clk: arm: sunxi: Add a new clock driver for sunxi SOCs
This commit implements the base CPU clocks for sunxi devices. It has
been tested using a slightly modified cpufreq driver from the
linux-sunxi 3.0 tree.
Additionally, document the new bindings introduced by this patch.
Idling:
/ # cat /sys/kernel/debug/clk/clk_summary
clock enable_cnt prepare_cnt rate
---------------------------------------------------------------------
osc32k 0 0 32768
osc24M_fixed 0 0 24000000
osc24M 0 0 24000000
apb1_mux 0 0 24000000
apb1 0 0 24000000
pll1 0 0 60000000
cpu 0 0 60000000
axi 0 0 60000000
ahb 0 0 60000000
apb0 0 0 30000000
dummy 0 0 0
After "yes >/dev/null &":
/ # cat /sys/kernel/debug/clk/clk_summary
clock enable_cnt prepare_cnt rate
---------------------------------------------------------------------
osc32k 0 0 32768
osc24M_fixed 0 0 24000000
osc24M 0 0 24000000
apb1_mux 0 0 24000000
apb1 0 0 24000000
pll1 0 0 1008000000
cpu 0 0 1008000000
axi 0 0 336000000
ahb 0 0 168000000
apb0 0 0 84000000
dummy 0 0 0
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c
new file mode 100644
index 0000000..88523f9
--- /dev/null
+++ b/drivers/clk/sunxi/clk-factors.c
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2013 Emilio López <emilio@elopez.com.ar>
+ *
+ * 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.
+ *
+ * Adjustable factor-based clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+
+#include <linux/delay.h>
+
+#include "clk-factors.h"
+
+/*
+ * DOC: basic adjustable factor-based clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is adjustable.
+ * clk->rate = (parent->rate * N * (K + 1) >> P) / (M + 1)
+ * parent - fixed parent. No clk_set_parent support
+ */
+
+struct clk_factors {
+ struct clk_hw hw;
+ void __iomem *reg;
+ struct clk_factors_config *config;
+ void (*get_factors) (u32 *rate, u32 parent, u8 *n, u8 *k, u8 *m, u8 *p);
+ spinlock_t *lock;
+};
+
+#define to_clk_factors(_hw) container_of(_hw, struct clk_factors, hw)
+
+#define SETMASK(len, pos) (((-1U) >> (31-len)) << (pos))
+#define CLRMASK(len, pos) (~(SETMASK(len, pos)))
+#define FACTOR_GET(bit, len, reg) (((reg) & SETMASK(len, bit)) >> (bit))
+
+#define FACTOR_SET(bit, len, reg, val) \
+ (((reg) & CLRMASK(len, bit)) | (val << (bit)))
+
+static unsigned long clk_factors_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ u8 n = 1, k = 0, p = 0, m = 0;
+ u32 reg;
+ unsigned long rate;
+ struct clk_factors *factors = to_clk_factors(hw);
+ struct clk_factors_config *config = factors->config;
+
+ /* Fetch the register value */
+ reg = readl(factors->reg);
+
+ /* Get each individual factor if applicable */
+ if (config->nwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+ n = FACTOR_GET(config->nshift, config->nwidth, reg);
+ if (config->kwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+ k = FACTOR_GET(config->kshift, config->kwidth, reg);
+ if (config->mwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+ m = FACTOR_GET(config->mshift, config->mwidth, reg);
+ if (config->pwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+ p = FACTOR_GET(config->pshift, config->pwidth, reg);
+
+ /* Calculate the rate */
+ rate = (parent_rate * n * (k + 1) >> p) / (m + 1);
+
+ return rate;
+}
+
+static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct clk_factors *factors = to_clk_factors(hw);
+ factors->get_factors((u32 *)&rate, (u32)*parent_rate,
+ NULL, NULL, NULL, NULL);
+
+ return rate;
+}
+
+static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ u8 n, k, m, p;
+ u32 reg;
+ struct clk_factors *factors = to_clk_factors(hw);
+ struct clk_factors_config *config = factors->config;
+ unsigned long flags = 0;
+
+ factors->get_factors((u32 *)&rate, (u32)parent_rate, &n, &k, &m, &p);
+
+ if (factors->lock)
+ spin_lock_irqsave(factors->lock, flags);
+
+ /* Fetch the register value */
+ reg = readl(factors->reg);
+
+ /* Set up the new factors - macros do not do anything if width is 0 */
+ reg = FACTOR_SET(config->nshift, config->nwidth, reg, n);
+ reg = FACTOR_SET(config->kshift, config->kwidth, reg, k);
+ reg = FACTOR_SET(config->mshift, config->mwidth, reg, m);
+ reg = FACTOR_SET(config->pshift, config->pwidth, reg, p);
+
+ /* Apply them now */
+ writel(reg, factors->reg);
+
+ /* delay 500us so pll stabilizes */
+ __delay((rate >> 20) * 500 / 2);
+
+ if (factors->lock)
+ spin_unlock_irqrestore(factors->lock, flags);
+
+ return 0;
+}
+
+static const struct clk_ops clk_factors_ops = {
+ .recalc_rate = clk_factors_recalc_rate,
+ .round_rate = clk_factors_round_rate,
+ .set_rate = clk_factors_set_rate,
+};
+
+/**
+ * clk_register_factors - register a factors clock with
+ * the clock framework
+ * @dev: device registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @flags: framework-specific flags
+ * @reg: register address to adjust factors
+ * @config: shift and width of factors n, k, m and p
+ * @get_factors: function to calculate the factors for a given frequency
+ * @lock: shared register lock for this clock
+ */
+struct clk *clk_register_factors(struct device *dev, const char *name,
+ const char *parent_name,
+ unsigned long flags, void __iomem *reg,
+ struct clk_factors_config *config,
+ void (*get_factors)(u32 *rate, u32 parent,
+ u8 *n, u8 *k, u8 *m, u8 *p),
+ spinlock_t *lock)
+{
+ struct clk_factors *factors;
+ struct clk *clk;
+ struct clk_init_data init;
+
+ /* allocate the factors */
+ factors = kzalloc(sizeof(struct clk_factors), GFP_KERNEL);
+ if (!factors) {
+ pr_err("%s: could not allocate factors clk\n", __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ init.name = name;
+ init.ops = &clk_factors_ops;
+ init.flags = flags;
+ init.parent_names = (parent_name ? &parent_name : NULL);
+ init.num_parents = (parent_name ? 1 : 0);
+
+ /* struct clk_factors assignments */
+ factors->reg = reg;
+ factors->config = config;
+ factors->lock = lock;
+ factors->hw.init = &init;
+ factors->get_factors = get_factors;
+
+ /* register the clock */
+ clk = clk_register(dev, &factors->hw);
+
+ if (IS_ERR(clk))
+ kfree(factors);
+
+ return clk;
+}