[1/4] spi: qup: Remove chip select function

Commit Message

Andy Gross May 13, 2014, 9:34 p.m. UTC

This patch removes the chip select function.  Chip select should instead be
supported using GPIOs, defining the DT entry "cs-gpios", and letting the SPI
core assert/deassert the chip select as it sees fit.

Signed-off-by: Andy Gross <[e-mail]>
---
 .../devicetree/bindings/spi/qcom,spi-qup.txt       |    6 +++++
 drivers/spi/spi-qup.c                              |   28 ++------------------
 2 files changed, 8 insertions(+), 26 deletions(-)

Comments

Ivan T. Ivanov May 19, 2014, 8:07 a.m. UTC | #1

Hi Andy,

On Tue, 2014-05-13 at 16:34 -0500, Andy Gross wrote:
> This patch removes the chip select function.  Chip select should instead be
> supported using GPIOs, defining the DT entry "cs-gpios", and letting the SPI
> core assert/deassert the chip select as it sees fit.
> 
> Signed-off-by: Andy Gross <[e-mail]>

<snip>

> +- num-cs:	total number of chipselects

My understanding is that "num-cs" have to be parsed by
master driver, not by core SPI driver.

> -
> -	/* Disable auto CS toggle and use manual */
> -	iocontol &= ~SPI_IO_C_MX_CS_MODE;

Probably we should keep this?

Regards,
Ivan

Andy Gross June 12, 2014, 4:02 a.m. UTC | #2

On Mon, May 19, 2014 at 11:07:38AM +0300, Ivan T. Ivanov wrote:
<snip>
 
> > +- num-cs:	total number of chipselects
> 
> My understanding is that "num-cs" have to be parsed by
> master driver, not by core SPI driver.

Right.  I need to parse it and check vs the max cs and use that value to set the
master->num_chipselect

> 
> > -
> > -	/* Disable auto CS toggle and use manual */
> > -	iocontol &= ~SPI_IO_C_MX_CS_MODE;
> 
> Probably we should keep this?

Actually this is cleared in the probe during the initial settings of IO_CONTROL.
So this isn't necessary.

Patch

diff --git a/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt b/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
index b82a268..bee6ff2 100644
--- a/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
+++ b/Documentation/devicetree/bindings/spi/qcom,spi-qup.txt
@@ -23,6 +23,12 @@  Optional properties:
 - spi-max-frequency: Specifies maximum SPI clock frequency,
                      Units - Hz. Definition as per
                      Documentation/devicetree/bindings/spi/spi-bus.txt
+- num-cs:	total number of chipselects
+- cs-gpios:	should specify GPIOs used for chipselects.
+		The gpios will be referred to as reg = <index> in the SPI child
+		nodes.  If unspecified, a single SPI device without a chip
+		select can be used.
+
 
 SPI slave nodes must be children of the SPI master node and can contain
 properties described in Documentation/devicetree/bindings/spi/spi-bus.txt
diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index b032e88..ea7017b 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -18,7 +18,9 @@ 
 #include <linux/io.h>
 #include <linux/list.h>
 #include <linux/module.h>
+#include <linux/gpio.h>
 #include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/spi/spi.h>
@@ -424,31 +426,6 @@  static int spi_qup_io_config(struct spi_device *spi, struct spi_transfer *xfer)
 	return 0;
 }
 
-static void spi_qup_set_cs(struct spi_device *spi, bool enable)
-{
-	struct spi_qup *controller = spi_master_get_devdata(spi->master);
-
-	u32 iocontol, mask;
-
-	iocontol = readl_relaxed(controller->base + SPI_IO_CONTROL);
-
-	/* Disable auto CS toggle and use manual */
-	iocontol &= ~SPI_IO_C_MX_CS_MODE;
-	iocontol |= SPI_IO_C_FORCE_CS;
-
-	iocontol &= ~SPI_IO_C_CS_SELECT_MASK;
-	iocontol |= SPI_IO_C_CS_SELECT(spi->chip_select);
-
-	mask = SPI_IO_C_CS_N_POLARITY_0 << spi->chip_select;
-
-	if (enable)
-		iocontol |= mask;
-	else
-		iocontol &= ~mask;
-
-	writel_relaxed(iocontol, controller->base + SPI_IO_CONTROL);
-}
-
 static int spi_qup_transfer_one(struct spi_master *master,
 			      struct spi_device *spi,
 			      struct spi_transfer *xfer)
@@ -576,7 +553,6 @@  static int spi_qup_probe(struct platform_device *pdev)
 	master->num_chipselect = SPI_NUM_CHIPSELECTS;
 	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
 	master->max_speed_hz = max_freq;
-	master->set_cs = spi_qup_set_cs;
 	master->transfer_one = spi_qup_transfer_one;
 	master->dev.of_node = pdev->dev.of_node;
 	master->auto_runtime_pm = true;