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SubjectRe: [PATCH 4/6] tty: serial: lpuart: add imx7ulp support
On 2017-05-09 00:50, Dong Aisheng wrote:
> The lpuart of imx7ulp is basically the same as ls1021a. It's also
> 32 bit width register, but unlike ls1021a, it's little endian.
> Besides that, imx7ulp lpuart has a minor different register layout
> from ls1021a that it has four extra registers (verid, param, global,
> pincfg) located at the beginning of register map, which are currently
> not used by the driver and less to be used later.
>
> To ease the register difference handling, we add a reg_off member
> in lpuart_soc_data structure to represent if the normal
> lpuart32_{read|write} requires plus a offset to hide the issue.
>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Jiri Slaby <jslaby@suse.com>
> Cc: Fugang Duan <fugang.duan@nxp.com>
> Cc: Stefan Agner <stefan@agner.ch>
> Cc: Mingkai Hu <Mingkai.Hu@nxp.com>
> Cc: Yangbo Lu <yangbo.lu@nxp.com>
> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
> ---
> drivers/tty/serial/fsl_lpuart.c | 21 ++++++++++++++++++---
> 1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index bddd041..1cdb3f9 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -231,7 +231,11 @@
> #define DEV_NAME "ttyLP"
> #define UART_NR 6
>
> +/* IMX lpuart has four extra unused regs located at the beginning */
> +#define IMX_REG_OFF 0x10
> +
> static bool lpuart_is_be;
> +static u8 lpuart_reg_off;

Global variables? That hardly works once you have two UARTs...

Instead of adding a fixed offset to any write you could just add the
offset to sport->port.membase...

--
Stefan

>
> struct lpuart_port {
> struct uart_port port;
> @@ -263,6 +267,7 @@ struct lpuart_port {
> struct lpuart_soc_data {
> bool is_32;
> bool is_be;
> + u8 reg_off;
> };
>
> static struct lpuart_soc_data vf_data = {
> @@ -272,11 +277,19 @@ static struct lpuart_soc_data vf_data = {
> static struct lpuart_soc_data ls_data = {
> .is_32 = true,
> .is_be = true,
> + .reg_off = 0x0,
> +};
> +
> +static struct lpuart_soc_data imx_data = {
> + .is_32 = true,
> + .is_be = false,
> + .reg_off = IMX_REG_OFF,
> };
>
> static const struct of_device_id lpuart_dt_ids[] = {
> { .compatible = "fsl,vf610-lpuart", .data = &vf_data, },
> { .compatible = "fsl,ls1021a-lpuart", .data = &ls_data, },
> + { .compatible = "fsl,imx7ulp-lpuart", .data = &imx_data, },
> { /* sentinel */ }
> };
> MODULE_DEVICE_TABLE(of, lpuart_dt_ids);
> @@ -286,15 +299,16 @@ static void lpuart_dma_tx_complete(void *arg);
>
> static u32 lpuart32_read(void __iomem *addr)
> {
> - return lpuart_is_be ? ioread32be(addr) : readl(addr);
> + return lpuart_is_be ? ioread32be(addr + lpuart_reg_off) :
> + readl(addr + lpuart_reg_off);
> }
>
> static void lpuart32_write(u32 val, void __iomem *addr)
> {
> if (lpuart_is_be)
> - iowrite32be(val, addr);
> + iowrite32be(val, addr + lpuart_reg_off);
> else
> - writel(val, addr);
> + writel(val, addr + lpuart_reg_off);
> }
>
> static void lpuart_stop_tx(struct uart_port *port)
> @@ -2008,6 +2022,7 @@ static int lpuart_probe(struct platform_device *pdev)
> sport->port.line = ret;
> sport->lpuart32 = sdata->is_32;
> lpuart_is_be = sdata->is_be;
> + lpuart_reg_off = sdata->reg_off;
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> sport->port.membase = devm_ioremap_resource(&pdev->dev, res);

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