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authorRob Herring <rob.herring@calxeda.com>2012-03-13 18:19:19 -0500
committerMike Turquette <mturquette@linaro.org>2012-07-11 17:58:47 -0700
commit8d4d9f52081cd45bde42b9452eba95f38feb7dae (patch)
tree81b614f5f842150c910737a9e1f5414de3b49b4b /drivers/clk/clk-highbank.c
parent260b6aa03edd87a3a85c137e7b95305d9eb40485 (diff)
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clk: add highbank clock support
This adds real clock support to Calxeda Highbank SOC using the common clock infrastructure. Signed-off-by: Rob Herring <rob.herring@calxeda.com> [mturquette@linaro.org: fixed up invalid writes to const struct member] Signed-off-by: Mike Turquette <mturquette@linaro.org>
Diffstat (limited to 'drivers/clk/clk-highbank.c')
-rw-r--r--drivers/clk/clk-highbank.c346
1 files changed, 346 insertions, 0 deletions
diff --git a/drivers/clk/clk-highbank.c b/drivers/clk/clk-highbank.c
new file mode 100644
index 000000000000..52fecadf004a
--- /dev/null
+++ b/drivers/clk/clk-highbank.c
@@ -0,0 +1,346 @@
+/*
+ * Copyright 2011-2012 Calxeda, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+extern void __iomem *sregs_base;
+
+#define HB_PLL_LOCK_500 0x20000000
+#define HB_PLL_LOCK 0x10000000
+#define HB_PLL_DIVF_SHIFT 20
+#define HB_PLL_DIVF_MASK 0x0ff00000
+#define HB_PLL_DIVQ_SHIFT 16
+#define HB_PLL_DIVQ_MASK 0x00070000
+#define HB_PLL_DIVR_SHIFT 8
+#define HB_PLL_DIVR_MASK 0x00001f00
+#define HB_PLL_RANGE_SHIFT 4
+#define HB_PLL_RANGE_MASK 0x00000070
+#define HB_PLL_BYPASS 0x00000008
+#define HB_PLL_RESET 0x00000004
+#define HB_PLL_EXT_BYPASS 0x00000002
+#define HB_PLL_EXT_ENA 0x00000001
+
+#define HB_PLL_VCO_MIN_FREQ 2133000000
+#define HB_PLL_MAX_FREQ HB_PLL_VCO_MIN_FREQ
+#define HB_PLL_MIN_FREQ (HB_PLL_VCO_MIN_FREQ / 64)
+
+#define HB_A9_BCLK_DIV_MASK 0x00000006
+#define HB_A9_BCLK_DIV_SHIFT 1
+#define HB_A9_PCLK_DIV 0x00000001
+
+struct hb_clk {
+ struct clk_hw hw;
+ void __iomem *reg;
+ char *parent_name;
+};
+#define to_hb_clk(p) container_of(p, struct hb_clk, hw)
+
+static int clk_pll_prepare(struct clk_hw *hwclk)
+ {
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 reg;
+
+ reg = readl(hbclk->reg);
+ reg &= ~HB_PLL_RESET;
+ writel(reg, hbclk->reg);
+
+ while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
+ ;
+ while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
+ ;
+
+ return 0;
+}
+
+static void clk_pll_unprepare(struct clk_hw *hwclk)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 reg;
+
+ reg = readl(hbclk->reg);
+ reg |= HB_PLL_RESET;
+ writel(reg, hbclk->reg);
+}
+
+static int clk_pll_enable(struct clk_hw *hwclk)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 reg;
+
+ reg = readl(hbclk->reg);
+ reg |= HB_PLL_EXT_ENA;
+ writel(reg, hbclk->reg);
+
+ return 0;
+}
+
+static void clk_pll_disable(struct clk_hw *hwclk)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 reg;
+
+ reg = readl(hbclk->reg);
+ reg &= ~HB_PLL_EXT_ENA;
+ writel(reg, hbclk->reg);
+}
+
+static unsigned long clk_pll_recalc_rate(struct clk_hw *hwclk,
+ unsigned long parent_rate)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ unsigned long divf, divq, vco_freq, reg;
+
+ reg = readl(hbclk->reg);
+ if (reg & HB_PLL_EXT_BYPASS)
+ return parent_rate;
+
+ divf = (reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT;
+ divq = (reg & HB_PLL_DIVQ_MASK) >> HB_PLL_DIVQ_SHIFT;
+ vco_freq = parent_rate * (divf + 1);
+
+ return vco_freq / (1 << divq);
+}
+
+static void clk_pll_calc(unsigned long rate, unsigned long ref_freq,
+ u32 *pdivq, u32 *pdivf)
+{
+ u32 divq, divf;
+ unsigned long vco_freq;
+
+ if (rate < HB_PLL_MIN_FREQ)
+ rate = HB_PLL_MIN_FREQ;
+ if (rate > HB_PLL_MAX_FREQ)
+ rate = HB_PLL_MAX_FREQ;
+
+ for (divq = 1; divq <= 6; divq++) {
+ if ((rate * (1 << divq)) >= HB_PLL_VCO_MIN_FREQ)
+ break;
+ }
+
+ vco_freq = rate * (1 << divq);
+ divf = (vco_freq + (ref_freq / 2)) / ref_freq;
+ divf--;
+
+ *pdivq = divq;
+ *pdivf = divf;
+}
+
+static long clk_pll_round_rate(struct clk_hw *hwclk, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ u32 divq, divf;
+ unsigned long ref_freq = *parent_rate;
+
+ clk_pll_calc(rate, ref_freq, &divq, &divf);
+
+ return (ref_freq * (divf + 1)) / (1 << divq);
+}
+
+static int clk_pll_set_rate(struct clk_hw *hwclk, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 divq, divf;
+ u32 reg;
+
+ clk_pll_calc(rate, parent_rate, &divq, &divf);
+
+ reg = readl(hbclk->reg);
+ if (divf != ((reg & HB_PLL_DIVF_MASK) >> HB_PLL_DIVF_SHIFT)) {
+ /* Need to re-lock PLL, so put it into bypass mode */
+ reg |= HB_PLL_EXT_BYPASS;
+ writel(reg | HB_PLL_EXT_BYPASS, hbclk->reg);
+
+ writel(reg | HB_PLL_RESET, hbclk->reg);
+ reg &= ~(HB_PLL_DIVF_MASK | HB_PLL_DIVQ_MASK);
+ reg |= (divf << HB_PLL_DIVF_SHIFT) | (divq << HB_PLL_DIVQ_SHIFT);
+ writel(reg | HB_PLL_RESET, hbclk->reg);
+ writel(reg, hbclk->reg);
+
+ while ((readl(hbclk->reg) & HB_PLL_LOCK) == 0)
+ ;
+ while ((readl(hbclk->reg) & HB_PLL_LOCK_500) == 0)
+ ;
+ reg |= HB_PLL_EXT_ENA;
+ reg &= ~HB_PLL_EXT_BYPASS;
+ } else {
+ reg &= ~HB_PLL_DIVQ_MASK;
+ reg |= divq << HB_PLL_DIVQ_SHIFT;
+ }
+ writel(reg, hbclk->reg);
+
+ return 0;
+}
+
+static const struct clk_ops clk_pll_ops = {
+ .prepare = clk_pll_prepare,
+ .unprepare = clk_pll_unprepare,
+ .enable = clk_pll_enable,
+ .disable = clk_pll_disable,
+ .recalc_rate = clk_pll_recalc_rate,
+ .round_rate = clk_pll_round_rate,
+ .set_rate = clk_pll_set_rate,
+};
+
+static unsigned long clk_cpu_periphclk_recalc_rate(struct clk_hw *hwclk,
+ unsigned long parent_rate)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 div = (readl(hbclk->reg) & HB_A9_PCLK_DIV) ? 8 : 4;
+ return parent_rate / div;
+}
+
+static const struct clk_ops a9periphclk_ops = {
+ .recalc_rate = clk_cpu_periphclk_recalc_rate,
+};
+
+static unsigned long clk_cpu_a9bclk_recalc_rate(struct clk_hw *hwclk,
+ unsigned long parent_rate)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 div = (readl(hbclk->reg) & HB_A9_BCLK_DIV_MASK) >> HB_A9_BCLK_DIV_SHIFT;
+
+ return parent_rate / (div + 2);
+}
+
+static const struct clk_ops a9bclk_ops = {
+ .recalc_rate = clk_cpu_a9bclk_recalc_rate,
+};
+
+static unsigned long clk_periclk_recalc_rate(struct clk_hw *hwclk,
+ unsigned long parent_rate)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 div;
+
+ div = readl(hbclk->reg) & 0x1f;
+ div++;
+ div *= 2;
+
+ return parent_rate / div;
+}
+
+static long clk_periclk_round_rate(struct clk_hw *hwclk, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ u32 div;
+
+ div = *parent_rate / rate;
+ div++;
+ div &= ~0x1;
+
+ return *parent_rate / div;
+}
+
+static int clk_periclk_set_rate(struct clk_hw *hwclk, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct hb_clk *hbclk = to_hb_clk(hwclk);
+ u32 div;
+
+ div = parent_rate / rate;
+ if (div & 0x1)
+ return -EINVAL;
+
+ writel(div >> 1, hbclk->reg);
+ return 0;
+}
+
+static const struct clk_ops periclk_ops = {
+ .recalc_rate = clk_periclk_recalc_rate,
+ .round_rate = clk_periclk_round_rate,
+ .set_rate = clk_periclk_set_rate,
+};
+
+static __init struct clk *hb_clk_init(struct device_node *node, const struct clk_ops *ops)
+{
+ u32 reg;
+ struct clk *clk;
+ struct hb_clk *hb_clk;
+ const char *clk_name = node->name;
+ const char *parent_name;
+ struct clk_init_data init;
+ int rc;
+
+ rc = of_property_read_u32(node, "reg", &reg);
+ if (WARN_ON(rc))
+ return NULL;
+
+ hb_clk = kzalloc(sizeof(*hb_clk), GFP_KERNEL);
+ if (WARN_ON(!hb_clk))
+ return NULL;
+
+ hb_clk->reg = sregs_base + reg;
+
+ of_property_read_string(node, "clock-output-names", &clk_name);
+
+ init.name = clk_name;
+ init.ops = ops;
+ init.flags = 0;
+ parent_name = of_clk_get_parent_name(node, 0);
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+
+ hb_clk->hw.init = &init;
+
+ clk = clk_register(NULL, &hb_clk->hw);
+ if (WARN_ON(IS_ERR(clk))) {
+ kfree(hb_clk);
+ return NULL;
+ }
+ rc = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+ return clk;
+}
+
+static void __init hb_pll_init(struct device_node *node)
+{
+ hb_clk_init(node, &clk_pll_ops);
+}
+
+static void __init hb_a9periph_init(struct device_node *node)
+{
+ hb_clk_init(node, &a9periphclk_ops);
+}
+
+static void __init hb_a9bus_init(struct device_node *node)
+{
+ struct clk *clk = hb_clk_init(node, &a9bclk_ops);
+ clk_prepare_enable(clk);
+}
+
+static void __init hb_emmc_init(struct device_node *node)
+{
+ hb_clk_init(node, &periclk_ops);
+}
+
+static const __initconst struct of_device_id clk_match[] = {
+ { .compatible = "fixed-clock", .data = of_fixed_clk_setup, },
+ { .compatible = "calxeda,hb-pll-clock", .data = hb_pll_init, },
+ { .compatible = "calxeda,hb-a9periph-clock", .data = hb_a9periph_init, },
+ { .compatible = "calxeda,hb-a9bus-clock", .data = hb_a9bus_init, },
+ { .compatible = "calxeda,hb-emmc-clock", .data = hb_emmc_init, },
+ {}
+};
+
+void __init highbank_clocks_init(void)
+{
+ of_clk_init(clk_match);
+}