crypto: mxs-dcp - Add support for dcp clk

On 6ull and 6sll the DCP block has a clock which needs to be explicitly
enabled.

Add minimal handling for this at probe/remove time.
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/mxs-dcp.c

@@ -20,6 +20,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/stmp_device.h>
+#include <linux/clk.h>
 
 #include <crypto/aes.h>
 #include <crypto/sha.h>
@@ -82,6 +83,7 @@ struct dcp {
 	spinlock_t			lock[DCP_MAX_CHANS];
 	struct task_struct		*thread[DCP_MAX_CHANS];
 	struct crypto_queue		queue[DCP_MAX_CHANS];
+	struct clk			*dcp_clk;
 };
 
 enum dcp_chan {
@@ -1053,11 +1055,24 @@ static int mxs_dcp_probe(struct platform_device *pdev)
 	/* Re-align the structure so it fits the DCP constraints. */
 	sdcp->coh = PTR_ALIGN(sdcp->coh, DCP_ALIGNMENT);
 
-	/* Restart the DCP block. */
-	ret = stmp_reset_block(sdcp->base);
+	/* DCP clock is optional, only used on some SOCs */
+	sdcp->dcp_clk = devm_clk_get(dev, "dcp");
+	if (IS_ERR(sdcp->dcp_clk)) {
+		if (sdcp->dcp_clk != ERR_PTR(-ENOENT))
+			return PTR_ERR(sdcp->dcp_clk);
+		sdcp->dcp_clk = NULL;
+	}
+	ret = clk_prepare_enable(sdcp->dcp_clk);
 	if (ret)
 		return ret;
 
+	/* Restart the DCP block. */
+	ret = stmp_reset_block(sdcp->base);
+	if (ret) {
+		dev_err(dev, "Failed reset\n");
+		goto err_disable_unprepare_clk;
+	}
+
 	/* Initialize control register. */
 	writel(MXS_DCP_CTRL_GATHER_RESIDUAL_WRITES |
 	       MXS_DCP_CTRL_ENABLE_CONTEXT_CACHING | 0xf,
@@ -1094,7 +1109,8 @@ static int mxs_dcp_probe(struct platform_device *pdev)
 						      NULL, "mxs_dcp_chan/sha");
 	if (IS_ERR(sdcp->thread[DCP_CHAN_HASH_SHA])) {
 		dev_err(dev, "Error starting SHA thread!\n");
-		return PTR_ERR(sdcp->thread[DCP_CHAN_HASH_SHA]);
+		ret = PTR_ERR(sdcp->thread[DCP_CHAN_HASH_SHA]);
+		goto err_disable_unprepare_clk;
 	}
 
 	sdcp->thread[DCP_CHAN_CRYPTO] = kthread_run(dcp_chan_thread_aes,
@@ -1151,6 +1167,10 @@ static int mxs_dcp_probe(struct platform_device *pdev)
 
 err_destroy_sha_thread:
 	kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
+
+err_disable_unprepare_clk:
+	clk_disable_unprepare(sdcp->dcp_clk);
+
 	return ret;
 }
 
@@ -1170,6 +1190,8 @@ static int mxs_dcp_remove(struct platform_device *pdev)
 	kthread_stop(sdcp->thread[DCP_CHAN_HASH_SHA]);
 	kthread_stop(sdcp->thread[DCP_CHAN_CRYPTO]);
 
+	clk_disable_unprepare(sdcp->dcp_clk);
+
 	platform_set_drvdata(pdev, NULL);
 
 	global_sdcp = NULL;