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>

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)"

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);

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;
 }
 

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();