i2c: sh_mobile: rework deferred probing

[firefly-linux-kernel-4.4.55.git] / drivers / i2c / busses / i2c-sh_mobile.c

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index d7efaf44868b24d9348219c39426811240903a90..a12297e7680ac1f4168204fab6ff12d8fa980fd8 100644 (file)
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -140,6 +140,7 @@ struct sh_mobile_i2c_data {
        int sr;
        bool send_stop;
 
+       struct resource *res;
        struct dma_chan *dma_tx;
        struct dma_chan *dma_rx;
        struct scatterlist sg;
@@ -539,6 +540,41 @@ static void sh_mobile_i2c_dma_callback(void *data)
        iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
 }
 
+static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
+                               enum dma_transfer_direction dir, dma_addr_t port_addr)
+{
+       struct dma_chan *chan;
+       struct dma_slave_config cfg;
+       char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
+       int ret;
+
+       chan = dma_request_slave_channel_reason(dev, chan_name);
+       if (IS_ERR(chan)) {
+               dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
+               return chan;
+       }
+
+       memset(&cfg, 0, sizeof(cfg));
+       cfg.direction = dir;
+       if (dir == DMA_MEM_TO_DEV) {
+               cfg.dst_addr = port_addr;
+               cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+       } else {
+               cfg.src_addr = port_addr;
+               cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+       }
+
+       ret = dmaengine_slave_config(chan, &cfg);
+       if (ret) {
+               dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
+               dma_release_channel(chan);
+               return ERR_PTR(ret);
+       }
+
+       dev_dbg(dev, "got DMA channel for %s\n", chan_name);
+       return chan;
+}
+
 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
 {
        bool read = pd->msg->flags & I2C_M_RD;
@@ -548,7 +584,16 @@ static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
        dma_addr_t dma_addr;
        dma_cookie_t cookie;
 
-       if (!chan)
+       if (PTR_ERR(chan) == -EPROBE_DEFER) {
+               if (read)
+                       chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
+                                                                          pd->res->start + ICDR);
+               else
+                       chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
+                                                                          pd->res->start + ICDR);
+       }
+
+       if (IS_ERR(chan))
                return;
 
        dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir);
@@ -747,56 +792,16 @@ static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
 
-static int sh_mobile_i2c_request_dma_chan(struct device *dev, enum dma_transfer_direction dir,
-                                         dma_addr_t port_addr, struct dma_chan **chan_ptr)
-{
-       struct dma_chan *chan;
-       struct dma_slave_config cfg;
-       char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
-       int ret;
-
-       *chan_ptr = NULL;
-
-       chan = dma_request_slave_channel_reason(dev, chan_name);
-       if (IS_ERR(chan)) {
-               ret = PTR_ERR(chan);
-               dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
-               return ret;
-       }
-
-       memset(&cfg, 0, sizeof(cfg));
-       cfg.direction = dir;
-       if (dir == DMA_MEM_TO_DEV) {
-               cfg.dst_addr = port_addr;
-               cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-       } else {
-               cfg.src_addr = port_addr;
-               cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-       }
-
-       ret = dmaengine_slave_config(chan, &cfg);
-       if (ret) {
-               dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
-               dma_release_channel(chan);
-               return ret;
-       }
-
-       *chan_ptr = chan;
-
-       dev_dbg(dev, "got DMA channel for %s\n", chan_name);
-       return 0;
-}
-
 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
 {
-       if (pd->dma_tx) {
+       if (!IS_ERR(pd->dma_tx)) {
                dma_release_channel(pd->dma_tx);
-               pd->dma_tx = NULL;
+               pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
        }
 
-       if (pd->dma_rx) {
+       if (!IS_ERR(pd->dma_rx)) {
                dma_release_channel(pd->dma_rx);
-               pd->dma_rx = NULL;
+               pd->dma_rx = ERR_PTR(-EPROBE_DEFER);
        }
 }
 
@@ -849,6 +854,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
 
        res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 
+       pd->res = res;
        pd->reg = devm_ioremap_resource(&dev->dev, res);
        if (IS_ERR(pd->reg))
                return PTR_ERR(pd->reg);
@@ -889,17 +895,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
        /* Init DMA */
        sg_init_table(&pd->sg, 1);
        pd->dma_direction = DMA_NONE;
-       ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
-                                            res->start + ICDR, &pd->dma_rx);
-       if (ret == -EPROBE_DEFER)
-               return ret;
-
-       ret = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
-                                            res->start + ICDR, &pd->dma_tx);
-       if (ret == -EPROBE_DEFER) {
-               sh_mobile_i2c_release_dma(pd);
-               return ret;
-       }
+       pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
 
        /* Enable Runtime PM for this device.
         *
@@ -937,8 +933,7 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
                return ret;
        }
 
-       dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz, DMA=%c\n",
-                adap->nr, pd->bus_speed, (pd->dma_rx || pd->dma_tx) ? 'y' : 'n');
+       dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
 
        return 0;
 }