Hi Geert,
Nice patch! It took me a while to understand why you didn't need to read
the register before writing to it in cpg_mssr_deassert() :-)
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
On 2017-01-20 15:08:22 +0100, Geert Uytterhoeven wrote:
> 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>
> ---
> drivers/clk/renesas/renesas-cpg-mssr.c | 122 +++++++++++++++++++++++++++++++++
> 1 file changed, 122 insertions(+)
>
> diff --git a/drivers/clk/renesas/renesas-cpg-mssr.c b/drivers/clk/renesas/renesas-cpg-mssr.c
> index f1161a585c57e433..ea4af714ac14603a 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 +500,118 @@ 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;
> + 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));
> + writel(value | BIT(bit), 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;
> +
> + dev_dbg(priv->dev, "deassert %u%02u\n", reg, bit);
> +
> + writel(BIT(bit), 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;
> +
> + return !!(readl(priv->base + SRCR(reg)) & BIT(bit));
> +}
> +
> +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 +709,10 @@ 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
>
--
Regards,
Niklas Söderlund
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