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clk: renesas: cpg-mssr: Add support for reset control 

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@glider.be>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
hifive-unleashed-5.1
Geert Uytterhoeven 2017-01-20 11:03:03 +01:00
parent a4ea6a0f83
commit 6197aa65c4
1 changed files with 126 additions and 0 deletions
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126
drivers/clk/renesas/renesas-cpg-mssr.c
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@ -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 @@ static const u16 srcr[] = {
/**
* 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 @@ static const u16 srcr[] = {
* @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;
}