[ARM] versatile: convert to clkdev and lookup clocks by device name

People often point to the Integrator/Versatile/Realview
implementations to justify using the consumer name as the sole
selector for clocks.

Eliminate this excuse by changing the Versatile implementation, so
it provides a better example of how it should be done.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -231,6 +231,7 @@ config ARCH_VERSATILE
 	select ARM_AMBA
 	select ARM_VIC
 	select HAVE_CLK
+	select COMMON_CLKDEV
 	select ICST307
 	select GENERIC_TIME
 	select GENERIC_CLOCKEVENTS

arch/arm/mach-versatile/clock.c

@@ -10,6 +10,7 @@
  */
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/device.h>
 #include <linux/list.h>
 #include <linux/errno.h>
 #include <linux/err.h>
@@ -17,36 +18,11 @@
 #include <linux/clk.h>
 #include <linux/mutex.h>
 
+#include <asm/clkdev.h>
 #include <asm/hardware/icst307.h>
 
 #include "clock.h"
 
-static LIST_HEAD(clocks);
-static DEFINE_MUTEX(clocks_mutex);
-
-struct clk *clk_get(struct device *dev, const char *id)
-{
-	struct clk *p, *clk = ERR_PTR(-ENOENT);
-
-	mutex_lock(&clocks_mutex);
-	list_for_each_entry(p, &clocks, node) {
-		if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
-			clk = p;
-			break;
-		}
-	}
-	mutex_unlock(&clocks_mutex);
-
-	return clk;
-}
-EXPORT_SYMBOL(clk_get);
-
-void clk_put(struct clk *clk)
-{
-	module_put(clk->owner);
-}
-EXPORT_SYMBOL(clk_put);
-
 int clk_enable(struct clk *clk)
 {
 	return 0;
@@ -66,7 +42,9 @@ EXPORT_SYMBOL(clk_get_rate);
 
 long clk_round_rate(struct clk *clk, unsigned long rate)
 {
-	return rate;
+	struct icst307_vco vco;
+	vco = icst307_khz_to_vco(clk->params, rate / 1000);
+	return icst307_khz(clk->params, vco) * 1000;
 }
 EXPORT_SYMBOL(clk_round_rate);
 
@@ -79,57 +57,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
 
 		vco = icst307_khz_to_vco(clk->params, rate / 1000);
 		clk->rate = icst307_khz(clk->params, vco) * 1000;
-
-		printk("Clock %s: setting VCO reg params: S=%d R=%d V=%d\n",
-			clk->name, vco.s, vco.r, vco.v);
-
 		clk->setvco(clk, vco);
 		ret = 0;
 	}
 	return ret;
 }
 EXPORT_SYMBOL(clk_set_rate);
-
-/*
- * These are fixed clocks.
- */
-static struct clk kmi_clk = {
-	.name	= "KMIREFCLK",
-	.rate	= 24000000,
-};
-
-static struct clk uart_clk = {
-	.name	= "UARTCLK",
-	.rate	= 24000000,
-};
-
-static struct clk mmci_clk = {
-	.name	= "MCLK",
-	.rate	= 24000000,
-};
-
-int clk_register(struct clk *clk)
-{
-	mutex_lock(&clocks_mutex);
-	list_add(&clk->node, &clocks);
-	mutex_unlock(&clocks_mutex);
-	return 0;
-}
-EXPORT_SYMBOL(clk_register);
-
-void clk_unregister(struct clk *clk)
-{
-	mutex_lock(&clocks_mutex);
-	list_del(&clk->node);
-	mutex_unlock(&clocks_mutex);
-}
-EXPORT_SYMBOL(clk_unregister);
-
-static int __init clk_init(void)
-{
-	clk_register(&kmi_clk);
-	clk_register(&uart_clk);
-	clk_register(&mmci_clk);
-	return 0;
-}
-arch_initcall(clk_init);

arch/arm/mach-versatile/clock.h

@@ -12,14 +12,9 @@ struct module;
 struct icst307_params;
 
 struct clk {
-	struct list_head	node;
 	unsigned long		rate;
-	struct module		*owner;
-	const char		*name;
 	const struct icst307_params *params;
+	u32			oscoff;
 	void			*data;
 	void			(*setvco)(struct clk *, struct icst307_vco vco);
 };
-
-int clk_register(struct clk *clk);
-void clk_unregister(struct clk *clk);

arch/arm/mach-versatile/core.c

@@ -31,6 +31,7 @@
 #include <linux/cnt32_to_63.h>
 #include <linux/io.h>
 
+#include <asm/clkdev.h>
 #include <asm/system.h>
 #include <mach/hardware.h>
 #include <asm/irq.h>
@@ -373,24 +374,62 @@ static const struct icst307_params versatile_oscvco_params = {
 
 static void versatile_oscvco_set(struct clk *clk, struct icst307_vco vco)
 {
-	void __iomem *sys_lock = __io_address(VERSATILE_SYS_BASE) + VERSATILE_SYS_LOCK_OFFSET;
-	void __iomem *sys_osc = __io_address(VERSATILE_SYS_BASE) + VERSATILE_SYS_OSCCLCD_OFFSET;
+	void __iomem *sys = __io_address(VERSATILE_SYS_BASE);
+	void __iomem *sys_lock = sys + VERSATILE_SYS_LOCK_OFFSET;
 	u32 val;
 
-	val = readl(sys_osc) & ~0x7ffff;
+	val = readl(sys + clk->oscoff) & ~0x7ffff;
 	val |= vco.v | (vco.r << 9) | (vco.s << 16);
 
 	writel(0xa05f, sys_lock);
-	writel(val, sys_osc);
+	writel(val, sys + clk->oscoff);
 	writel(0, sys_lock);
 }
 
-static struct clk versatile_clcd_clk = {
-	.name	= "CLCDCLK",
+static struct clk osc4_clk = {
 	.params	= &versatile_oscvco_params,
+	.oscoff	= VERSATILE_SYS_OSCCLCD_OFFSET,
 	.setvco	= versatile_oscvco_set,
 };
 
+/*
+ * These are fixed clocks.
+ */
+static struct clk ref24_clk = {
+	.rate	= 24000000,
+};
+
+static struct clk_lookup lookups[] __initdata = {
+	{	/* UART0 */
+		.dev_id		= "dev:f1",
+		.clk		= &ref24_clk,
+	}, {	/* UART1 */
+		.dev_id		= "dev:f2",
+		.clk		= &ref24_clk,
+	}, {	/* UART2 */
+		.dev_id		= "dev:f3",
+		.clk		= &ref24_clk,
+	}, {	/* UART3 */
+		.dev_id		= "fpga:09",
+		.clk		= &ref24_clk,
+	}, {	/* KMI0 */
+		.dev_id		= "fpga:06",
+		.clk		= &ref24_clk,
+	}, {	/* KMI1 */
+		.dev_id		= "fpga:07",
+		.clk		= &ref24_clk,
+	}, {	/* MMC0 */
+		.dev_id		= "fpga:05",
+		.clk		= &ref24_clk,
+	}, {	/* MMC1 */
+		.dev_id		= "fpga:0b",
+		.clk		= &ref24_clk,
+	}, {	/* CLCD */
+		.dev_id		= "dev:20",
+		.clk		= &osc4_clk,
+	}
+};
+
 /*
  * CLCD support.
  */
@@ -786,7 +825,8 @@ void __init versatile_init(void)
 {
 	int i;
 
-	clk_register(&versatile_clcd_clk);
+	for (i = 0; i < ARRAY_SIZE(lookups); i++)
+		clkdev_add(&lookups[i]);
 
 	platform_device_register(&versatile_flash_device);
 	platform_device_register(&versatile_i2c_device);

arch/arm/mach-versatile/include/mach/clkdev.h

+#ifndef __ASM_MACH_CLKDEV_H
+#define __ASM_MACH_CLKDEV_H
+
+#define __clk_get(clk) ({ 1; })
+#define __clk_put(clk) do { } while (0)
+
+#endif