[PATCH 2/3 v2] clk: add versatile ICST307 driver

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

The ICST307 VCO clock has a shared driver in the ARM
architecture. This patch provides a wrapper into the common
clock framework so we can use the implementation in the
ARM architecture without duplicating the code until all
ARM platforms using this VCO are moved over. At that point
we can merge the driver from the ARM platform into the
generic file altogether.

Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Mike Turquette <mturquette@xxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
ChangeLog v1->v2:
- Create a versatile subdirectory, and put the clock in there,
  as only the ARM reference designs use this clock right now.
  Also create a Kconfig entry for the versatile stuff.
- Rename clock register function to *_register
---
 drivers/clk/Kconfig              |    2 +
 drivers/clk/Makefile             |    1 +
 drivers/clk/versatile/Kconfig    |    8 +++
 drivers/clk/versatile/Makefile   |    2 +
 drivers/clk/versatile/clk-icst.c |  100 ++++++++++++++++++++++++++++++++++++++
 drivers/clk/versatile/clk-icst.h |   10 ++++
 6 files changed, 123 insertions(+)
 create mode 100644 drivers/clk/versatile/Kconfig
 create mode 100644 drivers/clk/versatile/Makefile
 create mode 100644 drivers/clk/versatile/clk-icst.c
 create mode 100644 drivers/clk/versatile/clk-icst.h

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 4864407..6742ad9 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -34,4 +34,6 @@ config COMMON_CLK_DEBUG
 	  clk_flags, clk_prepare_count, clk_enable_count &
 	  clk_notifier_count.
 
+source "drivers/clk/versatile/Kconfig"
+
 endmenu
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index b9a5158..3cf5da7 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-fixed-rate.o clk-gate.o \
 # SoCs specific
 obj-$(CONFIG_ARCH_MXS)		+= mxs/
 obj-$(CONFIG_PLAT_SPEAR)	+= spear/
+obj-$(CONFIG_CLK_VERSATILE)	+= versatile/
diff --git a/drivers/clk/versatile/Kconfig b/drivers/clk/versatile/Kconfig
new file mode 100644
index 0000000..169b1bc
--- /dev/null
+++ b/drivers/clk/versatile/Kconfig
@@ -0,0 +1,8 @@
+config CLK_VERSATILE
+	bool "Clocks for the ARM Versatile family"
+	depends on COMMON_CLK
+
+config CLK_ICST
+	bool "ICST307 VCO clock driver"
+	depends on COMMON_CLK
+	depends on ICST
diff --git a/drivers/clk/versatile/Makefile b/drivers/clk/versatile/Makefile
new file mode 100644
index 0000000..c70e18e
--- /dev/null
+++ b/drivers/clk/versatile/Makefile
@@ -0,0 +1,2 @@
+# Makefile for Versatile-specific clocks
+obj-$(CONFIG_CLK_ICST)		+= clk-icst.o
diff --git a/drivers/clk/versatile/clk-icst.c b/drivers/clk/versatile/clk-icst.c
new file mode 100644
index 0000000..f555b50
--- /dev/null
+++ b/drivers/clk/versatile/clk-icst.c
@@ -0,0 +1,100 @@
+/*
+ * Driver for the ICST307 VCO clock found in the ARM Reference designs.
+ * We wrap the custom interface from <asm/hardware/icst.h> into the generic
+ * clock framework.
+ *
+ * TODO: when all ARM reference designs are migrated to generic clocks, the
+ * ICST clock code from the ARM tree should probably be merged into this
+ * file.
+ */
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+
+#include "clk-icst.h"
+
+/**
+ * struct clk_icst - ICST VCO clock wrapper
+ * @hw: corresponding clock hardware entry
+ * @params: parameters for this ICST instance
+ * @rate: current rate
+ * @setvco: function to commit ICST settings to hardware
+ */
+struct clk_icst {
+	struct clk_hw hw;
+	const struct icst_params *params;
+	unsigned long rate;
+	struct icst_vco (*getvco)(void);
+	void (*setvco)(struct icst_vco);
+};
+
+#define to_icst(_hw) container_of(_hw, struct clk_icst, hw)
+
+static unsigned long icst_recalc_rate(struct clk_hw *hw,
+				      unsigned long parent_rate)
+{
+	struct clk_icst *icst = to_icst(hw);
+	struct icst_vco vco;
+
+	vco = icst->getvco();
+	icst->rate = icst_hz(icst->params, vco);
+	return icst->rate;
+}
+
+static long icst_round_rate(struct clk_hw *hw, unsigned long rate,
+			    unsigned long *prate)
+{
+	struct clk_icst *icst = to_icst(hw);
+	struct icst_vco vco;
+
+	vco = icst_hz_to_vco(icst->params, rate);
+	return icst_hz(icst->params, vco);
+}
+
+static int icst_set_rate(struct clk_hw *hw, unsigned long rate,
+			 unsigned long parent_rate)
+{
+	struct clk_icst *icst = to_icst(hw);
+	struct icst_vco vco;
+
+	vco = icst_hz_to_vco(icst->params, rate);
+	icst->rate = icst_hz(icst->params, vco);
+	icst->setvco(vco);
+	return 0;
+}
+
+static const struct clk_ops icst_ops = {
+	.recalc_rate = icst_recalc_rate,
+	.round_rate = icst_round_rate,
+	.set_rate = icst_set_rate,
+};
+
+struct clk * __init icst_clk_register(struct device *dev,
+				      const struct clk_icst_desc *desc)
+{
+	struct clk *clk;
+	struct clk_icst *icst;
+	struct clk_init_data init;
+
+	icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL);
+	if (!icst) {
+		pr_err("could not allocate ICST clock!\n");
+		return ERR_PTR(-ENOMEM);
+	}
+	init.name = "icst";
+	init.ops = &icst_ops;
+	init.flags = CLK_IS_ROOT;
+	init.parent_names = NULL;
+	init.num_parents = 0;
+	icst->hw.init = &init;
+	icst->params = desc->params;
+	icst->getvco = desc->getvco;
+	icst->setvco = desc->setvco;
+
+	clk = clk_register(dev, &icst->hw);
+	if (IS_ERR(clk))
+		kfree(icst);
+
+	return clk;
+}
diff --git a/drivers/clk/versatile/clk-icst.h b/drivers/clk/versatile/clk-icst.h
new file mode 100644
index 0000000..71b4c56
--- /dev/null
+++ b/drivers/clk/versatile/clk-icst.h
@@ -0,0 +1,10 @@
+#include <asm/hardware/icst.h>
+
+struct clk_icst_desc {
+	const struct icst_params *params;
+	struct icst_vco (*getvco)(void);
+	void (*setvco)(struct icst_vco);
+};
+
+struct clk *icst_clk_register(struct device *dev,
+			      const struct clk_icst_desc *desc);
-- 
1.7.10.2

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