs->slave_abort = false;
+
        cr0 |= rs->rsd << CR0_RSD_OFFSET;
        cr0 |= (spi->mode & 0x3U) << CR0_SCPH_OFFSET;
        if (spi->mode & SPI_LSB_FIRST)
@@ -535,6 +541,16 @@ static size_t rockchip_spi_max_transfer_size(struct spi_device *spi)
        return ROCKCHIP_SPI_MAX_TRANLEN;
 }
 
+static int rockchip_spi_slave_abort(struct spi_controller *ctlr)
+{
+       struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
+
+       rs->slave_abort = true;
+       complete(&ctlr->xfer_completion);
+
+       return 0;
+}
+
 static int rockchip_spi_transfer_one(
                struct spi_controller *ctlr,
                struct spi_device *spi,
@@ -560,7 +576,7 @@ static int rockchip_spi_transfer_one(
 
        use_dma = ctlr->can_dma ? ctlr->can_dma(ctlr, spi, xfer) : false;
 
-       rockchip_spi_config(rs, spi, xfer, use_dma);
+       rockchip_spi_config(rs, spi, xfer, use_dma, ctlr->slave);
 
        if (use_dma)
                return rockchip_spi_prepare_dma(rs, ctlr, xfer);
@@ -588,15 +604,26 @@ static int rockchip_spi_probe(struct platform_device *pdev)
        struct rockchip_spi *rs;
        struct spi_controller *ctlr;
        struct resource *mem;
+       struct device_node *np = pdev->dev.of_node;
        u32 rsd_nsecs;
+       bool slave_mode;
+
+       slave_mode = of_property_read_bool(np, "spi-slave");
+
+       if (slave_mode)
+               ctlr = spi_alloc_slave(&pdev->dev,
+                               sizeof(struct rockchip_spi));
+       else
+               ctlr = spi_alloc_master(&pdev->dev,
+                               sizeof(struct rockchip_spi));
 
-       ctlr = spi_alloc_master(&pdev->dev, sizeof(struct rockchip_spi));
        if (!ctlr)
                return -ENOMEM;
 
        platform_set_drvdata(pdev, ctlr);
 
        rs = spi_controller_get_devdata(ctlr);
+       ctlr->slave = slave_mode;
 
        /* Get basic io resource and map it */
        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -676,6 +703,12 @@ static int rockchip_spi_probe(struct platform_device *pdev)
        ctlr->auto_runtime_pm = true;
        ctlr->bus_num = pdev->id;
        ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP | SPI_LSB_FIRST;
+       if (slave_mode) {
+               ctlr->mode_bits |= SPI_NO_CS;
+               ctlr->slave_abort = rockchip_spi_slave_abort;
+       } else {
+               ctlr->flags = SPI_MASTER_GPIO_SS;
+       }
        ctlr->num_chipselect = ROCKCHIP_SPI_MAX_CS_NUM;
        ctlr->dev.of_node = pdev->dev.of_node;
        ctlr->bits_per_word_mask = SPI_BPW_MASK(16) | SPI_BPW_MASK(8) | SPI_BPW_MASK(4);
@@ -686,7 +719,6 @@ static int rockchip_spi_probe(struct platform_device *pdev)
        ctlr->transfer_one = rockchip_spi_transfer_one;
        ctlr->max_transfer_size = rockchip_spi_max_transfer_size;
        ctlr->handle_err = rockchip_spi_handle_err;
-       ctlr->flags = SPI_MASTER_GPIO_SS;
 
        ctlr->dma_tx = dma_request_chan(rs->dev, "tx");
        if (IS_ERR(ctlr->dma_tx)) {