clk: zte: add audio clocks for zx296718

The audio related clock support is missing from the existing zx296718
clock driver.  Let's add it, so that the upstream ZX SPDIF driver can
work for HDMI audio support.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
[sboyd@codeaurora.org: Staticize some more structures]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

1 files changed, 127 insertions, 0 deletions

diff --git a/drivers/clk/zte/clk.c b/drivers/clk/zte/clk.c
index c4c1251bc1e7..878d879b23ff 100644
--- a/drivers/clk/zte/clk.c
+++ b/drivers/clk/zte/clk.c
@@ -9,6 +9,7 @@
 
 #include <linux/clk-provider.h>
 #include <linux/err.h>
+#include <linux/gcd.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/slab.h>
@@ -310,3 +311,129 @@ struct clk *clk_register_zx_audio(const char *name,
 
 	return clk;
 }
+
+#define CLK_AUDIO_DIV_FRAC	BIT(0)
+#define CLK_AUDIO_DIV_INT	BIT(1)
+#define CLK_AUDIO_DIV_UNCOMMON	BIT(1)
+
+#define CLK_AUDIO_DIV_FRAC_NSHIFT	16
+#define CLK_AUDIO_DIV_INT_FRAC_RE	BIT(16)
+#define CLK_AUDIO_DIV_INT_FRAC_MAX	(0xffff)
+#define CLK_AUDIO_DIV_INT_FRAC_MIN	(0x2)
+#define CLK_AUDIO_DIV_INT_INT_SHIFT	24
+#define CLK_AUDIO_DIV_INT_INT_WIDTH	4
+
+struct zx_clk_audio_div_table {
+	unsigned long rate;
+	unsigned int int_reg;
+	unsigned int frac_reg;
+};
+
+#define to_clk_zx_audio_div(_hw) container_of(_hw, struct clk_zx_audio_divider, hw)
+
+static unsigned long audio_calc_rate(struct clk_zx_audio_divider *audio_div,
+				     u32 reg_frac, u32 reg_int,
+				     unsigned long parent_rate)
+{
+	unsigned long rate, m, n;
+
+	m = reg_frac & 0xffff;
+	n = (reg_frac >> 16) & 0xffff;
+
+	m = (reg_int & 0xffff) * n + m;
+	rate = (parent_rate * n) / m;
+
+	return rate;
+}
+
+static void audio_calc_reg(struct clk_zx_audio_divider *audio_div,
+			   struct zx_clk_audio_div_table *div_table,
+			   unsigned long rate, unsigned long parent_rate)
+{
+	unsigned int reg_int, reg_frac;
+	unsigned long m, n, div;
+
+	reg_int = parent_rate / rate;
+
+	if (reg_int > CLK_AUDIO_DIV_INT_FRAC_MAX)
+		reg_int = CLK_AUDIO_DIV_INT_FRAC_MAX;
+	else if (reg_int < CLK_AUDIO_DIV_INT_FRAC_MIN)
+		reg_int = 0;
+	m = parent_rate - rate * reg_int;
+	n = rate;
+
+	div = gcd(m, n);
+	m = m / div;
+	n = n / div;
+
+	if ((m >> 16) || (n >> 16)) {
+		if (m > n) {
+			n = n * 0xffff / m;
+			m = 0xffff;
+		} else {
+			m = m * 0xffff / n;
+			n = 0xffff;
+		}
+	}
+	reg_frac = m | (n << 16);
+
+	div_table->rate = parent_rate * n / (reg_int * n + m);
+	div_table->int_reg = reg_int;
+	div_table->frac_reg = reg_frac;
+}
+
+static unsigned long zx_audio_div_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct clk_zx_audio_divider *zx_audio_div = to_clk_zx_audio_div(hw);
+	u32 reg_frac, reg_int;
+
+	reg_frac = readl_relaxed(zx_audio_div->reg_base);
+	reg_int = readl_relaxed(zx_audio_div->reg_base + 0x4);
+
+	return audio_calc_rate(zx_audio_div, reg_frac, reg_int, parent_rate);
+}
+
+static long zx_audio_div_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *prate)
+{
+	struct clk_zx_audio_divider *zx_audio_div = to_clk_zx_audio_div(hw);
+	struct zx_clk_audio_div_table divt;
+
+	audio_calc_reg(zx_audio_div, &divt, rate, *prate);
+
+	return audio_calc_rate(zx_audio_div, divt.frac_reg, divt.int_reg, *prate);
+}
+
+static int zx_audio_div_set_rate(struct clk_hw *hw, unsigned long rate,
+				    unsigned long parent_rate)
+{
+	struct clk_zx_audio_divider *zx_audio_div = to_clk_zx_audio_div(hw);
+	struct zx_clk_audio_div_table divt;
+	unsigned int val;
+
+	audio_calc_reg(zx_audio_div, &divt, rate, parent_rate);
+	if (divt.rate != rate)
+		pr_debug("the real rate is:%ld", divt.rate);
+
+	writel_relaxed(divt.frac_reg, zx_audio_div->reg_base);
+
+	val = readl_relaxed(zx_audio_div->reg_base + 0x4);
+	val &= ~0xffff;
+	val |= divt.int_reg | CLK_AUDIO_DIV_INT_FRAC_RE;
+	writel_relaxed(val, zx_audio_div->reg_base + 0x4);
+
+	mdelay(1);
+
+	val = readl_relaxed(zx_audio_div->reg_base + 0x4);
+	val &= ~CLK_AUDIO_DIV_INT_FRAC_RE;
+	writel_relaxed(val, zx_audio_div->reg_base + 0x4);
+
+	return 0;
+}
+
+const struct clk_ops zx_audio_div_ops = {
+	.recalc_rate = zx_audio_div_recalc_rate,
+	.round_rate = zx_audio_div_round_rate,
+	.set_rate = zx_audio_div_set_rate,
+};