[PATCH v6 02/16] spi/spi-atmel: detect the capabilities of SPI core by reading the VERSION register.

Wenyou Yang
2013-03-07T03:30:20Z

The "has_dma_support" needed for future use with dmaengine driver.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Cc: spi-devel-general@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org
---
drivers/spi/spi-atmel.c | 66 +++++++++++++++++++++++++++++++++++------------
1 file changed, 50 insertions(+), 16 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 1eca815..8724157 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -22,9 +22,8 @@
#include <linux/platform_data/atmel.h>
#include <linux/of.h>

-#include <asm/io.h>
-#include <asm/gpio.h>
-#include <mach/cpu.h>
+#include <linux/io.h>
+#include <linux/gpio.h>

/* SPI register offsets */
#define SPI_CR 0x0000
@@ -39,6 +38,7 @@
#define SPI_CSR1 0x0034
#define SPI_CSR2 0x0038
#define SPI_CSR3 0x003c
+#define SPI_VERSION 0x00fc
#define SPI_RPR 0x0100
#define SPI_RCR 0x0104
#define SPI_TPR 0x0108
@@ -71,6 +71,8 @@
#define SPI_FDIV_SIZE 1
#define SPI_MODFDIS_OFFSET 4
#define SPI_MODFDIS_SIZE 1
+#define SPI_WDRBT_OFFSET 5
+#define SPI_WDRBT_SIZE 1
#define SPI_LLB_OFFSET 7
#define SPI_LLB_SIZE 1
#define SPI_PCS_OFFSET 16
@@ -180,6 +182,11 @@
#define spi_writel(port,reg,value) \
__raw_writel((value), (port)->regs + SPI_##reg)

+struct atmel_spi_caps {
+ bool is_spi2;
+ bool has_wdrbt;
+ bool has_dma_support;
+};

/*
* The core SPI transfer engine just talks to a register bank to set up
@@ -204,6 +211,8 @@ struct atmel_spi {

void *buffer;
dma_addr_t buffer_dma;
+
+ struct atmel_spi_caps caps;
};

/* Controller-specific per-slave state */
@@ -222,14 +231,10 @@ struct atmel_spi_device {
* - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
* - SPI_CSRx.CSAAT
* - SPI_CSRx.SBCR allows faster clocking
- *
- * We can determine the controller version by reading the VERSION
- * register, but I haven't checked that it exists on all chips, and
- * this is cheaper anyway.
*/
-static bool atmel_spi_is_v2(void)
+static bool atmel_spi_is_v2(struct atmel_spi *as)
{
- return !cpu_is_at91rm9200();
+ return as->caps.is_spi2;
}

/*
@@ -263,15 +268,20 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;

- if (atmel_spi_is_v2()) {
+ if (atmel_spi_is_v2(as)) {
/*
* Always use CSR0. This ensures that the clock
* switches to the correct idle polarity before we
* toggle the CS.
*/
spi_writel(as, CSR0, asd->csr);
- spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
+ if (as->caps.has_wdrbt) {
+ spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(WDRBT)
+ | SPI_BIT(MODFDIS) | SPI_BIT(MSTR));
+ } else {
+ spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
| SPI_BIT(MSTR));
+ }
mr = spi_readl(as, MR);
gpio_set_value(asd->npcs_pin, active);
} else {
@@ -318,7 +328,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
asd->npcs_pin, active ? " (low)" : "",
mr);

- if (atmel_spi_is_v2() || spi->chip_select != 0)
+ if (atmel_spi_is_v2(as) || spi->chip_select != 0)
gpio_set_value(asd->npcs_pin, !active);
}

@@ -719,7 +729,7 @@ static int atmel_spi_setup(struct spi_device *spi)
}

/* see notes above re chipselect */
- if (!atmel_spi_is_v2()
+ if (!atmel_spi_is_v2(as)
&& spi->chip_select == 0
&& (spi->mode & SPI_CS_HIGH)) {
dev_dbg(&spi->dev, "setup: can't be active-high\n");
@@ -728,7 +738,7 @@ static int atmel_spi_setup(struct spi_device *spi)

/* v1 chips start out at half the peripheral bus speed. */
bus_hz = clk_get_rate(as->clk);
- if (!atmel_spi_is_v2())
+ if (!atmel_spi_is_v2(as))
bus_hz /= 2;

if (spi->max_speed_hz) {
@@ -804,7 +814,7 @@ static int atmel_spi_setup(struct spi_device *spi)
"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);

- if (!atmel_spi_is_v2())
+ if (!atmel_spi_is_v2(as))
spi_writel(as, CSR0 + 4 * spi->chip_select, csr);

return 0;
@@ -910,6 +920,23 @@ static void atmel_spi_cleanup(struct spi_device *spi)
kfree(asd);
}

+static inline unsigned int atmel_get_version(struct atmel_spi *as)
+{
+ return spi_readl(as, VERSION) & 0x00000fff;
+}
+
+static void atmel_get_caps(struct atmel_spi *as)
+{
+ unsigned int version;
+
+ version = atmel_get_version(as);
+ dev_info(&as->pdev->dev, "version: 0x%x\n", version);
+
+ as->caps.is_spi2 = (version > 0x121) ? true : false;
+ as->caps.has_wdrbt = (version >= 0x210) ? true : false;
+ as->caps.has_dma_support = (version >= 0x212) ? true : false;
+}
+
/*-------------------------------------------------------------------------*/

static int atmel_spi_probe(struct platform_device *pdev)
@@ -970,6 +997,8 @@ static int atmel_spi_probe(struct platform_device *pdev)
as->irq = irq;
as->clk = clk;

+ atmel_get_caps(as);
+
ret = request_irq(irq, atmel_spi_interrupt, 0,
dev_name(&pdev->dev), master);
if (ret)
@@ -979,7 +1008,12 @@ static int atmel_spi_probe(struct platform_device *pdev)
clk_enable(clk);
spi_writel(as, CR, SPI_BIT(SWRST));
spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
- spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
+ if (as->caps.has_wdrbt) {
+ spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
+ | SPI_BIT(MSTR));
+ } else {
+ spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
+ }
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
spi_writel(as, CR, SPI_BIT(SPIEN));

--
1.7.9.5