Merge remote-tracking branches 'spi/topic/qup', 'spi/topic/rockchip', 'spi/topic...

[cascardo/linux.git] / drivers / spi / spi-rockchip.c

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 1a777dc..68e7efe 100644 (file)
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -179,6 +179,7 @@ struct rockchip_spi {
        u8 tmode;
        u8 bpw;
        u8 n_bytes;
+       u8 rsd_nsecs;
        unsigned len;
        u32 speed;
 
@@ -302,8 +303,8 @@ static int rockchip_spi_prepare_message(struct spi_master *master,
        return 0;
 }
 
-static int rockchip_spi_unprepare_message(struct spi_master *master,
-                                         struct spi_message *msg)
+static void rockchip_spi_handle_err(struct spi_master *master,
+                                   struct spi_message *msg)
 {
        unsigned long flags;
        struct rockchip_spi *rs = spi_master_get_devdata(master);
@@ -313,8 +314,8 @@ static int rockchip_spi_unprepare_message(struct spi_master *master,
        /*
         * For DMA mode, we need terminate DMA channel and flush
         * fifo for the next transfer if DMA thansfer timeout.
-        * unprepare_message() was called by core if transfer complete
-        * or timeout. Maybe it is reasonable for error handling here.
+        * handle_err() was called by core if transfer failed.
+        * Maybe it is reasonable for error handling here.
         */
        if (rs->use_dma) {
                if (rs->state & RXBUSY) {
@@ -327,6 +328,12 @@ static int rockchip_spi_unprepare_message(struct spi_master *master,
        }
 
        spin_unlock_irqrestore(&rs->lock, flags);
+}
+
+static int rockchip_spi_unprepare_message(struct spi_master *master,
+                                         struct spi_message *msg)
+{
+       struct rockchip_spi *rs = spi_master_get_devdata(master);
 
        spi_enable_chip(rs, 0);
 
@@ -493,6 +500,7 @@ static void rockchip_spi_config(struct rockchip_spi *rs)
 {
        u32 div = 0;
        u32 dmacr = 0;
+       int rsd = 0;
 
        u32 cr0 = (CR0_BHT_8BIT << CR0_BHT_OFFSET)
                | (CR0_SSD_ONE << CR0_SSD_OFFSET);
@@ -519,9 +527,23 @@ static void rockchip_spi_config(struct rockchip_spi *rs)
        }
 
        /* div doesn't support odd number */
-       div = max_t(u32, rs->max_freq / rs->speed, 1);
+       div = DIV_ROUND_UP(rs->max_freq, rs->speed);
        div = (div + 1) & 0xfffe;
 
+       /* Rx sample delay is expressed in parent clock cycles (max 3) */
+       rsd = DIV_ROUND_CLOSEST(rs->rsd_nsecs * (rs->max_freq >> 8),
+                               1000000000 >> 8);
+       if (!rsd && rs->rsd_nsecs) {
+               pr_warn_once("rockchip-spi: %u Hz are too slow to express %u ns delay\n",
+                            rs->max_freq, rs->rsd_nsecs);
+       } else if (rsd > 3) {
+               rsd = 3;
+               pr_warn_once("rockchip-spi: %u Hz are too fast to express %u ns delay, clamping at %u ns\n",
+                            rs->max_freq, rs->rsd_nsecs,
+                            rsd * 1000000000U / rs->max_freq);
+       }
+       cr0 |= rsd << CR0_RSD_OFFSET;
+
        writel_relaxed(cr0, rs->regs + ROCKCHIP_SPI_CTRLR0);
 
        writel_relaxed(rs->len - 1, rs->regs + ROCKCHIP_SPI_CTRLR1);
@@ -614,6 +636,7 @@ static int rockchip_spi_probe(struct platform_device *pdev)
        struct rockchip_spi *rs;
        struct spi_master *master;
        struct resource *mem;
+       u32 rsd_nsecs;
 
        master = spi_alloc_master(&pdev->dev, sizeof(struct rockchip_spi));
        if (!master)
@@ -665,6 +688,10 @@ static int rockchip_spi_probe(struct platform_device *pdev)
        rs->dev = &pdev->dev;
        rs->max_freq = clk_get_rate(rs->spiclk);
 
+       if (!of_property_read_u32(pdev->dev.of_node, "rx-sample-delay-ns",
+                                 &rsd_nsecs))
+               rs->rsd_nsecs = rsd_nsecs;
+
        rs->fifo_len = get_fifo_len(rs);
        if (!rs->fifo_len) {
                dev_err(&pdev->dev, "Failed to get fifo length\n");
@@ -688,6 +715,7 @@ static int rockchip_spi_probe(struct platform_device *pdev)
        master->prepare_message = rockchip_spi_prepare_message;
        master->unprepare_message = rockchip_spi_unprepare_message;
        master->transfer_one = rockchip_spi_transfer_one;
+       master->handle_err = rockchip_spi_handle_err;
 
        rs->dma_tx.ch = dma_request_slave_channel(rs->dev, "tx");
        if (!rs->dma_tx.ch)