clk: Add support for fundamental zynq clks

Provide simplified models for the necessary clocks on the zynq-7000
platform.  Currently, the PLLs, the CPU clock network, and the basic
peripheral clock networks (for SDIO, SMC, SPI, QSPI, UART) are modelled.

OF bindings are also provided and documented.

Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Michal Simek <michal.simek@xilinx.com>

1 files changed, 383 insertions, 0 deletions

diff --git a/drivers/clk/clk-zynq.c b/drivers/clk/clk-zynq.c
new file mode 100644
index 000000000000..37a30514fd66
--- /dev/null
+++ b/drivers/clk/clk-zynq.c
@@ -0,0 +1,383 @@
+/*
+ * Copyright (c) 2012 National Instruments
+ *
+ * Josh Cartwright <josh.cartwright@ni.com>
+ *
+ * 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/io.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/clk-provider.h>
+
+static void __iomem *slcr_base;
+
+struct zynq_pll_clk {
+        struct clk_hw   hw;
+        void __iomem    *pll_ctrl;
+        void __iomem    *pll_cfg;
+};
+
+#define to_zynq_pll_clk(hw)     container_of(hw, struct zynq_pll_clk, hw)
+
+#define CTRL_PLL_FDIV(x)        ((x) >> 12)
+
+static unsigned long zynq_pll_recalc_rate(struct clk_hw *hw,
+                                          unsigned long parent_rate)
+{
+        struct zynq_pll_clk *pll = to_zynq_pll_clk(hw);
+        return parent_rate * CTRL_PLL_FDIV(ioread32(pll->pll_ctrl));
+}
+
+static const struct clk_ops zynq_pll_clk_ops = {
+        .recalc_rate    = zynq_pll_recalc_rate,
+};
+
+static void __init zynq_pll_clk_setup(struct device_node *np)
+{
+        struct clk_init_data init;
+        struct zynq_pll_clk *pll;
+        const char *parent_name;
+        struct clk *clk;
+        u32 regs[2];
+        int ret;
+
+        ret = of_property_read_u32_array(np, "reg", regs, ARRAY_SIZE(regs));
+        if (WARN_ON(ret))
+                return;
+
+        pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+        if (WARN_ON(!pll))
+                return;
+
+        pll->pll_ctrl = slcr_base + regs[0];
+        pll->pll_cfg  = slcr_base + regs[1];
+
+        of_property_read_string(np, "clock-output-names", &init.name);
+
+        init.ops = &zynq_pll_clk_ops;
+        parent_name = of_clk_get_parent_name(np, 0);
+        init.parent_names = &parent_name;
+        init.num_parents = 1;
+
+        pll->hw.init = &init;
+
+        clk = clk_register(NULL, &pll->hw);
+        if (WARN_ON(IS_ERR(clk)))
+                return;
+
+        ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+        if (WARN_ON(ret))
+                return;
+}
+
+struct zynq_periph_clk {
+        struct clk_hw           hw;
+        struct clk_onecell_data onecell_data;
+        struct clk              *gates[2];
+        void __iomem            *clk_ctrl;
+        spinlock_t              clkact_lock;
+};
+
+#define to_zynq_periph_clk(hw)  container_of(hw, struct zynq_periph_clk, hw)
+
+static const u8 periph_clk_parent_map[] = {
+        0, 0, 1, 2
+};
+#define PERIPH_CLK_CTRL_SRC(x)  (periph_clk_parent_map[((x) & 0x30) >> 4])
+#define PERIPH_CLK_CTRL_DIV(x)  (((x) & 0x3F00) >> 8)
+
+static unsigned long zynq_periph_recalc_rate(struct clk_hw *hw,
+                                             unsigned long parent_rate)
+{
+        struct zynq_periph_clk *periph = to_zynq_periph_clk(hw);
+        return parent_rate / PERIPH_CLK_CTRL_DIV(ioread32(periph->clk_ctrl));
+}
+
+static u8 zynq_periph_get_parent(struct clk_hw *hw)
+{
+        struct zynq_periph_clk *periph = to_zynq_periph_clk(hw);
+        return PERIPH_CLK_CTRL_SRC(ioread32(periph->clk_ctrl));
+}
+
+static const struct clk_ops zynq_periph_clk_ops = {
+        .recalc_rate    = zynq_periph_recalc_rate,
+        .get_parent     = zynq_periph_get_parent,
+};
+
+static void __init zynq_periph_clk_setup(struct device_node *np)
+{
+        struct zynq_periph_clk *periph;
+        const char *parent_names[3];
+        struct clk_init_data init;
+        int clk_num = 0, err;
+        const char *name;
+        struct clk *clk;
+        u32 reg;
+        int i;
+
+        err = of_property_read_u32(np, "reg", &reg);
+        if (WARN_ON(err))
+                return;
+
+        periph = kzalloc(sizeof(*periph), GFP_KERNEL);
+        if (WARN_ON(!periph))
+                return;
+
+        periph->clk_ctrl = slcr_base + reg;
+        spin_lock_init(&periph->clkact_lock);
+
+        init.name = np->name;
+        init.ops = &zynq_periph_clk_ops;
+        for (i = 0; i < ARRAY_SIZE(parent_names); i++)
+                parent_names[i] = of_clk_get_parent_name(np, i);
+        init.parent_names = parent_names;
+        init.num_parents = ARRAY_SIZE(parent_names);
+
+        periph->hw.init = &init;
+
+        clk = clk_register(NULL, &periph->hw);
+        if (WARN_ON(IS_ERR(clk)))
+                return;
+
+        err = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+        if (WARN_ON(err))
+                return;
+
+        err = of_property_read_string_index(np, "clock-output-names", 0,
+                                            &name);
+        if (WARN_ON(err))
+                return;
+
+        periph->gates[0] = clk_register_gate(NULL, name, np->name, 0,
+                                             periph->clk_ctrl, 0, 0,
+                                             &periph->clkact_lock);
+        if (WARN_ON(IS_ERR(periph->gates[0])))
+                return;
+        clk_num++;
+
+        /* some periph clks have 2 downstream gates */
+        err = of_property_read_string_index(np, "clock-output-names", 1,
+                                            &name);
+        if (err != -ENODATA) {
+                periph->gates[1] = clk_register_gate(NULL, name, np->name, 0,
+                                                     periph->clk_ctrl, 1, 0,
+                                                     &periph->clkact_lock);
+                if (WARN_ON(IS_ERR(periph->gates[1])))
+                        return;
+                clk_num++;
+        }
+
+        periph->onecell_data.clks = periph->gates;
+        periph->onecell_data.clk_num = clk_num;
+
+        err = of_clk_add_provider(np, of_clk_src_onecell_get,
+                                  &periph->onecell_data);
+        if (WARN_ON(err))
+                return;
+}
+
+/* CPU Clock domain is modelled as a mux with 4 children subclks, whose
+ * derivative rates depend on CLK_621_TRUE
+ */
+
+struct zynq_cpu_clk {
+        struct clk_hw           hw;
+        struct clk_onecell_data onecell_data;
+        struct clk              *subclks[4];
+        void __iomem            *clk_ctrl;
+        spinlock_t              clkact_lock;
+};
+
+#define to_zynq_cpu_clk(hw)     container_of(hw, struct zynq_cpu_clk, hw)
+
+static const u8 zynq_cpu_clk_parent_map[] = {
+        1, 1, 2, 0
+};
+#define CPU_CLK_SRCSEL(x)       (zynq_cpu_clk_parent_map[(((x) & 0x30) >> 4)])
+#define CPU_CLK_CTRL_DIV(x)     (((x) & 0x3F00) >> 8)
+
+static u8 zynq_cpu_clk_get_parent(struct clk_hw *hw)
+{
+        struct zynq_cpu_clk *cpuclk = to_zynq_cpu_clk(hw);
+        return CPU_CLK_SRCSEL(ioread32(cpuclk->clk_ctrl));
+}
+
+static unsigned long zynq_cpu_clk_recalc_rate(struct clk_hw *hw,
+                                              unsigned long parent_rate)
+{
+        struct zynq_cpu_clk *cpuclk = to_zynq_cpu_clk(hw);
+        return parent_rate / CPU_CLK_CTRL_DIV(ioread32(cpuclk->clk_ctrl));
+}
+
+static const struct clk_ops zynq_cpu_clk_ops = {
+        .get_parent     = zynq_cpu_clk_get_parent,
+        .recalc_rate    = zynq_cpu_clk_recalc_rate,
+};
+
+struct zynq_cpu_subclk {
+        struct clk_hw   hw;
+        void __iomem    *clk_621;
+        enum {
+                CPU_SUBCLK_6X4X,
+                CPU_SUBCLK_3X2X,
+                CPU_SUBCLK_2X,
+                CPU_SUBCLK_1X,
+        } which;
+};
+
+#define CLK_621_TRUE(x) ((x) & 1)
+
+#define to_zynq_cpu_subclk(hw)  container_of(hw, struct zynq_cpu_subclk, hw);
+
+static unsigned long zynq_cpu_subclk_recalc_rate(struct clk_hw *hw,
+                                                 unsigned long parent_rate)
+{
+        unsigned long uninitialized_var(rate);
+        struct zynq_cpu_subclk *subclk;
+        bool is_621;
+
+        subclk = to_zynq_cpu_subclk(hw)
+        is_621 = CLK_621_TRUE(ioread32(subclk->clk_621));
+
+        switch (subclk->which) {
+        case CPU_SUBCLK_6X4X:
+                rate = parent_rate;
+                break;
+        case CPU_SUBCLK_3X2X:
+                rate = parent_rate / 2;
+                break;
+        case CPU_SUBCLK_2X:
+                rate = parent_rate / (is_621 ? 3 : 2);
+                break;
+        case CPU_SUBCLK_1X:
+                rate = parent_rate / (is_621 ? 6 : 4);
+                break;
+        };
+
+        return rate;
+}
+
+static const struct clk_ops zynq_cpu_subclk_ops = {
+        .recalc_rate    = zynq_cpu_subclk_recalc_rate,
+};
+
+static struct clk *zynq_cpu_subclk_setup(struct device_node *np, u8 which,
+                                         void __iomem *clk_621)
+{
+        struct zynq_cpu_subclk *subclk;
+        struct clk_init_data init;
+        struct clk *clk;
+        int err;
+
+        err = of_property_read_string_index(np, "clock-output-names",
+                                            which, &init.name);
+        if (WARN_ON(err))
+                goto err_read_output_name;
+
+        subclk = kzalloc(sizeof(*subclk), GFP_KERNEL);
+        if (!subclk)
+                goto err_subclk_alloc;
+
+        subclk->clk_621 = clk_621;
+        subclk->which = which;
+
+        init.ops = &zynq_cpu_subclk_ops;
+        init.parent_names = &np->name;
+        init.num_parents = 1;
+
+        subclk->hw.init = &init;
+
+        clk = clk_register(NULL, &subclk->hw);
+        if (WARN_ON(IS_ERR(clk)))
+                goto err_clk_register;
+
+        return clk;
+
+err_clk_register:
+        kfree(subclk);
+err_subclk_alloc:
+err_read_output_name:
+        return ERR_PTR(-EINVAL);
+}
+
+static void __init zynq_cpu_clk_setup(struct device_node *np)
+{
+        struct zynq_cpu_clk *cpuclk;
+        const char *parent_names[3];
+        struct clk_init_data init;
+        void __iomem *clk_621;
+        struct clk *clk;
+        u32 reg[2];
+        int err;
+        int i;
+
+        err = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
+        if (WARN_ON(err))
+                return;
+
+        cpuclk = kzalloc(sizeof(*cpuclk), GFP_KERNEL);
+        if (WARN_ON(!cpuclk))
+                return;
+
+        cpuclk->clk_ctrl = slcr_base + reg[0];
+        clk_621 = slcr_base + reg[1];
+        spin_lock_init(&cpuclk->clkact_lock);
+
+        init.name = np->name;
+        init.ops = &zynq_cpu_clk_ops;
+        for (i = 0; i < ARRAY_SIZE(parent_names); i++)
+                parent_names[i] = of_clk_get_parent_name(np, i);
+        init.parent_names = parent_names;
+        init.num_parents = ARRAY_SIZE(parent_names);
+
+        cpuclk->hw.init = &init;
+
+        clk = clk_register(NULL, &cpuclk->hw);
+        if (WARN_ON(IS_ERR(clk)))
+                return;
+
+        err = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+        if (WARN_ON(err))
+                return;
+
+        for (i = 0; i < 4; i++) {
+                cpuclk->subclks[i] = zynq_cpu_subclk_setup(np, i, clk_621);
+                if (WARN_ON(IS_ERR(cpuclk->subclks[i])))
+                        return;
+        }
+
+        cpuclk->onecell_data.clks = cpuclk->subclks;
+        cpuclk->onecell_data.clk_num = i;
+
+        err = of_clk_add_provider(np, of_clk_src_onecell_get,
+                                  &cpuclk->onecell_data);
+        if (WARN_ON(err))
+                return;
+}
+
+static const __initconst struct of_device_id zynq_clk_match[] = {
+        { .compatible = "fixed-clock", .data = of_fixed_clk_setup, },
+        { .compatible = "xlnx,zynq-pll", .data = zynq_pll_clk_setup, },
+        { .compatible = "xlnx,zynq-periph-clock",
+                .data = zynq_periph_clk_setup, },
+        { .compatible = "xlnx,zynq-cpu-clock", .data = zynq_cpu_clk_setup, },
+        {}
+};
+
+void __init xilinx_zynq_clocks_init(void __iomem *slcr)
+{
+        slcr_base = slcr;
+        of_clk_init(zynq_clk_match);
+}