clk: shmobile: Add R8A7740-specific clock support

Driver for the R8A7740's clocks that are too specific to be supported by a
generic driver.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

2 files changed, 200 insertions, 0 deletions

diff --git a/drivers/clk/shmobile/Makefile b/drivers/clk/shmobile/Makefile
index bdf342daefa5..e0029237827a 100644
--- a/drivers/clk/shmobile/Makefile
+++ b/drivers/clk/shmobile/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_ARCH_EMEV2)                += clk-emev2.o
 obj-$(CONFIG_ARCH_R7S72100)             += clk-rz.o
+obj-$(CONFIG_ARCH_R8A7740)              += clk-r8a7740.o
 obj-$(CONFIG_ARCH_R8A7779)              += clk-r8a7779.o
 obj-$(CONFIG_ARCH_R8A7790)              += clk-rcar-gen2.o
 obj-$(CONFIG_ARCH_R8A7791)              += clk-rcar-gen2.o
diff --git a/drivers/clk/shmobile/clk-r8a7740.c b/drivers/clk/shmobile/clk-r8a7740.c
new file mode 100644
index 000000000000..1e2eaae21e01
--- /dev/null
+++ b/drivers/clk/shmobile/clk-r8a7740.c
@@ -0,0 +1,199 @@
+/*
+ * r8a7740 Core CPG Clocks
+ *
+ * Copyright (C) 2014  Ulrich Hecht
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/shmobile.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/spinlock.h>
+
+struct r8a7740_cpg {
+        struct clk_onecell_data data;
+        spinlock_t lock;
+        void __iomem *reg;
+};
+
+#define CPG_FRQCRA      0x00
+#define CPG_FRQCRB      0x04
+#define CPG_PLLC2CR     0x2c
+#define CPG_USBCKCR     0x8c
+#define CPG_FRQCRC      0xe0
+
+#define CLK_ENABLE_ON_INIT BIT(0)
+
+struct div4_clk {
+        const char *name;
+        unsigned int reg;
+        unsigned int shift;
+        int flags;
+};
+
+static struct div4_clk div4_clks[] = {
+        { "i", CPG_FRQCRA, 20, CLK_ENABLE_ON_INIT },
+        { "zg", CPG_FRQCRA, 16, CLK_ENABLE_ON_INIT },
+        { "b", CPG_FRQCRA,  8, CLK_ENABLE_ON_INIT },
+        { "m1", CPG_FRQCRA,  4, CLK_ENABLE_ON_INIT },
+        { "hp", CPG_FRQCRB,  4, 0 },
+        { "hpp", CPG_FRQCRC, 20, 0 },
+        { "usbp", CPG_FRQCRC, 16, 0 },
+        { "s", CPG_FRQCRC, 12, 0 },
+        { "zb", CPG_FRQCRC,  8, 0 },
+        { "m3", CPG_FRQCRC,  4, 0 },
+        { "cp", CPG_FRQCRC,  0, 0 },
+        { NULL, 0, 0, 0 },
+};
+
+static const struct clk_div_table div4_div_table[] = {
+        { 0, 2 }, { 1, 3 }, { 2, 4 }, { 3, 6 }, { 4, 8 }, { 5, 12 },
+        { 6, 16 }, { 7, 18 }, { 8, 24 }, { 9, 32 }, { 10, 36 }, { 11, 48 },
+        { 13, 72 }, { 14, 96 }, { 0, 0 }
+};
+
+static u32 cpg_mode __initdata;
+
+static struct clk * __init
+r8a7740_cpg_register_clock(struct device_node *np, struct r8a7740_cpg *cpg,
+                             const char *name)
+{
+        const struct clk_div_table *table = NULL;
+        const char *parent_name;
+        unsigned int shift, reg;
+        unsigned int mult = 1;
+        unsigned int div = 1;
+
+        if (!strcmp(name, "r")) {
+                switch (cpg_mode & (BIT(2) | BIT(1))) {
+                case BIT(1) | BIT(2):
+                        /* extal1 */
+                        parent_name = of_clk_get_parent_name(np, 0);
+                        div = 2048;
+                        break;
+                case BIT(2):
+                        /* extal1 */
+                        parent_name = of_clk_get_parent_name(np, 0);
+                        div = 1024;
+                        break;
+                default:
+                        /* extalr */
+                        parent_name = of_clk_get_parent_name(np, 2);
+                        break;
+                }
+        } else if (!strcmp(name, "system")) {
+                parent_name = of_clk_get_parent_name(np, 0);
+                if (cpg_mode & BIT(1))
+                        div = 2;
+        } else if (!strcmp(name, "pllc0")) {
+                /* PLLC0/1 are configurable multiplier clocks. Register them as
+                 * fixed factor clocks for now as there's no generic multiplier
+                 * clock implementation and we currently have no need to change
+                 * the multiplier value.
+                 */
+                u32 value = clk_readl(cpg->reg + CPG_FRQCRC);
+                parent_name = "system";
+                mult = ((value >> 24) & 0x7f) + 1;
+        } else if (!strcmp(name, "pllc1")) {
+                u32 value = clk_readl(cpg->reg + CPG_FRQCRA);
+                parent_name = "system";
+                mult = ((value >> 24) & 0x7f) + 1;
+                div = 2;
+        } else if (!strcmp(name, "pllc2")) {
+                u32 value = clk_readl(cpg->reg + CPG_PLLC2CR);
+                parent_name = "system";
+                mult = ((value >> 24) & 0x3f) + 1;
+        } else if (!strcmp(name, "usb24s")) {
+                u32 value = clk_readl(cpg->reg + CPG_USBCKCR);
+                if (value & BIT(7))
+                        /* extal2 */
+                        parent_name = of_clk_get_parent_name(np, 1);
+                else
+                        parent_name = "system";
+                if (!(value & BIT(6)))
+                        div = 2;
+        } else {
+                struct div4_clk *c;
+                for (c = div4_clks; c->name; c++) {
+                        if (!strcmp(name, c->name)) {
+                                parent_name = "pllc1";
+                                table = div4_div_table;
+                                reg = c->reg;
+                                shift = c->shift;
+                                break;
+                        }
+                }
+                if (!c->name)
+                        return ERR_PTR(-EINVAL);
+        }
+
+        if (!table) {
+                return clk_register_fixed_factor(NULL, name, parent_name, 0,
+                                                 mult, div);
+        } else {
+                return clk_register_divider_table(NULL, name, parent_name, 0,
+                                                  cpg->reg + reg, shift, 4, 0,
+                                                  table, &cpg->lock);
+        }
+}
+
+static void __init r8a7740_cpg_clocks_init(struct device_node *np)
+{
+        struct r8a7740_cpg *cpg;
+        struct clk **clks;
+        unsigned int i;
+        int num_clks;
+
+        if (of_property_read_u32(np, "renesas,mode", &cpg_mode))
+                pr_warn("%s: missing renesas,mode property\n", __func__);
+
+        num_clks = of_property_count_strings(np, "clock-output-names");
+        if (num_clks < 0) {
+                pr_err("%s: failed to count clocks\n", __func__);
+                return;
+        }
+
+        cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
+        clks = kzalloc(num_clks * sizeof(*clks), GFP_KERNEL);
+        if (cpg == NULL || clks == NULL) {
+                /* We're leaking memory on purpose, there's no point in cleaning
+                 * up as the system won't boot anyway.
+                 */
+                return;
+        }
+
+        spin_lock_init(&cpg->lock);
+
+        cpg->data.clks = clks;
+        cpg->data.clk_num = num_clks;
+
+        cpg->reg = of_iomap(np, 0);
+        if (WARN_ON(cpg->reg == NULL))
+                return;
+
+        for (i = 0; i < num_clks; ++i) {
+                const char *name;
+                struct clk *clk;
+
+                of_property_read_string_index(np, "clock-output-names", i,
+                                              &name);
+
+                clk = r8a7740_cpg_register_clock(np, cpg, name);
+                if (IS_ERR(clk))
+                        pr_err("%s: failed to register %s %s clock (%ld)\n",
+                               __func__, np->name, name, PTR_ERR(clk));
+                else
+                        cpg->data.clks[i] = clk;
+        }
+
+        of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
+}
+CLK_OF_DECLARE(r8a7740_cpg_clks, "renesas,r8a7740-cpg-clocks",
+               r8a7740_cpg_clocks_init);