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Re: [PATCH 2/6] tty: serial: lpuart: add little endian 32 bit register support

Started byStefan Agner <stefan@agner.ch>
First post2017-05-10 06:00 +0200
Last post2017-05-10 08:30 +0200
Articles 2 — 2 participants

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  Re: [PATCH 2/6] tty: serial: lpuart: add little endian 32 bit  register support Stefan Agner <stefan@agner.ch> - 2017-05-10 06:00 +0200
    Re: [PATCH 2/6] tty: serial: lpuart: add little endian 32 bit  register support Dong Aisheng <dongas86@gmail.com> - 2017-05-10 08:30 +0200

#1638544 — Re: [PATCH 2/6] tty: serial: lpuart: add little endian 32 bit register support

FromStefan Agner <stefan@agner.ch>
Date2017-05-10 06:00 +0200
SubjectRe: [PATCH 2/6] tty: serial: lpuart: add little endian 32 bit register support
Message-ID<tFqX8-3rf-7@gated-at.bofh.it>
On 2017-05-09 00:50, Dong Aisheng wrote:
> It's based on the exist lpuart32 read/write implementation.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Jiri Slaby <jslaby@suse.com> (supporter:TTY LAYER)
> 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 | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index cd4e905..bddd041 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -231,6 +231,8 @@
>  #define DEV_NAME	"ttyLP"
>  #define UART_NR		6
>  
> +static bool lpuart_is_be;
> +

Other LS1021a IP's such as SPI use the big-endian device tree property
along with regmap.

See e.g.
drivers/spi/spi-fsl-dspi.c

(Used in vf610 in little endian mode and ls1021a in big endian)

Not sure if we want to switch to regmap, but you can also get the
property using of_get_property.

The ls1021a lpuart node do not specify big-endian at the moment (would
probably good to add it), so I would leave big-endian the driver default
and check for little-endian for the new device and check whether that is
specified:
of_get_property(dn, "little-endian", NULL)

--
Stefan

>  struct lpuart_port {
>  	struct uart_port	port;
>  	struct clk		*clk;
> @@ -260,6 +262,7 @@ struct lpuart_port {
>  
>  struct lpuart_soc_data {
>  	bool	is_32;
> +	bool	is_be;
>  };
>  
>  static struct lpuart_soc_data vf_data = {
> @@ -268,6 +271,7 @@ static struct lpuart_soc_data vf_data = {
>  
>  static struct lpuart_soc_data ls_data = {
>  	.is_32 = true,
> +	.is_be = true,
>  };
>  
>  static const struct of_device_id lpuart_dt_ids[] = {
> @@ -282,12 +286,15 @@ static void lpuart_dma_tx_complete(void *arg);
>  
>  static u32 lpuart32_read(void __iomem *addr)
>  {
> -	return ioread32be(addr);
> +	return lpuart_is_be ? ioread32be(addr) : readl(addr);
>  }
>  
>  static void lpuart32_write(u32 val, void __iomem *addr)
>  {
> -	iowrite32be(val, addr);
> +	if (lpuart_is_be)
> +		iowrite32be(val, addr);
> +	else
> +		writel(val, addr);
>  }
>  
>  static void lpuart_stop_tx(struct uart_port *port)
> @@ -2000,6 +2007,7 @@ static int lpuart_probe(struct platform_device *pdev)
>  	}
>  	sport->port.line = ret;
>  	sport->lpuart32 = sdata->is_32;
> +	lpuart_is_be = sdata->is_be;
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	sport->port.membase = devm_ioremap_resource(&pdev->dev, res);

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#1638583

FromDong Aisheng <dongas86@gmail.com>
Date2017-05-10 08:30 +0200
Message-ID<tFtii-5D5-3@gated-at.bofh.it>
In reply to#1638544
On Wed, May 10, 2017 at 11:58 AM, Stefan Agner <stefan@agner.ch> wrote:
> On 2017-05-09 00:50, Dong Aisheng wrote:
>> It's based on the exist lpuart32 read/write implementation.
>>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Jiri Slaby <jslaby@suse.com> (supporter:TTY LAYER)
>> 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 | 12 ++++++++++--
>>  1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
>> index cd4e905..bddd041 100644
>> --- a/drivers/tty/serial/fsl_lpuart.c
>> +++ b/drivers/tty/serial/fsl_lpuart.c
>> @@ -231,6 +231,8 @@
>>  #define DEV_NAME     "ttyLP"
>>  #define UART_NR              6
>>
>> +static bool lpuart_is_be;
>> +
>
> Other LS1021a IP's such as SPI use the big-endian device tree property
> along with regmap.
>
> See e.g.
> drivers/spi/spi-fsl-dspi.c
>
> (Used in vf610 in little endian mode and ls1021a in big endian)
>
> Not sure if we want to switch to regmap, but you can also get the
> property using of_get_property.
>
> The ls1021a lpuart node do not specify big-endian at the moment (would
> probably good to add it),

That's why i did not check for little-endian initially.

> so I would leave big-endian the driver default
> and check for little-endian for the new device and check whether that is
> specified:
> of_get_property(dn, "little-endian", NULL)

As we already have the platform data, it's not too necessary to get the endian
from device tree.

Regards
Dong Aisheng

>
> --
> Stefan
>
>>  struct lpuart_port {
>>       struct uart_port        port;
>>       struct clk              *clk;
>> @@ -260,6 +262,7 @@ struct lpuart_port {
>>
>>  struct lpuart_soc_data {
>>       bool    is_32;
>> +     bool    is_be;
>>  };
>>
>>  static struct lpuart_soc_data vf_data = {
>> @@ -268,6 +271,7 @@ static struct lpuart_soc_data vf_data = {
>>
>>  static struct lpuart_soc_data ls_data = {
>>       .is_32 = true,
>> +     .is_be = true,
>>  };
>>
>>  static const struct of_device_id lpuart_dt_ids[] = {
>> @@ -282,12 +286,15 @@ static void lpuart_dma_tx_complete(void *arg);
>>
>>  static u32 lpuart32_read(void __iomem *addr)
>>  {
>> -     return ioread32be(addr);
>> +     return lpuart_is_be ? ioread32be(addr) : readl(addr);
>>  }
>>
>>  static void lpuart32_write(u32 val, void __iomem *addr)
>>  {
>> -     iowrite32be(val, addr);
>> +     if (lpuart_is_be)
>> +             iowrite32be(val, addr);
>> +     else
>> +             writel(val, addr);
>>  }
>>
>>  static void lpuart_stop_tx(struct uart_port *port)
>> @@ -2000,6 +2007,7 @@ static int lpuart_probe(struct platform_device *pdev)
>>       }
>>       sport->port.line = ret;
>>       sport->lpuart32 = sdata->is_32;
>> +     lpuart_is_be = sdata->is_be;
>>
>>       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>       sport->port.membase = devm_ioremap_resource(&pdev->dev, res);

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