diff --git a/arch/arm/mach-shmobile/clock-sh73a0.c b/arch/arm/mach-shmobile/clock-sh73a0.c
index 784fbaa..acb9e09 100644
--- a/arch/arm/mach-shmobile/clock-sh73a0.c
+++ b/arch/arm/mach-shmobile/clock-sh73a0.c
@@ -228,6 +228,11 @@ enum { DIV4_I, DIV4_ZG, DIV4_M3, DIV4_B, DIV4_M1, DIV4_M2,
 
 static struct clk div4_clks[DIV4_NR] = {
 	[DIV4_I] = DIV4(FRQCRA, 20, 0xdff, CLK_ENABLE_ON_INIT),
+	/*
+	 * ZG clock is dividing PLL0 frequency to supply SGX. Make sure not to
+	 * exceed maximum frequencies of 201.5MHz for VDD_DVFS=1.175 and
+	 * 239.2MHz for VDD_DVFS=1.315V.
+	 */
 	[DIV4_ZG] = SH_CLK_DIV4(&pll0_clk, FRQCRA, 16, 0xd7f, CLK_ENABLE_ON_INIT),
 	[DIV4_M3] = DIV4(FRQCRA, 12, 0x1dff, CLK_ENABLE_ON_INIT),
 	[DIV4_B] = DIV4(FRQCRA, 8, 0xdff, CLK_ENABLE_ON_INIT),
@@ -252,6 +257,85 @@ static struct clk twd_clk = {
 	.ops = &twd_clk_ops,
 };
 
+static int (*div4_set_rate)(struct clk *clk, unsigned long rate);
+static unsigned long (*div4_recalc)(struct clk *clk);
+static long (*div4_round_rate)(struct clk *clk, unsigned long rate);
+
+static int zclk_set_rate(struct clk *clk, unsigned long rate)
+{
+	int ret;
+
+	if (!clk->parent || !__clk_get(clk->parent))
+		return -ENODEV;
+
+	if (readl(FRQCRB) & (1 << 31))
+		return -EBUSY;
+
+	if (rate == clk_get_rate(clk->parent)) {
+		/* 1:1 - switch off divider */
+		__raw_writel(__raw_readl(FRQCRB) & ~(1 << 28), FRQCRB);
+		/* nullify the divider to prepare for the next time */
+		ret = div4_set_rate(clk, rate / 2);
+		if (!ret)
+			ret = frqcr_kick();
+		if (ret > 0)
+			ret = 0;
+	} else {
+		/* Enable the divider */
+		__raw_writel(__raw_readl(FRQCRB) | (1 << 28), FRQCRB);
+
+		ret = frqcr_kick();
+		if (ret >= 0)
+			/*
+			 * set the divider - call the DIV4 method, it will kick
+			 * FRQCRB too
+			 */
+			ret = div4_set_rate(clk, rate);
+		if (ret < 0)
+			goto esetrate;
+	}
+
+esetrate:
+	__clk_put(clk->parent);
+	return ret;
+}
+
+static long zclk_round_rate(struct clk *clk, unsigned long rate)
+{
+	unsigned long div_freq = div4_round_rate(clk, rate),
+		parent_freq = clk_get_rate(clk->parent);
+
+	if (rate > div_freq && abs(parent_freq - rate) < rate - div_freq)
+		return parent_freq;
+
+	return div_freq;
+}
+
+static unsigned long zclk_recalc(struct clk *clk)
+{
+	/*
+	 * Must recalculate frequencies in case PLL0 has been changed, even if
+	 * the divisor is unused ATM!
+	 */
+	unsigned long div_freq = div4_recalc(clk);
+
+	if (__raw_readl(FRQCRB) & (1 << 28))
+		return div_freq;
+
+	return clk_get_rate(clk->parent);
+}
+
+static void zclk_extend(void)
+{
+	/* We extend the DIV4 clock with a 1:1 pass-through case */
+	div4_set_rate = div4_clks[DIV4_Z].ops->set_rate;
+	div4_round_rate = div4_clks[DIV4_Z].ops->round_rate;
+	div4_recalc = div4_clks[DIV4_Z].ops->recalc;
+	div4_clks[DIV4_Z].ops->set_rate = zclk_set_rate;
+	div4_clks[DIV4_Z].ops->round_rate = zclk_round_rate;
+	div4_clks[DIV4_Z].ops->recalc = zclk_recalc;
+}
+
 enum { DIV6_VCK1, DIV6_VCK2, DIV6_VCK3, DIV6_ZB1,
 	DIV6_FLCTL, DIV6_SDHI0, DIV6_SDHI1, DIV6_SDHI2,
 	DIV6_FSIA, DIV6_FSIB, DIV6_SUB,
@@ -450,7 +534,7 @@ static struct clk *late_main_clks[] = {
 };
 
 enum { MSTP001,
-	MSTP129, MSTP128, MSTP127, MSTP126, MSTP125, MSTP118, MSTP116, MSTP100,
+	MSTP129, MSTP128, MSTP127, MSTP126, MSTP125, MSTP118, MSTP116, MSTP112, MSTP100,
 	MSTP219, MSTP218, MSTP217,
 	MSTP207, MSTP206, MSTP204, MSTP203, MSTP202, MSTP201, MSTP200,
 	MSTP331, MSTP329, MSTP328, MSTP325, MSTP323, MSTP322,
@@ -471,6 +555,7 @@ static struct clk mstp_clks[MSTP_NR] = {
 	[MSTP125] = MSTP(&div6_clks[DIV6_SUB], SMSTPCR1, 25, 0), /* TMU0 */
 	[MSTP118] = MSTP(&div4_clks[DIV4_B], SMSTPCR1, 18, 0), /* DSITX0 */
 	[MSTP116] = MSTP(&div4_clks[DIV4_HP], SMSTPCR1, 16, 0), /* IIC0 */
+	[MSTP112] = MSTP(&div4_clks[DIV4_ZG], SMSTPCR1, 12, 0), /* SGX */
 	[MSTP100] = MSTP(&div4_clks[DIV4_B], SMSTPCR1, 0, 0), /* LCDC0 */
 	[MSTP219] = MSTP(&div6_clks[DIV6_SUB], SMSTPCR2, 19, 0), /* SCIFA7 */
 	[MSTP218] = MSTP(&div4_clks[DIV4_HP], SMSTPCR2, 18, 0), /* SY-DMAC */
@@ -513,6 +598,9 @@ static struct clk_lookup lookups[] = {
 	CLKDEV_CON_ID("r_clk", &r_clk),
 	CLKDEV_DEV_ID("smp_twd", &twd_clk), /* smp_twd */
 
+	/* DIV4 clocks */
+	CLKDEV_DEV_ID("cpufreq-cpu0", &div4_clks[DIV4_Z]),
+
 	/* DIV6 clocks */
 	CLKDEV_CON_ID("vck1_clk", &div6_clks[DIV6_VCK1]),
 	CLKDEV_CON_ID("vck2_clk", &div6_clks[DIV6_VCK2]),
@@ -604,8 +692,11 @@ void __init sh73a0_clock_init(void)
 	for (k = 0; !ret && (k < ARRAY_SIZE(main_clks)); k++)
 		ret = clk_register(main_clks[k]);
 
-	if (!ret)
+	if (!ret) {
 		ret = sh_clk_div4_register(div4_clks, DIV4_NR, &div4_table);
+		if (!ret)
+			zclk_extend();
+	}
 
 	if (!ret)
 		ret = sh_clk_div6_reparent_register(div6_clks, DIV6_NR);
