[U-Boot] [PATCH v2 03/13] ns16550: add generic binding to unify the drivers

[Bin Meng]

On Wed, Nov 18, 2015 at 9:44 PM, Thomas Chou <thomas at wytron.com.tw> wrote:
> Add generic binding to unify ns16550 drivers. There are
> several drivers using almost the same code, such as serial_dw,
> serial_keystone, serial_omap, serial_ppc, serial_rockchip,
> serial_tegra.c, and serial_x86. But each is platform specific.
>
> The key difference between these drivers is the way to get
> input clock frequency. With this unified approach, fixed clock
> frequency should be extracted from "clock-frequency" property of
> device tree blob. If this property is not available, the macro
> CONFIG_SYS_NS16550_CLK will be used. It can be a constant or a
> function to get clock, eg, get_serial_clock().
>
> Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
> Reviewed-by: Tom Rini <trini at konsulko.com>
> ---
>  drivers/serial/Kconfig   | 11 +++++++++++
>  drivers/serial/ns16550.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 55 insertions(+)
>
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index 2a50771..0f0e92d 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -195,6 +195,17 @@ config ROCKCHIP_SERIAL
>           your board config header. The clock input is automatically set to
>           use the oscillator (24MHz).
>
> +config NS16550_SERIAL
> +       bool "NS16550 UART or compatible"
> +       depends on DM_SERIAL
> +       help
> +         Support NS16550 UART or compatible with driver model. This can be
> +         enabled in the device tree with the correct input clock frequency.
> +         If the input clock frequency is not defined in the device tree,
> +         the macro CONFIG_SYS_NS16550_CLK defined in a legacy board header
> +         file will be used. It can be a constant or a function to get clock,
> +         eg, get_serial_clock().
> +
>  config SANDBOX_SERIAL
>         bool "Sandbox UART support"
>         depends on SANDBOX
> diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
> index 8d028de..f0a9aac 100644
> --- a/drivers/serial/ns16550.c
> +++ b/drivers/serial/ns16550.c
> @@ -56,6 +56,10 @@ DECLARE_GLOBAL_DATA_PTR;
>
>  #ifdef CONFIG_DM_SERIAL
>
> +#ifndef CONFIG_SYS_NS16550_CLK
> +#define CONFIG_SYS_NS16550_CLK  0
> +#endif
> +
>  static inline void serial_out_shift(void *addr, int shift, int value)
>  {
>  #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
> @@ -400,6 +404,15 @@ int ns16550_serial_ofdata_to_platdata(struct udevice *dev)
>         plat->base = addr;
>         plat->reg_shift = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
>                                          "reg-shift", 1);
> +#ifdef CONFIG_NS16550_SERIAL
> +       plat->clock = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
> +                                    "clock-frequency",
> +                                    CONFIG_SYS_NS16550_CLK);
> +       if (!plat->clock) {
> +               debug("ns16550 clock not defined\n");
> +               return -EINVAL;
> +       }
> +#endif /* CONFIG_NS16550_SERIAL */
>
>         return 0;
>  }
> @@ -411,4 +424,35 @@ const struct dm_serial_ops ns16550_serial_ops = {
>         .getc = ns16550_serial_getc,
>         .setbrg = ns16550_serial_setbrg,
>  };
> +
> +#ifdef CONFIG_NS16550_SERIAL
> +#if CONFIG_IS_ENABLED(OF_CONTROL)
> +static const struct udevice_id ns16550_serial_ids[] = {
> +       { .compatible = "ns16550" },
> +       { .compatible = "ns16550a" },
> +       { .compatible = "nvidia,tegra20-uart" },
> +       { .compatible = "snps,dw-apb-uart" },
> +       { .compatible = "ti,omap2-uart" },
> +       { .compatible = "ti,omap3-uart" },
> +       { .compatible = "ti,omap4-uart" },
> +       { .compatible = "ti,am3352-uart" },
> +       { .compatible = "ti,am4372-uart" },
> +       { .compatible = "ti,dra742-uart" },
> +       {}
> +};
> +#endif
> +
> +U_BOOT_DRIVER(ns16550_serial) = {
> +       .name   = "ns16550_serial",
> +       .id     = UCLASS_SERIAL,
> +#if CONFIG_IS_ENABLED(OF_CONTROL)
> +       .of_match = ns16550_serial_ids,
> +       .ofdata_to_platdata = ns16550_serial_ofdata_to_platdata,
> +       .platdata_auto_alloc_size = sizeof(struct ns16550_platdata),
> +#endif
> +       .priv_auto_alloc_size = sizeof(struct NS16550),
> +       .probe = ns16550_serial_probe,
> +       .ops    = &ns16550_serial_ops,
> +};
> +#endif /* CONFIG_NS16550_SERIAL */
>  #endif /* CONFIG_DM_SERIAL */
> --

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>