[v2] clk: npcm7xx: get fixed clocks from DT

Message ID 20181206084431.315559-1-tali.perry1@gmail.com
State Not Applicable, archived
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  • [v2] clk: npcm7xx: get fixed clocks from DT
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Commit Message

Tali Perry Dec. 6, 2018, 8:44 a.m.
The npcm7xx clock module includes 4 PLLs and then a tree of muxes and dividers.
All muxes and dividers are preset before Linux boots. The presetting can change
according to the board.
Linux drivers need to know what the frequencies are, but they cannot change it,
so this whole driver is intended as read only mechanism for clocks.

Before this change PLLs input clk value was defined inside the driver.
With this fix clock will be on the DT.

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>

---

 drivers/clk/clk-npcm7xx.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

Comments

Stephen Boyd Dec. 6, 2018, 6:49 p.m. | #1
Quoting Tali Perry (2018-12-06 00:44:31)
> diff --git a/drivers/clk/clk-npcm7xx.c b/drivers/clk/clk-npcm7xx.c
> index 27a86b7a34db..4bd2e40997d4 100644
> --- a/drivers/clk/clk-npcm7xx.c
> +++ b/drivers/clk/clk-npcm7xx.c
> @@ -8,13 +8,19 @@
>   */
>  
>  #include <linux/module.h>
> +#include <linux/clk.h>
>  #include <linux/clk-provider.h>
> +#include <linux/device.h>
>  #include <linux/io.h>
>  #include <linux/kernel.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_platform.h>
>  #include <linux/of_address.h>
> +#include <linux/platform_device.h>
>  #include <linux/slab.h>
>  #include <linux/err.h>
> +#include <linux/rational.h>

Why?

>  #include <linux/bitfield.h>
>  
>  #include <dt-bindings/clock/nuvoton,npcm7xx-clock.h>
> @@ -568,6 +575,31 @@ static void __init npcm7xx_clk_init(struct device_node *clk_np)
>         for (i = 0; i < NPCM7XX_NUM_CLOCKS; i++)
>                 npcm7xx_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
>  
> +       /* Read fixed clocks. These 3 clocks must be defined in DT */
> +       clk = of_clk_get_by_name(clk_np, NPCM7XX_CLK_S_REFCLK);
> +       if (IS_ERR(clk)) {
> +               pr_err("failed to find external REFCLK on device tree, err=%ld\n",
> +                       PTR_ERR(clk));
> +               clk_put(clk);
> +               goto npcm7xx_init_fail_no_clk_on_dt;
> +       }
> +
> +       clk = of_clk_get_by_name(clk_np, NPCM7XX_CLK_S_SYSBYPCK);
> +       if (IS_ERR(clk)) {
> +               pr_err("failed to find external SYSBYPCK on device tree, err=%ld\n",
> +                       PTR_ERR(clk));
> +               clk_put(clk);
> +               goto npcm7xx_init_fail_no_clk_on_dt;
> +       }
> +
> +       clk = of_clk_get_by_name(clk_np, NPCM7XX_CLK_S_MCBYPCK);
> +       if (IS_ERR(clk)) {
> +               pr_err("failed to find external MCBYPCK on device tree, err=%ld\n",
> +                       PTR_ERR(clk));
> +               clk_put(clk);
> +               goto npcm7xx_init_fail_no_clk_on_dt;
> +       }

Now this looks like a DT validator in the kernel. DT folks are working
on a schema and validator, which should be able to make sure that the
DTS file has the proper set of clks specified for this drivers' node so
that we don't need to check in the kernel.

So it looks like nothing needs to change here?

Patch

diff --git a/drivers/clk/clk-npcm7xx.c b/drivers/clk/clk-npcm7xx.c
index 27a86b7a34db..4bd2e40997d4 100644
--- a/drivers/clk/clk-npcm7xx.c
+++ b/drivers/clk/clk-npcm7xx.c
@@ -8,13 +8,19 @@ 
  */
 
 #include <linux/module.h>
+#include <linux/clk.h>
 #include <linux/clk-provider.h>
+#include <linux/device.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
 #include <linux/of_address.h>
+#include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/err.h>
+#include <linux/rational.h>
 #include <linux/bitfield.h>
 
 #include <dt-bindings/clock/nuvoton,npcm7xx-clock.h>
@@ -544,6 +550,7 @@  static void __init npcm7xx_clk_init(struct device_node *clk_np)
 	void __iomem *clk_base;
 	struct resource res;
 	struct clk_hw *hw;
+	struct clk *clk;
 	int ret;
 	int i;
 
@@ -568,6 +575,31 @@  static void __init npcm7xx_clk_init(struct device_node *clk_np)
 	for (i = 0; i < NPCM7XX_NUM_CLOCKS; i++)
 		npcm7xx_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
 
+	/* Read fixed clocks. These 3 clocks must be defined in DT */
+	clk = of_clk_get_by_name(clk_np, NPCM7XX_CLK_S_REFCLK);
+	if (IS_ERR(clk)) {
+		pr_err("failed to find external REFCLK on device tree, err=%ld\n",
+			PTR_ERR(clk));
+		clk_put(clk);
+		goto npcm7xx_init_fail_no_clk_on_dt;
+	}
+
+	clk = of_clk_get_by_name(clk_np, NPCM7XX_CLK_S_SYSBYPCK);
+	if (IS_ERR(clk)) {
+		pr_err("failed to find external SYSBYPCK on device tree, err=%ld\n",
+			PTR_ERR(clk));
+		clk_put(clk);
+		goto npcm7xx_init_fail_no_clk_on_dt;
+	}
+
+	clk = of_clk_get_by_name(clk_np, NPCM7XX_CLK_S_MCBYPCK);
+	if (IS_ERR(clk)) {
+		pr_err("failed to find external MCBYPCK on device tree, err=%ld\n",
+			PTR_ERR(clk));
+		clk_put(clk);
+		goto npcm7xx_init_fail_no_clk_on_dt;
+	}
+
 	/* Register plls */
 	for (i = 0; i < ARRAY_SIZE(npcm7xx_plls); i++) {
 		const struct npcm7xx_clk_pll_data *pll_data = &npcm7xx_plls[i];
@@ -646,11 +678,16 @@  static void __init npcm7xx_clk_init(struct device_node *clk_np)
 
 	return;
 
+npcm7xx_init_fail_no_clk_on_dt:
+	pr_err("see Documentation/devicetree/bindings/clock/");
+	pr_err("nuvoton,npcm750-clk.txt  for details\n");
 npcm7xx_init_fail:
-	kfree(npcm7xx_clk_data->hws);
+	if (npcm7xx_clk_data->num)
+		kfree(npcm7xx_clk_data->hws);
 npcm7xx_init_np_err:
 	iounmap(clk_base);
 npcm7xx_init_error:
 	of_node_put(clk_np);
+	pr_err("clk setup fail\n");
 }
 CLK_OF_DECLARE(npcm7xx_clk_init, "nuvoton,npcm750-clk", npcm7xx_clk_init);