RE: [PATCH V3 5/7] tty: serial: lpuart: add imx7ulp support

[A.s. Dong]

> -----Original Message-----
> From: Andy Duan
> Sent: Tuesday, June 13, 2017 11:02 AM
> To: A.s. Dong; linux-serial@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> gregkh@xxxxxxxxxxxxxxxxxxx; jslaby@xxxxxxxx; stefan@xxxxxxxx; Mingkai Hu;
> Y.b. Lu; nikita.yoush@xxxxxxxxxxxxxxxxxx; andy.shevchenko@xxxxxxxxx;
> dongas86@xxxxxxxxx; A.s. Dong
> Subject: RE: [PATCH V3 5/7] tty: serial: lpuart: add imx7ulp support
> 
> From: Dong Aisheng <aisheng.dong@xxxxxxx> Sent: Monday, June 12, 2017
> 11:37 PM
> >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@xxxxxxxxxxxxxxxxxxx>
> >Cc: Jiri Slaby <jslaby@xxxxxxxx>
> >Cc: Stefan Agner <stefan@xxxxxxxx>
> >Cc: Mingkai Hu <Mingkai.Hu@xxxxxxx>
> >Cc: Yangbo Lu <yangbo.lu@xxxxxxx>
> >Cc: Fugang Duan <fugang.duan@xxxxxxx>
> >Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> >
> >---
> >ChangeLog:
> >v2->v3:
> > * use standard port->iotype to represent the endians.
> >v1->v2:
> > * remove lpuart_reg_off according to Stefan's suggestion
> >---
> > drivers/tty/serial/fsl_lpuart.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> >diff --git a/drivers/tty/serial/fsl_lpuart.c
> >b/drivers/tty/serial/fsl_lpuart.c index
> >bbf47a0..9d05e53 100644
> >--- a/drivers/tty/serial/fsl_lpuart.c
> >+++ b/drivers/tty/serial/fsl_lpuart.c
> >@@ -231,6 +231,9 @@
> > #define DEV_NAME	"ttyLP"
> > #define UART_NR		6
> >
> >+/* IMX lpuart has four extra unused regs located at the beginning */
> >+#define IMX_REG_OFF	0x10
> >+
> > struct lpuart_port {
> > 	struct uart_port	port;
> > 	struct clk		*clk;
> >@@ -259,6 +262,7 @@ struct lpuart_port {
> >
> > struct lpuart_soc_data {
> > 	char	iotype;
> >+	u8	reg_off;
> > };
> >
> > static const struct lpuart_soc_data vf_data = { @@ -267,12 +271,17 @@
> >static const struct lpuart_soc_data vf_data = {
> >
> > static const struct lpuart_soc_data ls_data = {
> > 	.iotype = UPIO_MEM32BE,
> >+};
> >
> >+static struct lpuart_soc_data imx_data = {
> >+	.iotype = UPIO_MEM32,
> >+	.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); @@ -2020,6 +2029,7 @@ static
> >int lpuart_probe(struct platform_device *pdev)
> > 	if (IS_ERR(sport->port.membase))
> > 		return PTR_ERR(sport->port.membase);
> >
> >+	sport->port.membase += sdata->reg_off;
> > 	sport->port.mapbase = res->start;
> 
> Also update the mapbase.
> 

The idea behind is only do the quirk for io remapped address.
Mapbase(physical address) is not needed for lpuart32 currently.

Probably it could be changed when lpuart32 DMA function is added.

Regards
Dong Aisheng

> > 	sport->port.dev = &pdev->dev;
> > 	sport->port.type = PORT_LPUART;
> >--
> >2.7.4