atmel_spi: Driver for the Atmel SPI controller
authorHans-Christian Egtvedt <hcegtvedt@atmel.com>
Fri, 16 May 2008 09:10:32 +0000 (11:10 +0200)
committerWolfgang Denk <wd@denx.de>
Tue, 3 Jun 2008 18:30:05 +0000 (20:30 +0200)
This adds a driver for the SPI controller found on most AT91 and AVR32
chips, implementing the new SPI API.

Changed in v4:
  - Update to new API
  - Handle zero-length transfers appropriately. The user may send a
    zero-length SPI transfer with SPI_XFER_END set in order to
    deactivate the chip select after a series of transfers with chip
    select active. This is useful e.g. when polling the status
    register of DataFlash.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
cpu/at32ap/at32ap700x/gpio.c
drivers/spi/Makefile
drivers/spi/atmel_spi.c [new file with mode: 0644]
drivers/spi/atmel_spi.h [new file with mode: 0644]
include/asm-avr32/arch-at32ap700x/chip-features.h
include/asm-avr32/arch-at32ap700x/clk.h
include/asm-avr32/arch-at32ap700x/gpio.h

index 859124a91f6b8b4e1c7c80094bb3245750beaa3f..3da35d4fe231c4c882c0551113a9b2e8dbcd3d0d 100644 (file)
  */
 #include <common.h>
 
+#include <asm/io.h>
+
 #include <asm/arch/chip-features.h>
 #include <asm/arch/gpio.h>
+#include <asm/arch/memory-map.h>
 
 /*
  * Lots of small functions here. We depend on --gc-sections getting
@@ -142,3 +145,43 @@ void gpio_enable_mmci(void)
        gpio_select_periph_A(GPIO_PIN_PA15, 0); /* DATA3 */
 }
 #endif
+
+#ifdef AT32AP700x_CHIP_HAS_SPI
+void gpio_enable_spi0(unsigned long cs_mask)
+{
+       u32 pa_mask = 0;
+
+       gpio_select_periph_A(GPIO_PIN_PA0,  0); /* MISO */
+       gpio_select_periph_A(GPIO_PIN_PA1,  0); /* MOSI */
+       gpio_select_periph_A(GPIO_PIN_PA2,  0); /* SCK  */
+
+       if (cs_mask & (1 << 0))
+               pa_mask |= 1 << 3;      /* NPCS0 */
+       if (cs_mask & (1 << 1))
+               pa_mask |= 1 << 4;      /* NPCS1 */
+       if (cs_mask & (1 << 2))
+               pa_mask |= 1 << 5;      /* NPCS2 */
+       if (cs_mask & (1 << 3))
+               pa_mask |= 1 << 20;     /* NPCS3 */
+
+       __raw_writel(pa_mask, PIOA_BASE + 0x00);
+       __raw_writel(pa_mask, PIOA_BASE + 0x30);
+       __raw_writel(pa_mask, PIOA_BASE + 0x10);
+}
+
+void gpio_enable_spi1(unsigned long cs_mask)
+{
+       gpio_select_periph_B(GPIO_PIN_PA0,  0); /* MISO */
+       gpio_select_periph_B(GPIO_PIN_PB1,  0); /* MOSI */
+       gpio_select_periph_B(GPIO_PIN_PB5,  0); /* SCK  */
+
+       if (cs_mask & (1 << 0))
+               gpio_select_periph_B(GPIO_PIN_PB2,  0); /* NPCS0 */
+       if (cs_mask & (1 << 1))
+               gpio_select_periph_B(GPIO_PIN_PB3,  0); /* NPCS1 */
+       if (cs_mask & (1 << 2))
+               gpio_select_periph_B(GPIO_PIN_PB4,  0); /* NPCS2 */
+       if (cs_mask & (1 << 3))
+               gpio_select_periph_A(GPIO_PIN_PA27, 0); /* NPCS3 */
+}
+#endif
index bc8a1041210ddce8d33174e42b85f893652752a2..e66e0ee092f341fc87af6d2dafbfc417e079cf54 100644 (file)
@@ -26,6 +26,7 @@ include $(TOPDIR)/config.mk
 LIB    := $(obj)libspi.a
 
 COBJS-y += mpc8xxx_spi.o
+COBJS-$(CONFIG_ATMEL_SPI) += atmel_spi.o
 COBJS-$(CONFIG_MXC_SPI) += mxc_spi.o
 
 COBJS  := $(COBJS-y)
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
new file mode 100644 (file)
index 0000000..317c0b4
--- /dev/null
@@ -0,0 +1,210 @@
+/*
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#include <common.h>
+#include <spi.h>
+#include <malloc.h>
+
+#include <asm/io.h>
+
+#include <asm/arch/clk.h>
+#include <asm/arch/memory-map.h>
+
+#include "atmel_spi.h"
+
+void spi_init()
+{
+
+}
+
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+                       unsigned int max_hz, unsigned int mode)
+{
+       struct atmel_spi_slave  *as;
+       unsigned int            scbr;
+       u32                     csrx;
+       void                    *regs;
+
+       if (cs > 3 || !spi_cs_is_valid(bus, cs))
+               return NULL;
+
+       switch (bus) {
+       case 0:
+               regs = (void *)SPI0_BASE;
+               break;
+#ifdef SPI1_BASE
+       case 1:
+               regs = (void *)SPI1_BASE;
+               break;
+#endif
+#ifdef SPI2_BASE
+       case 2:
+               regs = (void *)SPI2_BASE;
+               break;
+#endif
+#ifdef SPI3_BASE
+       case 3:
+               regs = (void *)SPI3_BASE;
+               break;
+#endif
+       default:
+               return NULL;
+       }
+
+
+       scbr = (get_spi_clk_rate(bus) + max_hz - 1) / max_hz;
+       if (scbr > ATMEL_SPI_CSRx_SCBR_MAX)
+               /* Too low max SCK rate */
+               return NULL;
+       if (scbr < 1)
+               scbr = 1;
+
+       csrx = ATMEL_SPI_CSRx_SCBR(scbr);
+       csrx |= ATMEL_SPI_CSRx_BITS(ATMEL_SPI_BITS_8);
+       if (!(mode & SPI_CPHA))
+               csrx |= ATMEL_SPI_CSRx_NCPHA;
+       if (mode & SPI_CPOL)
+               csrx |= ATMEL_SPI_CSRx_CPOL;
+
+       as = malloc(sizeof(struct atmel_spi_slave));
+       if (!as)
+               return NULL;
+
+       as->slave.bus = bus;
+       as->slave.cs = cs;
+       as->regs = regs;
+       as->mr = ATMEL_SPI_MR_MSTR | ATMEL_SPI_MR_MODFDIS
+                       | ATMEL_SPI_MR_PCS(~(1 << cs) & 0xf);
+       spi_writel(as, CSR(cs), csrx);
+
+       return &as->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+       struct atmel_spi_slave *as = to_atmel_spi(slave);
+
+       free(as);
+}
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+       struct atmel_spi_slave *as = to_atmel_spi(slave);
+
+       /* Enable the SPI hardware */
+       spi_writel(as, CR, ATMEL_SPI_CR_SPIEN);
+
+       /*
+        * Select the slave. This should set SCK to the correct
+        * initial state, etc.
+        */
+       spi_writel(as, MR, as->mr);
+
+       return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+       struct atmel_spi_slave *as = to_atmel_spi(slave);
+
+       /* Disable the SPI hardware */
+       spi_writel(as, CR, ATMEL_SPI_CR_SPIDIS);
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
+               const void *dout, void *din, unsigned long flags)
+{
+       struct atmel_spi_slave *as = to_atmel_spi(slave);
+       unsigned int    len_tx;
+       unsigned int    len_rx;
+       unsigned int    len;
+       int             ret;
+       u32             status;
+       const u8        *txp = dout;
+       u8              *rxp = din;
+       u8              value;
+
+       ret = 0;
+       if (bitlen == 0)
+               /* Finish any previously submitted transfers */
+               goto out;
+
+       /*
+        * TODO: The controller can do non-multiple-of-8 bit
+        * transfers, but this driver currently doesn't support it.
+        *
+        * It's also not clear how such transfers are supposed to be
+        * represented as a stream of bytes...this is a limitation of
+        * the current SPI interface.
+        */
+       if (bitlen % 8) {
+               /* Errors always terminate an ongoing transfer */
+               flags |= SPI_XFER_END;
+               goto out;
+       }
+
+       len = bitlen / 8;
+
+       /*
+        * The controller can do automatic CS control, but it is
+        * somewhat quirky, and it doesn't really buy us much anyway
+        * in the context of U-Boot.
+        */
+       if (flags & SPI_XFER_BEGIN)
+               spi_cs_activate(slave);
+
+       for (len_tx = 0, len_rx = 0; len_rx < len; ) {
+               status = spi_readl(as, SR);
+
+               if (status & ATMEL_SPI_SR_OVRES)
+                       return -1;
+
+               if (len_tx < len && (status & ATMEL_SPI_SR_TDRE)) {
+                       if (txp)
+                               value = *txp++;
+                       else
+                               value = 0;
+                       spi_writel(as, TDR, value);
+                       len_tx++;
+               }
+               if (status & ATMEL_SPI_SR_RDRF) {
+                       value = spi_readl(as, RDR);
+                       if (rxp)
+                               *rxp++ = value;
+                       len_rx++;
+               }
+       }
+
+out:
+       if (flags & SPI_XFER_END) {
+               /*
+                * Wait until the transfer is completely done before
+                * we deactivate CS.
+                */
+               do {
+                       status = spi_readl(as, SR);
+               } while (!(status & ATMEL_SPI_SR_TXEMPTY));
+
+               spi_cs_deactivate(slave);
+       }
+
+       return 0;
+}
diff --git a/drivers/spi/atmel_spi.h b/drivers/spi/atmel_spi.h
new file mode 100644 (file)
index 0000000..8b69a6d
--- /dev/null
@@ -0,0 +1,95 @@
+/*
+ * Register definitions for the Atmel AT32/AT91 SPI Controller
+ */
+
+/* Register offsets */
+#define ATMEL_SPI_CR                   0x0000
+#define ATMEL_SPI_MR                   0x0004
+#define ATMEL_SPI_RDR                  0x0008
+#define ATMEL_SPI_TDR                  0x000c
+#define ATMEL_SPI_SR                   0x0010
+#define ATMEL_SPI_IER                  0x0014
+#define ATMEL_SPI_IDR                  0x0018
+#define ATMEL_SPI_IMR                  0x001c
+#define ATMEL_SPI_CSR(x)               (0x0030 + 4 * (x))
+#define ATMEL_SPI_VERSION              0x00fc
+
+/* Bits in CR */
+#define ATMEL_SPI_CR_SPIEN             (1 << 0)
+#define ATMEL_SPI_CR_SPIDIS            (1 << 1)
+#define ATMEL_SPI_CR_SWRST             (1 << 7)
+#define ATMEL_SPI_CR_LASTXFER          (1 << 24)
+
+/* Bits in MR */
+#define ATMEL_SPI_MR_MSTR              (1 << 0)
+#define ATMEL_SPI_MR_PS                        (1 << 1)
+#define ATMEL_SPI_MR_PCSDEC            (1 << 2)
+#define ATMEL_SPI_MR_FDIV              (1 << 3)
+#define ATMEL_SPI_MR_MODFDIS           (1 << 4)
+#define ATMEL_SPI_MR_LLB               (1 << 7)
+#define ATMEL_SPI_MR_PCS(x)            (((x) & 15) << 16)
+#define ATMEL_SPI_MR_DLYBCS(x)         ((x) << 24)
+
+/* Bits in RDR */
+#define ATMEL_SPI_RDR_RD(x)            (x)
+#define ATMEL_SPI_RDR_PCS(x)           ((x) << 16)
+
+/* Bits in TDR */
+#define ATMEL_SPI_TDR_TD(x)            (x)
+#define ATMEL_SPI_TDR_PCS(x)           ((x) << 16)
+#define ATMEL_SPI_TDR_LASTXFER         (1 << 24)
+
+/* Bits in SR/IER/IDR/IMR */
+#define ATMEL_SPI_SR_RDRF              (1 << 0)
+#define ATMEL_SPI_SR_TDRE              (1 << 1)
+#define ATMEL_SPI_SR_MODF              (1 << 2)
+#define ATMEL_SPI_SR_OVRES             (1 << 3)
+#define ATMEL_SPI_SR_ENDRX             (1 << 4)
+#define ATMEL_SPI_SR_ENDTX             (1 << 5)
+#define ATMEL_SPI_SR_RXBUFF            (1 << 6)
+#define ATMEL_SPI_SR_TXBUFE            (1 << 7)
+#define ATMEL_SPI_SR_NSSR              (1 << 8)
+#define ATMEL_SPI_SR_TXEMPTY           (1 << 9)
+#define ATMEL_SPI_SR_SPIENS            (1 << 16)
+
+/* Bits in CSRx */
+#define ATMEL_SPI_CSRx_CPOL            (1 << 0)
+#define ATMEL_SPI_CSRx_NCPHA           (1 << 1)
+#define ATMEL_SPI_CSRx_CSAAT           (1 << 3)
+#define ATMEL_SPI_CSRx_BITS(x)         ((x) << 4)
+#define ATMEL_SPI_CSRx_SCBR(x)         ((x) << 8)
+#define ATMEL_SPI_CSRx_SCBR_MAX                0xff
+#define ATMEL_SPI_CSRx_DLYBS(x)                ((x) << 16)
+#define ATMEL_SPI_CSRx_DLYBCT(x)       ((x) << 24)
+
+/* Bits in VERSION */
+#define ATMEL_SPI_VERSION_REV(x)       ((x) << 0)
+#define ATMEL_SPI_VERSION_MFN(x)       ((x) << 16)
+
+/* Constants for CSRx:BITS */
+#define ATMEL_SPI_BITS_8               0
+#define ATMEL_SPI_BITS_9               1
+#define ATMEL_SPI_BITS_10              2
+#define ATMEL_SPI_BITS_11              3
+#define ATMEL_SPI_BITS_12              4
+#define ATMEL_SPI_BITS_13              5
+#define ATMEL_SPI_BITS_14              6
+#define ATMEL_SPI_BITS_15              7
+#define ATMEL_SPI_BITS_16              8
+
+struct atmel_spi_slave {
+       struct spi_slave slave;
+       void            *regs;
+       u32             mr;
+};
+
+static inline struct atmel_spi_slave *to_atmel_spi(struct spi_slave *slave)
+{
+       return container_of(slave, struct atmel_spi_slave, slave);
+}
+
+/* Register access macros */
+#define spi_readl(as, reg)                                     \
+       readl(as->regs + ATMEL_SPI_##reg)
+#define spi_writel(as, reg, value)                             \
+       writel(value, as->regs + ATMEL_SPI_##reg)
index 29b1fd663d0e125a4c502500b280c9ec960ac0f6..c47107e2a641bf6e11c6d66a64611ce2b7b52817 100644 (file)
@@ -25,6 +25,7 @@
 /* Currently, all the AP700x chips have these */
 #define AT32AP700x_CHIP_HAS_USART
 #define AT32AP700x_CHIP_HAS_MMCI
+#define AT32AP700x_CHIP_HAS_SPI
 
 /* Only AP7000 has ethernet interface */
 #ifdef CONFIG_AT32AP7000
index 4a1dd33b56b0c259b7bbebb91ef8e5a9ae02524c..a9d8431a66c84d3ce326ccf7717356c56c9f4898 100644 (file)
@@ -74,6 +74,12 @@ static inline unsigned long get_mci_clk_rate(void)
        return get_pbb_clk_rate();
 }
 #endif
+#ifdef AT32AP700x_CHIP_HAS_SPI
+static inline unsigned long get_spi_clk_rate(unsigned int dev_id)
+{
+       return get_pba_clk_rate();
+}
+#endif
 
 extern void clk_init(void);
 
index b10a3e4f868494a87c5ca6674da2292ce8cd8a5b..ef20ceaab7cfc85d5e2807b2cad8061f56ffbc2d 100644 (file)
@@ -216,5 +216,9 @@ void gpio_enable_macb1(void);
 #ifdef AT32AP700x_CHIP_HAS_MMCI
 void gpio_enable_mmci(void);
 #endif
+#ifdef AT32AP700x_CHIP_HAS_SPI
+void gpio_enable_spi0(unsigned long cs_mask);
+void gpio_enable_spi1(unsigned long cs_mask);
+#endif
 
 #endif /* __ASM_AVR32_ARCH_GPIO_H__ */