MIPS: ralink: Add support for reset-controller API

Add a helper for reseting different devices on the SoC.

Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5804/
Patchwork: https://patchwork.linux-mips.org/patch/5797/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

4 files changed, 69 insertions, 0 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 24727a082e19..a1a088b2d54d 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -446,6 +446,8 @@ config RALINK
         select SYS_HAS_EARLY_PRINTK
         select HAVE_MACH_CLKDEV
         select CLKDEV_LOOKUP
+        select ARCH_HAS_RESET_CONTROLLER
+        select RESET_CONTROLLER
 
 config SGI_IP22
         bool "SGI IP22 (Indy/Indigo2)"
diff --git a/arch/mips/ralink/common.h b/arch/mips/ralink/common.h
index 83144c3fc5ac..42dfd6100a2d 100644
--- a/arch/mips/ralink/common.h
+++ b/arch/mips/ralink/common.h
@@ -46,6 +46,8 @@ extern void ralink_of_remap(void);
 extern void ralink_clk_init(void);
 extern void ralink_clk_add(const char *dev, unsigned long rate);
 
+extern void ralink_rst_init(void);
+
 extern void prom_soc_init(struct ralink_soc_info *soc_info);
 
 __iomem void *plat_of_remap_node(const char *node);
diff --git a/arch/mips/ralink/of.c b/arch/mips/ralink/of.c
index f25ea5b45051..ce38d11f9da5 100644
--- a/arch/mips/ralink/of.c
+++ b/arch/mips/ralink/of.c
@@ -110,6 +110,9 @@ static int __init plat_of_setup(void)
         if (of_platform_populate(NULL, of_ids, NULL, NULL))
                 panic("failed to populate DT\n");
 
+        /* make sure ithat the reset controller is setup early */
+        ralink_rst_init();
+
         return 0;
 }
 
diff --git a/arch/mips/ralink/reset.c b/arch/mips/ralink/reset.c
index 22120e512e7e..55c7ec59df3c 100644
--- a/arch/mips/ralink/reset.c
+++ b/arch/mips/ralink/reset.c
@@ -10,6 +10,8 @@
 
 #include <linux/pm.h>
 #include <linux/io.h>
+#include <linux/of.h>
+#include <linux/reset-controller.h>
 
 #include <asm/reboot.h>
 
@@ -19,6 +21,66 @@
 #define SYSC_REG_RESET_CTRL     0x034
 #define RSTCTL_RESET_SYSTEM     BIT(0)
 
+static int ralink_assert_device(struct reset_controller_dev *rcdev,
+                                unsigned long id)
+{
+        u32 val;
+
+        if (id < 8)
+                return -1;
+
+        val = rt_sysc_r32(SYSC_REG_RESET_CTRL);
+        val |= BIT(id);
+        rt_sysc_w32(val, SYSC_REG_RESET_CTRL);
+
+        return 0;
+}
+
+static int ralink_deassert_device(struct reset_controller_dev *rcdev,
+                                  unsigned long id)
+{
+        u32 val;
+
+        if (id < 8)
+                return -1;
+
+        val = rt_sysc_r32(SYSC_REG_RESET_CTRL);
+        val &= ~BIT(id);
+        rt_sysc_w32(val, SYSC_REG_RESET_CTRL);
+
+        return 0;
+}
+
+static int ralink_reset_device(struct reset_controller_dev *rcdev,
+                               unsigned long id)
+{
+        ralink_assert_device(rcdev, id);
+        return ralink_deassert_device(rcdev, id);
+}
+
+static struct reset_control_ops reset_ops = {
+        .reset = ralink_reset_device,
+        .assert = ralink_assert_device,
+        .deassert = ralink_deassert_device,
+};
+
+static struct reset_controller_dev reset_dev = {
+        .ops                    = &reset_ops,
+        .owner                  = THIS_MODULE,
+        .nr_resets              = 32,
+        .of_reset_n_cells       = 1,
+};
+
+void ralink_rst_init(void)
+{
+        reset_dev.of_node = of_find_compatible_node(NULL, NULL,
+                                                "ralink,rt2880-reset");
+        if (!reset_dev.of_node)
+                pr_err("Failed to find reset controller node");
+        else
+                reset_controller_register(&reset_dev);
+}
+
 static void ralink_restart(char *command)
 {
         local_irq_disable();