clk: hi6220: Clock driver support for Hisilicon hi6220 SoC

Add clock drivers for hi6220 SoC, this driver controls the SoC
registers to supply different clocks to different IPs in the SoC.

We add one divider clock for hi6220 because the divider in hi6220
also has a mask bit but it doesnot obey the rule defined by flag
"CLK_DIVIDER_HIWORD_MASK", we can not get index of the mask bit by
left shift fixed bits (e.g. 16 bits), so we add this divider clock
to handle it.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Bintian Wang <bintian.wang@huawei.com>
Acked-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Reviewed-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Will Deacon <will.deacon@arm.com>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>

1 files changed, 156 insertions, 0 deletions

diff --git a/drivers/clk/hisilicon/clkdivider-hi6220.c b/drivers/clk/hisilicon/clkdivider-hi6220.c
new file mode 100644
index 000000000000..113eee8ed23a
--- /dev/null
+++ b/drivers/clk/hisilicon/clkdivider-hi6220.c
@@ -0,0 +1,156 @@
+/*
+ * Hisilicon hi6220 SoC divider clock driver
+ *
+ * Copyright (c) 2015 Hisilicon Limited.
+ *
+ * Author: Bintian Wang <bintian.wang@huawei.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+
+#define div_mask(width)	((1 << (width)) - 1)
+
+/**
+ * struct hi6220_clk_divider - divider clock for hi6220
+ *
+ * @hw:		handle between common and hardware-specific interfaces
+ * @reg:	register containing divider
+ * @shift:	shift to the divider bit field
+ * @width:	width of the divider bit field
+ * @mask:	mask for setting divider rate
+ * @table:	the div table that the divider supports
+ * @lock:	register lock
+ */
+struct hi6220_clk_divider {
+	struct clk_hw	hw;
+	void __iomem	*reg;
+	u8		shift;
+	u8		width;
+	u32		mask;
+	const struct clk_div_table *table;
+	spinlock_t	*lock;
+};
+
+#define to_hi6220_clk_divider(_hw)	\
+	container_of(_hw, struct hi6220_clk_divider, hw)
+
+static unsigned long hi6220_clkdiv_recalc_rate(struct clk_hw *hw,
+					unsigned long parent_rate)
+{
+	unsigned int val;
+	struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
+
+	val = readl_relaxed(dclk->reg) >> dclk->shift;
+	val &= div_mask(dclk->width);
+
+	return divider_recalc_rate(hw, parent_rate, val, dclk->table,
+				   CLK_DIVIDER_ROUND_CLOSEST);
+}
+
+static long hi6220_clkdiv_round_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long *prate)
+{
+	struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
+
+	return divider_round_rate(hw, rate, prate, dclk->table,
+				  dclk->width, CLK_DIVIDER_ROUND_CLOSEST);
+}
+
+static int hi6220_clkdiv_set_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long parent_rate)
+{
+	int value;
+	unsigned long flags = 0;
+	u32 data;
+	struct hi6220_clk_divider *dclk = to_hi6220_clk_divider(hw);
+
+	value = divider_get_val(rate, parent_rate, dclk->table,
+				dclk->width, CLK_DIVIDER_ROUND_CLOSEST);
+
+	if (dclk->lock)
+		spin_lock_irqsave(dclk->lock, flags);
+
+	data = readl_relaxed(dclk->reg);
+	data &= ~(div_mask(dclk->width) << dclk->shift);
+	data |= value << dclk->shift;
+	data |= dclk->mask;
+
+	writel_relaxed(data, dclk->reg);
+
+	if (dclk->lock)
+		spin_unlock_irqrestore(dclk->lock, flags);
+
+	return 0;
+}
+
+static const struct clk_ops hi6220_clkdiv_ops = {
+	.recalc_rate = hi6220_clkdiv_recalc_rate,
+	.round_rate = hi6220_clkdiv_round_rate,
+	.set_rate = hi6220_clkdiv_set_rate,
+};
+
+struct clk *hi6220_register_clkdiv(struct device *dev, const char *name,
+	const char *parent_name, unsigned long flags, void __iomem *reg,
+	u8 shift, u8 width, u32 mask_bit, spinlock_t *lock)
+{
+	struct hi6220_clk_divider *div;
+	struct clk *clk;
+	struct clk_init_data init;
+	struct clk_div_table *table;
+	u32 max_div, min_div;
+	int i;
+
+	/* allocate the divider */
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		return ERR_PTR(-ENOMEM);
+
+	/* Init the divider table */
+	max_div = div_mask(width) + 1;
+	min_div = 1;
+
+	table = kcalloc(max_div + 1, sizeof(*table), GFP_KERNEL);
+	if (!table) {
+		kfree(div);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	for (i = 0; i < max_div; i++) {
+		table[i].div = min_div + i;
+		table[i].val = table[i].div - 1;
+	}
+
+	init.name = name;
+	init.ops = &hi6220_clkdiv_ops;
+	init.flags = flags;
+	init.parent_names = parent_name ? &parent_name : NULL;
+	init.num_parents = parent_name ? 1 : 0;
+
+	/* struct hi6220_clk_divider assignments */
+	div->reg = reg;
+	div->shift = shift;
+	div->width = width;
+	div->mask = mask_bit ? BIT(mask_bit) : 0;
+	div->lock = lock;
+	div->hw.init = &init;
+	div->table = table;
+
+	/* register the clock */
+	clk = clk_register(dev, &div->hw);
+	if (IS_ERR(clk)) {
+		kfree(table);
+		kfree(div);
+	}
+
+	return clk;
+}