Re: [PATCH 2/2] clk: ti: get register address from device tree

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On 02/04/2021 22:20, Dario Binacchi wrote:
Until now, only the register offset was retrieved from the device tree
to be added, during access, to a common base address for the clocks.
If possible, we try to retrieve the physical address of the register
directly from the device tree.

The physical address is derived from the base address of the clock provider, it is not derived from the clock node itself.

Doing what this patch does may actually break things, as you end up creating an individual ioremap for every single clock register, and they are typically a word apart from each other. In the TI clock driver case, the ioremap is done only once for the whole clock register space.

-Tero


Signed-off-by: Dario Binacchi <dariobin@xxxxxxxxx>

---

  drivers/clk/ti/clk.c | 13 ++++++++++++-
  1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/ti/clk.c b/drivers/clk/ti/clk.c
index 3da33c786d77..938f5a2cb425 100644
--- a/drivers/clk/ti/clk.c
+++ b/drivers/clk/ti/clk.c
@@ -265,9 +265,21 @@ int __init ti_clk_retry_init(struct device_node *node, void *user,
  int ti_clk_get_reg_addr(struct device_node *node, int index,
  			struct clk_omap_reg *reg)
  {
+	const __be32 *addrp;
+	u64 size, addr = OF_BAD_ADDR;
+	unsigned int flags;
  	u32 val;
  	int i;
+ addrp = of_get_address(node, index, &size, &flags);
+	if (addrp)
+		addr = of_translate_address(node, addrp);
+
+	if (addr != OF_BAD_ADDR) {
+		reg->ptr = ioremap(addr, sizeof(u32));
+		return 0;
+	}
+
  	for (i = 0; i < CLK_MAX_MEMMAPS; i++) {
  		if (clocks_node_ptr[i] == node->parent)
  			break;
@@ -287,7 +299,6 @@ int ti_clk_get_reg_addr(struct device_node *node, int index,
reg->offset = val;
  	reg->ptr = NULL;
-
  	return 0;
  }




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