[PATCH V3 01/12] clk: shmobile: add CPG driver for rz-platforms

Wolfram Sang
2014-03-07T16:00:37Z

From: Wolfram Sang <wsa@sang-engineering.com>

Signed-off-by: Wolfram Sang <wsa@sang-engineering.com>
---

Changes since V2:

* Document the input clocks for r7s72100
* revamp and simplify the error paths of the driver

Changes since V1:
* added docs
* preparation for usb_x1 support by documenting two input clocks
* static-consted frqcr_tab
* bail out if num_clks == 0
* cosmetic fixes

Mike: if you are fine with this driver, it would be good if you could apply it.
Then, we can deal with the orthogonal dependencies in mach-shmobile seperately
and know that the driver is already in place when the rest gets resolved.
Thanks!

.../bindings/clock/renesas,rz-cpg-clocks.txt | 29 ++++++
drivers/clk/shmobile/Makefile | 1 +
drivers/clk/shmobile/clk-rz.c | 103 +++++++++++++++++++++
3 files changed, 133 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/renesas,rz-cpg-clocks.txt
create mode 100644 drivers/clk/shmobile/clk-rz.c

diff --git a/Documentation/devicetree/bindings/clock/renesas,rz-cpg-clocks.txt b/Documentation/devicetree/bindings/clock/renesas,rz-cpg-clocks.txt
new file mode 100644
index 000000000000..98a257492522
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/renesas,rz-cpg-clocks.txt
@@ -0,0 +1,29 @@
+* Renesas RZ Clock Pulse Generator (CPG)
+
+The CPG generates core clocks for the RZ SoCs. It includes the PLL, variable
+CPU and GPU clocks, and several fixed ratio dividers.
+
+Required Properties:
+
+ - compatible: Must be one of
+ - "renesas,r7s72100-cpg-clocks" for the r7s72100 CPG
+ - "renesas,rz-cpg-clocks" for the generic RZ CPG
+ - reg: Base address and length of the memory resource used by the CPG
+ - clocks: References to possible parent clocks. Order must match clock modes
+ in the datasheet. For the r7s72100, this is extal, usb_x1.
+ - #clock-cells: Must be 1
+ - clock-output-names: The names of the clocks. Supported clocks are "pll",
+ "i", and "g"
+
+
+Example
+-------
+
+ cpg_clocks: cpg_clocks at fcfe0000 {
+ #clock-cells = <1>;
+ compatible = "renesas,r7s72100-cpg-clocks",
+ "renesas,rz-cpg-clocks";
+ reg = <0xfcfe0000 0x18>;
+ clocks = <&extal_clk>, <&usb_x1_clk>;
+ clock-output-names = "pll", "i", "g";
+ };
diff --git a/drivers/clk/shmobile/Makefile b/drivers/clk/shmobile/Makefile
index 9ecef140dba7..5404cb931ebf 100644
--- a/drivers/clk/shmobile/Makefile
+++ b/drivers/clk/shmobile/Makefile
@@ -1,4 +1,5 @@
obj-$(CONFIG_ARCH_EMEV2) += clk-emev2.o
+obj-$(CONFIG_ARCH_R7S72100) += clk-rz.o
obj-$(CONFIG_ARCH_R8A7790) += clk-rcar-gen2.o
obj-$(CONFIG_ARCH_R8A7791) += clk-rcar-gen2.o
obj-$(CONFIG_ARCH_SHMOBILE_MULTI) += clk-div6.o
diff --git a/drivers/clk/shmobile/clk-rz.c b/drivers/clk/shmobile/clk-rz.c
new file mode 100644
index 000000000000..7e68e8630962
--- /dev/null
+++ b/drivers/clk/shmobile/clk-rz.c
@@ -0,0 +1,103 @@
+/*
+ * rz Core CPG Clocks
+ *
+ * Copyright (C) 2013 Ideas On Board SPRL
+ * Copyright (C) 2014 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
+ *
+ * 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/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+
+struct rz_cpg {
+ struct clk_onecell_data data;
+ void __iomem *reg;
+};
+
+#define CPG_FRQCR 0x10
+#define CPG_FRQCR2 0x14
+
+/* -----------------------------------------------------------------------------
+ * Initialization
+ */
+
+static struct clk * __init
+rz_cpg_register_clock(struct device_node *np, struct rz_cpg *cpg, const char *name)
+{
+ u32 val;
+ unsigned mult;
+ static const unsigned frqcr_tab[4] = { 3, 2, 0, 1 };
+
+ if (strcmp(name, "pll") == 0) {
+ /* FIXME: cpg_mode should be read from GPIO. But no GPIO support yet */
+ unsigned cpg_mode = 0; /* hardcoded to EXTAL for now */
+ const char *parent_name = of_clk_get_parent_name(np, cpg_mode);
+
+ mult = cpg_mode ? (32 / 4) : 30;
+
+ return clk_register_fixed_factor(NULL, name, parent_name, 0, mult, 1);
+ }
+
+ /* If mapping regs failed, skip non-pll clocks. System will boot anyhow */
+ if (!cpg->reg)
+ return ERR_PTR(-ENXIO);
+
+ /* FIXME:"i" and "g" are variable clocks with non-integer dividers (e.g. 2/3)
+ * and the constraint that always g <= i. To get the rz platform started,
+ * let them run@fixed current speed and implement the details later.
+ */
+ if (strcmp(name, "i") == 0)
+ val = (clk_readl(cpg->reg + CPG_FRQCR) >> 8) & 3;
+ else if (strcmp(name, "g") == 0)
+ val = clk_readl(cpg->reg + CPG_FRQCR2) & 3;
+ else
+ return ERR_PTR(-EINVAL);
+
+ mult = frqcr_tab[val];
+ return clk_register_fixed_factor(NULL, name, "pll", 0, mult, 3);
+}
+
+static void __init rz_cpg_clocks_init(struct device_node *np)
+{
+ struct rz_cpg *cpg;
+ struct clk **clks;
+ unsigned i;
+ int num_clks;
+
+ num_clks = of_property_count_strings(np, "clock-output-names");
+ if (WARN(num_clks <= 0, "can't count CPG clocks\n"))
+ return;
+
+ cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
+ clks = kzalloc(num_clks * sizeof(*clks), GFP_KERNEL);
+ BUG_ON(!cpg || !clks);
+
+ cpg->data.clks = clks;
+ cpg->data.clk_num = num_clks;
+
+ cpg->reg = of_iomap(np, 0);
+
+ 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 = rz_cpg_register_clock(np, cpg, 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(rz_cpg_clks, "renesas,rz-cpg-clocks", rz_cpg_clocks_init);
--
1.9.0