lkml.org 
[lkml]   [2017]   [May]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 4/6] tty: serial: lpuart: add imx7ulp support
On 2017-05-09 23:14, Dong Aisheng wrote:
> Hi Stefan,
>
> On Wed, May 10, 2017 at 12:10 PM, Stefan Agner <stefan@agner.ch> wrote:
>> 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...
>>
>
> lpuart_reg_off is SoC specific and there's no two UART
> with two different reg offset.
>
>> Instead of adding a fixed offset to any write you could just add the
>> offset to sport->port.membase...
>>
>
> That's intended as i don't want the changes to be too intrusive.
> If adding offset in sport->port.xxx, then we have to change the basic
> lpuart32_read/write API which is called through the whole driver.

Every lpuart32_write/read call passes port.membase, so if you offset
port.membase when it is assigned in probe you should be fine not?

--
Stefan

>
> Regards
> Dong Aisheng
>
>> --
>> 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);

\
 
 \ /
  Last update: 2017-05-10 22:38    [W:0.064 / U:4.380 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site