Re: [PATCH v5 10/12] serial: 8250: add Ambarella UART driver
Andy Shevchenko <[email protected]>
| Newsgroups | dev.linux.lists.soc,dev.linux.lists.mfd,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-clk,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-gpio,org.kernel.vger.linux-kernel,org.kernel.vger.linux-serial |
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On Tue, Aug 18, 2026 at 06:31:24PM +0800, Long Zhao via B4 Relay wrote:
> Add an 8250 platform driver for Ambarella CV75 instead of claiming
> snps,dw-apb-uart compatibility.
This is a record from a changelog. There is nothing in the commit message.
...
The code seems like an almost blind copy of 8250_dw.c.
> +#define AMBARELLA_UART_USR 0x1f
> +#define AMBARELLA_UART_USR_BUSY BIT(0)
So, is it Synopsys IP-based design? How this gets into this platform? This
whole story completely made me lost.
> +#define AMBARELLA_UART_IIR_IID GENMASK(3, 0)
> +#define AMBARELLA_UART_IIR_STATUS GENMASK(5, 0)
...
> + of_property_read_u32(dev->of_node, "reg-shift", ®_shift);
> + of_property_read_u32(dev->of_node, "reg-io-width", ®_io_width);
> + uart.port.regshift = reg_shift;
> + switch (reg_io_width) {
> + case 4:
> + uart.port.iotype = UPIO_MEM32;
> + uart.port.serial_in = ambarella_serial_in;
> + uart.port.serial_out = ambarella_serial_out;
> + break;
> + default:
> + return dev_err_probe(dev, -EINVAL,
> + "unsupported reg-io-width %u\n",
> + reg_io_width);
> + }
This is handled by uart_read_port_properties().
--
With Best Regards,
Andy Shevchenko