Add optional support for the Reset Control feature of the Renesas Clock
Pulse Generator / Module Standby and Software Reset module on R-Car
Gen2, R-Car Gen3, and RZ/G1 SoCs.
This allows to reset SoC devices using the Reset Controller API.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Acked-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Acked-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
---
v2:
- Add Acked-by, Reviewed-by,
- Use variable bitmask in all reset operations, to make them more
similar.
---
drivers/clk/renesas/renesas-cpg-mssr.c | 126 +++++++++++++++++++++++++++++++++
1 file changed, 126 insertions(+)
diff --git a/drivers/clk/renesas/renesas-cpg-mssr.c b/drivers/clk/renesas/renesas-cpg-mssr.c
index f1161a585c57e433..eadcbd43ff88319b 100644
--- a/drivers/clk/renesas/renesas-cpg-mssr.c
+++ b/drivers/clk/renesas/renesas-cpg-mssr.c
@@ -16,6 +16,7 @@
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/clk/renesas.h>
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/mod_devicetable.h>
@@ -25,6 +26,7 @@
#include <linux/platform_device.h>
#include <linux/pm_clock.h>
#include <linux/pm_domain.h>
+#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <dt-bindings/clock/renesas-cpg-mssr.h>
@@ -96,6 +98,7 @@
/**
* Clock Pulse Generator / Module Standby and Software Reset Private Data
*
+ * @rcdev: Optional reset controller entity
* @dev: CPG/MSSR device
* @base: CPG/MSSR register block base address
* @rmw_lock: protects RMW register accesses
@@ -105,6 +108,9 @@
* @last_dt_core_clk: ID of the last Core Clock exported to DT
*/
struct cpg_mssr_priv {
+#ifdef CONFIG_RESET_CONTROLLER
+ struct reset_controller_dev rcdev;
+#endif
struct device *dev;
void __iomem *base;
spinlock_t rmw_lock;
@@ -494,6 +500,122 @@ static int __init cpg_mssr_add_clk_domain(struct device *dev,
return 0;
}
+#ifdef CONFIG_RESET_CONTROLLER
+
+#define rcdev_to_priv(x) container_of(x, struct cpg_mssr_priv, rcdev)
+
+static int cpg_mssr_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
+ unsigned int reg = id / 32;
+ unsigned int bit = id % 32;
+ u32 bitmask = BIT(bit);
+ unsigned long flags;
+ u32 value;
+
+ dev_dbg(priv->dev, "reset %u%02u\n", reg, bit);
+
+ /* Reset module */
+ spin_lock_irqsave(&priv->rmw_lock, flags);
+ value = readl(priv->base + SRCR(reg));
+ value |= bitmask;
+ writel(value, priv->base + SRCR(reg));
+ spin_unlock_irqrestore(&priv->rmw_lock, flags);
+
+ /* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
+ udelay(35);
+
+ /* Release module from reset state */
+ writel(bitmask, priv->base + SRSTCLR(reg));
+
+ return 0;
+}
+
+static int cpg_mssr_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+ struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
+ unsigned int reg = id / 32;
+ unsigned int bit = id % 32;
+ u32 bitmask = BIT(bit);
+ unsigned long flags;
+ u32 value;
+
+ dev_dbg(priv->dev, "assert %u%02u\n", reg, bit);
+
+ spin_lock_irqsave(&priv->rmw_lock, flags);
+ value = readl(priv->base + SRCR(reg));
+ value |= bitmask;
+ writel(value, priv->base + SRCR(reg));
+ spin_unlock_irqrestore(&priv->rmw_lock, flags);
+ return 0;
+}
+
+static int cpg_mssr_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
+ unsigned int reg = id / 32;
+ unsigned int bit = id % 32;
+ u32 bitmask = BIT(bit);
+
+ dev_dbg(priv->dev, "deassert %u%02u\n", reg, bit);
+
+ writel(bitmask, priv->base + SRSTCLR(reg));
+ return 0;
+}
+
+static int cpg_mssr_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
+ unsigned int reg = id / 32;
+ unsigned int bit = id % 32;
+ u32 bitmask = BIT(bit);
+
+ return !!(readl(priv->base + SRCR(reg)) & bitmask);
+}
+
+static const struct reset_control_ops cpg_mssr_reset_ops = {
+ .reset = cpg_mssr_reset,
+ .assert = cpg_mssr_assert,
+ .deassert = cpg_mssr_deassert,
+ .status = cpg_mssr_status,
+};
+
+static int cpg_mssr_reset_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ struct cpg_mssr_priv *priv = rcdev_to_priv(rcdev);
+ unsigned int unpacked = reset_spec->args[0];
+ unsigned int idx = MOD_CLK_PACK(unpacked);
+
+ if (unpacked % 100 > 31 || idx >= rcdev->nr_resets) {
+ dev_err(priv->dev, "Invalid reset index %u\n", unpacked);
+ return -EINVAL;
+ }
+
+ return idx;
+}
+
+static int cpg_mssr_reset_controller_register(struct cpg_mssr_priv *priv)
+{
+ priv->rcdev.ops = &cpg_mssr_reset_ops;
+ priv->rcdev.of_node = priv->dev->of_node;
+ priv->rcdev.of_reset_n_cells = 1;
+ priv->rcdev.of_xlate = cpg_mssr_reset_xlate;
+ priv->rcdev.nr_resets = priv->num_mod_clks;
+ return devm_reset_controller_register(priv->dev, &priv->rcdev);
+}
+
+#else /* !CONFIG_RESET_CONTROLLER */
+static inline int cpg_mssr_reset_controller_register(struct cpg_mssr_priv *priv)
+{
+ return 0;
+}
+#endif /* !CONFIG_RESET_CONTROLLER */
+
+
static const struct of_device_id cpg_mssr_match[] = {
#ifdef CONFIG_ARCH_R8A7743
{
@@ -591,6 +713,10 @@ static int __init cpg_mssr_probe(struct platform_device *pdev)
if (error)
return error;
+ error = cpg_mssr_reset_controller_register(priv);
+ if (error)
+ return error;
+
return 0;
}
--
1.9.1
