2015-08-25 06:40:51

by Kuninori Morimoto

[permalink] [raw]
Subject: [PATCH 0/2] clk: shmobile: add Renesas R-Car Gen3 CPG support


Hi Stephen, Michael
Cc: Simon, Magnus, Geert

These are Renesas R-Car Gen3 clock support patches.
We need incremental update for it, but it is good enough for initial booting.
Renesas R-Car Gen3 initial SoC/board support patch-set depends on these patches.

Renesas SoC series maintainer is Simon and Magnus.
Simon can accept (?) these patches as part of Renesas SoC if Stephen / Michael
can give it Ack. Or Simon can merge Stephen or Michael's branch.
I'm not sure which one is good choice

Gaku Inami (1):
clk: shmobile: add Renesas R-Car Gen3 CPG support

Kuninori Morimoto (1):
clk: shmobile: Add r8a7795 SoC to MSTP bindings

Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt | 1 +
Documentation/devicetree/bindings/clock/renesas,rcar-gen3-cpg-clocks.txt | 31 ++++++++++++
drivers/clk/shmobile/Makefile | 1 +
drivers/clk/shmobile/clk-rcar-gen3.c | 232 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 265 insertions(+)


2015-08-25 06:42:30

by Kuninori Morimoto

[permalink] [raw]
Subject: [PATCH 1/2] clk: shmobile: add Renesas R-Car Gen3 CPG support

From: Gaku Inami <[email protected]>

This patch adds very initial CPG support.
R-Car Gen3 write function should use CPG write protection method
which is shared with MSTP driver. This patch has it but not used.

Signed-off-by: Gaku Inami <[email protected]>
Signed-off-by: Kuninori Morimoto <[email protected]>
---
.../clock/renesas,rcar-gen3-cpg-clocks.txt | 31 +++
drivers/clk/shmobile/Makefile | 1 +
drivers/clk/shmobile/clk-rcar-gen3.c | 232 +++++++++++++++++++++
3 files changed, 264 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/renesas,rcar-gen3-cpg-clocks.txt
create mode 100644 drivers/clk/shmobile/clk-rcar-gen3.c

diff --git a/Documentation/devicetree/bindings/clock/renesas,rcar-gen3-cpg-clocks.txt b/Documentation/devicetree/bindings/clock/renesas,rcar-gen3-cpg-clocks.txt
new file mode 100644
index 0000000..b1a7e01
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/renesas,rcar-gen3-cpg-clocks.txt
@@ -0,0 +1,31 @@
+* Renesas R-Car Gen3 Clock Pulse Generator (CPG)
+
+The CPG generates core clocks for the R-Car Gen3 SoCs. It includes three PLLs
+and several fixed ratio dividers.
+
+Required Properties:
+
+ - compatible: Must be one of
+ - "renesas,r8a7795-cpg-clocks" for the r8a7795 CPG
+ - "renesas,rcar-gen3-cpg-clocks" for the generic R-Car Gen3 CPG
+
+ - reg: Base address and length of the memory resource used by the CPG
+
+ - clocks: References to the parent clocks: first to the EXTAL clock
+ - #clock-cells: Must be 1
+ - clock-output-names: The names of the clocks. Supported clocks are
+ "main", "pll0", "pll1", "pll2", "pll3", "pll4"
+
+
+Example
+-------
+
+ cpg_clocks: cpg_clocks@e6150000 {
+ compatible = "renesas,r8a7795-cpg-clocks",
+ "renesas,rcar-gen3-cpg-clocks";
+ reg = <0 0xe6150000 0 0x1000>;
+ clocks = <&extal_clk>;
+ #clock-cells = <1>;
+ clock-output-names = "main", "pll0", "pll1","pll2",
+ "pll3", "pll4";
+ };
diff --git a/drivers/clk/shmobile/Makefile b/drivers/clk/shmobile/Makefile
index 97c71c8..4e70a73 100644
--- a/drivers/clk/shmobile/Makefile
+++ b/drivers/clk/shmobile/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_ARCH_R8A7790) += clk-rcar-gen2.o
obj-$(CONFIG_ARCH_R8A7791) += clk-rcar-gen2.o
obj-$(CONFIG_ARCH_R8A7793) += clk-rcar-gen2.o
obj-$(CONFIG_ARCH_R8A7794) += clk-rcar-gen2.o
+obj-$(CONFIG_ARCH_RCAR_GEN3) += clk-rcar-gen3.o
obj-$(CONFIG_ARCH_SH73A0) += clk-sh73a0.o
obj-$(CONFIG_ARCH_SHMOBILE_MULTI) += clk-div6.o
obj-$(CONFIG_ARCH_SHMOBILE_MULTI) += clk-mstp.o
diff --git a/drivers/clk/shmobile/clk-rcar-gen3.c b/drivers/clk/shmobile/clk-rcar-gen3.c
new file mode 100644
index 0000000..098caac
--- /dev/null
+++ b/drivers/clk/shmobile/clk-rcar-gen3.c
@@ -0,0 +1,232 @@
+/*
+ * rcar_gen3 Core CPG Clocks
+ *
+ * Copyright (C) 2015 Renesas Electronics Corp.
+ *
+ * Based on rcar_gen2 Core CPG Clocks driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/shmobile.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/spinlock.h>
+
+struct rcar_gen3_cpg {
+ struct clk_onecell_data data;
+ spinlock_t lock;
+ void __iomem *reg;
+};
+
+#define CPG_PLL0CR 0x00d8
+#define CPG_PLL2CR 0x002c
+
+/*
+ * common function
+ */
+#define rcar_clk_readl(cpg, _reg) clk_readl(cpg->reg + _reg)
+
+/*
+ * Reset register definitions.
+ */
+#define MODEMR 0xe6160060
+
+static u32 rcar_gen3_read_mode_pins(void)
+{
+ static u32 mode;
+ static bool mode_valid;
+
+ if (!mode_valid) {
+ void __iomem *modemr = ioremap_nocache(MODEMR, 4);
+
+ BUG_ON(!modemr);
+ mode = ioread32(modemr);
+ iounmap(modemr);
+ mode_valid = true;
+ }
+
+ return mode;
+}
+
+/* -----------------------------------------------------------------------------
+ * CPG Clock Data
+ */
+
+/*
+ * MD EXTAL PLL0 PLL1 PLL2 PLL3 PLL4
+ * 14 13 19 17 (MHz) *1 *1 *1
+ *-------------------------------------------------------------------
+ * 0 0 0 0 16.66 x 1 x180/2 x192/2 x144/2 x192 x144
+ * 0 0 0 1 16.66 x 1 x180/2 x192/2 x144/2 x128 x144
+ * 0 0 1 0 Prohibited setting
+ * 0 0 1 1 16.66 x 1 x180/2 x192/2 x144/2 x192 x144
+ * 0 1 0 0 20 x 1 x150/2 x156/2 x120/2 x156 x120
+ * 0 1 0 1 20 x 1 x150/2 x156/2 x120/2 x106 x120
+ * 0 1 1 0 Prohibited setting
+ * 0 1 1 1 20 x 1 x150/2 x156/2 x120/2 x156 x120
+ * 1 0 0 0 25 x 1 x120/2 x128/2 x96/2 x128 x96
+ * 1 0 0 1 25 x 1 x120/2 x128/2 x96/2 x84 x96
+ * 1 0 1 0 Prohibited setting
+ * 1 0 1 1 25 x 1 x120/2 x128/2 x96/2 x128 x96
+ * 1 1 0 0 33.33 / 2 x180/2 x192/2 x144/2 x192 x144
+ * 1 1 0 1 33.33 / 2 x180/2 x192/2 x144/2 x128 x144
+ * 1 1 1 0 Prohibited setting
+ * 1 1 1 1 33.33 / 2 x180/2 x192/2 x144/2 x192 x144
+ *
+ * *1 : datasheet indicates VCO output (PLLx = VCO/2)
+ *
+ */
+#define CPG_PLL_CONFIG_INDEX(md) ((((md) & BIT(14)) >> 11) | \
+ (((md) & BIT(13)) >> 11) | \
+ (((md) & BIT(19)) >> 18) | \
+ (((md) & BIT(17)) >> 17))
+struct cpg_pll_config {
+ unsigned int extal_div;
+ unsigned int pll1_mult;
+ unsigned int pll3_mult;
+ unsigned int pll4_mult;
+};
+
+static const struct cpg_pll_config cpg_pll_configs[16] __initconst = {
+/* EXTAL div PLL1 PLL3 PLL4 */
+ { 1, 192, 192, 144, },
+ { 1, 192, 128, 144, },
+ { 0, 0, 0, 0, }, /* Prohibited setting */
+ { 1, 192, 192, 144, },
+ { 1, 156, 156, 120, },
+ { 1, 156, 106, 120, },
+ { 0, 0, 0, 0, }, /* Prohibited setting */
+ { 1, 156, 156, 120, },
+ { 1, 128, 128, 96, },
+ { 1, 128, 84, 96, },
+ { 0, 0, 0, 0, }, /* Prohibited setting */
+ { 1, 128, 128, 96, },
+ { 2, 192, 192, 144, },
+ { 2, 192, 128, 144, },
+ { 0, 0, 0, 0, }, /* Prohibited setting */
+ { 2, 192, 192, 144, },
+};
+
+/* -----------------------------------------------------------------------------
+ * Initialization
+ */
+
+static u32 cpg_mode __initdata;
+
+static struct clk * __init
+rcar_gen3_cpg_register_clock(struct device_node *np, struct rcar_gen3_cpg *cpg,
+ const struct cpg_pll_config *config,
+ const char *name)
+{
+ const char *parent_name;
+ unsigned int mult = 1;
+ unsigned int div = 1;
+
+ if (!strcmp(name, "main")) {
+ parent_name = of_clk_get_parent_name(np, 0);
+ div = config->extal_div;
+ } else if (!strcmp(name, "pll0")) {
+ /* PLL0 is a configurable multiplier clock. Register it as a
+ * fixed factor clock for now as there's no generic multiplier
+ * clock implementation and we currently have no need to change
+ * the multiplier value.
+ */
+ u32 value = rcar_clk_readl(cpg, CPG_PLL0CR);
+
+ parent_name = "main";
+ mult = ((value >> 24) & ((1 << 7) - 1)) + 1;
+ } else if (!strcmp(name, "pll1")) {
+ parent_name = "main";
+ mult = config->pll1_mult / 2;
+ } else if (!strcmp(name, "pll2")) {
+ /* PLL2 is a configurable multiplier clock. Register it as a
+ * fixed factor clock for now as there's no generic multiplier
+ * clock implementation and we currently have no need to change
+ * the multiplier value.
+ */
+ u32 value = rcar_clk_readl(cpg, CPG_PLL2CR);
+
+ parent_name = "main";
+ mult = ((value >> 24) & ((1 << 7) - 1)) + 1;
+ } else if (!strcmp(name, "pll3")) {
+ parent_name = "main";
+ mult = config->pll3_mult;
+ } else if (!strcmp(name, "pll4")) {
+ parent_name = "main";
+ mult = config->pll4_mult;
+ } else {
+ return ERR_PTR(-EINVAL);
+ }
+
+ return clk_register_fixed_factor(NULL, name, parent_name, 0, mult, div);
+}
+
+static void __init rcar_gen3_cpg_clocks_init(struct device_node *np)
+{
+ const struct cpg_pll_config *config;
+ struct rcar_gen3_cpg *cpg;
+ struct clk **clks;
+ unsigned int i;
+ int num_clks;
+
+ cpg_mode = rcar_gen3_read_mode_pins();
+
+ num_clks = of_property_count_strings(np, "clock-output-names");
+ if (num_clks < 0) {
+ pr_err("%s: failed to count clocks\n", __func__);
+ return;
+ }
+
+ cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
+ clks = kzalloc((num_clks * sizeof(*clks)), GFP_KERNEL);
+ if (cpg == NULL || clks == NULL) {
+ /* We're leaking memory on purpose, there's no point in cleaning
+ * up as the system won't boot anyway.
+ */
+ pr_err("%s: failed to allocate cpg\n", __func__);
+ return;
+ }
+
+ spin_lock_init(&cpg->lock);
+
+ cpg->data.clks = clks;
+ cpg->data.clk_num = num_clks;
+
+ cpg->reg = of_iomap(np, 0);
+ if (WARN_ON(cpg->reg == NULL))
+ return;
+
+ config = &cpg_pll_configs[CPG_PLL_CONFIG_INDEX(cpg_mode)];
+ if (!config->extal_div) {
+ pr_err("%s: Prohibited setting (cpg_mode=0x%x)\n",
+ __func__, cpg_mode);
+ return;
+ }
+
+ for (i = 0; i < num_clks; ++i) {
+ const char *name;
+ struct clk *clk;
+
+ of_property_read_string_index(np, "clock-output-names", i,
+ &name);
+
+ clk = rcar_gen3_cpg_register_clock(np, cpg, config, name);
+ if (IS_ERR(clk))
+ pr_err("%s: failed to register %s %s clock (%ld)\n",
+ __func__, np->name, name, PTR_ERR(clk));
+ else
+ cpg->data.clks[i] = clk;
+ }
+
+ of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
+}
+CLK_OF_DECLARE(rcar_gen3_cpg_clks, "renesas,rcar-gen3-cpg-clocks",
+ rcar_gen3_cpg_clocks_init);
--
1.9.1

2015-08-25 06:43:11

by Kuninori Morimoto

[permalink] [raw]
Subject: [PATCH 2/2] clk: shmobile: Add r8a7795 SoC to MSTP bindings

From: Kuninori Morimoto <[email protected]>

Signed-off-by: Kuninori Morimoto <[email protected]>
---
Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt | 1 +
1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt b/Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt
index 16ed181..4169c76 100644
--- a/Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt
+++ b/Documentation/devicetree/bindings/clock/renesas,cpg-mstp-clocks.txt
@@ -19,6 +19,7 @@ Required Properties:
- "renesas,r8a7791-mstp-clocks" for R8A7791 (R-Car M2-W) MSTP gate clocks
- "renesas,r8a7793-mstp-clocks" for R8A7793 (R-Car M2-N) MSTP gate clocks
- "renesas,r8a7794-mstp-clocks" for R8A7794 (R-Car E2) MSTP gate clocks
+ - "renesas,r8a7795-mstp-clocks" for R8A7795 (R-Car H3) MSTP gate clocks
- "renesas,sh73a0-mstp-clocks" for SH73A0 (SH-MobileAG5) MSTP gate clocks
and "renesas,cpg-mstp-clocks" as a fallback.
- reg: Base address and length of the I/O mapped registers used by the MSTP
--
1.9.1

2015-08-25 22:46:42

by Stephen Boyd

[permalink] [raw]
Subject: Re: [PATCH 1/2] clk: shmobile: add Renesas R-Car Gen3 CPG support

On 08/25, Kuninori Morimoto wrote:
> diff --git a/drivers/clk/shmobile/clk-rcar-gen3.c b/drivers/clk/shmobile/clk-rcar-gen3.c
> new file mode 100644
> index 0000000..098caac
> --- /dev/null
> +++ b/drivers/clk/shmobile/clk-rcar-gen3.c
> @@ -0,0 +1,232 @@
> +/*
> + * rcar_gen3 Core CPG Clocks
> + *
> + * Copyright (C) 2015 Renesas Electronics Corp.
> + *
> + * Based on rcar_gen2 Core CPG Clocks driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>

Is this include used?

> +#include <linux/clk/shmobile.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/math64.h>

Is this include used?

> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/spinlock.h>
> +
> +struct rcar_gen3_cpg {
> + struct clk_onecell_data data;
> + spinlock_t lock;
> + void __iomem *reg;
> +};
> +
> +#define CPG_PLL0CR 0x00d8
> +#define CPG_PLL2CR 0x002c
> +
> +/*
> + * common function
> + */
> +#define rcar_clk_readl(cpg, _reg) clk_readl(cpg->reg + _reg)

Please just use readl instead of clk_readl.

> +
> +/*
> + * Reset register definitions.
> + */
> +#define MODEMR 0xe6160060
> +
> +static u32 rcar_gen3_read_mode_pins(void)
> +{
> + static u32 mode;
> + static bool mode_valid;
> +
> + if (!mode_valid) {
> + void __iomem *modemr = ioremap_nocache(MODEMR, 4);
> +
> + BUG_ON(!modemr);
> + mode = ioread32(modemr);
> + iounmap(modemr);
> + mode_valid = true;
> + }
> +
> + return mode;
> +}

Perhaps this should be read using a syscon?

> +struct cpg_pll_config {
> + unsigned int extal_div;
> + unsigned int pll1_mult;
> + unsigned int pll3_mult;
> + unsigned int pll4_mult;
> +};
> +
> +static const struct cpg_pll_config cpg_pll_configs[16] __initconst = {

We don't actually need the 16, but ok.

> +/* EXTAL div PLL1 PLL3 PLL4 */
> + { 1, 192, 192, 144, },
> + { 1, 192, 128, 144, },
> + { 0, 0, 0, 0, }, /* Prohibited setting */
> + { 1, 192, 192, 144, },
> + { 1, 156, 156, 120, },
> + { 1, 156, 106, 120, },
> + { 0, 0, 0, 0, }, /* Prohibited setting */
> + { 1, 156, 156, 120, },
> + { 1, 128, 128, 96, },
> + { 1, 128, 84, 96, },
> + { 0, 0, 0, 0, }, /* Prohibited setting */
> + { 1, 128, 128, 96, },
> + { 2, 192, 192, 144, },
> + { 2, 192, 128, 144, },
> + { 0, 0, 0, 0, }, /* Prohibited setting */
> + { 2, 192, 192, 144, },
> +};
> +
> +/* -----------------------------------------------------------------------------
> + * Initialization
> + */
> +
> +static u32 cpg_mode __initdata;

Why isn't this local to the only function that uses it?

> +
> +static void __init rcar_gen3_cpg_clocks_init(struct device_node *np)
> +{
> + const struct cpg_pll_config *config;
> + struct rcar_gen3_cpg *cpg;
> + struct clk **clks;
> + unsigned int i;
> + int num_clks;
> +
> + cpg_mode = rcar_gen3_read_mode_pins();
> +
> + num_clks = of_property_count_strings(np, "clock-output-names");
> + if (num_clks < 0) {
> + pr_err("%s: failed to count clocks\n", __func__);
> + return;
> + }
> +
> + cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
> + clks = kzalloc((num_clks * sizeof(*clks)), GFP_KERNEL);

kcalloc()

> + if (cpg == NULL || clks == NULL) {
> + /* We're leaking memory on purpose, there's no point in cleaning
> + * up as the system won't boot anyway.
> + */

kfree() does nothing on NULL, so it should be easy enough to
delete this comment and replace it with two calls to kfree().

> + pr_err("%s: failed to allocate cpg\n", __func__);
> + return;
> + }
> +
> + spin_lock_init(&cpg->lock);
> +
> + cpg->data.clks = clks;
> + cpg->data.clk_num = num_clks;
> +
> + cpg->reg = of_iomap(np, 0);
> + if (WARN_ON(cpg->reg == NULL))
> + return;
> +
> + config = &cpg_pll_configs[CPG_PLL_CONFIG_INDEX(cpg_mode)];
> + if (!config->extal_div) {
> + pr_err("%s: Prohibited setting (cpg_mode=0x%x)\n",
> + __func__, cpg_mode);
> + return;
> + }
> +
> + for (i = 0; i < num_clks; ++i) {
> + const char *name;
> + struct clk *clk;
> +
> + of_property_read_string_index(np, "clock-output-names", i,
> + &name);
> +
> + clk = rcar_gen3_cpg_register_clock(np, cpg, config, name);

Is there any reason why we need to register clocks based on
what's in DT? I would prefer to see a method where we register
clocks based on the compatible string in DT. This would get rid
of all the string comparisons in rcar_gen3_cpg_register_clock()
and make for cleaner code.

Furthermore, we could make this into a platform driver so that we
can benefit from the device model.

> + if (IS_ERR(clk))
> + pr_err("%s: failed to register %s %s clock (%ld)\n",
> + __func__, np->name, name, PTR_ERR(clk));
> + else
> + cpg->data.clks[i] = clk;
> + }
> +
> + of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
> +}
> +CLK_OF_DECLARE(rcar_gen3_cpg_clks, "renesas,rcar-gen3-cpg-clocks",
> + rcar_gen3_cpg_clocks_init);

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

2015-08-26 07:29:05

by Geert Uytterhoeven

[permalink] [raw]
Subject: Re: [PATCH 1/2] clk: shmobile: add Renesas R-Car Gen3 CPG support

Hi Stephen,

On Wed, Aug 26, 2015 at 12:46 AM, Stephen Boyd <[email protected]> wrote:
>> --- /dev/null
>> +++ b/drivers/clk/shmobile/clk-rcar-gen3.c

>> +
>> +/*
>> + * Reset register definitions.
>> + */
>> +#define MODEMR 0xe6160060
>> +
>> +static u32 rcar_gen3_read_mode_pins(void)
>> +{
>> + static u32 mode;
>> + static bool mode_valid;
>> +
>> + if (!mode_valid) {
>> + void __iomem *modemr = ioremap_nocache(MODEMR, 4);
>> +
>> + BUG_ON(!modemr);
>> + mode = ioread32(modemr);
>> + iounmap(modemr);
>> + mode_valid = true;
>> + }
>> +
>> + return mode;
>> +}
>
> Perhaps this should be read using a syscon?

Like "[PATCH/RFC 00/11] ARM: shmobile: Let CPG use syscon for MD pin values"
(http://www.spinics.net/lists/linux-clk/msg01478.html)?

It wasn't so well received...

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

2015-08-28 10:52:47

by Magnus Damm

[permalink] [raw]
Subject: Re: [PATCH 1/2] clk: shmobile: add Renesas R-Car Gen3 CPG support

Hi Geert,

On Wed, Aug 26, 2015 at 4:29 PM, Geert Uytterhoeven
<[email protected]> wrote:
> Hi Stephen,
>
> On Wed, Aug 26, 2015 at 12:46 AM, Stephen Boyd <[email protected]> wrote:
>>> --- /dev/null
>>> +++ b/drivers/clk/shmobile/clk-rcar-gen3.c
>
>>> +
>>> +/*
>>> + * Reset register definitions.
>>> + */
>>> +#define MODEMR 0xe6160060
>>> +
>>> +static u32 rcar_gen3_read_mode_pins(void)
>>> +{
>>> + static u32 mode;
>>> + static bool mode_valid;
>>> +
>>> + if (!mode_valid) {
>>> + void __iomem *modemr = ioremap_nocache(MODEMR, 4);
>>> +
>>> + BUG_ON(!modemr);
>>> + mode = ioread32(modemr);
>>> + iounmap(modemr);
>>> + mode_valid = true;
>>> + }
>>> +
>>> + return mode;
>>> +}
>>
>> Perhaps this should be read using a syscon?
>
> Like "[PATCH/RFC 00/11] ARM: shmobile: Let CPG use syscon for MD pin values"
> (http://www.spinics.net/lists/linux-clk/msg01478.html)?
>
> It wasn't so well received...

I happen to think it is a great idea. At the same time I'm too lazy to
step up. =)

Shall we reconsider making it mandatory for R-Car Gen3?

Cheers,

/ magnus