[ARM] 5509/1: ep93xx: clkdev enable UARTS

Fix the clkdev API support for the ep93xx uart clocks.

The uarts available in the ep93xx have individual clock controls.
The current implementation assumes that the bootloader has enabled
the clocks before the kernel has booted. It also assumes that the
bootloader has set the UARTBAUD bit indicating that the uarts are
running off the 14.7456MHz external crystal.

This fixes both issues. It also allows the uart clocks to be stopped
when there are no users.

Tested-by: Matthias Kaehlcke <matthias@kaehlcke.net>

Cc: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 61 insertions, 8 deletions

diff --git a/arch/arm/mach-ep93xx/clock.c b/arch/arm/mach-ep93xx/clock.c
index e8ebeaea6c4..b2eede5531c 100644
--- a/arch/arm/mach-ep93xx/clock.c
+++ b/arch/arm/mach-ep93xx/clock.c
@@ -21,15 +21,50 @@
 #include <asm/div64.h>
 #include <mach/hardware.h>
 
+
+/*
+ * The EP93xx has two external crystal oscillators.  To generate the
+ * required high-frequency clocks, the processor uses two phase-locked-
+ * loops (PLLs) to multiply the incoming external clock signal to much
+ * higher frequencies that are then divided down by programmable dividers
+ * to produce the needed clocks.  The PLLs operate independently of one
+ * another.
+ */
+#define EP93XX_EXT_CLK_RATE	14745600
+#define EP93XX_EXT_RTC_RATE	32768
+
+
 struct clk {
 	unsigned long	rate;
 	int		users;
+	int		sw_locked;
 	u32		enable_reg;
 	u32		enable_mask;
+
+	unsigned long	(*get_rate)(struct clk *clk);
 };
 
-static struct clk clk_uart = {
-	.rate		= 14745600,
+
+static unsigned long get_uart_rate(struct clk *clk);
+
+
+static struct clk clk_uart1 = {
+	.sw_locked	= 1,
+	.enable_reg	= EP93XX_SYSCON_DEVICE_CONFIG,
+	.enable_mask	= EP93XX_SYSCON_DEVICE_CONFIG_U1EN,
+	.get_rate	= get_uart_rate,
+};
+static struct clk clk_uart2 = {
+	.sw_locked	= 1,
+	.enable_reg	= EP93XX_SYSCON_DEVICE_CONFIG,
+	.enable_mask	= EP93XX_SYSCON_DEVICE_CONFIG_U2EN,
+	.get_rate	= get_uart_rate,
+};
+static struct clk clk_uart3 = {
+	.sw_locked	= 1,
+	.enable_reg	= EP93XX_SYSCON_DEVICE_CONFIG,
+	.enable_mask	= EP93XX_SYSCON_DEVICE_CONFIG_U3EN,
+	.get_rate	= get_uart_rate,
 };
 static struct clk clk_pll1;
 static struct clk clk_f;
@@ -95,9 +130,9 @@ static struct clk clk_m2m1 = {
 	{ .dev_id = dev, .con_id = con, .clk = ck }
 
 static struct clk_lookup clocks[] = {
-	INIT_CK("apb:uart1", NULL, &clk_uart),
-	INIT_CK("apb:uart2", NULL, &clk_uart),
-	INIT_CK("apb:uart3", NULL, &clk_uart),
+	INIT_CK("apb:uart1", NULL, &clk_uart1),
+	INIT_CK("apb:uart2", NULL, &clk_uart2),
+	INIT_CK("apb:uart3", NULL, &clk_uart3),
 	INIT_CK(NULL, "pll1", &clk_pll1),
 	INIT_CK(NULL, "fclk", &clk_f),
 	INIT_CK(NULL, "hclk", &clk_h),
@@ -125,6 +160,8 @@ int clk_enable(struct clk *clk)
 		u32 value;
 
 		value = __raw_readl(clk->enable_reg);
+		if (clk->sw_locked)
+			__raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
 		__raw_writel(value | clk->enable_mask, clk->enable_reg);
 	}
 
@@ -138,13 +175,29 @@ void clk_disable(struct clk *clk)
 		u32 value;
 
 		value = __raw_readl(clk->enable_reg);
+		if (clk->sw_locked)
+			__raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
 		__raw_writel(value & ~clk->enable_mask, clk->enable_reg);
 	}
 }
 EXPORT_SYMBOL(clk_disable);
 
+static unsigned long get_uart_rate(struct clk *clk)
+{
+	u32 value;
+
+	value = __raw_readl(EP93XX_SYSCON_CLOCK_CONTROL);
+	if (value & EP93XX_SYSCON_CLOCK_UARTBAUD)
+		return EP93XX_EXT_CLK_RATE;
+	else
+		return EP93XX_EXT_CLK_RATE / 2;
+}
+
 unsigned long clk_get_rate(struct clk *clk)
 {
+	if (clk->get_rate)
+		return clk->get_rate(clk);
+
 	return clk->rate;
 }
 EXPORT_SYMBOL(clk_get_rate);
@@ -162,7 +215,7 @@ static unsigned long calc_pll_rate(u32 config_word)
 	unsigned long long rate;
 	int i;
 
-	rate = 14745600;
+	rate = EP93XX_EXT_CLK_RATE;
 	rate *= ((config_word >> 11) & 0x1f) + 1;		/* X1FBD */
 	rate *= ((config_word >> 5) & 0x3f) + 1;		/* X2FBD */
 	do_div(rate, (config_word & 0x1f) + 1);			/* X2IPD */
@@ -195,7 +248,7 @@ static int __init ep93xx_clock_init(void)
 
 	value = __raw_readl(EP93XX_SYSCON_CLOCK_SET1);
 	if (!(value & 0x00800000)) {			/* PLL1 bypassed?  */
-		clk_pll1.rate = 14745600;
+		clk_pll1.rate = EP93XX_EXT_CLK_RATE;
 	} else {
 		clk_pll1.rate = calc_pll_rate(value);
 	}
@@ -206,7 +259,7 @@ static int __init ep93xx_clock_init(void)
 
 	value = __raw_readl(EP93XX_SYSCON_CLOCK_SET2);
 	if (!(value & 0x00080000)) {			/* PLL2 bypassed?  */
-		clk_pll2.rate = 14745600;
+		clk_pll2.rate = EP93XX_EXT_CLK_RATE;
 	} else if (value & 0x00040000) {		/* PLL2 enabled?  */
 		clk_pll2.rate = calc_pll_rate(value);
 	} else {