diff mbox

[v2,5/8] spi: imx: Add support for loopback for ECSPI controllers

Message ID ca96561d8010acf587a93d0f357774bf77efbe16.1442923630.git.anton_bondarenko@mentor.com (mailing list archive)
State Superseded
Headers show

Commit Message

Anton Bondarenko Sept. 25, 2015, 5:57 p.m. UTC 
Support for ECSPI loopback for IMX51,IMX53 and IMX6Q using TEST register.

Signed-off-by: Mohsin Kazmi <mohsin_kazmi@mentor.com>
Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.com>
---
 drivers/spi/spi-imx.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

Comments

Robin Gong Sept. 30, 2015, 8:42 a.m. UTC | #1 
On Fri, Sep 25, 2015 at 07:57:12PM +0200, Anton Bondarenko wrote:
> Support for ECSPI loopback for IMX51,IMX53 and IMX6Q using TEST register.
> 
> Signed-off-by: Mohsin Kazmi <mohsin_kazmi@mentor.com>
> Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.com>
> ---
>  drivers/spi/spi-imx.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 41c9cef..4b3c16e 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -265,6 +265,9 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
>  #define MX51_ECSPI_STAT		0x18
>  #define MX51_ECSPI_STAT_RR		(1 <<  3)
>  
> +#define MX51_ECSPI_TEST			0x20
> +#define MX51_ECSPI_LOOP			BIT(31)
> +
>  /* MX51 eCSPI */
>  static unsigned int mx51_ecspi_clkdiv(unsigned int fin, unsigned int fspi,
>  				      unsigned int *fres)
> @@ -338,6 +341,7 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>  	u32 ctrl = MX51_ECSPI_CTRL_ENABLE, dma = 0;
>  	u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG);
>  	u32 delay;
> +	u32 lpb = 0;
>  
>  	/*
>  	 * The hardware seems to have a race condition when changing modes. The
> @@ -370,8 +374,12 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>  	if (config->mode & SPI_CS_HIGH)
>  		cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
>  
> +	if (config->mode & SPI_LOOP)
> +		lpb |= MX51_ECSPI_LOOP;
> +
>  	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
>  	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
> +	writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
It's better write this MX51_ECSPI_TEST only in LOOP mode.
>  
>  	/*
>  	 * Wait until the changes in the configuration register CONFIGREG
> @@ -1252,6 +1260,9 @@ static int spi_imx_probe(struct platform_device *pdev)
>  	spi_imx = spi_master_get_devdata(master);
>  	spi_imx->bitbang.master = master;
>  
> +	spi_imx->devtype_data = of_id ? of_id->data :
> +		(struct spi_imx_devtype_data *)pdev->id_entry->driver_data;
> +
>  	for (i = 0; i < master->num_chipselect; i++) {
>  		int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
>  		if (!gpio_is_valid(cs_gpio) && mxc_platform_info)
> @@ -1276,12 +1287,13 @@ static int spi_imx_probe(struct platform_device *pdev)
>  	spi_imx->bitbang.master->cleanup = spi_imx_cleanup;
>  	spi_imx->bitbang.master->prepare_message = spi_imx_prepare_message;
>  	spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
> -	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
> +	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA |
> +				SPI_CS_HIGH;
Any change?
>  
> -	init_completion(&spi_imx->xfer_done);
> +	if (is_imx5x_ecspi(spi_imx))
> +		spi_imx->bitbang.master->mode_bits |= SPI_LOOP;
>  
> -	spi_imx->devtype_data = of_id ? of_id->data :
> -		(struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
> +	init_completion(&spi_imx->xfer_done);
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	spi_imx->base = devm_ioremap_resource(&pdev->dev, res);
> -- 
> 2.5.2
> 
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Anton Bondarenko Oct. 1, 2015, 12:16 a.m. UTC | #2 
On 30.09.2015 10:42, Robin Gong wrote:
> On Fri, Sep 25, 2015 at 07:57:12PM +0200, Anton Bondarenko wrote:
>> @@ -370,8 +374,12 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>>  	if (config->mode & SPI_CS_HIGH)
>>  		cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
>>  
>> +	if (config->mode & SPI_LOOP)
>> +		lpb |= MX51_ECSPI_LOOP;
>> +
>>  	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
>>  	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
>> +	writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
> It's better write this MX51_ECSPI_TEST only in LOOP mode.
LOOP mode can be set dynamically. This mean we should be able to set and clear the flag.
Currently only LOOP flag is used. I did not find any problems with writing 0 in the rest
fields of TEST register.
>>  
>>  	/*
>>  	 * Wait until the changes in the configuration register CONFIGREG
>> @@ -1276,12 +1287,13 @@ static int spi_imx_probe(struct platform_device *pdev)
>>  	spi_imx->bitbang.master->cleanup = spi_imx_cleanup;
>>  	spi_imx->bitbang.master->prepare_message = spi_imx_prepare_message;
>>  	spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
>> -	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
>> +	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA |
>> +				SPI_CS_HIGH;
> Any change?
Will be fixed in V3
>>  
>> -	init_completion(&spi_imx->xfer_done);
>> +	if (is_imx5x_ecspi(spi_imx))
>> +		spi_imx->bitbang.master->mode_bits |= SPI_LOOP;
>>  
>> -	spi_imx->devtype_data = of_id ? of_id->data :
>> -		(struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
>> +	init_completion(&spi_imx->xfer_done);
>>  
>>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>  	spi_imx->base = devm_ioremap_resource(&pdev->dev, res);
>> -- 
>> 2.5.2
>>

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Robin Gong Oct. 8, 2015, 9:28 a.m. UTC | #3 
On Thu, Oct 01, 2015 at 12:16:49AM +0000, Bondarenko, Anton wrote:
> On 30.09.2015 10:42, Robin Gong wrote:
> > On Fri, Sep 25, 2015 at 07:57:12PM +0200, Anton Bondarenko wrote:
> >> @@ -370,8 +374,12 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
> >>  	if (config->mode & SPI_CS_HIGH)
> >>  		cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
> >>  
> >> +	if (config->mode & SPI_LOOP)
> >> +		lpb |= MX51_ECSPI_LOOP;
> >> +
> >>  	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
> >>  	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
> >> +	writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
> > It's better write this MX51_ECSPI_TEST only in LOOP mode.
> LOOP mode can be set dynamically. This mean we should be able to set and clear the flag.
> Currently only LOOP flag is used. I did not find any problems with writing 0 in the rest
> fields of TEST register.
Yes, I know writing 0 is harmless, but we never need to touch this register if
SPI_LOOP flags not set, I'd like below:
	if (config->mode & SPI_LOOP) {
		lpb |= MX51_ECSPI_LOOP;
		writel(lgb, spi_imx->base + MX51_ECSPI_TEST);
	}

> >>  
> >>  	/*
> >>  	 * Wait until the changes in the configuration register CONFIGREG
> >> @@ -1276,12 +1287,13 @@ static int spi_imx_probe(struct platform_device *pdev)
> >>  	spi_imx->bitbang.master->cleanup = spi_imx_cleanup;
> >>  	spi_imx->bitbang.master->prepare_message = spi_imx_prepare_message;
> >>  	spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
> >> -	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
> >> +	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA |
> >> +				SPI_CS_HIGH;
> > Any change?
> Will be fixed in V3
> >>  
> >> -	init_completion(&spi_imx->xfer_done);
> >> +	if (is_imx5x_ecspi(spi_imx))
> >> +		spi_imx->bitbang.master->mode_bits |= SPI_LOOP;
> >>  
> >> -	spi_imx->devtype_data = of_id ? of_id->data :
> >> -		(struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
> >> +	init_completion(&spi_imx->xfer_done);
> >>  
> >>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >>  	spi_imx->base = devm_ioremap_resource(&pdev->dev, res);
> >> -- 
> >> 2.5.2
> >>
> 
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Anton Bondarenko Oct. 20, 2015, 11:08 p.m. UTC | #4 
On 08.10.2015 11:28, Robin Gong wrote:
> On Thu, Oct 01, 2015 at 12:16:49AM +0000, Bondarenko, Anton wrote:
>> On 30.09.2015 10:42, Robin Gong wrote:
>>> On Fri, Sep 25, 2015 at 07:57:12PM +0200, Anton Bondarenko wrote:
>>>> @@ -370,8 +374,12 @@ static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
>>>>   	if (config->mode & SPI_CS_HIGH)
>>>>   		cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
>>>>
>>>> +	if (config->mode & SPI_LOOP)
>>>> +		lpb |= MX51_ECSPI_LOOP;
>>>> +
>>>>   	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
>>>>   	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
>>>> +	writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
>>> It's better write this MX51_ECSPI_TEST only in LOOP mode.
>> LOOP mode can be set dynamically. This mean we should be able to set and clear the flag.
>> Currently only LOOP flag is used. I did not find any problems with writing 0 in the rest
>> fields of TEST register.
> Yes, I know writing 0 is harmless, but we never need to touch this register if
> SPI_LOOP flags not set, I'd like below:
> 	if (config->mode & SPI_LOOP) {
> 		lpb |= MX51_ECSPI_LOOP;
> 		writel(lgb, spi_imx->base + MX51_ECSPI_TEST);
> 	}
>
Proposed code not able to clear LOOP mode in TEST register. What about 
something like this:
if (config->mode & SPI_LOOP)
	lpb |= MX51_ECSPI_LOOP;

if ((readl(spi_imx->base + MX51_ECSPI_TEST) & MX51_ECSPI_LOOP) != lpb)
	writel(lpb, spi_imx->base + MX51_ECSPI_TEST);

In this case driver will write TEST register only if needed.
>>>>
>>>>   	/*
>>>>   	 * Wait until the changes in the configuration register CONFIGREG

Regards,
Anton
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diff mbox

Patch

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 41c9cef..4b3c16e 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -265,6 +265,9 @@  static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
 #define MX51_ECSPI_STAT		0x18
 #define MX51_ECSPI_STAT_RR		(1 <<  3)
 
+#define MX51_ECSPI_TEST			0x20
+#define MX51_ECSPI_LOOP			BIT(31)
+
 /* MX51 eCSPI */
 static unsigned int mx51_ecspi_clkdiv(unsigned int fin, unsigned int fspi,
 				      unsigned int *fres)
@@ -338,6 +341,7 @@  static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
 	u32 ctrl = MX51_ECSPI_CTRL_ENABLE, dma = 0;
 	u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG);
 	u32 delay;
+	u32 lpb = 0;
 
 	/*
 	 * The hardware seems to have a race condition when changing modes. The
@@ -370,8 +374,12 @@  static int __maybe_unused mx51_ecspi_config(struct spi_imx_data *spi_imx,
 	if (config->mode & SPI_CS_HIGH)
 		cfg |= MX51_ECSPI_CONFIG_SSBPOL(config->cs);
 
+	if (config->mode & SPI_LOOP)
+		lpb |= MX51_ECSPI_LOOP;
+
 	writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL);
 	writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG);
+	writel(lpb, spi_imx->base + MX51_ECSPI_TEST);
 
 	/*
 	 * Wait until the changes in the configuration register CONFIGREG
@@ -1252,6 +1260,9 @@  static int spi_imx_probe(struct platform_device *pdev)
 	spi_imx = spi_master_get_devdata(master);
 	spi_imx->bitbang.master = master;
 
+	spi_imx->devtype_data = of_id ? of_id->data :
+		(struct spi_imx_devtype_data *)pdev->id_entry->driver_data;
+
 	for (i = 0; i < master->num_chipselect; i++) {
 		int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
 		if (!gpio_is_valid(cs_gpio) && mxc_platform_info)
@@ -1276,12 +1287,13 @@  static int spi_imx_probe(struct platform_device *pdev)
 	spi_imx->bitbang.master->cleanup = spi_imx_cleanup;
 	spi_imx->bitbang.master->prepare_message = spi_imx_prepare_message;
 	spi_imx->bitbang.master->unprepare_message = spi_imx_unprepare_message;
-	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+	spi_imx->bitbang.master->mode_bits = SPI_CPOL | SPI_CPHA |
+				SPI_CS_HIGH;
 
-	init_completion(&spi_imx->xfer_done);
+	if (is_imx5x_ecspi(spi_imx))
+		spi_imx->bitbang.master->mode_bits |= SPI_LOOP;
 
-	spi_imx->devtype_data = of_id ? of_id->data :
-		(struct spi_imx_devtype_data *) pdev->id_entry->driver_data;
+	init_completion(&spi_imx->xfer_done);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	spi_imx->base = devm_ioremap_resource(&pdev->dev, res);