serial: tegra: convert to standard DMA DT bindings

By using dma_request_slave_channel_or_err(), the DMA slave ID can be
looked up from standard DT properties, and squirrelled away during
channel allocation. Hence, there's no need to use a custom DT property
to store the slave ID.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>

1 files changed, 6 insertions, 18 deletions

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index 4455481a3517..d5c2a287b7e7 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -120,7 +120,6 @@ struct tegra_uart_port {
         bool                                    rx_timeout;
         int                                     rx_in_progress;
         int                                     symb_bit;
-        int                                     dma_req_sel;
 
         struct dma_chan                         *rx_dma_chan;
         struct dma_chan                         *tx_dma_chan;
@@ -910,15 +909,14 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
         dma_addr_t dma_phys;
         int ret;
         struct dma_slave_config dma_sconfig;
-        dma_cap_mask_t mask;
 
-        dma_cap_zero(mask);
-        dma_cap_set(DMA_SLAVE, mask);
-        dma_chan = dma_request_channel(mask, NULL, NULL);
-        if (!dma_chan) {
+        dma_chan = dma_request_slave_channel_reason(tup->uport.dev,
+                                                dma_to_memory ? "rx" : "tx");
+        if (IS_ERR(dma_chan)) {
+                ret = PTR_ERR(dma_chan);
                 dev_err(tup->uport.dev,
-                        "Dma channel is not available, will try later\n");
-                return -EPROBE_DEFER;
+                        "DMA channel alloc failed: %d\n", ret);
+                return ret;
         }
 
         if (dma_to_memory) {
@@ -938,7 +936,6 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
                 dma_buf = tup->uport.state->xmit.buf;
         }
 
-        dma_sconfig.slave_id = tup->dma_req_sel;
         if (dma_to_memory) {
                 dma_sconfig.src_addr = tup->uport.mapbase;
                 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
@@ -1222,17 +1219,8 @@ static int tegra_uart_parse_dt(struct platform_device *pdev,
         struct tegra_uart_port *tup)
 {
         struct device_node *np = pdev->dev.of_node;
-        u32 of_dma[2];
         int port;
 
-        if (of_property_read_u32_array(np, "nvidia,dma-request-selector",
-                                of_dma, 2) >= 0) {
-                tup->dma_req_sel = of_dma[1];
-        } else {
-                dev_err(&pdev->dev, "missing dma requestor in device tree\n");
-                return -EINVAL;
-        }
-
         port = of_alias_get_id(np, "serial");
         if (port < 0) {
                 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port);