Re: [PATCH 3/8] soc: renesas: rzn1-sysc: Export function to set dmamux

Geert Uytterhoeven
2022-02-21T09:38:08Z

Hi Miquel,

On Fri, Feb 18, 2022 at 7:12 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> The dmamux register is located within the system controller.
>
> Without syscon, we need an extra helper in order to give write access to
> this register to a dmamux driver.
>
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks for your patch!

> --- a/drivers/clk/renesas/r9a06g032-clocks.c
> +++ b/drivers/clk/renesas/r9a06g032-clocks.c

Missing #include <linux/soc/renesas/r9a06g032-syscon.h>

> @@ -315,6 +315,27 @@ struct r9a06g032_priv {
> void __iomem *reg;
> };
>
> +/* Exported helper to access the DMAMUX register */
> +static struct r9a06g032_priv *syscon_priv;

I'd call this sysctrl_priv, as that matches the bindings and
binding header file name.

> +int r9a06g032_syscon_set_dmamux(u32 mask, u32 val)
> +{
> + u32 dmamux;
> +
> + if (!syscon_priv)
> + return -EPROBE_DEFER;
> +
> + spin_lock(&syscon_priv->lock);

This needs propection against interrupts => spin_lock_irqsave().

> +
> + dmamux = readl(syscon_priv->reg + R9A06G032_SYSCON_DMAMUX);
> + dmamux &= ~mask;
> + dmamux |= val & mask;
> + writel(dmamux, syscon_priv->reg + R9A06G032_SYSCON_DMAMUX);
> +
> + spin_unlock(&syscon_priv->lock);
> +
> + return 0;
> +}
> +
> /* register/bit pairs are encoded as an uint16_t */
> static void
> clk_rdesc_set(struct r9a06g032_priv *clocks,

> --- a/include/dt-bindings/clock/r9a06g032-sysctrl.h
> +++ b/include/dt-bindings/clock/r9a06g032-sysctrl.h
> @@ -145,4 +145,6 @@
> #define R9A06G032_CLK_UART6 152
> #define R9A06G032_CLK_UART7 153
>
> +#define R9A06G032_SYSCON_DMAMUX 0xA0

I don't think this needs to be part of the bindings, so please move
it to the driver source file.

> --- /dev/null
> +++ b/include/linux/soc/renesas/r9a06g032-syscon.h

r9a06g032-sysctrl.h etc.

> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __LINUX_SOC_RENESAS_R9A06G032_SYSCON_H__
> +#define __LINUX_SOC_RENESAS_R9A06G032_SYSCON_H__
> +
> +#ifdef CONFIG_CLK_R9A06G032
> +int r9a06g032_syscon_set_dmamux(u32 mask, u32 val);
> +#else
> +static inline int r9a06g032_syscon_set_dmamux(u32 mask, u32 val) { return -ENODEV; }
> +#endif
> +
> +#endif /* __LINUX_SOC_RENESAS_R9A06G032_SYSCON_H__ */
> --
> 2.27.0

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds