[PATCH 0/2 v2] SPI: spi-pxa2xx: Add support for Intel Quark X1000 SPI controller

[PATCH 0/2 v2] SPI: spi-pxa2xx: Add support for Intel Quark X1000 SPI controller

[Weike Chen]

Hi,
Intel Quark X1000 consists of two SPI controllers which can be PCI enumerated.
SPI-PXA2XX PCI layer doesn't support it. Thus, we add support for Intel Quark
X1000 SPI as well.

---
v2:
  Split into two patches: one is for helper functions,
  and another is for quark supporting.

[PATCH 1/2]
* Add helper functions to access registers.
* Use 'switch' instead of 'if-else'.
[PATCH 2/2]
* Use 'switch' instead of 'if-else'.
* Add comments for the 'dds'&'clk_div' caculation.
* A couple of minor fixes.

Weike Chen (2):
  SPI: spi-pxa2xx: Add helpers for regiseters' accessing
  SPI: spi-pxa2xx: SPI support for Intel Quark X1000

 drivers/spi/spi-pxa2xx-pci.c |    8 ++
 drivers/spi/spi-pxa2xx.c     |  306 ++++++++++++++++++++++++++++++++++++------
 drivers/spi/spi-pxa2xx.h     |   16 ++-
 include/linux/pxa2xx_ssp.h   |   21 +++
 4 files changed, 306 insertions(+), 45 deletions(-)

-- 
1.7.9.5

[PATCH 1/2 v2] SPI: spi-pxa2xx: Add helpers for regiseters' accessing

[Weike Chen]

Introduce helper functions to access the 'SSCR0' and 'SSCR1'.

Signed-off-by: Weike Chen <alvin.chen@intel.com>
---
 drivers/spi/spi-pxa2xx.c |  108 ++++++++++++++++++++++++++++++++++++----------
 1 file changed, 85 insertions(+), 23 deletions(-)

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index 256c0ab..e7ff9c5 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -80,6 +80,73 @@ static bool is_lpss_ssp(const struct driver_data *drv_data)
 	return drv_data->ssp_type == LPSS_SSP;
 }
 
+static u32 pxa2xx_spi_get_ssrc1_change_mask(const struct driver_data *drv_data)
+{
+	switch (drv_data->ssp_type) {
+	default:
+		return SSCR1_CHANGE_MASK;
+	}
+}
+
+static u32
+pxa2xx_spi_get_rx_default_thre(const struct driver_data *drv_data)
+{
+	switch (drv_data->ssp_type) {
+	default:
+		return RX_THRESH_DFLT;
+	}
+}
+
+static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
+{
+	void __iomem *reg = drv_data->ioaddr;
+	u32 mask;
+
+	switch (drv_data->ssp_type) {
+	default:
+		mask = SSSR_TFL_MASK;
+		break;
+	}
+
+	return (read_SSSR(reg) & mask) == mask;
+}
+
+static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
+				     u32 *sccr1_reg)
+{
+	u32 mask;
+
+	switch (drv_data->ssp_type) {
+	default:
+		mask = SSCR1_RFT;
+		break;
+	}
+	*sccr1_reg &= ~mask;
+}
+
+static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
+				   u32 *sccr1_reg, u32 threshold)
+{
+	switch (drv_data->ssp_type) {
+	default:
+		*sccr1_reg |= SSCR1_RxTresh(threshold);
+		break;
+	}
+}
+
+static u32 pxa2xx_configure_sscr0(const struct driver_data *drv_data,
+				  u32 clk_div, u8 bits)
+{
+	switch (drv_data->ssp_type) {
+	default:
+		return clk_div
+			| SSCR0_Motorola
+			| SSCR0_DataSize(bits > 16 ? bits - 16 : bits)
+			| SSCR0_SSE
+			| (bits > 16 ? SSCR0_EDSS : 0);
+	}
+}
+
 /*
  * Read and write LPSS SSP private registers. Caller must first check that
  * is_lpss_ssp() returns true before these can be called.
@@ -234,7 +301,7 @@ static int null_writer(struct driver_data *drv_data)
 	void __iomem *reg = drv_data->ioaddr;
 	u8 n_bytes = drv_data->n_bytes;
 
-	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
+	if (pxa2xx_spi_txfifo_full(drv_data)
 		|| (drv_data->tx == drv_data->tx_end))
 		return 0;
 
@@ -262,7 +329,7 @@ static int u8_writer(struct driver_data *drv_data)
 {
 	void __iomem *reg = drv_data->ioaddr;
 
-	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
+	if (pxa2xx_spi_txfifo_full(drv_data)
 		|| (drv_data->tx == drv_data->tx_end))
 		return 0;
 
@@ -289,7 +356,7 @@ static int u16_writer(struct driver_data *drv_data)
 {
 	void __iomem *reg = drv_data->ioaddr;
 
-	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
+	if (pxa2xx_spi_txfifo_full(drv_data)
 		|| (drv_data->tx == drv_data->tx_end))
 		return 0;
 
@@ -316,7 +383,7 @@ static int u32_writer(struct driver_data *drv_data)
 {
 	void __iomem *reg = drv_data->ioaddr;
 
-	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
+	if (pxa2xx_spi_txfifo_full(drv_data)
 		|| (drv_data->tx == drv_data->tx_end))
 		return 0;
 
@@ -508,8 +575,9 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
 		 * remaining RX bytes.
 		 */
 		if (pxa25x_ssp_comp(drv_data)) {
+			u32 rx_thre;
 
-			sccr1_reg &= ~SSCR1_RFT;
+			pxa2xx_spi_clear_rx_thre(drv_data, &sccr1_reg);
 
 			bytes_left = drv_data->rx_end - drv_data->rx;
 			switch (drv_data->n_bytes) {
@@ -519,10 +587,12 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
 				bytes_left >>= 1;
 			}
 
-			if (bytes_left > RX_THRESH_DFLT)
-				bytes_left = RX_THRESH_DFLT;
+			rx_thre = pxa2xx_spi_get_rx_default_thre(drv_data);
+			if (rx_thre > bytes_left)
+				rx_thre = bytes_left;
 
-			sccr1_reg |= SSCR1_RxTresh(bytes_left);
+			pxa2xx_spi_set_rx_thre(drv_data, &sccr1_reg,
+					       rx_thre);
 		}
 		write_SSCR1(sccr1_reg, reg);
 	}
@@ -613,6 +683,7 @@ static void pump_transfers(unsigned long data)
 	u32 cr1;
 	u32 dma_thresh = drv_data->cur_chip->dma_threshold;
 	u32 dma_burst = drv_data->cur_chip->dma_burst_size;
+	u32 change_mask = pxa2xx_spi_get_ssrc1_change_mask(drv_data);
 
 	/* Get current state information */
 	message = drv_data->cur_msg;
@@ -731,11 +802,7 @@ static void pump_transfers(unsigned long data)
 						     "pump_transfers: DMA burst size reduced to match bits_per_word\n");
 		}
 
-		cr0 = clk_div
-			| SSCR0_Motorola
-			| SSCR0_DataSize(bits > 16 ? bits - 16 : bits)
-			| SSCR0_SSE
-			| (bits > 16 ? SSCR0_EDSS : 0);
+		cr0 = pxa2xx_configure_sscr0(drv_data, clk_div, bits);
 	}
 
 	message->state = RUNNING_STATE;
@@ -772,16 +839,15 @@ static void pump_transfers(unsigned long data)
 	}
 
 	/* see if we need to reload the config registers */
-	if ((read_SSCR0(reg) != cr0)
-		|| (read_SSCR1(reg) & SSCR1_CHANGE_MASK) !=
-			(cr1 & SSCR1_CHANGE_MASK)) {
+	if ((read_SSCR0(reg) != cr0) ||
+	    (read_SSCR1(reg) & change_mask) != (cr1 & change_mask)) {
 
 		/* stop the SSP, and update the other bits */
 		write_SSCR0(cr0 & ~SSCR0_SSE, reg);
 		if (!pxa25x_ssp_comp(drv_data))
 			write_SSTO(chip->timeout, reg);
 		/* first set CR1 without interrupt and service enables */
-		write_SSCR1(cr1 & SSCR1_CHANGE_MASK, reg);
+		write_SSCR1(cr1 & change_mask, reg);
 		/* restart the SSP */
 		write_SSCR0(cr0, reg);
 
@@ -959,12 +1025,8 @@ static int setup(struct spi_device *spi)
 	clk_div = ssp_get_clk_div(drv_data, spi->max_speed_hz);
 	chip->speed_hz = spi->max_speed_hz;
 
-	chip->cr0 = clk_div
-			| SSCR0_Motorola
-			| SSCR0_DataSize(spi->bits_per_word > 16 ?
-				spi->bits_per_word - 16 : spi->bits_per_word)
-			| SSCR0_SSE
-			| (spi->bits_per_word > 16 ? SSCR0_EDSS : 0);
+	chip->cr0 = pxa2xx_configure_sscr0(drv_data, clk_div,
+					   spi->bits_per_word);
 	chip->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
 	chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
 			| (((spi->mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);
-- 
1.7.9.5

[PATCH 1/2 v2] SPI: spi-pxa2xx: Add helpers for regiseters' accessing

[Andy Shevchenko]

On Mon, 2014-09-29 at 07:22 -0700, Weike Chen wrote:


I'm okay with the current version, though I have few minor comments
below.

> Introduce helper functions to access the 'SSCR0' and 'SSCR1'.
> 

Like you said in the summary there are many accessors to many registers,
not only cr1/cr0. Perhaps, you may extend your commit message.

In any case
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>


More comments below.

> Signed-off-by: Weike Chen <alvin.chen@intel.com>
> ---
>  drivers/spi/spi-pxa2xx.c |  108 ++++++++++++++++++++++++++++++++++++----------
>  1 file changed, 85 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
> index 256c0ab..e7ff9c5 100644
> --- a/drivers/spi/spi-pxa2xx.c
> +++ b/drivers/spi/spi-pxa2xx.c
> @@ -80,6 +80,73 @@ static bool is_lpss_ssp(const struct driver_data *drv_data)
>  	return drv_data->ssp_type == LPSS_SSP;
>  }
>  
> +static u32 pxa2xx_spi_get_ssrc1_change_mask(const struct driver_data *drv_data)
> +{
> +	switch (drv_data->ssp_type) {
> +	default:
> +		return SSCR1_CHANGE_MASK;
> +	}
> +}
> +
> +static u32
> +pxa2xx_spi_get_rx_default_thre(const struct driver_data *drv_data)
> +{
> +	switch (drv_data->ssp_type) {
> +	default:
> +		return RX_THRESH_DFLT;
> +	}
> +}
> +
> +static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
> +{
> +	void __iomem *reg = drv_data->ioaddr;
> +	u32 mask;
> +
> +	switch (drv_data->ssp_type) {
> +	default:
> +		mask = SSSR_TFL_MASK;
> +		break;
> +	}
> +
> +	return (read_SSSR(reg) & mask) == mask;
> +}
> +
> +static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
> +				     u32 *sccr1_reg)
> +{
> +	u32 mask;
> +
> +	switch (drv_data->ssp_type) {
> +	default:
> +		mask = SSCR1_RFT;
> +		break;
> +	}
> +	*sccr1_reg &= ~mask;
> +}
> +
> +static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
> +				   u32 *sccr1_reg, u32 threshold)
> +{
> +	switch (drv_data->ssp_type) {
> +	default:
> +		*sccr1_reg |= SSCR1_RxTresh(threshold);
> +		break;
> +	}
> +}
> +
> +static u32 pxa2xx_configure_sscr0(const struct driver_data *drv_data,
> +				  u32 clk_div, u8 bits)
> +{
> +	switch (drv_data->ssp_type) {
> +	default:
> +		return clk_div
> +			| SSCR0_Motorola
> +			| SSCR0_DataSize(bits > 16 ? bits - 16 : bits)
> +			| SSCR0_SSE
> +			| (bits > 16 ? SSCR0_EDSS : 0);
> +	}
> +}
> +
>  /*
>   * Read and write LPSS SSP private registers. Caller must first check that
>   * is_lpss_ssp() returns true before these can be called.
> @@ -234,7 +301,7 @@ static int null_writer(struct driver_data *drv_data)
>  	void __iomem *reg = drv_data->ioaddr;
>  	u8 n_bytes = drv_data->n_bytes;
>  
> -	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
> +	if (pxa2xx_spi_txfifo_full(drv_data)
>  		|| (drv_data->tx == drv_data->tx_end))

Just wondering if those two could fit one line.

>  		return 0;
>  
> @@ -262,7 +329,7 @@ static int u8_writer(struct driver_data *drv_data)
>  {
>  	void __iomem *reg = drv_data->ioaddr;
>  
> -	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
> +	if (pxa2xx_spi_txfifo_full(drv_data)
>  		|| (drv_data->tx == drv_data->tx_end))

Ditto.

>  		return 0;
>  
> @@ -289,7 +356,7 @@ static int u16_writer(struct driver_data *drv_data)
>  {
>  	void __iomem *reg = drv_data->ioaddr;
>  
> -	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
> +	if (pxa2xx_spi_txfifo_full(drv_data)
>  		|| (drv_data->tx == drv_data->tx_end))

Ditto.

>  		return 0;
>  
> @@ -316,7 +383,7 @@ static int u32_writer(struct driver_data *drv_data)
>  {
>  	void __iomem *reg = drv_data->ioaddr;
>  
> -	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
> +	if (pxa2xx_spi_txfifo_full(drv_data)
>  		|| (drv_data->tx == drv_data->tx_end))

Ditto.

>  		return 0;
>  
> @@ -508,8 +575,9 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
>  		 * remaining RX bytes.
>  		 */
>  		if (pxa25x_ssp_comp(drv_data)) {
> +			u32 rx_thre;
>  
> -			sccr1_reg &= ~SSCR1_RFT;
> +			pxa2xx_spi_clear_rx_thre(drv_data, &sccr1_reg);
>  
>  			bytes_left = drv_data->rx_end - drv_data->rx;
>  			switch (drv_data->n_bytes) {
> @@ -519,10 +587,12 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
>  				bytes_left >>= 1;
>  			}
>  
> -			if (bytes_left > RX_THRESH_DFLT)
> -				bytes_left = RX_THRESH_DFLT;
> +			rx_thre = pxa2xx_spi_get_rx_default_thre(drv_data);
> +			if (rx_thre > bytes_left)
> +				rx_thre = bytes_left;
>  
> -			sccr1_reg |= SSCR1_RxTresh(bytes_left);
> +			pxa2xx_spi_set_rx_thre(drv_data, &sccr1_reg,
> +					       rx_thre);
>  		}
>  		write_SSCR1(sccr1_reg, reg);
>  	}
> @@ -613,6 +683,7 @@ static void pump_transfers(unsigned long data)
>  	u32 cr1;
>  	u32 dma_thresh = drv_data->cur_chip->dma_threshold;
>  	u32 dma_burst = drv_data->cur_chip->dma_burst_size;
> +	u32 change_mask = pxa2xx_spi_get_ssrc1_change_mask(drv_data);
>  
>  	/* Get current state information */
>  	message = drv_data->cur_msg;
> @@ -731,11 +802,7 @@ static void pump_transfers(unsigned long data)
>  						     "pump_transfers: DMA burst size reduced to match bits_per_word\n");
>  		}
>  
> -		cr0 = clk_div
> -			| SSCR0_Motorola
> -			| SSCR0_DataSize(bits > 16 ? bits - 16 : bits)
> -			| SSCR0_SSE
> -			| (bits > 16 ? SSCR0_EDSS : 0);
> +		cr0 = pxa2xx_configure_sscr0(drv_data, clk_div, bits);
>  	}
>  
>  	message->state = RUNNING_STATE;
> @@ -772,16 +839,15 @@ static void pump_transfers(unsigned long data)
>  	}
>  
>  	/* see if we need to reload the config registers */
> -	if ((read_SSCR0(reg) != cr0)
> -		|| (read_SSCR1(reg) & SSCR1_CHANGE_MASK) !=
> -			(cr1 & SSCR1_CHANGE_MASK)) {
> +	if ((read_SSCR0(reg) != cr0) ||
> +	    (read_SSCR1(reg) & change_mask) != (cr1 & change_mask)) {
>  
>  		/* stop the SSP, and update the other bits */
>  		write_SSCR0(cr0 & ~SSCR0_SSE, reg);
>  		if (!pxa25x_ssp_comp(drv_data))
>  			write_SSTO(chip->timeout, reg);
>  		/* first set CR1 without interrupt and service enables */
> -		write_SSCR1(cr1 & SSCR1_CHANGE_MASK, reg);
> +		write_SSCR1(cr1 & change_mask, reg);
>  		/* restart the SSP */
>  		write_SSCR0(cr0, reg);
>  
> @@ -959,12 +1025,8 @@ static int setup(struct spi_device *spi)
>  	clk_div = ssp_get_clk_div(drv_data, spi->max_speed_hz);
>  	chip->speed_hz = spi->max_speed_hz;
>  
> -	chip->cr0 = clk_div
> -			| SSCR0_Motorola
> -			| SSCR0_DataSize(spi->bits_per_word > 16 ?
> -				spi->bits_per_word - 16 : spi->bits_per_word)
> -			| SSCR0_SSE
> -			| (spi->bits_per_word > 16 ? SSCR0_EDSS : 0);
> +	chip->cr0 = pxa2xx_configure_sscr0(drv_data, clk_div,
> +					   spi->bits_per_word);
>  	chip->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
>  	chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
>  			| (((spi->mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);


-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

[PATCH 1/2 v2] SPI: spi-pxa2xx: Add helpers for regiseters' accessing

[Chen, Alvin]

> I'm okay with the current version, though I have few minor comments below.
> 
> > Introduce helper functions to access the 'SSCR0' and 'SSCR1'.
> >
> 
> Like you said in the summary there are many accessors to many registers, not
> only cr1/cr0. Perhaps, you may extend your commit message.
> 
OK.

> In any case
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
OK.
> > +
> >  /*
> >   * Read and write LPSS SSP private registers. Caller must first check that
> >   * is_lpss_ssp() returns true before these can be called.
> > @@ -234,7 +301,7 @@ static int null_writer(struct driver_data *drv_data)
> >  	void __iomem *reg = drv_data->ioaddr;
> >  	u8 n_bytes = drv_data->n_bytes;
> >
> > -	if (((read_SSSR(reg) & SSSR_TFL_MASK) == SSSR_TFL_MASK)
> > +	if (pxa2xx_spi_txfifo_full(drv_data)
> >  		|| (drv_data->tx == drv_data->tx_end))
> 
> Just wondering if those two could fit one line.
> 
No, if make the two in one line, it is 84 characters.

[PATCH 1/2 v2] SPI: spi-pxa2xx: Add helpers for regiseters' accessing

[Mika Westerberg]

On Mon, Sep 29, 2014 at 07:22:27AM -0700, Weike Chen wrote:
> Introduce helper functions to access the 'SSCR0' and 'SSCR1'.
> 
> Signed-off-by: Weike Chen <alvin.chen@intel.com>

Please fix the minor issues Andy pointed out and then you can have my,

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Weike Chen]

There are two SPI controllers exported by PCI subsystem for Intel Quark X1000.
The SPI memory mapped I/O registers supported by Quark are different from
the current implementation, and Quark only supports the registers of 'SSCR0',
'SSCR1', 'SSSR', 'SSDR', and 'DDS_RATE'. This patch is to enable the SPI for
Intel Quark X1000.

This piece of work is derived from Dan O'Donovan's initial work for Intel Quark
X1000 SPI enabling.

Signed-off-by: Weike Chen <alvin.chen@intel.com>
---
 drivers/spi/spi-pxa2xx-pci.c |    8 ++
 drivers/spi/spi-pxa2xx.c     |  204 +++++++++++++++++++++++++++++++++++++-----
 drivers/spi/spi-pxa2xx.h     |   16 ++--
 include/linux/pxa2xx_ssp.h   |   21 +++++
 4 files changed, 224 insertions(+), 25 deletions(-)

diff --git a/drivers/spi/spi-pxa2xx-pci.c b/drivers/spi/spi-pxa2xx-pci.c
index b285294..b888aeb 100644
--- a/drivers/spi/spi-pxa2xx-pci.c
+++ b/drivers/spi/spi-pxa2xx-pci.c
@@ -19,6 +19,7 @@ enum {
 	PORT_BSW0,
 	PORT_BSW1,
 	PORT_BSW2,
+	PORT_QUARK_X1000,
 };
 
 struct pxa_spi_info {
@@ -92,6 +93,12 @@ static struct pxa_spi_info spi_info_configs[] = {
 		.tx_param = &bsw2_tx_param,
 		.rx_param = &bsw2_rx_param,
 	},
+	[PORT_QUARK_X1000] = {
+		.type = QUARK_X1000_SSP,
+		.port_id = -1,
+		.num_chipselect = 4,
+		.max_clk_rate = 50000000,
+	},
 };
 
 static int pxa2xx_spi_pci_probe(struct pci_dev *dev,
@@ -192,6 +199,7 @@ static void pxa2xx_spi_pci_remove(struct pci_dev *dev)
 
 static const struct pci_device_id pxa2xx_spi_pci_devices[] = {
 	{ PCI_VDEVICE(INTEL, 0x2e6a), PORT_CE4100 },
+	{ PCI_VDEVICE(INTEL, 0x0935), PORT_QUARK_X1000 },
 	{ PCI_VDEVICE(INTEL, 0x0f0e), PORT_BYT },
 	{ PCI_VDEVICE(INTEL, 0x228e), PORT_BSW0 },
 	{ PCI_VDEVICE(INTEL, 0x2290), PORT_BSW1 },
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index e7ff9c5..7efa55e 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -63,10 +63,64 @@ MODULE_ALIAS("platform:pxa2xx-spi");
 				| SSCR1_RFT | SSCR1_TFT | SSCR1_MWDS \
 				| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)
 
+#define QUARK_X1000_SSCR1_CHANGE_MASK (QUARK_X1000_SSCR1_STRF	\
+				| QUARK_X1000_SSCR1_EFWR	\
+				| QUARK_X1000_SSCR1_RFT		\
+				| QUARK_X1000_SSCR1_TFT		\
+				| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)
+
 #define LPSS_RX_THRESH_DFLT	64
 #define LPSS_TX_LOTHRESH_DFLT	160
 #define LPSS_TX_HITHRESH_DFLT	224
 
+struct quark_spi_rate {
+	u32 bitrate;
+	u32 dds_clk_rate;
+	u32 clk_div;
+};
+
+/*
+ * 'rate', 'dds', 'clk_div' lookup table, which is defined in
+ * the Quark SPI datasheet.
+ */
+static const struct quark_spi_rate quark_spi_rate_table[] = {
+/*	bitrate,	dds_clk_rate,	clk_div */
+	{50000000,	0x800000,	0},
+	{40000000,	0x666666,	0},
+	{25000000,	0x400000,	0},
+	{20000000,	0x666666,	1},
+	{16667000,	0x800000,	2},
+	{13333000,	0x666666,	2},
+	{12500000,	0x200000,	0},
+	{10000000,	0x800000,	4},
+	{8000000,	0x666666,	4},
+	{6250000,	0x400000,	3},
+	{5000000,	0x400000,	4},
+	{4000000,	0x666666,	9},
+	{3125000,	0x80000,	0},
+	{2500000,	0x400000,	9},
+	{2000000,	0x666666,	19},
+	{1563000,	0x40000,	0},
+	{1250000,	0x200000,	9},
+	{1000000,	0x400000,	24},
+	{800000,	0x666666,	49},
+	{781250,	0x20000,	0},
+	{625000,	0x200000,	19},
+	{500000,	0x400000,	49},
+	{400000,	0x666666,	99},
+	{390625,	0x10000,	0},
+	{250000,	0x400000,	99},
+	{200000,	0x666666,	199},
+	{195313,	0x8000,		0},
+	{125000,	0x100000,	49},
+	{100000,	0x200000,	124},
+	{50000,		0x100000,	124},
+	{25000,		0x80000,	124},
+	{10016,		0x20000,	77},
+	{5040,		0x20000,	154},
+	{1002,		0x8000,		194},
+};
+
 /* Offset from drv_data->lpss_base */
 #define GENERAL_REG		0x08
 #define GENERAL_REG_RXTO_HOLDOFF_DISABLE BIT(24)
@@ -80,9 +134,16 @@ static bool is_lpss_ssp(const struct driver_data *drv_data)
 	return drv_data->ssp_type == LPSS_SSP;
 }
 
+static bool is_quark_x1000_ssp(const struct driver_data *drv_data)
+{
+	return drv_data->ssp_type == QUARK_X1000_SSP;
+}
+
 static u32 pxa2xx_spi_get_ssrc1_change_mask(const struct driver_data *drv_data)
 {
 	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		return QUARK_X1000_SSCR1_CHANGE_MASK;
 	default:
 		return SSCR1_CHANGE_MASK;
 	}
@@ -92,9 +153,12 @@ static u32
 pxa2xx_spi_get_rx_default_thre(const struct driver_data *drv_data)
 {
 	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		return RX_THRESH_QUARK_X1000_DFLT;
 	default:
 		return RX_THRESH_DFLT;
 	}
+
 }
 
 static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
@@ -103,6 +167,9 @@ static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
 	u32 mask;
 
 	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		mask = QUARK_X1000_SSSR_TFL_MASK;
+		break;
 	default:
 		mask = SSSR_TFL_MASK;
 		break;
@@ -112,11 +179,14 @@ static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
 }
 
 static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
-				     u32 *sccr1_reg)
+					  u32 *sccr1_reg)
 {
 	u32 mask;
 
 	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		mask = QUARK_X1000_SSCR1_RFT;
+		break;
 	default:
 		mask = SSCR1_RFT;
 		break;
@@ -125,9 +195,12 @@ static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
 }
 
 static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
-				   u32 *sccr1_reg, u32 threshold)
+					u32 *sccr1_reg, u32 threshold)
 {
 	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		*sccr1_reg |= QUARK_X1000_SSCR1_RxTresh(threshold);
+		break;
 	default:
 		*sccr1_reg |= SSCR1_RxTresh(threshold);
 		break;
@@ -138,6 +211,11 @@ static u32 pxa2xx_configure_sscr0(const struct driver_data *drv_data,
 				  u32 clk_div, u8 bits)
 {
 	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		return clk_div
+			| QUARK_X1000_SSCR0_Motorola
+			| QUARK_X1000_SSCR0_DataSize(bits > 32 ? 8 : bits)
+			| SSCR0_SSE;
 	default:
 		return clk_div
 			| SSCR0_Motorola
@@ -592,7 +670,7 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
 				rx_thre = bytes_left;
 
 			pxa2xx_spi_set_rx_thre(drv_data, &sccr1_reg,
-					       rx_thre);
+						    rx_thre);
 		}
 		write_SSCR1(sccr1_reg, reg);
 	}
@@ -655,6 +733,28 @@ static irqreturn_t ssp_int(int irq, void *dev_id)
 	return drv_data->transfer_handler(drv_data);
 }
 
+/*
+ * The Quark SPI data sheet gives a table, and for the given 'rate',
+ * the 'dds' and 'clk_div' can be found in the table.
+ */
+static u32 quark_x1000_set_clk_regvals(u32 rate, u32 *dds, u32 *clk_div)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(quark_spi_rate_table); i++) {
+		if (rate >= quark_spi_rate_table[i].bitrate) {
+			*dds = quark_spi_rate_table[i].dds_clk_rate;
+			*clk_div = quark_spi_rate_table[i].clk_div;
+			return quark_spi_rate_table[i].bitrate;
+		}
+	}
+
+	*dds = quark_spi_rate_table[i-1].dds_clk_rate;
+	*clk_div = quark_spi_rate_table[i-1].clk_div;
+
+	return quark_spi_rate_table[i-1].bitrate;
+}
+
 static unsigned int ssp_get_clk_div(struct driver_data *drv_data, int rate)
 {
 	unsigned long ssp_clk = drv_data->max_clk_rate;
@@ -668,6 +768,20 @@ static unsigned int ssp_get_clk_div(struct driver_data *drv_data, int rate)
 		return ((ssp_clk / rate - 1) & 0xfff) << 8;
 }
 
+static unsigned int pxa2xx_ssp_get_clk_div(struct driver_data *drv_data,
+					   struct chip_data *chip, int rate)
+{
+	u32 clk_div;
+
+	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		quark_x1000_set_clk_regvals(rate, &chip->dds_rate, &clk_div);
+		return clk_div << 8;
+	default:
+		return ssp_get_clk_div(drv_data, rate);
+	}
+}
+
 static void pump_transfers(unsigned long data)
 {
 	struct driver_data *drv_data = (struct driver_data *)data;
@@ -770,7 +884,7 @@ static void pump_transfers(unsigned long data)
 		if (transfer->bits_per_word)
 			bits = transfer->bits_per_word;
 
-		clk_div = ssp_get_clk_div(drv_data, speed);
+		clk_div = pxa2xx_ssp_get_clk_div(drv_data, chip, speed);
 
 		if (bits <= 8) {
 			drv_data->n_bytes = 1;
@@ -838,6 +952,10 @@ static void pump_transfers(unsigned long data)
 			write_SSITF(chip->lpss_tx_threshold, reg);
 	}
 
+	if (is_quark_x1000_ssp(drv_data) &&
+	    (read_DDS_RATE(reg) != chip->dds_rate))
+		write_DDS_RATE(chip->dds_rate, reg);
+
 	/* see if we need to reload the config registers */
 	if ((read_SSCR0(reg) != cr0) ||
 	    (read_SSCR1(reg) & change_mask) != (cr1 & change_mask)) {
@@ -941,14 +1059,22 @@ static int setup(struct spi_device *spi)
 	unsigned int clk_div;
 	uint tx_thres, tx_hi_thres, rx_thres;
 
-	if (is_lpss_ssp(drv_data)) {
+	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		tx_thres = TX_THRESH_QUARK_X1000_DFLT;
+		tx_hi_thres = 0;
+		rx_thres = RX_THRESH_QUARK_X1000_DFLT;
+		break;
+	case LPSS_SSP:
 		tx_thres = LPSS_TX_LOTHRESH_DFLT;
 		tx_hi_thres = LPSS_TX_HITHRESH_DFLT;
 		rx_thres = LPSS_RX_THRESH_DFLT;
-	} else {
+		break;
+	default:
 		tx_thres = TX_THRESH_DFLT;
 		tx_hi_thres = 0;
 		rx_thres = RX_THRESH_DFLT;
+		break;
 	}
 
 	/* Only alloc on first setup */
@@ -1001,9 +1127,6 @@ static int setup(struct spi_device *spi)
 		chip->enable_dma = drv_data->master_info->enable_dma;
 	}
 
-	chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
-			(SSCR1_TxTresh(tx_thres) & SSCR1_TFT);
-
 	chip->lpss_rx_threshold = SSIRF_RxThresh(rx_thres);
 	chip->lpss_tx_threshold = SSITF_TxLoThresh(tx_thres)
 				| SSITF_TxHiThresh(tx_hi_thres);
@@ -1022,11 +1145,24 @@ static int setup(struct spi_device *spi)
 		}
 	}
 
-	clk_div = ssp_get_clk_div(drv_data, spi->max_speed_hz);
+	clk_div = pxa2xx_ssp_get_clk_div(drv_data, chip, spi->max_speed_hz);
 	chip->speed_hz = spi->max_speed_hz;
 
 	chip->cr0 = pxa2xx_configure_sscr0(drv_data, clk_div,
 					   spi->bits_per_word);
+	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		chip->threshold = (QUARK_X1000_SSCR1_RxTresh(rx_thres)
+				   & QUARK_X1000_SSCR1_RFT)
+				   | (QUARK_X1000_SSCR1_TxTresh(tx_thres)
+				   & QUARK_X1000_SSCR1_TFT);
+		break;
+	default:
+		chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
+			(SSCR1_TxTresh(tx_thres) & SSCR1_TFT);
+		break;
+	}
+
 	chip->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
 	chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
 			| (((spi->mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);
@@ -1055,7 +1191,8 @@ static int setup(struct spi_device *spi)
 		chip->read = u16_reader;
 		chip->write = u16_writer;
 	} else if (spi->bits_per_word <= 32) {
-		chip->cr0 |= SSCR0_EDSS;
+		if (!is_quark_x1000_ssp(drv_data))
+			chip->cr0 |= SSCR0_EDSS;
 		chip->n_bytes = 4;
 		chip->read = u32_reader;
 		chip->write = u32_writer;
@@ -1205,7 +1342,15 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
 	drv_data->ioaddr = ssp->mmio_base;
 	drv_data->ssdr_physical = ssp->phys_base + SSDR;
 	if (pxa25x_ssp_comp(drv_data)) {
-		master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
+		switch (drv_data->ssp_type) {
+		case QUARK_X1000_SSP:
+			master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
+			break;
+		default:
+			master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
+			break;
+		}
+
 		drv_data->int_cr1 = SSCR1_TIE | SSCR1_RIE;
 		drv_data->dma_cr1 = 0;
 		drv_data->clear_sr = SSSR_ROR;
@@ -1243,16 +1388,35 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
 
 	/* Load default SSP configuration */
 	write_SSCR0(0, drv_data->ioaddr);
-	write_SSCR1(SSCR1_RxTresh(RX_THRESH_DFLT) |
-				SSCR1_TxTresh(TX_THRESH_DFLT),
-				drv_data->ioaddr);
-	write_SSCR0(SSCR0_SCR(2)
-			| SSCR0_Motorola
-			| SSCR0_DataSize(8),
-			drv_data->ioaddr);
+	switch (drv_data->ssp_type) {
+	case QUARK_X1000_SSP:
+		write_SSCR1(QUARK_X1000_SSCR1_RxTresh(
+					RX_THRESH_QUARK_X1000_DFLT) |
+			    QUARK_X1000_SSCR1_TxTresh(
+					TX_THRESH_QUARK_X1000_DFLT),
+			    drv_data->ioaddr);
+
+		/* using the Motorola SPI protocol and use 8 bit frame */
+		write_SSCR0(QUARK_X1000_SSCR0_Motorola
+			    | QUARK_X1000_SSCR0_DataSize(8),
+			    drv_data->ioaddr);
+		break;
+	default:
+		write_SSCR1(SSCR1_RxTresh(RX_THRESH_DFLT) |
+			    SSCR1_TxTresh(TX_THRESH_DFLT),
+			    drv_data->ioaddr);
+		write_SSCR0(SSCR0_SCR(2)
+			    | SSCR0_Motorola
+			    | SSCR0_DataSize(8),
+			    drv_data->ioaddr);
+		break;
+	}
+
 	if (!pxa25x_ssp_comp(drv_data))
 		write_SSTO(0, drv_data->ioaddr);
-	write_SSPSP(0, drv_data->ioaddr);
+
+	if (!is_quark_x1000_ssp(drv_data))
+		write_SSPSP(0, drv_data->ioaddr);
 
 	lpss_ssp_setup(drv_data);
 
diff --git a/drivers/spi/spi-pxa2xx.h b/drivers/spi/spi-pxa2xx.h
index 5adc2a1..6bec59c 100644
--- a/drivers/spi/spi-pxa2xx.h
+++ b/drivers/spi/spi-pxa2xx.h
@@ -93,6 +93,7 @@ struct driver_data {
 struct chip_data {
 	u32 cr0;
 	u32 cr1;
+	u32 dds_rate;
 	u32 psp;
 	u32 timeout;
 	u8 n_bytes;
@@ -126,6 +127,7 @@ DEFINE_SSP_REG(SSCR1, 0x04)
 DEFINE_SSP_REG(SSSR, 0x08)
 DEFINE_SSP_REG(SSITR, 0x0c)
 DEFINE_SSP_REG(SSDR, 0x10)
+DEFINE_SSP_REG(DDS_RATE, 0x28)  /* DDS Clock Rate */
 DEFINE_SSP_REG(SSTO, 0x28)
 DEFINE_SSP_REG(SSPSP, 0x2c)
 DEFINE_SSP_REG(SSITF, SSITF)
@@ -141,18 +143,22 @@ DEFINE_SSP_REG(SSIRF, SSIRF)
 
 static inline int pxa25x_ssp_comp(struct driver_data *drv_data)
 {
-	if (drv_data->ssp_type == PXA25x_SSP)
+	switch (drv_data->ssp_type) {
+	case PXA25x_SSP:
+	case CE4100_SSP:
+	case QUARK_X1000_SSP:
 		return 1;
-	if (drv_data->ssp_type == CE4100_SSP)
-		return 1;
-	return 0;
+	default:
+		return 0;
+	}
 }
 
 static inline void write_SSSR_CS(struct driver_data *drv_data, u32 val)
 {
 	void __iomem *reg = drv_data->ioaddr;
 
-	if (drv_data->ssp_type == CE4100_SSP)
+	if (drv_data->ssp_type == CE4100_SSP ||
+	    drv_data->ssp_type == QUARK_X1000_SSP)
 		val |= read_SSSR(reg) & SSSR_ALT_FRM_MASK;
 
 	write_SSSR(val, reg);
diff --git a/include/linux/pxa2xx_ssp.h b/include/linux/pxa2xx_ssp.h
index f2b4051..a4668e6 100644
--- a/include/linux/pxa2xx_ssp.h
+++ b/include/linux/pxa2xx_ssp.h
@@ -106,6 +106,26 @@
 #define SSCR1_TxTresh(x) (((x) - 1) << 6) /* level [1..4] */
 #define SSCR1_RFT	(0x00000c00)	/* Receive FIFO Threshold (mask) */
 #define SSCR1_RxTresh(x) (((x) - 1) << 10) /* level [1..4] */
+
+/* QUARK_X1000 SSCR0 bit definition */
+#define QUARK_X1000_SSCR0_DSS	(0x1F)		/* Data Size Select (mask) */
+#define QUARK_X1000_SSCR0_DataSize(x)  ((x) - 1)	/* Data Size Select [4..32] */
+#define QUARK_X1000_SSCR0_FRF	(0x3 << 5)	/* FRame Format (mask) */
+#define QUARK_X1000_SSCR0_Motorola	(0x0 << 5)	/* Motorola's Serial Peripheral Interface (SPI) */
+
+#define RX_THRESH_QUARK_X1000_DFLT	1
+#define TX_THRESH_QUARK_X1000_DFLT	16
+
+#define QUARK_X1000_SSSR_TFL_MASK	(0x1F << 8)	/* Transmit FIFO Level mask */
+#define QUARK_X1000_SSSR_RFL_MASK	(0x1F << 13)	/* Receive FIFO Level mask */
+
+#define QUARK_X1000_SSCR1_TFT	(0x1F << 6)	/* Transmit FIFO Threshold (mask) */
+#define QUARK_X1000_SSCR1_TxTresh(x) (((x) - 1) << 6)	/* level [1..32] */
+#define QUARK_X1000_SSCR1_RFT	(0x1F << 11)	/* Receive FIFO Threshold (mask) */
+#define QUARK_X1000_SSCR1_RxTresh(x) (((x) - 1) << 11)	/* level [1..32] */
+#define QUARK_X1000_SSCR1_STRF       (1 << 17)		/* Select FIFO or EFWR */
+#define QUARK_X1000_SSCR1_EFWR	(1 << 16)		/* Enable FIFO Write/Read */
+
 #endif
 
 /* extra bits in PXA255, PXA26x and PXA27x SSP ports */
@@ -175,6 +195,7 @@ enum pxa_ssp_type {
 	PXA910_SSP,
 	CE4100_SSP,
 	LPSS_SSP,
+	QUARK_X1000_SSP,
 };
 
 struct ssp_device {
-- 
1.7.9.5

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Andy Shevchenko]

On Mon, 2014-09-29 at 07:22 -0700, Weike Chen wrote:
> There are two SPI controllers exported by PCI subsystem for Intel Quark X1000.
> The SPI memory mapped I/O registers supported by Quark are different from
> the current implementation, and Quark only supports the registers of 'SSCR0',
> 'SSCR1', 'SSSR', 'SSDR', and 'DDS_RATE'. This patch is to enable the SPI for
> Intel Quark X1000.
> 
> This piece of work is derived from Dan O'Donovan's initial work for Intel Quark
> X1000 SPI enabling.

Minor comments are below.

After addressing them
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>


> 
> Signed-off-by: Weike Chen <alvin.chen@intel.com>
> ---
>  drivers/spi/spi-pxa2xx-pci.c |    8 ++
>  drivers/spi/spi-pxa2xx.c     |  204 +++++++++++++++++++++++++++++++++++++-----
>  drivers/spi/spi-pxa2xx.h     |   16 ++--
>  include/linux/pxa2xx_ssp.h   |   21 +++++
>  4 files changed, 224 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/spi/spi-pxa2xx-pci.c b/drivers/spi/spi-pxa2xx-pci.c
> index b285294..b888aeb 100644
> --- a/drivers/spi/spi-pxa2xx-pci.c
> +++ b/drivers/spi/spi-pxa2xx-pci.c
> @@ -19,6 +19,7 @@ enum {
>  	PORT_BSW0,
>  	PORT_BSW1,
>  	PORT_BSW2,
> +	PORT_QUARK_X1000,
>  };
>  
>  struct pxa_spi_info {
> @@ -92,6 +93,12 @@ static struct pxa_spi_info spi_info_configs[] = {
>  		.tx_param = &bsw2_tx_param,
>  		.rx_param = &bsw2_rx_param,
>  	},
> +	[PORT_QUARK_X1000] = {
> +		.type = QUARK_X1000_SSP,
> +		.port_id = -1,
> +		.num_chipselect = 4,
> +		.max_clk_rate = 50000000,
> +	},
>  };
>  
>  static int pxa2xx_spi_pci_probe(struct pci_dev *dev,
> @@ -192,6 +199,7 @@ static void pxa2xx_spi_pci_remove(struct pci_dev *dev)
>  
>  static const struct pci_device_id pxa2xx_spi_pci_devices[] = {
>  	{ PCI_VDEVICE(INTEL, 0x2e6a), PORT_CE4100 },
> +	{ PCI_VDEVICE(INTEL, 0x0935), PORT_QUARK_X1000 },
>  	{ PCI_VDEVICE(INTEL, 0x0f0e), PORT_BYT },
>  	{ PCI_VDEVICE(INTEL, 0x228e), PORT_BSW0 },
>  	{ PCI_VDEVICE(INTEL, 0x2290), PORT_BSW1 },
> diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
> index e7ff9c5..7efa55e 100644
> --- a/drivers/spi/spi-pxa2xx.c
> +++ b/drivers/spi/spi-pxa2xx.c
> @@ -63,10 +63,64 @@ MODULE_ALIAS("platform:pxa2xx-spi");
>  				| SSCR1_RFT | SSCR1_TFT | SSCR1_MWDS \
>  				| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)
>  
> +#define QUARK_X1000_SSCR1_CHANGE_MASK (QUARK_X1000_SSCR1_STRF	\
> +				| QUARK_X1000_SSCR1_EFWR	\
> +				| QUARK_X1000_SSCR1_RFT		\
> +				| QUARK_X1000_SSCR1_TFT		\
> +				| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)
> +
>  #define LPSS_RX_THRESH_DFLT	64
>  #define LPSS_TX_LOTHRESH_DFLT	160
>  #define LPSS_TX_HITHRESH_DFLT	224
>  
> +struct quark_spi_rate {
> +	u32 bitrate;
> +	u32 dds_clk_rate;
> +	u32 clk_div;
> +};
> +
> +/*
> + * 'rate', 'dds', 'clk_div' lookup table, which is defined in
> + * the Quark SPI datasheet.
> + */
> +static const struct quark_spi_rate quark_spi_rate_table[] = {
> +/*	bitrate,	dds_clk_rate,	clk_div */
> +	{50000000,	0x800000,	0},
> +	{40000000,	0x666666,	0},
> +	{25000000,	0x400000,	0},
> +	{20000000,	0x666666,	1},
> +	{16667000,	0x800000,	2},
> +	{13333000,	0x666666,	2},
> +	{12500000,	0x200000,	0},
> +	{10000000,	0x800000,	4},
> +	{8000000,	0x666666,	4},
> +	{6250000,	0x400000,	3},
> +	{5000000,	0x400000,	4},
> +	{4000000,	0x666666,	9},
> +	{3125000,	0x80000,	0},
> +	{2500000,	0x400000,	9},
> +	{2000000,	0x666666,	19},
> +	{1563000,	0x40000,	0},
> +	{1250000,	0x200000,	9},
> +	{1000000,	0x400000,	24},
> +	{800000,	0x666666,	49},
> +	{781250,	0x20000,	0},
> +	{625000,	0x200000,	19},
> +	{500000,	0x400000,	49},
> +	{400000,	0x666666,	99},
> +	{390625,	0x10000,	0},
> +	{250000,	0x400000,	99},
> +	{200000,	0x666666,	199},
> +	{195313,	0x8000,		0},
> +	{125000,	0x100000,	49},
> +	{100000,	0x200000,	124},
> +	{50000,		0x100000,	124},
> +	{25000,		0x80000,	124},
> +	{10016,		0x20000,	77},
> +	{5040,		0x20000,	154},
> +	{1002,		0x8000,		194},
> +};
> +

Regarding to table vs. formula I will agree with whatever Mark suggested.

>  /* Offset from drv_data->lpss_base */
>  #define GENERAL_REG		0x08
>  #define GENERAL_REG_RXTO_HOLDOFF_DISABLE BIT(24)
> @@ -80,9 +134,16 @@ static bool is_lpss_ssp(const struct driver_data *drv_data)
>  	return drv_data->ssp_type == LPSS_SSP;
>  }
>  
> +static bool is_quark_x1000_ssp(const struct driver_data *drv_data)
> +{
> +	return drv_data->ssp_type == QUARK_X1000_SSP;
> +}
> +
>  static u32 pxa2xx_spi_get_ssrc1_change_mask(const struct driver_data *drv_data)
>  {
>  	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		return QUARK_X1000_SSCR1_CHANGE_MASK;
>  	default:
>  		return SSCR1_CHANGE_MASK;
>  	}
> @@ -92,9 +153,12 @@ static u32
>  pxa2xx_spi_get_rx_default_thre(const struct driver_data *drv_data)
>  {
>  	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		return RX_THRESH_QUARK_X1000_DFLT;
>  	default:
>  		return RX_THRESH_DFLT;
>  	}
> +

Redundant empty line.

>  }
>  
>  static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
> @@ -103,6 +167,9 @@ static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
>  	u32 mask;
>  
>  	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		mask = QUARK_X1000_SSSR_TFL_MASK;
> +		break;
>  	default:
>  		mask = SSSR_TFL_MASK;
>  		break;
> @@ -112,11 +179,14 @@ static bool pxa2xx_spi_txfifo_full(const struct driver_data *drv_data)
>  }
>  
>  static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
> -				     u32 *sccr1_reg)
> +					  u32 *sccr1_reg)

Unnecessary change.

>  {
>  	u32 mask;
>  
>  	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		mask = QUARK_X1000_SSCR1_RFT;
> +		break;
>  	default:
>  		mask = SSCR1_RFT;
>  		break;
> @@ -125,9 +195,12 @@ static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
>  }
>  
>  static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
> -				   u32 *sccr1_reg, u32 threshold)
> +					u32 *sccr1_reg, u32 threshold)

Ditto.

Or you may do that in the first patch.

>  {
>  	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		*sccr1_reg |= QUARK_X1000_SSCR1_RxTresh(threshold);
> +		break;
>  	default:
>  		*sccr1_reg |= SSCR1_RxTresh(threshold);
>  		break;
> @@ -138,6 +211,11 @@ static u32 pxa2xx_configure_sscr0(const struct driver_data *drv_data,
>  				  u32 clk_div, u8 bits)
>  {
>  	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		return clk_div
> +			| QUARK_X1000_SSCR0_Motorola
> +			| QUARK_X1000_SSCR0_DataSize(bits > 32 ? 8 : bits)
> +			| SSCR0_SSE;
>  	default:
>  		return clk_div
>  			| SSCR0_Motorola
> @@ -592,7 +670,7 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
>  				rx_thre = bytes_left;
>  
>  			pxa2xx_spi_set_rx_thre(drv_data, &sccr1_reg,
> -					       rx_thre);
> +						    rx_thre);

Ditto.


>  		}
>  		write_SSCR1(sccr1_reg, reg);
>  	}
> @@ -655,6 +733,28 @@ static irqreturn_t ssp_int(int irq, void *dev_id)
>  	return drv_data->transfer_handler(drv_data);
>  }
>  
> +/*
> + * The Quark SPI data sheet gives a table, and for the given 'rate',
> + * the 'dds' and 'clk_div' can be found in the table.
> + */
> +static u32 quark_x1000_set_clk_regvals(u32 rate, u32 *dds, u32 *clk_div)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(quark_spi_rate_table); i++) {
> +		if (rate >= quark_spi_rate_table[i].bitrate) {
> +			*dds = quark_spi_rate_table[i].dds_clk_rate;
> +			*clk_div = quark_spi_rate_table[i].clk_div;
> +			return quark_spi_rate_table[i].bitrate;
> +		}
> +	}
> +
> +	*dds = quark_spi_rate_table[i-1].dds_clk_rate;
> +	*clk_div = quark_spi_rate_table[i-1].clk_div;
> +
> +	return quark_spi_rate_table[i-1].bitrate;
> +}
> +
>  static unsigned int ssp_get_clk_div(struct driver_data *drv_data, int rate)
>  {
>  	unsigned long ssp_clk = drv_data->max_clk_rate;
> @@ -668,6 +768,20 @@ static unsigned int ssp_get_clk_div(struct driver_data *drv_data, int rate)
>  		return ((ssp_clk / rate - 1) & 0xfff) << 8;
>  }
>  
> +static unsigned int pxa2xx_ssp_get_clk_div(struct driver_data *drv_data,
> +					   struct chip_data *chip, int rate)
> +{
> +	u32 clk_div;
> +
> +	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		quark_x1000_set_clk_regvals(rate, &chip->dds_rate, &clk_div);
> +		return clk_div << 8;
> +	default:
> +		return ssp_get_clk_div(drv_data, rate);
> +	}
> +}
> +
>  static void pump_transfers(unsigned long data)
>  {
>  	struct driver_data *drv_data = (struct driver_data *)data;
> @@ -770,7 +884,7 @@ static void pump_transfers(unsigned long data)
>  		if (transfer->bits_per_word)
>  			bits = transfer->bits_per_word;
>  
> -		clk_div = ssp_get_clk_div(drv_data, speed);
> +		clk_div = pxa2xx_ssp_get_clk_div(drv_data, chip, speed);
>  
>  		if (bits <= 8) {
>  			drv_data->n_bytes = 1;
> @@ -838,6 +952,10 @@ static void pump_transfers(unsigned long data)
>  			write_SSITF(chip->lpss_tx_threshold, reg);
>  	}
>  
> +	if (is_quark_x1000_ssp(drv_data) &&
> +	    (read_DDS_RATE(reg) != chip->dds_rate))

Could it be one line?

> +		write_DDS_RATE(chip->dds_rate, reg);
> +
>  	/* see if we need to reload the config registers */
>  	if ((read_SSCR0(reg) != cr0) ||
>  	    (read_SSCR1(reg) & change_mask) != (cr1 & change_mask)) {
> @@ -941,14 +1059,22 @@ static int setup(struct spi_device *spi)
>  	unsigned int clk_div;
>  	uint tx_thres, tx_hi_thres, rx_thres;
>  
> -	if (is_lpss_ssp(drv_data)) {
> +	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		tx_thres = TX_THRESH_QUARK_X1000_DFLT;
> +		tx_hi_thres = 0;
> +		rx_thres = RX_THRESH_QUARK_X1000_DFLT;
> +		break;
> +	case LPSS_SSP:
>  		tx_thres = LPSS_TX_LOTHRESH_DFLT;
>  		tx_hi_thres = LPSS_TX_HITHRESH_DFLT;
>  		rx_thres = LPSS_RX_THRESH_DFLT;
> -	} else {
> +		break;
> +	default:
>  		tx_thres = TX_THRESH_DFLT;
>  		tx_hi_thres = 0;
>  		rx_thres = RX_THRESH_DFLT;
> +		break;
>  	}
>  
>  	/* Only alloc on first setup */
> @@ -1001,9 +1127,6 @@ static int setup(struct spi_device *spi)
>  		chip->enable_dma = drv_data->master_info->enable_dma;
>  	}
>  
> -	chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
> -			(SSCR1_TxTresh(tx_thres) & SSCR1_TFT);
> -
>  	chip->lpss_rx_threshold = SSIRF_RxThresh(rx_thres);
>  	chip->lpss_tx_threshold = SSITF_TxLoThresh(tx_thres)
>  				| SSITF_TxHiThresh(tx_hi_thres);
> @@ -1022,11 +1145,24 @@ static int setup(struct spi_device *spi)
>  		}
>  	}
>  
> -	clk_div = ssp_get_clk_div(drv_data, spi->max_speed_hz);
> +	clk_div = pxa2xx_ssp_get_clk_div(drv_data, chip, spi->max_speed_hz);
>  	chip->speed_hz = spi->max_speed_hz;
>  
>  	chip->cr0 = pxa2xx_configure_sscr0(drv_data, clk_div,
>  					   spi->bits_per_word);
> +	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		chip->threshold = (QUARK_X1000_SSCR1_RxTresh(rx_thres)
> +				   & QUARK_X1000_SSCR1_RFT)
> +				   | (QUARK_X1000_SSCR1_TxTresh(tx_thres)
> +				   & QUARK_X1000_SSCR1_TFT);
> +		break;
> +	default:
> +		chip->threshold = (SSCR1_RxTresh(rx_thres) & SSCR1_RFT) |
> +			(SSCR1_TxTresh(tx_thres) & SSCR1_TFT);
> +		break;
> +	}
> +
>  	chip->cr1 &= ~(SSCR1_SPO | SSCR1_SPH);
>  	chip->cr1 |= (((spi->mode & SPI_CPHA) != 0) ? SSCR1_SPH : 0)
>  			| (((spi->mode & SPI_CPOL) != 0) ? SSCR1_SPO : 0);
> @@ -1055,7 +1191,8 @@ static int setup(struct spi_device *spi)
>  		chip->read = u16_reader;
>  		chip->write = u16_writer;
>  	} else if (spi->bits_per_word <= 32) {
> -		chip->cr0 |= SSCR0_EDSS;
> +		if (!is_quark_x1000_ssp(drv_data))
> +			chip->cr0 |= SSCR0_EDSS;
>  		chip->n_bytes = 4;
>  		chip->read = u32_reader;
>  		chip->write = u32_writer;
> @@ -1205,7 +1342,15 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
>  	drv_data->ioaddr = ssp->mmio_base;
>  	drv_data->ssdr_physical = ssp->phys_base + SSDR;
>  	if (pxa25x_ssp_comp(drv_data)) {
> -		master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
> +		switch (drv_data->ssp_type) {
> +		case QUARK_X1000_SSP:
> +			master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
> +			break;
> +		default:
> +			master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
> +			break;
> +		}
> +
>  		drv_data->int_cr1 = SSCR1_TIE | SSCR1_RIE;
>  		drv_data->dma_cr1 = 0;
>  		drv_data->clear_sr = SSSR_ROR;
> @@ -1243,16 +1388,35 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
>  
>  	/* Load default SSP configuration */
>  	write_SSCR0(0, drv_data->ioaddr);
> -	write_SSCR1(SSCR1_RxTresh(RX_THRESH_DFLT) |
> -				SSCR1_TxTresh(TX_THRESH_DFLT),
> -				drv_data->ioaddr);
> -	write_SSCR0(SSCR0_SCR(2)
> -			| SSCR0_Motorola
> -			| SSCR0_DataSize(8),
> -			drv_data->ioaddr);
> +	switch (drv_data->ssp_type) {
> +	case QUARK_X1000_SSP:
> +		write_SSCR1(QUARK_X1000_SSCR1_RxTresh(
> +					RX_THRESH_QUARK_X1000_DFLT) |
> +			    QUARK_X1000_SSCR1_TxTresh(
> +					TX_THRESH_QUARK_X1000_DFLT),
> +			    drv_data->ioaddr);
> +
> +		/* using the Motorola SPI protocol and use 8 bit frame */
> +		write_SSCR0(QUARK_X1000_SSCR0_Motorola
> +			    | QUARK_X1000_SSCR0_DataSize(8),
> +			    drv_data->ioaddr);
> +		break;
> +	default:
> +		write_SSCR1(SSCR1_RxTresh(RX_THRESH_DFLT) |
> +			    SSCR1_TxTresh(TX_THRESH_DFLT),
> +			    drv_data->ioaddr);
> +		write_SSCR0(SSCR0_SCR(2)
> +			    | SSCR0_Motorola
> +			    | SSCR0_DataSize(8),
> +			    drv_data->ioaddr);
> +		break;
> +	}
> +
>  	if (!pxa25x_ssp_comp(drv_data))
>  		write_SSTO(0, drv_data->ioaddr);
> -	write_SSPSP(0, drv_data->ioaddr);
> +
> +	if (!is_quark_x1000_ssp(drv_data))
> +		write_SSPSP(0, drv_data->ioaddr);
>  
>  	lpss_ssp_setup(drv_data);
>  
> diff --git a/drivers/spi/spi-pxa2xx.h b/drivers/spi/spi-pxa2xx.h
> index 5adc2a1..6bec59c 100644
> --- a/drivers/spi/spi-pxa2xx.h
> +++ b/drivers/spi/spi-pxa2xx.h
> @@ -93,6 +93,7 @@ struct driver_data {
>  struct chip_data {
>  	u32 cr0;
>  	u32 cr1;
> +	u32 dds_rate;
>  	u32 psp;
>  	u32 timeout;
>  	u8 n_bytes;
> @@ -126,6 +127,7 @@ DEFINE_SSP_REG(SSCR1, 0x04)
>  DEFINE_SSP_REG(SSSR, 0x08)
>  DEFINE_SSP_REG(SSITR, 0x0c)
>  DEFINE_SSP_REG(SSDR, 0x10)
> +DEFINE_SSP_REG(DDS_RATE, 0x28)  /* DDS Clock Rate */
>  DEFINE_SSP_REG(SSTO, 0x28)
>  DEFINE_SSP_REG(SSPSP, 0x2c)
>  DEFINE_SSP_REG(SSITF, SSITF)
> @@ -141,18 +143,22 @@ DEFINE_SSP_REG(SSIRF, SSIRF)
>  
>  static inline int pxa25x_ssp_comp(struct driver_data *drv_data)
>  {
> -	if (drv_data->ssp_type == PXA25x_SSP)
> +	switch (drv_data->ssp_type) {
> +	case PXA25x_SSP:
> +	case CE4100_SSP:
> +	case QUARK_X1000_SSP:
>  		return 1;
> -	if (drv_data->ssp_type == CE4100_SSP)
> -		return 1;
> -	return 0;
> +	default:
> +		return 0;
> +	}
>  }
>  
>  static inline void write_SSSR_CS(struct driver_data *drv_data, u32 val)
>  {
>  	void __iomem *reg = drv_data->ioaddr;
>  
> -	if (drv_data->ssp_type == CE4100_SSP)
> +	if (drv_data->ssp_type == CE4100_SSP ||
> +	    drv_data->ssp_type == QUARK_X1000_SSP)
>  		val |= read_SSSR(reg) & SSSR_ALT_FRM_MASK;
>  
>  	write_SSSR(val, reg);
> diff --git a/include/linux/pxa2xx_ssp.h b/include/linux/pxa2xx_ssp.h
> index f2b4051..a4668e6 100644
> --- a/include/linux/pxa2xx_ssp.h
> +++ b/include/linux/pxa2xx_ssp.h
> @@ -106,6 +106,26 @@
>  #define SSCR1_TxTresh(x) (((x) - 1) << 6) /* level [1..4] */
>  #define SSCR1_RFT	(0x00000c00)	/* Receive FIFO Threshold (mask) */
>  #define SSCR1_RxTresh(x) (((x) - 1) << 10) /* level [1..4] */
> +
> +/* QUARK_X1000 SSCR0 bit definition */
> +#define QUARK_X1000_SSCR0_DSS	(0x1F)		/* Data Size Select (mask) */
> +#define QUARK_X1000_SSCR0_DataSize(x)  ((x) - 1)	/* Data Size Select [4..32] */
> +#define QUARK_X1000_SSCR0_FRF	(0x3 << 5)	/* FRame Format (mask) */
> +#define QUARK_X1000_SSCR0_Motorola	(0x0 << 5)	/* Motorola's Serial Peripheral Interface (SPI) */
> +
> +#define RX_THRESH_QUARK_X1000_DFLT	1
> +#define TX_THRESH_QUARK_X1000_DFLT	16
> +
> +#define QUARK_X1000_SSSR_TFL_MASK	(0x1F << 8)	/* Transmit FIFO Level mask */
> +#define QUARK_X1000_SSSR_RFL_MASK	(0x1F << 13)	/* Receive FIFO Level mask */
> +
> +#define QUARK_X1000_SSCR1_TFT	(0x1F << 6)	/* Transmit FIFO Threshold (mask) */
> +#define QUARK_X1000_SSCR1_TxTresh(x) (((x) - 1) << 6)	/* level [1..32] */
> +#define QUARK_X1000_SSCR1_RFT	(0x1F << 11)	/* Receive FIFO Threshold (mask) */
> +#define QUARK_X1000_SSCR1_RxTresh(x) (((x) - 1) << 11)	/* level [1..32] */
> +#define QUARK_X1000_SSCR1_STRF       (1 << 17)		/* Select FIFO or EFWR */
> +#define QUARK_X1000_SSCR1_EFWR	(1 << 16)		/* Enable FIFO Write/Read */
> +
>  #endif
>  
>  /* extra bits in PXA255, PXA26x and PXA27x SSP ports */
> @@ -175,6 +195,7 @@ enum pxa_ssp_type {
>  	PXA910_SSP,
>  	CE4100_SSP,
>  	LPSS_SSP,
> +	QUARK_X1000_SSP,
>  };
>  
>  struct ssp_device {


-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Chen, Alvin]

> > The SPI memory mapped I/O registers supported by Quark are different
> > from the current implementation, and Quark only supports the registers
> > of 'SSCR0', 'SSCR1', 'SSSR', 'SSDR', and 'DDS_RATE'. This patch is to
> > enable the SPI for Intel Quark X1000.
> >
> > This piece of work is derived from Dan O'Donovan's initial work for
> > Intel Quark
> > X1000 SPI enabling.
> 
> Minor comments are below.
> 
> After addressing them
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
OK.
> > +	case QUARK_X1000_SSP:
> > +		return RX_THRESH_QUARK_X1000_DFLT;
> >  	default:
> >  		return RX_THRESH_DFLT;
> >  	}
> > +
> 
> Redundant empty line.
> 
OK. I will remove it.

> >  static void pxa2xx_spi_clear_rx_thre(const struct driver_data *drv_data,
> > -				     u32 *sccr1_reg)
> > +					  u32 *sccr1_reg)
> 
> Unnecessary change.
> 
Improve it in the first patch.
> >  static void pxa2xx_spi_set_rx_thre(const struct driver_data *drv_data,
> > -				   u32 *sccr1_reg, u32 threshold)
> > +					u32 *sccr1_reg, u32 threshold)
> 
> Ditto.
> 
> Or you may do that in the first patch.
> 
Improve it in the first patch.
> >
> >  			pxa2xx_spi_set_rx_thre(drv_data, &sccr1_reg,
> > -					       rx_thre);
> > +						    rx_thre);
> 
> Ditto.
> 
Improve it in the first patch.
> > +	if (is_quark_x1000_ssp(drv_data) &&
> > +	    (read_DDS_RATE(reg) != chip->dds_rate))
> 
> Could it be one line?
> 
No, it is beyond 80 characters if it is in one line.

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Mika Westerberg]

On Mon, Sep 29, 2014 at 07:22:28AM -0700, Weike Chen wrote:
> There are two SPI controllers exported by PCI subsystem for Intel Quark X1000.
> The SPI memory mapped I/O registers supported by Quark are different from
> the current implementation, and Quark only supports the registers of 'SSCR0',
> 'SSCR1', 'SSSR', 'SSDR', and 'DDS_RATE'. This patch is to enable the SPI for
> Intel Quark X1000.
> 
> This piece of work is derived from Dan O'Donovan's initial work for Intel Quark
> X1000 SPI enabling.
> 
> Signed-off-by: Weike Chen <alvin.chen@intel.com>

Same here, please fix the minor issues pointed out by Andy and then you
can add,

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Bryan O'Donoghue]

On 29/09/14 15:22, Weike Chen wrote:
> +		.num_chipselect = 4,

How is this right ?

There's only one physical chip-select line per SPI master...

It's a 1:1 mapping.

Best,
Bryan

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Chen, Alvin]

> 
> On 29/09/14 15:22, Weike Chen wrote:
> > +		.num_chipselect = 4,
> 
> How is this right ?
> 
> There's only one physical chip-select line per SPI master...
> 
> It's a 1:1 mapping.
> 
Now, we have another board which can support 4 slave spi per master, but not only Galileo. Since that board is not public, after discussing with team, we decide to make the
upstream code to support '1'.

I will change it back to 
.num_chipselect = 1,


> Best,
> Bryan

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Bryan O'Donoghue]

On 08/10/14 08:48, Chen, Alvin wrote:

> Now, we have another board which can support 4 slave spi per master, but not only Galileo. Since that board is not public, after discussing with team, we decide to make the
> upstream code to support '1'.
>
> I will change it back to
> .num_chipselect = 1,

Hi Alvin.

The important thing in terms of Galileo is to ensure that a GPIO can be 
used for chip-select.

The user-space API ported from Arduino to Linux wants to control it's 
own chip-select directly - so the internal chip-select of the Quark SPI 
master can - and does de-assert while doing SPI transactions on Galileo. 
The CS on the master is tied to FIFO occupancy - so at higher bit-rates 
we can fail to keep the FIFO occupied :(

That doesn't matter though, because the pinned out SPI:CS on the Arduino 
header is a GPIO.

 From the perspective of the Arduino code in user-space and the slave 
hardware @ the other end of the SPI bus - we see a nice and consistent 
chip-select for the entire duration of the SPI transaction - even though 
the actual SPI:CS coming from the SoC can *waggle* - when FIFOs go empty.

IMO - so long as you've tested on Galileo and seen working SPI - you're 
good to go anyway.

Bryan

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Olof Johansson]

Hi,

On Mon, Sep 29, 2014 at 7:22 AM, Weike Chen <alvin.chen@intel.com> wrote:
> There are two SPI controllers exported by PCI subsystem for Intel Quark X1000.
> The SPI memory mapped I/O registers supported by Quark are different from
> the current implementation, and Quark only supports the registers of 'SSCR0',
> 'SSCR1', 'SSSR', 'SSDR', and 'DDS_RATE'. This patch is to enable the SPI for
> Intel Quark X1000.
>
> This piece of work is derived from Dan O'Donovan's initial work for Intel Quark
> X1000 SPI enabling.
>
> Signed-off-by: Weike Chen <alvin.chen@intel.com>

How about build testing for other platforms that share this driver
when you make changes to it? This is obviously completely broken.

Doing these constants under ifdef seems fragile at best, braindead at
worst. Please don't proliferate that coding style.

Mark, can you revert until Intel learns how to play well with others?



This is from a pxa3xx-defconfig build:

/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function
'pxa2xx_spi_get_ssrc1_change_mask':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:66:40: error:
'QUARK_X1000_SSCR1_STRF' undeclared (first use in this function)
 #define QUARK_X1000_SSCR1_CHANGE_MASK (QUARK_X1000_SSCR1_STRF \
                                        ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:146:10: note: in
expansion of macro 'QUARK_X1000_SSCR1_CHANGE_MASK'
   return QUARK_X1000_SSCR1_CHANGE_MASK;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:66:40: note: each
undeclared identifier is reported only once for each function it
appears in
 #define QUARK_X1000_SSCR1_CHANGE_MASK (QUARK_X1000_SSCR1_STRF \
                                        ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:146:10: note: in
expansion of macro 'QUARK_X1000_SSCR1_CHANGE_MASK'
   return QUARK_X1000_SSCR1_CHANGE_MASK;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:67:7: error:
'QUARK_X1000_SSCR1_EFWR' undeclared (first use in this function)
     | QUARK_X1000_SSCR1_EFWR \
       ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:146:10: note: in
expansion of macro 'QUARK_X1000_SSCR1_CHANGE_MASK'
   return QUARK_X1000_SSCR1_CHANGE_MASK;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:68:7: error:
'QUARK_X1000_SSCR1_RFT' undeclared (first use in this function)
     | QUARK_X1000_SSCR1_RFT  \
       ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:146:10: note: in
expansion of macro 'QUARK_X1000_SSCR1_CHANGE_MASK'
   return QUARK_X1000_SSCR1_CHANGE_MASK;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:69:7: error:
'QUARK_X1000_SSCR1_TFT' undeclared (first use in this function)
     | QUARK_X1000_SSCR1_TFT  \
       ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:146:10: note: in
expansion of macro 'QUARK_X1000_SSCR1_CHANGE_MASK'
   return QUARK_X1000_SSCR1_CHANGE_MASK;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function
'pxa2xx_spi_get_rx_default_thre':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:157:10: error:
'RX_THRESH_QUARK_X1000_DFLT' undeclared (first use in this function)
   return RX_THRESH_QUARK_X1000_DFLT;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function
'pxa2xx_spi_txfifo_full':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:170:10: error:
'QUARK_X1000_SSSR_TFL_MASK' undeclared (first use in this function)
   mask = QUARK_X1000_SSSR_TFL_MASK;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function
'pxa2xx_spi_clear_rx_thre':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:187:10: error:
'QUARK_X1000_SSCR1_RFT' undeclared (first use in this function)
   mask = QUARK_X1000_SSCR1_RFT;
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function
'pxa2xx_spi_set_rx_thre':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:201:3: error: implicit
declaration of function 'QUARK_X1000_SSCR1_RxTresh'
[-Werror=implicit-function-declaration]
   *sccr1_reg |= QUARK_X1000_SSCR1_RxTresh(threshold);
   ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function
'pxa2xx_configure_sscr0':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:215:6: error:
'QUARK_X1000_SSCR0_Motorola' undeclared (first use in this function)
    | QUARK_X1000_SSCR0_Motorola
      ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:216:4: error: implicit
declaration of function 'QUARK_X1000_SSCR0_DataSize'
[-Werror=implicit-function-declaration]
    | QUARK_X1000_SSCR0_DataSize(bits > 32 ? 8 : bits)
    ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function 'setup':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1062:14: error:
'TX_THRESH_QUARK_X1000_DFLT' undeclared (first use in this function)
   tx_thres = TX_THRESH_QUARK_X1000_DFLT;
              ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1064:14: error:
'RX_THRESH_QUARK_X1000_DFLT' undeclared (first use in this function)
   rx_thres = RX_THRESH_QUARK_X1000_DFLT;
              ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1154:10: error:
'QUARK_X1000_SSCR1_RFT' undeclared (first use in this function)
        & QUARK_X1000_SSCR1_RFT)
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1155:8: error:
implicit declaration of function 'QUARK_X1000_SSCR1_TxTresh'
[-Werror=implicit-function-declaration]
        | (QUARK_X1000_SSCR1_TxTresh(tx_thres)
        ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1156:10: error:
'QUARK_X1000_SSCR1_TFT' undeclared (first use in this function)
        & QUARK_X1000_SSCR1_TFT);
          ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c: In function 'pxa2xx_spi_probe':
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1393:6: error:
'RX_THRESH_QUARK_X1000_DFLT' undeclared (first use in this function)
      RX_THRESH_QUARK_X1000_DFLT) |
      ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1395:6: error:
'TX_THRESH_QUARK_X1000_DFLT' undeclared (first use in this function)
      TX_THRESH_QUARK_X1000_DFLT),
      ^
/home/build/work/batch/drivers/spi/spi-pxa2xx.c:1399:15: error:
'QUARK_X1000_SSCR0_Motorola' undeclared (first use in this function)
   write_SSCR0(QUARK_X1000_SSCR0_Motorola



-Olof

[PATCH 2/2 v2] SPI: spi-pxa2xx: SPI support for Intel Quark X1000

[Mark Brown]

On Tue, Nov 25, 2014 at 12:06:41PM -0800, Olof Johansson wrote:
> On Mon, Sep 29, 2014 at 7:22 AM, Weike Chen <alvin.chen@intel.com> wrote:

> > This piece of work is derived from Dan O'Donovan's initial work for Intel Quark
> > X1000 SPI enabling.

> How about build testing for other platforms that share this driver
> when you make changes to it? This is obviously completely broken.

> Doing these constants under ifdef seems fragile at best, braindead at
> worst. Please don't proliferate that coding style.

> Mark, can you revert until Intel learns how to play well with others?

Yeah.

> This is from a pxa3xx-defconfig build:

Ugh, why does this driver not have a COMPILE_TEST dependency?  Not that
it'd have caught this one.
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