commit 0691bb1b5a1865b3bbc9b7ce6e26eff546abb1cf
author Dinh Nguyen <dinguyen@altera.com> Mon May 12 12:27:22 2014 -0500
committer Dinh Nguyen <dinguyen@altera.com> Mon May 12 12:27:22 2014 -0500
tree 1011296d0c0a3ec703f73880c96667be0f569eee
parent d1db0eea852497762cab43b905b879dfcd3b8987

clk: socfpga: add divider registers to the main pll outputs

The C0(mpu_clk), C1(main_clk), and C2(dbg_base_clk) outputs from the main
PLL go through a pre-divider before coming into the system. These registers
were hidden for the CycloneV platform, but are now used for the ArriaV
platform.

This patch updates the clock driver to read the div-reg property for the
socfpga-periph-clk clocks. Also moves the div_mask define to clk.h for re-use.

Signed-off-by: Dinh Nguyen <dinguyen@altera.com>

drivers/clk/socfpga/clk-gate.c

diff --git a/drivers/clk/socfpga/clk-gate.c b/drivers/clk/socfpga/clk-gate.c
index 501d513..dd3a78c 100644
--- a/drivers/clk/socfpga/clk-gate.c
+++ b/drivers/clk/socfpga/clk-gate.c
@@ -32,7 +32,6 @@
 #define SOCFPGA_MMC_CLK			"sdmmc_clk"
 #define SOCFPGA_GPIO_DB_CLK_OFFSET	0xA8
 
-#define div_mask(width)	((1 << (width)) - 1)
 #define streq(a, b) (strcmp((a), (b)) == 0)
 
 #define to_socfpga_gate_clk(p) container_of(p, struct socfpga_gate_clk, hw.hw)

drivers/clk/socfpga/clk-periph.c

diff --git a/drivers/clk/socfpga/clk-periph.c b/drivers/clk/socfpga/clk-periph.c
index 81623a3..46531c3 100644
--- a/drivers/clk/socfpga/clk-periph.c
+++ b/drivers/clk/socfpga/clk-periph.c
@@ -29,12 +29,18 @@
 					     unsigned long parent_rate)
 {
 	struct socfpga_periph_clk *socfpgaclk = to_socfpga_periph_clk(hwclk);
-	u32 div;
+	u32 div, val;
 
-	if (socfpgaclk->fixed_div)
+	if (socfpgaclk->fixed_div) {
 		div = socfpgaclk->fixed_div;
-	else
+	} else {
+		if (socfpgaclk->div_reg) {
+			val = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
+			val &= div_mask(socfpgaclk->width);
+			parent_rate /= (val + 1);
+		}
 		div = ((readl(socfpgaclk->hw.reg) & 0x1ff) + 1);
+	}
 
 	return parent_rate / div;
 }
@@ -54,6 +60,7 @@
 	struct clk_init_data init;
 	int rc;
 	u32 fixed_div;
+	u32 div_reg[3];
 
 	of_property_read_u32(node, "reg", &reg);
 
@@ -63,6 +70,15 @@
 
 	periph_clk->hw.reg = clk_mgr_base_addr + reg;
 
+	rc = of_property_read_u32_array(node, "div-reg", div_reg, 3);
+	if (!rc) {
+		periph_clk->div_reg = clk_mgr_base_addr + div_reg[0];
+		periph_clk->shift = div_reg[1];
+		periph_clk->width = div_reg[2];
+	} else {
+		periph_clk->div_reg = 0;
+	}
+
 	rc = of_property_read_u32(node, "fixed-divider", &fixed_div);
 	if (rc)
 		periph_clk->fixed_div = 0;

drivers/clk/socfpga/clk.h

diff --git a/drivers/clk/socfpga/clk.h b/drivers/clk/socfpga/clk.h
index d2e5401..d291f60 100644
--- a/drivers/clk/socfpga/clk.h
+++ b/drivers/clk/socfpga/clk.h
@@ -27,6 +27,7 @@
 #define CLKMGR_PERPLL_SRC	0xAC
 
 #define SOCFPGA_MAX_PARENTS		3
+#define div_mask(width) ((1 << (width)) - 1)
 
 extern void __iomem *clk_mgr_base_addr;
 
@@ -52,6 +53,9 @@
 	struct clk_gate hw;
 	char *parent_name;
 	u32 fixed_div;
+	void __iomem *div_reg;
+	u32 width;      /* only valid if div_reg != 0 */
+	u32 shift;      /* only valid if div_reg != 0 */
 };
 
 #endif /* SOCFPGA_CLK_H */