[PATCH] ARM PL022 SSP/SPI driver v1

[PATCH] ARM PL022 SSP/SPI driver v1

[Linus Walleij]

This adds a driver for the ARM PL022 PrimeCell SSP/SPI
driver found in the U300 platforms as well as in some
ARM reference hardware, and in a modified version on the
Nomadik board.

Signed-off-by: Linus Walleij <linus.walleij-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org>
---
 drivers/spi/Kconfig        |    9 +
 drivers/spi/Makefile       |    1 +
 drivers/spi/amba-pl022.c   | 1887 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/amba/pl022.h |  264 ++++++
 4 files changed, 2161 insertions(+), 0 deletions(-)
 create mode 100644 drivers/spi/amba-pl022.c
 create mode 100644 include/linux/amba/pl022.h

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 83a185d..39cb8cf 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -171,6 +171,15 @@ config SPI_ORION
 	help
 	  This enables using the SPI master controller on the Orion chips.

+config SPI_PL022
+	tristate "ARM AMBA PL022 SSP controller"
+	depends on ARM_AMBA && EXPERIMENTAL
+	default y if MACH_U300
+	help
+	  This selects the ARM(R) AMBA(R) PrimeCell PL022 SSP
+	  controller. If you have an embedded system with an AMBA(R)
+	  bus and a PL022 controller, say Y or M here.
+
 config SPI_PXA2XX
 	tristate "PXA2xx SSP SPI master"
 	depends on ARCH_PXA && EXPERIMENTAL
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 5d04519..ecfadb1 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_SPI_PXA2XX)		+= pxa2xx_spi.o
 obj-$(CONFIG_SPI_OMAP_UWIRE)		+= omap_uwire.o
 obj-$(CONFIG_SPI_OMAP24XX)		+= omap2_mcspi.o
 obj-$(CONFIG_SPI_ORION)			+= orion_spi.o
+obj-$(CONFIG_SPI_PL022)			+= amba-pl022.o
 obj-$(CONFIG_SPI_MPC52xx_PSC)		+= mpc52xx_psc_spi.o
 obj-$(CONFIG_SPI_MPC83xx)		+= spi_mpc83xx.o
 obj-$(CONFIG_SPI_S3C24XX_GPIO)		+= spi_s3c24xx_gpio.o
diff --git a/drivers/spi/amba-pl022.c b/drivers/spi/amba-pl022.c
new file mode 100644
index 0000000..3939aeb
--- /dev/null
+++ b/drivers/spi/amba-pl022.c
@@ -0,0 +1,1887 @@
+/*
+ * drivers/spi/amba-pl022.c
+ *
+ * A driver for the ARM PL022 PrimeCell SSP/SPI bus master.
+ *
+ * Copyright (C) 2008-2009 ST-Ericsson AB
+ * Copyright (C) 2006 STMicroelectronics Pvt. Ltd.
+ *
+ * Author: Linus Walleij <linus.walleij-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org>
+ *
+ * Initial version inspired by:
+ *	linux-2.6.17-rc3-mm1/drivers/spi/pxa2xx_spi.c
+ * Initial adoption to PL022 by:
+ *      Sachin Verma <sachin.verma-qxv4g6HH51o@public.gmane.org>
+ *
+ * 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.
+ */
+
+/*
+ * TODO:
+ * - add timeout on polled transfers
+ * - add generic DMA framework support
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/ioport.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi.h>
+#include <linux/workqueue.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/amba/bus.h>
+#include <linux/amba/pl022.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <asm/irq.h>
+
+/*
+ * This macro is used to define some register default values.
+ * reg is masked with mask, the OR:ed with an (again masked)
+ * val shifted sb steps to the left.
+ */
+#define SSP_WRITE_BITS(reg, val, mask, sb) \
+ ((reg) = (((reg) & ~(mask)) | (((val)<<(sb)) & (mask))))
+
+/*
+ * This macro is also used to define some default values.
+ * It will just shift val by sb steps to the left and mask
+ * the result with mask.
+ */
+#define GEN_MASK_BITS(val, mask, sb) \
+ (((val)<<(sb)) & (mask))
+
+#define DRIVE_TX		0
+#define DO_NOT_DRIVE_TX		1
+
+#define DO_NOT_QUEUE_DMA	0
+#define QUEUE_DMA		1
+
+#define RX_TRANSFER		1
+#define TX_TRANSFER		2
+
+/*
+ * Macros to access SSP Registers with their offsets
+ */
+#define SSP_CR0(r)	(r + 0x000)
+#define SSP_CR1(r)	(r + 0x004)
+#define SSP_DR(r)	(r + 0x008)
+#define SSP_SR(r)	(r + 0x00C)
+#define SSP_CPSR(r)	(r + 0x010)
+#define SSP_IMSC(r)	(r + 0x014)
+#define SSP_RIS(r)	(r + 0x018)
+#define SSP_MIS(r)	(r + 0x01C)
+#define SSP_ICR(r)	(r + 0x020)
+#define SSP_DMACR(r)	(r + 0x024)
+#define SSP_ITCR(r)	(r + 0x080)
+#define SSP_ITIP(r)	(r + 0x084)
+#define SSP_ITOP(r)	(r + 0x088)
+#define SSP_TDR(r)	(r + 0x08C)
+
+#define SSP_PID0(r)	(r + 0xFE0)
+#define SSP_PID1(r)	(r + 0xFE4)
+#define SSP_PID2(r)	(r + 0xFE8)
+#define SSP_PID3(r)	(r + 0xFEC)
+
+#define SSP_CID0(r)	(r + 0xFF0)
+#define SSP_CID1(r)	(r + 0xFF4)
+#define SSP_CID2(r)	(r + 0xFF8)
+#define SSP_CID3(r)	(r + 0xFFC)
+
+/*
+ * SSP Control Register 0  - SSP_CR0
+ */
+#define SSP_CR0_MASK_DSS		(0x1FUL << 0)
+#define SSP_CR0_MASK_HALFDUP		(0x1UL << 5)
+#define SSP_CR0_MASK_SPO		(0x1UL << 6)
+#define SSP_CR0_MASK_SPH		(0x1UL << 7)
+#define SSP_CR0_MASK_SCR		(0xFFUL << 8)
+#define SSP_CR0_MASK_CSS		(0x1FUL << 16)
+#define SSP_CR0_MASK_FRF		(0x3UL << 21)
+
+/*
+ * SSP Control Register 0  - SSP_CR1
+ */
+#define SSP_CR1_MASK_LBM		(0x1UL << 0)
+#define SSP_CR1_MASK_SSE		(0x1UL << 1)
+#define SSP_CR1_MASK_MS			(0x1UL << 2)
+#define SSP_CR1_MASK_SOD		(0x1UL << 3)
+#define SSP_CR1_MASK_RENDN		(0x1UL << 4)
+#define SSP_CR1_MASK_TENDN		(0x1UL << 5)
+#define SSP_CR1_MASK_MWAIT		(0x1UL << 6)
+#define SSP_CR1_MASK_RXIFLSEL		(0x7UL << 7)
+#define SSP_CR1_MASK_TXIFLSEL		(0x7UL << 10)
+
+/*
+ * SSP Data Register - SSP_DR
+ */
+#define SSP_DR_MASK_DATA		0xFFFFFFFF
+
+/*
+ * SSP Status Register - SSP_SR
+ */
+/* Transmit FIFO empty */
+#define SSP_SR_MASK_TFE			(0x1UL << 0)
+/* Transmit FIFO not full */
+#define SSP_SR_MASK_TNF			(0x1UL << 1)
+/* Receive FIFO not empty */
+#define SSP_SR_MASK_RNE			(0x1UL << 2)
+/* Receive FIFO full */
+#define SSP_SR_MASK_RFF 		(0x1UL << 3)
+/* Busy Flag */
+#define SSP_SR_MASK_BSY			(0x1UL << 4)
+
+/*
+ * SSP Clock Prescale Register  - SSP_CPSR
+ */
+#define SSP_CPSR_MASK_CPSDVSR	 	(0xFFUL << 0)
+
+/*
+ * SSP Interrupt Mask Set/Clear Register - SSP_IMSC
+ */
+/* Receive Overrun Interrupt mask */
+#define SSP_IMSC_MASK_RORIM		(0x1UL << 0)
+/* Receive timeout Interrupt mask */
+#define SSP_IMSC_MASK_RTIM		(0x1UL << 1)
+/* Receive FIFO Interrupt mask */
+#define SSP_IMSC_MASK_RXIM		(0x1UL << 2)
+/* Transmit FIFO Interrupt mask */
+#define SSP_IMSC_MASK_TXIM		(0x1UL << 3)
+
+/*
+ * SSP Raw Interrupt Status Register - SSP_RIS
+ */
+/* Receive Overrun Raw Interrupt status */
+#define SSP_RIS_MASK_RORRIS		(0x1UL << 0)
+/* Receive Timeout Raw Interrupt status */
+#define SSP_RIS_MASK_RTRIS		(0x1UL << 1)
+/* Receive FIFO Raw Interrupt status */
+#define SSP_RIS_MASK_RXRIS		(0x1UL << 2)
+/* Transmit FIFO Raw Interrupt status */
+#define SSP_RIS_MASK_TXRIS		(0x1UL << 3)
+
+/*
+ * SSP Masked Interrupt Status Register - SSP_MIS
+ */
+/* Receive Overrun Masked Interrupt status */
+#define SSP_MIS_MASK_RORMIS		(0x1UL << 0)
+/* Receive Timeout Masked Interrupt status */
+#define SSP_MIS_MASK_RTMIS		(0x1UL << 1)
+/* Receive FIFO Masked Interrupt status */
+#define SSP_MIS_MASK_RXMIS		(0x1UL << 2)
+/* Transmit FIFO Masked Interrupt status */
+#define SSP_MIS_MASK_TXMIS		(0x1UL << 3)
+
+/*
+ * SSP Interrupt Clear Register - SSP_ICR
+ */
+/* Receive Overrun Raw Clear Interrupt bit */
+#define SSP_ICR_MASK_RORIC		(0x1UL << 0)
+/* Receive Timeout Clear Interrupt bit */
+#define SSP_ICR_MASK_RTIC		(0x1UL << 1)
+
+/*
+ * SSP DMA Control Register - SSP_DMACR
+ */
+/* Receive DMA Enable bit */
+#define SSP_DMACR_MASK_RXDMAE		(0x1UL << 0)
+/* Transmit DMA Enable bit */
+#define SSP_DMACR_MASK_TXDMAE		(0x1UL << 1)
+
+/*
+ * SSP Integration Test control Register - SSP_ITCR
+ */
+#define SSP_ITCR_MASK_ITEN		(0x1UL << 0)
+#define SSP_ITCR_MASK_TESTFIFO		(0x1UL << 1)
+
+/*
+ * SSP Integration Test Input Register - SSP_ITIP
+ */
+#define ITIP_MASK_SSPRXD		 (0x1UL << 0)
+#define ITIP_MASK_SSPFSSIN		 (0x1UL << 1)
+#define ITIP_MASK_SSPCLKIN		 (0x1UL << 2)
+#define ITIP_MASK_RXDMAC		 (0x1UL << 3)
+#define ITIP_MASK_TXDMAC		 (0x1UL << 4)
+#define ITIP_MASK_SSPTXDIN		 (0x1UL << 5)
+
+/*
+ * SSP Integration Test output Register - SSP_ITOP
+ */
+#define ITOP_MASK_SSPTXD		 (0x1UL << 0)
+#define ITOP_MASK_SSPFSSOUT		 (0x1UL << 1)
+#define ITOP_MASK_SSPCLKOUT		 (0x1UL << 2)
+#define ITOP_MASK_SSPOEn		 (0x1UL << 3)
+#define ITOP_MASK_SSPCTLOEn		 (0x1UL << 4)
+#define ITOP_MASK_RORINTR		 (0x1UL << 5)
+#define ITOP_MASK_RTINTR		 (0x1UL << 6)
+#define ITOP_MASK_RXINTR		 (0x1UL << 7)
+#define ITOP_MASK_TXINTR		 (0x1UL << 8)
+#define ITOP_MASK_INTR			 (0x1UL << 9)
+#define ITOP_MASK_RXDMABREQ		 (0x1UL << 10)
+#define ITOP_MASK_RXDMASREQ		 (0x1UL << 11)
+#define ITOP_MASK_TXDMABREQ		 (0x1UL << 12)
+#define ITOP_MASK_TXDMASREQ		 (0x1UL << 13)
+
+/*
+ * SSP Test Data Register - SSP_TDR
+ */
+#define TDR_MASK_TESTDATA 		(0xFFFFFFFF)
+
+/*
+ * Message State
+ * we use the spi_message.state (void *) pointer to
+ * hold a single state value, that's why all this
+ * (void *) casting is done here.
+ */
+#define START_STATE                     ((void *) 0)
+#define RUNNING_STATE                   ((void *) 1)
+#define DONE_STATE                      ((void *) 2)
+#define ERROR_STATE                     ((void *) -1)
+
+/*
+ * Queue State
+ */
+#define QUEUE_RUNNING                   (0)
+#define QUEUE_STOPPED                   (1)
+/*
+ * SSP State - Whether Enabled or Disabled
+ */
+#define SSP_DISABLED 			(0)
+#define SSP_ENABLED 			(1)
+
+/*
+ * SSP DMA State - Whether DMA Enabled or Disabled
+ */
+#define SSP_DMA_DISABLED 		(0)
+#define SSP_DMA_ENABLED 		(1)
+
+/*
+ * SSP Clock Defaults
+ */
+#define NMDK_SSP_DEFAULT_CLKRATE 0x2
+#define NMDK_SSP_DEFAULT_PRESCALE 0x40
+
+/*
+ * SSP Clock Parameter ranges
+ */
+#define MIN_CPSDVR 0x02
+#define MAX_CPSDVR 0xFE
+#define MIN_SCR 0x00
+#define MAX_SCR 0xFF
+
+/*
+ * SSP Interrupt related Macros
+ */
+#define DEFAULT_SSP_REG_IMSC  0x0UL
+#define DISABLE_ALL_INTERRUPTS DEFAULT_SSP_REG_IMSC
+#define ENABLE_ALL_INTERRUPTS (~DEFAULT_SSP_REG_IMSC)
+
+#define CLEAR_ALL_INTERRUPTS  0x3
+
+
+/*
+ * The type of reading going on on this chip
+ */
+enum ssp_reading {
+	NULL_READING,
+	U8_READING,
+	U16_READING,
+	U32_READING
+};
+
+/**
+ * The type of writing going on on this chip
+ */
+enum ssp_writing {
+	NULL_WRITING,
+	U8_WRITING,
+	U16_WRITING,
+	U32_WRITING
+};
+
+/**
+ * struct vendor_data - vendor-specific config parameters
+ * for PL022 derivates
+ * @fifodepth: depth of FIFOs (both)
+ * @max_bpw: maximum number of bits per word
+ * @unidir: supports unidirection transfers
+ */
+struct vendor_data {
+	int fifodepth;
+	int max_bpw;
+	bool unidir;
+};
+
+/**
+ * struct pl022 - This is the private SSP driver data structure
+ * @adev: AMBA device model hookup
+ * @phybase: The physical memory where the SSP device resides
+ * @virtbase: The virtual memory where the SSP is mapped
+ * @master: SPI framework hookup
+ * @master_info: controller-specific data from machine setup
+ * @regs: SSP controller register's virtual address
+ * @pump_messages: Work struct for scheduling work to the workqueue
+ * @lock: spinlock to syncronise access to driver data
+ * @workqueue: a workqueue on which any spi_message request is queued
+ * @busy: workqueue is busy
+ * @run: workqueue is running
+ * @pump_transfers: Tasklet used in Interrupt Transfer mode
+ * @cur_msg: Pointer to current spi_message being processed
+ * @cur_transfer: Pointer to current spi_transfer
+ * @cur_chip: pointer to current clients chip(assigned from controller_state)
+ * @tx: current position in Tx buffer to be read
+ * @tx_end: end position in Tx buffer to be read
+ * @rx: current position in Rx buffer to be written
+ * @rx_end: end position in Rx buffer to be written
+ * @readingtype: the type of read currently going on
+ * @writingtype: the type or write currently going on
+ */
+struct pl022 {
+	struct amba_device	    *adev;
+	struct vendor_data	    *vendor;
+	resource_size_t             phybase;
+	void __iomem		    *virtbase;
+	struct clk		    *clk;
+	struct spi_master           *master;
+	struct pl022_ssp_controller *master_info;
+	/* Driver message queue */
+	struct workqueue_struct	    *workqueue;
+	struct work_struct          pump_messages;
+	spinlock_t                  queue_lock;
+	struct list_head            queue;
+	int                         busy;
+	int                         run;
+	/* Message transfer pump */
+	struct tasklet_struct       pump_transfers;
+	struct spi_message          *cur_msg;
+	struct spi_transfer         *cur_transfer;
+	struct chip_data            *cur_chip;
+	void                        *tx;
+	void                        *tx_end;
+	void                        *rx;
+	void                        *rx_end;
+	enum ssp_reading            read;
+	enum ssp_writing            write;
+};
+
+/**
+ * struct chip_data - To maintain runtime state of SSP for each client chip
+ * @cr0: Value of control register CR0 of SSP
+ * @cr1: Value of control register CR1 of SSP
+ * @dmacr: Value of DMA control Register of SSP
+ * @cpsr: Value of Clock prescale register
+ * @n_bytes: how many bytes(power of 2) reqd for a given data width of client
+ * @enable_dma: Whether to enable DMA or not
+ * @write: function ptr to be used to write when doing xfer for this chip
+ * @read: function ptr to be used to read when doing xfer for this chip
+ * @cs_control: chip select callback provided by chip
+ * @xfer_type: polling/interrupt/DMA
+ *
+ * Runtime state of the SSP controller, maintained per chip,
+ * This would be set according to the current message that would be served
+ */
+struct chip_data {
+	u16 cr0;
+	u16 cr1;
+	u16 dmacr;
+	u16 cpsr;
+	u8 n_bytes;
+	u8 enable_dma:1;
+	enum ssp_reading read;
+	enum ssp_writing write;
+	void (*cs_control) (u32 command);
+	int xfer_type;
+};
+
+/**
+ * null_cs_control - Dummy chip select function
+ * @command: select/delect the chip
+ *
+ * If no chip select function is provided by client this is used as dummy
+ * chip select
+ */
+static void null_cs_control(u32 command)
+{
+	pr_debug("pl022: dummy chip select control, CS=0x%x\n", command);
+}
+
+/**
+ * giveback - current spi_message is over, schedule next message and call
+ * callback of this message. Assumes that caller already
+ * set message->status; dma and pio irqs are blocked
+ * @pl022: SSP driver private data structure
+ */
+static void giveback(struct pl022 *pl022)
+{
+	struct spi_transfer *last_transfer;
+	unsigned long flags;
+	struct spi_message *msg;
+	void (*curr_cs_control) (u32 command);
+
+	/*
+	 * This local reference to the chip select function
+	 * is needed because we set curr_chip to NULL
+	 * as a step toward termininating the message.
+	 */
+	curr_cs_control = pl022->cur_chip->cs_control;
+	spin_lock_irqsave(&pl022->queue_lock, flags);
+	msg = pl022->cur_msg;
+	pl022->cur_msg = NULL;
+	pl022->cur_transfer = NULL;
+	pl022->cur_chip = NULL;
+	queue_work(pl022->workqueue, &pl022->pump_messages);
+	spin_unlock_irqrestore(&pl022->queue_lock, flags);
+
+	last_transfer = list_entry(msg->transfers.prev,
+					struct spi_transfer,
+					transfer_list);
+
+	/* Delay if requested before any change in chip select */
+	if (last_transfer->delay_usecs)
+		/*
+		 * FIXME: This runs in interrupt context.
+		 * Is this really smart?
+		 */
+		udelay(last_transfer->delay_usecs);
+
+	/*
+	 * Drop chip select UNLESS cs_change is true or we are returning
+	 * a message with an error, or next message is for another chip
+	 */
+	if (!last_transfer->cs_change)
+		curr_cs_control(SSP_CHIP_DESELECT);
+	else {
+		struct spi_message *next_msg;
+
+		/* Holding of cs was hinted, but we need to make sure
+		 * the next message is for the same chip.  Don't waste
+		 * time with the following tests unless this was hinted.
+		 *
+		 * We cannot postpone this until pump_messages, because
+		 * after calling msg->complete (below) the driver that
+		 * sent the current message could be unloaded, which
+		 * could invalidate the cs_control() callback...
+		 */
+
+		/* get a pointer to the next message, if any */
+		spin_lock_irqsave(&pl022->queue_lock, flags);
+		if (list_empty(&pl022->queue))
+			next_msg = NULL;
+		else
+			next_msg = list_entry(pl022->queue.next,
+					struct spi_message, queue);
+		spin_unlock_irqrestore(&pl022->queue_lock, flags);
+
+		/* see if the next and current messages point
+		 * to the same chip
+		 */
+		if (next_msg && next_msg->spi != msg->spi)
+			next_msg = NULL;
+		if (!next_msg || msg->state == ERROR_STATE)
+			curr_cs_control(SSP_CHIP_DESELECT);
+	}
+	msg->state = NULL;
+	if (msg->complete)
+		msg->complete(msg->context);
+	/* This message is completed, so let's turn off the clock! */
+	clk_disable(pl022->clk);
+}
+
+/**
+ * flush - flush the FIFO to reach a clean state
+ * @pl022: SSP driver private data structure
+ */
+static int flush(struct pl022 *pl022)
+{
+	unsigned long limit = loops_per_jiffy << 1;
+
+	dev_dbg(&pl022->adev->dev, "flush\n");
+	do {
+		while (readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RNE)
+			readw(SSP_DR(pl022->virtbase));
+	} while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_BSY) && limit--);
+	return limit;
+}
+
+/**
+ * restore_state - Load configuration of current chip
+ * @pl022: SSP driver private data structure
+ */
+static void restore_state(struct pl022 *pl022)
+{
+	struct chip_data *chip = pl022->cur_chip;
+
+	writew(chip->cr0, SSP_CR0(pl022->virtbase));
+	writew(chip->cr1, SSP_CR1(pl022->virtbase));
+	writew(chip->dmacr, SSP_DMACR(pl022->virtbase));
+	writew(chip->cpsr, SSP_CPSR(pl022->virtbase));
+	writew(DISABLE_ALL_INTERRUPTS, SSP_IMSC(pl022->virtbase));
+	writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
+}
+
+/**
+ * load_ssp_default_config - Load default configuration for SSP
+ * @pl022: SSP driver private data structure
+ */
+
+/*
+ * Default SSP Register Values
+ */
+#define DEFAULT_SSP_REG_CR0 ( \
+	GEN_MASK_BITS(SSP_DATA_BITS_12, SSP_CR0_MASK_DSS, 0)	| \
+	GEN_MASK_BITS(SSP_MICROWIRE_CHANNEL_FULL_DUPLEX, SSP_CR0_MASK_HALFDUP, 5) | \
+	GEN_MASK_BITS(SSP_CLK_POL_IDLE_LOW, SSP_CR0_MASK_SPO, 6) | \
+	GEN_MASK_BITS(SSP_CLK_FALLING_EDGE, SSP_CR0_MASK_SPH, 7) | \
+	GEN_MASK_BITS(NMDK_SSP_DEFAULT_CLKRATE, SSP_CR0_MASK_SCR, 8) | \
+	GEN_MASK_BITS(SSP_BITS_8, SSP_CR0_MASK_CSS, 16)	| \
+	GEN_MASK_BITS(SSP_INTERFACE_MOTOROLA_SPI, SSP_CR0_MASK_FRF, 21) \
+)
+
+#define DEFAULT_SSP_REG_CR1 ( \
+	GEN_MASK_BITS(LOOPBACK_DISABLED, SSP_CR1_MASK_LBM, 0) | \
+	GEN_MASK_BITS(SSP_DISABLED, SSP_CR1_MASK_SSE, 1) | \
+	GEN_MASK_BITS(SSP_MASTER, SSP_CR1_MASK_MS, 2) | \
+	GEN_MASK_BITS(DO_NOT_DRIVE_TX, SSP_CR1_MASK_SOD, 3) | \
+	GEN_MASK_BITS(SSP_RX_MSB, SSP_CR1_MASK_RENDN, 4) | \
+	GEN_MASK_BITS(SSP_TX_MSB, SSP_CR1_MASK_TENDN, 5) | \
+	GEN_MASK_BITS(SSP_MWIRE_WAIT_ZERO, SSP_CR1_MASK_MWAIT, 6) |\
+	GEN_MASK_BITS(SSP_RX_1_OR_MORE_ELEM, SSP_CR1_MASK_RXIFLSEL, 7) | \
+	GEN_MASK_BITS(SSP_TX_1_OR_MORE_EMPTY_LOC, SSP_CR1_MASK_TXIFLSEL, 10) \
+)
+
+#define DEFAULT_SSP_REG_CPSR ( \
+	GEN_MASK_BITS(NMDK_SSP_DEFAULT_PRESCALE, SSP_CPSR_MASK_CPSDVSR, 0) \
+)
+
+#define DEFAULT_SSP_REG_DMACR (\
+	GEN_MASK_BITS(SSP_DMA_DISABLED, SSP_DMACR_MASK_RXDMAE, 0) | \
+	GEN_MASK_BITS(SSP_DMA_DISABLED, SSP_DMACR_MASK_TXDMAE, 1) \
+)
+
+
+static void load_ssp_default_config(struct pl022 *pl022)
+{
+	writew(DEFAULT_SSP_REG_CR0, SSP_CR0(pl022->virtbase));
+	writew(DEFAULT_SSP_REG_CR1, SSP_CR1(pl022->virtbase));
+	writew(DEFAULT_SSP_REG_DMACR, SSP_DMACR(pl022->virtbase));
+	writew(DEFAULT_SSP_REG_CPSR, SSP_CPSR(pl022->virtbase));
+	writew(DISABLE_ALL_INTERRUPTS, SSP_IMSC(pl022->virtbase));
+	writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
+}
+
+/**
+ * This will write to TX and read from RX according to the parameters
+ * set in pl022.
+ */
+static void readwriter(struct pl022 *pl022)
+{
+
+	/*
+	 * The FIFO depth is different inbetween primecell variants.
+	 * I believe filling in too much in the FIFO might cause
+	 * errons in 8bit wide transfers on ARM variants (just 8 words
+	 * FIFO, means only 8x8 = 64 bits in FIFO) at least.
+	 *
+	 * FIXME: currently we have no logic to account for this.
+	 * perhaps there is even something broken in HW regarding
+	 * 8bit transfers (it doesn't fail on 16bit) so this needs
+	 * more investigation...
+	 */
+	dev_dbg(&pl022->adev->dev,
+		"%s, rx: %p, rxend: %p, tx: %p, txend: %p\n",
+		__func__, pl022->rx, pl022->rx_end, pl022->tx, pl022->tx_end);
+
+	/* Read as much as you can */
+	while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RNE)
+	       && (pl022->rx < pl022->rx_end)) {
+		switch (pl022->read) {
+		case NULL_READING:
+			readw(SSP_DR(pl022->virtbase));
+			break;
+		case U8_READING:
+			*(u8 *) (pl022->rx) =
+				readw(SSP_DR(pl022->virtbase)) & 0xFFU;
+			break;
+		case U16_READING:
+			*(u16 *) (pl022->rx) =
+				(u16) readw(SSP_DR(pl022->virtbase));
+			break;
+		case U32_READING:
+			*(u32 *) (pl022->rx) =
+				readl(SSP_DR(pl022->virtbase));
+			break;
+		}
+		pl022->rx += (pl022->cur_chip->n_bytes);
+	}
+	/*
+	 * Write as much as you can, while keeping an eye on the RX FIFO!
+	 */
+	while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_TNF)
+	       && (pl022->tx < pl022->tx_end)) {
+		switch (pl022->write) {
+		case NULL_WRITING:
+			writew(0x0, SSP_DR(pl022->virtbase));
+			break;
+		case U8_WRITING:
+			writew(*(u8 *) (pl022->tx), SSP_DR(pl022->virtbase));
+			break;
+		case U16_WRITING:
+			writew((*(u16 *) (pl022->tx)), SSP_DR(pl022->virtbase));
+			break;
+		case U32_WRITING:
+			writel(*(u32 *) (pl022->tx), SSP_DR(pl022->virtbase));
+			break;
+		}
+		pl022->tx += (pl022->cur_chip->n_bytes);
+		/*
+		 * This inner reader takes care of things appearing in the RX
+		 * FIFO as we're transmitting. This will happen a lot since the
+		 * clock starts running when you put things into the TX FIFO,
+		 * and then things are continously clocked into the RX FIFO.
+		 */
+		while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RNE)
+		       && (pl022->rx < pl022->rx_end)) {
+			switch (pl022->read) {
+			case NULL_READING:
+				readw(SSP_DR(pl022->virtbase));
+				break;
+			case U8_READING:
+				*(u8 *) (pl022->rx) =
+					readw(SSP_DR(pl022->virtbase)) & 0xFFU;
+				break;
+			case U16_READING:
+				*(u16 *) (pl022->rx) =
+					(u16) readw(SSP_DR(pl022->virtbase));
+				break;
+			case U32_READING:
+				*(u32 *) (pl022->rx) =
+					readl(SSP_DR(pl022->virtbase));
+				break;
+			}
+			pl022->rx += (pl022->cur_chip->n_bytes);
+		}
+	}
+	/*
+	 * When we exit here the TX FIFO should be full and the RX FIFO
+	 * should be empty
+	 */
+}
+
+
+/**
+ * next_transfer - Move to the Next transfer in the current spi message
+ * @pl022: SSP driver private data structure
+ *
+ * This function moves though the linked list of spi transfers in the
+ * current spi message and returns with the state of current spi
+ * message i.e whether its last transfer is done(DONE_STATE) or
+ * Next transfer is ready(RUNNING_STATE)
+ */
+static void *next_transfer(struct pl022 *pl022)
+{
+	struct spi_message *msg = pl022->cur_msg;
+	struct spi_transfer *trans = pl022->cur_transfer;
+
+	/* Move to next transfer */
+	if (trans->transfer_list.next != &msg->transfers) {
+		pl022->cur_transfer =
+		    list_entry(trans->transfer_list.next,
+			       struct spi_transfer, transfer_list);
+		return RUNNING_STATE;
+	}
+	return DONE_STATE;
+}
+/**
+ * pl022_interrupt_handler - Interrupt handler for SSP controller
+ *
+ * This function handles interrupts generated for an interrupt based transfer.
+ * If a receive overrun (ROR) interrupt is there then we disable SSP, flag the
+ * current message's state as ERROR_STATE and schedule the tasklet
+ * pump_transfers which will do the postprocessing of the current message by
+ * calling giveback(). Otherwise it reads data from Rx FIFO till there is no
+ * more data, and writes data in Tx FIFO till it is not full. If we complete
+ * the transfer we move to the next transfer and schedule the tasklet.
+ */
+static irqreturn_t pl022_interrupt_handler(int irq, void *dev_id)
+{
+	struct pl022 *pl022 = dev_id;
+	struct spi_message *msg = pl022->cur_msg;
+	u16 irq_status = 0;
+	u16 flag = 0;
+
+	if (unlikely(!msg)) {
+		dev_err(&pl022->adev->dev,
+			"bad message state in interrupt handler");
+		/* Never fail */
+		return IRQ_HANDLED;
+	}
+	/* Read the Interrupt Status Register */
+	irq_status = readw(SSP_MIS(pl022->virtbase));
+
+	if (likely(irq_status)) {
+		if (unlikely(irq_status & SSP_MIS_MASK_RORMIS)) {
+			/*
+			 * Overrun interrupt - bail out since our Data has been
+			 * corrupted
+			 */
+			dev_err(&pl022->adev->dev,
+				"FIFO overrun\n");
+			if (readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RFF)
+				dev_err(&pl022->adev->dev,
+					"RXFIFO is full\n");
+			if (readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_TNF)
+				dev_err(&pl022->adev->dev,
+					"TXFIFO is full\n");
+			/* Disable and clear interrupts, disable SSP */
+			writew(DISABLE_ALL_INTERRUPTS,
+			       SSP_IMSC(pl022->virtbase));
+			writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
+			writew((readw(SSP_CR1(pl022->virtbase)) &
+				(~SSP_CR1_MASK_SSE)), SSP_CR1(pl022->virtbase));
+			msg->state = ERROR_STATE;
+			tasklet_schedule(&pl022->pump_transfers);
+			return IRQ_HANDLED;
+		}
+
+		readwriter(pl022);
+
+		if ((pl022->tx == pl022->tx_end) && (flag == 0)) {
+			flag = 1;
+			/* Disable Transmit interrupt */
+			writew(readw(SSP_IMSC(pl022->virtbase)) &
+			       (~SSP_IMSC_MASK_TXIM),
+			       SSP_IMSC(pl022->virtbase));
+		}
+		/*
+		 * Since all transactions must write as much as shall be read,
+		 * we can conclude the entire transaction once RX is complete.
+		 * At this point, all TX will always be finished.
+		 */
+		if (pl022->rx >= pl022->rx_end) {
+			writew(DISABLE_ALL_INTERRUPTS,
+			       SSP_IMSC(pl022->virtbase));
+			writew(CLEAR_ALL_INTERRUPTS, SSP_ICR(pl022->virtbase));
+			if (unlikely(pl022->rx > pl022->rx_end)) {
+				dev_warn(&pl022->adev->dev, "read %u surplus "
+					 "bytes (did you request an odd "
+					 "number of bytes on a 16bit bus?)\n",
+					 (u32) (pl022->rx - pl022->rx_end));
+			}
+			/* Update total bytes transfered */
+			msg->actual_length += pl022->cur_transfer->len;
+			if (pl022->cur_transfer->cs_change)
+				pl022->cur_chip->
+				    cs_control(SSP_CHIP_DESELECT);
+			/* Move to next transfer */
+			msg->state = next_transfer(pl022);
+			tasklet_schedule(&pl022->pump_transfers);
+			return IRQ_HANDLED;
+		}
+	}
+	return IRQ_HANDLED;
+}
+
+/**
+ * This sets up the pointers to memory for the next message to
+ * send out on the SPI bus.
+ */
+static int set_up_next_transfer(struct pl022 *pl022,
+				struct spi_transfer *transfer)
+{
+	int residue;
+
+	/* Sanity check the message for this bus width */
+	residue = pl022->cur_transfer->len % pl022->cur_chip->n_bytes;
+	if (unlikely(residue != 0)) {
+		dev_err(&pl022->adev->dev,
+			"message of %u bytes to transmit but the current "
+			"chip bus has a data width of %u bytes!\n",
+			pl022->cur_transfer->len,
+			pl022->cur_chip->n_bytes);
+		dev_err(&pl022->adev->dev, "skipping this message\n");
+		return -EIO;
+	}
+	pl022->tx = (void *)transfer->tx_buf;
+	pl022->tx_end = pl022->tx + pl022->cur_transfer->len;
+	pl022->rx = (void *)transfer->rx_buf;
+	pl022->rx_end = pl022->rx + pl022->cur_transfer->len;
+	pl022->write =
+	    pl022->tx ? pl022->cur_chip->write : NULL_WRITING;
+	pl022->read = pl022->rx ? pl022->cur_chip->read : NULL_READING;
+	return 0;
+}
+
+/**
+ * pump_transfers - Tasklet function which schedules next interrupt transfer
+ * when running in interrupt transfer mode.
+ * @data: SSP driver private data structure
+ *
+ */
+static void pump_transfers(unsigned long data)
+{
+	struct pl022 *pl022 = (struct pl022 *) data;
+	struct spi_message *message = NULL;
+	struct spi_transfer *transfer = NULL;
+	struct spi_transfer *previous = NULL;
+
+	/* Get current state information */
+	message = pl022->cur_msg;
+	transfer = pl022->cur_transfer;
+
+	/* Handle for abort */
+	if (message->state == ERROR_STATE) {
+		message->status = -EIO;
+		giveback(pl022);
+		return;
+	}
+
+	/* Handle end of message */
+	if (message->state == DONE_STATE) {
+		message->status = 0;
+		giveback(pl022);
+		return;
+	}
+
+	/* Delay if requested at end of transfer before CS change */
+	if (message->state == RUNNING_STATE) {
+		previous = list_entry(transfer->transfer_list.prev,
+					struct spi_transfer,
+					transfer_list);
+		if (previous->delay_usecs)
+			/*
+			 * FIXME: This runs in interrupt context.
+			 * Is this really smart?
+			 */
+			udelay(previous->delay_usecs);
+
+		/* Drop chip select only if cs_change is requested */
+		if (previous->cs_change)
+			pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+	} else {
+		/* START_STATE */
+		message->state = RUNNING_STATE;
+	}
+
+	if (set_up_next_transfer(pl022, transfer)) {
+		message->state = ERROR_STATE;
+		message->status = -EIO;
+		giveback(pl022);
+		return;
+	}
+	/* Flush the FIFOs and let's go! */
+	flush(pl022);
+	writew(ENABLE_ALL_INTERRUPTS, SSP_IMSC(pl022->virtbase));
+}
+
+/**
+ * NOT IMPLEMENTED
+ * configure_dma - It configures the DMA pipes for DMA transfers
+ * @data: SSP driver's private data structure
+ *
+ */
+static int configure_dma(void *data)
+{
+	struct pl022 *pl022 = data;
+	dev_dbg(&pl022->adev->dev, "configure DMA\n");
+	return -ENOTSUPP;
+}
+
+/**
+ * do_dma_transfer - It handles transfers of the current message
+ * if it is DMA xfer.
+ * NOT FULLY IMPLEMENTED
+ * @data: SSP driver's private data structure
+ */
+static void do_dma_transfer(void *data)
+{
+	struct pl022 *pl022 = data;
+
+	if (configure_dma(data)) {
+		dev_dbg(&pl022->adev->dev, "configuration of DMA Failed!\n");
+		goto err_config_dma;
+	}
+
+	/* TODO: Implememt DMA setup of pipes here */
+
+	/* Enable target chip, set up transfer */
+	pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+	if (set_up_next_transfer(pl022, pl022->cur_transfer)) {
+		/* Error path */
+		pl022->cur_msg->state = ERROR_STATE;
+		pl022->cur_msg->status = -EIO;
+		giveback(pl022);
+		return;
+	}
+	/* Enable SSP */
+	writew((readw(SSP_CR1(pl022->virtbase)) | SSP_CR1_MASK_SSE),
+	       SSP_CR1(pl022->virtbase));
+
+	/* TODO: Enable the DMA transfer here */
+	return;
+
+ err_config_dma:
+	pl022->cur_msg->state = ERROR_STATE;
+	pl022->cur_msg->status = -EIO;
+	giveback(pl022);
+	return;
+}
+
+static void do_interrupt_transfer(void *data)
+{
+	struct pl022 *pl022 = data;
+
+	/* Enable target chip */
+	pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+	if (set_up_next_transfer(pl022, pl022->cur_transfer)) {
+		/* Error path */
+		pl022->cur_msg->state = ERROR_STATE;
+		pl022->cur_msg->status = -EIO;
+		giveback(pl022);
+		return;
+	}
+	/* Enable SSP, turn on interrupts */
+	writew((readw(SSP_CR1(pl022->virtbase)) | SSP_CR1_MASK_SSE),
+	       SSP_CR1(pl022->virtbase));
+	writew(ENABLE_ALL_INTERRUPTS, SSP_IMSC(pl022->virtbase));
+}
+
+static void do_polling_transfer(void *data)
+{
+	struct pl022 *pl022 = data;
+	struct spi_message *message = NULL;
+	struct spi_transfer *transfer = NULL;
+	struct spi_transfer *previous = NULL;
+	struct chip_data *chip;
+
+	chip = pl022->cur_chip;
+	message = pl022->cur_msg;
+
+	while (message->state != DONE_STATE) {
+		/* Handle for abort */
+		if (message->state == ERROR_STATE)
+			break;
+		transfer = pl022->cur_transfer;
+
+		/* Delay if requested at end of transfer */
+		if (message->state == RUNNING_STATE) {
+			previous =
+			    list_entry(transfer->transfer_list.prev,
+				       struct spi_transfer, transfer_list);
+			if (previous->delay_usecs)
+				udelay(previous->delay_usecs);
+			if (previous->cs_change)
+				pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+		} else {
+			/* START_STATE */
+			message->state = RUNNING_STATE;
+			pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+		}
+
+		/* Configuration Changing Per Transfer */
+		if (set_up_next_transfer(pl022, transfer)) {
+			/* Error path */
+			message->state = ERROR_STATE;
+			break;
+		}
+		/* Flush FIFOs and enable SSP */
+		flush(pl022);
+		writew((readw(SSP_CR1(pl022->virtbase)) | SSP_CR1_MASK_SSE),
+		       SSP_CR1(pl022->virtbase));
+
+		dev_dbg(&pl022->adev->dev, "POLLING TRANSFER ONGOING ... \n");
+		/* FIXME: insert a timeout so we don't hang here indefinately */
+		while (pl022->tx < pl022->tx_end || pl022->rx < pl022->rx_end)
+			readwriter(pl022);
+
+		/* Update total byte transfered */
+		message->actual_length += pl022->cur_transfer->len;
+		if (pl022->cur_transfer->cs_change)
+			pl022->cur_chip->cs_control(SSP_CHIP_DESELECT);
+		/* Move to next transfer */
+		message->state = next_transfer(pl022);
+	}
+
+	/* Handle end of message */
+	if (message->state == DONE_STATE)
+		message->status = 0;
+	else
+		message->status = -EIO;
+
+	giveback(pl022);
+	return;
+}
+
+/**
+ * pump_messages - Workqueue function which processes spi message queue
+ * @data: pointer to private data of SSP driver
+ *
+ * This function checks if there is any spi message in the queue that
+ * needs processing and delegate control to appropriate function
+ * do_polling_transfer()/do_interrupt_transfer()/do_dma_transfer()
+ * based on the kind of the transfer
+ *
+ */
+static void pump_messages(struct work_struct *work)
+{
+	struct pl022 *pl022 =
+		container_of(work, struct pl022, pump_messages);
+	unsigned long flags;
+
+	/* Lock queue and check for queue work */
+	spin_lock_irqsave(&pl022->queue_lock, flags);
+	if (list_empty(&pl022->queue) || pl022->run == QUEUE_STOPPED) {
+		pl022->busy = 0;
+		spin_unlock_irqrestore(&pl022->queue_lock, flags);
+		return;
+	}
+	/* Make sure we are not already running a message */
+	if (pl022->cur_msg) {
+		spin_unlock_irqrestore(&pl022->queue_lock, flags);
+		return;
+	}
+	/* Extract head of queue */
+	pl022->cur_msg =
+	    list_entry(pl022->queue.next, struct spi_message, queue);
+
+	list_del_init(&pl022->cur_msg->queue);
+	pl022->busy = 1;
+	spin_unlock_irqrestore(&pl022->queue_lock, flags);
+
+	/* Initial message state */
+	pl022->cur_msg->state = START_STATE;
+	pl022->cur_transfer = list_entry(pl022->cur_msg->transfers.next,
+					    struct spi_transfer,
+					    transfer_list);
+
+	/* Setup the SPI using the per chip configuration */
+	pl022->cur_chip = spi_get_ctldata(pl022->cur_msg->spi);
+	/*
+	 * We enable the clock here, then the clock will be disabled when
+	 * giveback() is called in each method (poll/interrupt/DMA)
+	 */
+	clk_enable(pl022->clk);
+	restore_state(pl022);
+	flush(pl022);
+
+	if (pl022->cur_chip->xfer_type == POLLING_TRANSFER)
+		do_polling_transfer(pl022);
+	else if (pl022->cur_chip->xfer_type == INTERRUPT_TRANSFER)
+		do_interrupt_transfer(pl022);
+	else
+		do_dma_transfer(pl022);
+}
+
+
+static int __init init_queue(struct pl022 *pl022)
+{
+	INIT_LIST_HEAD(&pl022->queue);
+	spin_lock_init(&pl022->queue_lock);
+
+	pl022->run = QUEUE_STOPPED;
+	pl022->busy = 0;
+
+	tasklet_init(&pl022->pump_transfers,
+			pump_transfers,	(unsigned long)pl022);
+
+	INIT_WORK(&pl022->pump_messages, pump_messages);
+	pl022->workqueue = create_singlethread_workqueue(
+					dev_name(pl022->master->dev.parent));
+	if (pl022->workqueue == NULL)
+		return -EBUSY;
+
+	return 0;
+}
+
+
+static int start_queue(struct pl022 *pl022)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&pl022->queue_lock, flags);
+
+	if (pl022->run == QUEUE_RUNNING || pl022->busy) {
+		spin_unlock_irqrestore(&pl022->queue_lock, flags);
+		return -EBUSY;
+	}
+
+	pl022->run = QUEUE_RUNNING;
+	pl022->cur_msg = NULL;
+	pl022->cur_transfer = NULL;
+	pl022->cur_chip = NULL;
+	spin_unlock_irqrestore(&pl022->queue_lock, flags);
+
+	queue_work(pl022->workqueue, &pl022->pump_messages);
+
+	return 0;
+}
+
+
+static int stop_queue(struct pl022 *pl022)
+{
+	unsigned long flags;
+	unsigned limit = 500;
+	int status = 0;
+
+	spin_lock_irqsave(&pl022->queue_lock, flags);
+
+	/* This is a bit lame, but is optimized for the common execution path.
+	 * A wait_queue on the pl022->busy could be used, but then the common
+	 * execution path (pump_messages) would be required to call wake_up or
+	 * friends on every SPI message. Do this instead */
+	pl022->run = QUEUE_STOPPED;
+	while (!list_empty(&pl022->queue) && pl022->busy && limit--) {
+		spin_unlock_irqrestore(&pl022->queue_lock, flags);
+		msleep(10);
+		spin_lock_irqsave(&pl022->queue_lock, flags);
+	}
+
+	if (!list_empty(&pl022->queue) || pl022->busy)
+		status = -EBUSY;
+
+	spin_unlock_irqrestore(&pl022->queue_lock, flags);
+
+	return status;
+}
+
+static int destroy_queue(struct pl022 *pl022)
+{
+	int status;
+
+	status = stop_queue(pl022);
+	/* we are unloading the module or failing to load (only two calls
+	 * to this routine), and neither call can handle a return value.
+	 * However, destroy_workqueue calls flush_workqueue, and that will
+	 * block until all work is done.  If the reason that stop_queue
+	 * timed out is that the work will never finish, then it does no
+	 * good to call destroy_workqueue, so return anyway. */
+	if (status != 0)
+		return status;
+
+	destroy_workqueue(pl022->workqueue);
+
+	return 0;
+}
+
+static int verify_controller_parameters(struct pl022 *pl022,
+					struct pl022_config_chip *chip_info)
+{
+	if ((chip_info->lbm != LOOPBACK_ENABLED)
+	    && (chip_info->lbm != LOOPBACK_DISABLED)) {
+		dev_err(chip_info->dev,
+			"loopback Mode is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->iface < SSP_INTERFACE_MOTOROLA_SPI)
+	    || (chip_info->iface > SSP_INTERFACE_UNIDIRECTIONAL)) {
+		dev_err(chip_info->dev,
+			"interface is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->iface == SSP_INTERFACE_UNIDIRECTIONAL) &&
+	    (!pl022->vendor->unidir)) {
+		dev_err(chip_info->dev,
+			"unidirectional mode not supported in this "
+			"hardware version\n");
+		return -EINVAL;
+	}
+	if ((chip_info->hierarchy != SSP_MASTER)
+	    && (chip_info->hierarchy != SSP_SLAVE)) {
+		dev_err(chip_info->dev,
+			"hierarchy is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if (((chip_info->clk_freq).cpsdvsr < MIN_CPSDVR)
+	    || ((chip_info->clk_freq).cpsdvsr > MAX_CPSDVR)) {
+		dev_err(chip_info->dev,
+			"cpsdvsr is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->endian_rx != SSP_RX_MSB)
+	    && (chip_info->endian_rx != SSP_RX_LSB)) {
+		dev_err(chip_info->dev,
+			"Rx FIFO endianess is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->endian_tx != SSP_TX_MSB)
+	    && (chip_info->endian_tx != SSP_TX_LSB)) {
+		dev_err(chip_info->dev,
+			"Tx FIFO endianess is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->data_size < SSP_DATA_BITS_4)
+	    || (chip_info->data_size > SSP_DATA_BITS_32)) {
+		dev_err(chip_info->dev,
+			"DATA Size is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->com_mode != INTERRUPT_TRANSFER)
+	    && (chip_info->com_mode != DMA_TRANSFER)
+	    && (chip_info->com_mode != POLLING_TRANSFER)) {
+		dev_err(chip_info->dev,
+			"Communication mode is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->rx_lev_trig < SSP_RX_1_OR_MORE_ELEM)
+	    || (chip_info->rx_lev_trig > SSP_RX_32_OR_MORE_ELEM)) {
+		dev_err(chip_info->dev,
+			"Rx FIFO Trigger Level is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if ((chip_info->tx_lev_trig < SSP_TX_1_OR_MORE_EMPTY_LOC)
+	    || (chip_info->tx_lev_trig > SSP_TX_32_OR_MORE_EMPTY_LOC)) {
+		dev_err(chip_info->dev,
+			"Tx FIFO Trigger Level is configured incorrectly\n");
+		return -EINVAL;
+	}
+	if (chip_info->iface == SSP_INTERFACE_MOTOROLA_SPI) {
+		if ((chip_info->clk_phase != SSP_CLK_RISING_EDGE)
+		    && (chip_info->clk_phase != SSP_CLK_FALLING_EDGE)) {
+			dev_err(chip_info->dev,
+				"Clock Phase is configured incorrectly\n");
+			return -EINVAL;
+		}
+		if ((chip_info->clk_pol != SSP_CLK_POL_IDLE_LOW)
+		    && (chip_info->clk_pol != SSP_CLK_POL_IDLE_HIGH)) {
+			dev_err(chip_info->dev,
+				"Clock Polarity is configured incorrectly\n");
+			return -EINVAL;
+		}
+	}
+	if (chip_info->iface == SSP_INTERFACE_NATIONAL_MICROWIRE) {
+		if ((chip_info->ctrl_len < SSP_BITS_4)
+		    || (chip_info->ctrl_len > SSP_BITS_32)) {
+			dev_err(chip_info->dev,
+				"CTRL LEN is configured incorrectly\n");
+			return -EINVAL;
+		}
+		if ((chip_info->wait_state != SSP_MWIRE_WAIT_ZERO)
+		    && (chip_info->wait_state != SSP_MWIRE_WAIT_ONE)) {
+			dev_err(chip_info->dev,
+				"Wait State is configured incorrectly\n");
+			return -EINVAL;
+		}
+		if ((chip_info->duplex != SSP_MICROWIRE_CHANNEL_FULL_DUPLEX)
+		    && (chip_info->duplex !=
+			SSP_MICROWIRE_CHANNEL_HALF_DUPLEX)) {
+			dev_err(chip_info->dev,
+				"DUPLEX is configured incorrectly\n");
+			return -EINVAL;
+		}
+	}
+	if (chip_info->cs_control == NULL) {
+		dev_warn(chip_info->dev,
+			"Chip Select Function is NULL for this chip\n");
+		chip_info->cs_control = null_cs_control;
+	}
+	return 0;
+}
+
+/**
+ * pl022_transfer - transfer function registered to SPI master framework
+ * @spi: spi device which is requesting transfer
+ * @msg: spi message which is to handled is queued to driver queue
+ *
+ * This function is registered to the SPI framework for this SPI master
+ * controller. It will queue the spi_message in the queue of driver if
+ * the queue is not stopped and return.
+ */
+static int pl022_transfer(struct spi_device *spi, struct spi_message *msg)
+{
+	struct pl022 *pl022 = spi_master_get_devdata(spi->master);
+	unsigned long flags;
+
+	spin_lock_irqsave(&pl022->queue_lock, flags);
+
+	if (pl022->run == QUEUE_STOPPED) {
+		spin_unlock_irqrestore(&pl022->queue_lock, flags);
+		return -ESHUTDOWN;
+	}
+	msg->actual_length = 0;
+	msg->status = -EINPROGRESS;
+	msg->state = START_STATE;
+
+	list_add_tail(&msg->queue, &pl022->queue);
+	if (pl022->run == QUEUE_RUNNING && !pl022->busy)
+		queue_work(pl022->workqueue, &pl022->pump_messages);
+
+	spin_unlock_irqrestore(&pl022->queue_lock, flags);
+	return 0;
+}
+
+static int calculate_effective_freq(struct pl022 *pl022,
+				    int freq,
+				    struct ssp_clock_params *clk_freq)
+{
+	/* Lets calculate the frequency parameters */
+	u16 cpsdvsr = 2;
+	u16 scr = 0;
+	bool freq_found = false;
+	u32 rate;
+	u32 max_tclk;
+	u32 min_tclk;
+
+	rate = clk_get_rate(pl022->clk);
+	/* cpsdvscr = 2 & scr 0 */
+	max_tclk = (rate / (MIN_CPSDVR * (1 + MIN_SCR)));
+	/* cpsdvsr = 254 & scr = 255 */
+	min_tclk = (rate / (MAX_CPSDVR * (1 + MAX_SCR)));
+
+	if ((freq <= max_tclk) && (freq >= min_tclk)) {
+		while (cpsdvsr <= MAX_CPSDVR && !freq_found) {
+			while (scr <= MAX_SCR && !freq_found) {
+				if ((rate /
+				     (cpsdvsr * (1 + scr))) > freq)
+					scr += 1;
+				else {
+					/*
+					 * This bool is made true when
+					 * effective frequency >=
+					 * target frequency is found
+					 */
+					freq_found = true;
+					if ((rate /
+					     (cpsdvsr * (1 + scr))) != freq) {
+						if (scr == MIN_SCR) {
+							cpsdvsr -= 2;
+							scr = MAX_SCR;
+						} else
+							scr -= 1;
+					}
+				}
+			}
+			if (!freq_found) {
+				cpsdvsr += 2;
+				scr = MIN_SCR;
+			}
+		}
+		if (cpsdvsr != 0) {
+			dev_dbg(&pl022->adev->dev,
+				"SSP Effective Frequency is %u\n",
+				(rate / (cpsdvsr * (1 + scr))));
+			clk_freq->cpsdvsr = (u8) (cpsdvsr & 0xFF);
+			clk_freq->scr = (u8) (scr & 0xFF);
+			dev_dbg(&pl022->adev->dev,
+				"SSP cpsdvsr = %d, scr = %d\n",
+				clk_freq->cpsdvsr, clk_freq->scr);
+		}
+	} else {
+		dev_err(&pl022->adev->dev,
+			"controller data is incorrect: out of range frequency");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * NOT IMPLEMENTED
+ * process_dma_info - Processes the DMA info provided by client drivers
+ * @chip_info: chip info provided by client device
+ * @chip: Runtime state maintained by the SSP controller for each spi device
+ *
+ * This function processes and stores DMA config provided by client driver
+ * into the runtime state maintained by the SSP controller driver
+ */
+static int process_dma_info(struct pl022_config_chip *chip_info,
+			    struct chip_data *chip)
+{
+	dev_err(chip_info->dev,
+		"cannot process DMA info, DMA not implemented!\n");
+	return -ENOTSUPP;
+}
+
+/**
+ * pl022_setup - setup function registered to SPI master framework
+ * @spi: spi device which is requesting setup
+ *
+ * This function is registered to the SPI framework for this SPI master
+ * controller. If it is the first time when setup is called by this device,
+ * this function will initialize the runtime state for this chip and save
+ * the same in the device structure. Else it will update the runtime info
+ * with the updated chip info. Nothing is really being written to the
+ * controller hardware here, that is not done until the actual transfer
+ * commence.
+ */
+
+/* FIXME: JUST GUESSING the spi->mode bits understood by this driver */
+#define MODEBITS	(SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
+			| SPI_LSB_FIRST | SPI_LOOP)
+
+static int pl022_setup(struct spi_device *spi)
+{
+	struct pl022_config_chip *chip_info;
+	struct chip_data *chip;
+	int status = 0;
+	struct pl022 *pl022 = spi_master_get_devdata(spi->master);
+
+	if (spi->mode & ~MODEBITS) {
+		dev_dbg(&spi->dev, "unsupported mode bits %x\n",
+			spi->mode & ~MODEBITS);
+		return -EINVAL;
+	}
+
+	if (!spi->max_speed_hz)
+		return -EINVAL;
+
+	/* Get controller_state if one is supplied */
+	chip = spi_get_ctldata(spi);
+
+	if (chip == NULL) {
+		chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
+		if (!chip) {
+			dev_err(&spi->dev,
+				"cannot allocate controller state\n");
+			return -ENOMEM;
+		}
+		dev_dbg(&spi->dev,
+			"allocated memory for controller's runtime state\n");
+	}
+
+	/* Get controller data if one is supplied */
+	chip_info = spi->controller_data;
+
+	if (chip_info == NULL) {
+		/* spi_board_info.controller_data not is supplied */
+		dev_dbg(&spi->dev,
+			"using default controller_data settings\n");
+
+		chip_info =
+			kzalloc(sizeof(struct pl022_config_chip), GFP_KERNEL);
+
+		if (!chip_info) {
+			dev_err(&spi->dev,
+				"cannot allocate controller data\n");
+			status = -ENOMEM;
+			goto err_first_setup;
+		}
+
+		dev_dbg(&spi->dev, "allocated memory for controller data\n");
+
+		/* Pointer back to the SPI device */
+		chip_info->dev = &spi->dev;
+		/*
+		 * Set controller data default values:
+		 * Polling is supported by default
+		 */
+		chip_info->lbm = LOOPBACK_DISABLED;
+		chip_info->com_mode = POLLING_TRANSFER;
+		chip_info->iface = SSP_INTERFACE_MOTOROLA_SPI;
+		chip_info->hierarchy = SSP_SLAVE;
+		chip_info->slave_tx_disable = DO_NOT_DRIVE_TX;
+		chip_info->endian_tx = SSP_TX_LSB;
+		chip_info->endian_rx = SSP_RX_LSB;
+		chip_info->data_size = SSP_DATA_BITS_12;
+		chip_info->rx_lev_trig = SSP_RX_1_OR_MORE_ELEM;
+		chip_info->tx_lev_trig = SSP_TX_1_OR_MORE_EMPTY_LOC;
+		chip_info->clk_phase = SSP_CLK_FALLING_EDGE;
+		chip_info->clk_pol = SSP_CLK_POL_IDLE_LOW;
+		chip_info->ctrl_len = SSP_BITS_8;
+		chip_info->wait_state = SSP_MWIRE_WAIT_ZERO;
+		chip_info->duplex = SSP_MICROWIRE_CHANNEL_FULL_DUPLEX;
+		chip_info->cs_control = null_cs_control;
+	} else {
+		dev_dbg(&spi->dev,
+			"using user supplied controller_data settings\n");
+	}
+
+	/*
+	 * We can override with custom divisors, else we use the board
+	 * frequency setting
+	 */
+	if ((0 == chip_info->clk_freq.cpsdvsr)
+	    && (0 == chip_info->clk_freq.scr)) {
+		status = calculate_effective_freq(pl022,
+						  spi->max_speed_hz,
+						  &chip_info->clk_freq);
+		if (status < 0)
+			goto err_config_params;
+	} else {
+		if ((chip_info->clk_freq.cpsdvsr % 2) != 0)
+			chip_info->clk_freq.cpsdvsr =
+				chip_info->clk_freq.cpsdvsr - 1;
+	}
+	status = verify_controller_parameters(pl022, chip_info);
+	if (status) {
+		dev_err(&spi->dev, "controller data is incorrect");
+		goto err_config_params;
+	}
+	/* Now set controller state based on controller data */
+	chip->xfer_type = chip_info->com_mode;
+	chip->cs_control = chip_info->cs_control;
+
+	if (chip_info->data_size <= 8) {
+		dev_dbg(&spi->dev, "1 <= n <=8 bits per word\n");
+		chip->n_bytes = 1;
+		chip->read = U8_READING;
+		chip->write = U8_WRITING;
+	} else if (chip_info->data_size <= 16) {
+		dev_dbg(&spi->dev, "9 <= n <= 16 bits per word\n");
+		chip->n_bytes = 2;
+		chip->read = U16_READING;
+		chip->write = U16_WRITING;
+	} else {
+		if (pl022->vendor->max_bpw >= 32) {
+			dev_dbg(&spi->dev, "17 <= n <= 32 bits per word\n");
+			chip->n_bytes = 4;
+			chip->read = U32_READING;
+			chip->write = U32_WRITING;
+		} else {
+			dev_err(&spi->dev,
+				"illegal data size for this controller!\n");
+			dev_err(&spi->dev,
+				"a standard pl022 can only handle "
+				"1 <= n <= 16 bit words\n");
+			goto err_config_params;
+		}
+	}
+
+	/* Now Initialize all register settings required for this chip */
+	chip->cr0 = 0;
+	chip->cr1 = 0;
+	chip->dmacr = 0;
+	chip->cpsr = 0;
+	if ((chip_info->com_mode == DMA_TRANSFER)
+	    && ((pl022->master_info)->enable_dma)) {
+		chip->enable_dma = 1;
+		dev_dbg(&spi->dev, "DMA mode set in controller state\n");
+		status = process_dma_info(chip_info, chip);
+		if (status < 0)
+			goto err_config_params;
+		SSP_WRITE_BITS(chip->dmacr, SSP_DMA_ENABLED,
+			       SSP_DMACR_MASK_RXDMAE, 0);
+		SSP_WRITE_BITS(chip->dmacr, SSP_DMA_ENABLED,
+			       SSP_DMACR_MASK_TXDMAE, 1);
+	} else {
+		chip->enable_dma = 0;
+		dev_dbg(&spi->dev, "DMA mode NOT set in controller state\n");
+		SSP_WRITE_BITS(chip->dmacr, SSP_DMA_DISABLED,
+			       SSP_DMACR_MASK_RXDMAE, 0);
+		SSP_WRITE_BITS(chip->dmacr, SSP_DMA_DISABLED,
+			       SSP_DMACR_MASK_TXDMAE, 1);
+	}
+
+	chip->cpsr = chip_info->clk_freq.cpsdvsr;
+
+	SSP_WRITE_BITS(chip->cr0, chip_info->data_size, SSP_CR0_MASK_DSS, 0);
+	SSP_WRITE_BITS(chip->cr0, chip_info->duplex, SSP_CR0_MASK_HALFDUP, 5);
+	SSP_WRITE_BITS(chip->cr0, chip_info->clk_pol, SSP_CR0_MASK_SPO, 6);
+	SSP_WRITE_BITS(chip->cr0, chip_info->clk_phase, SSP_CR0_MASK_SPH, 7);
+	SSP_WRITE_BITS(chip->cr0, chip_info->clk_freq.scr, SSP_CR0_MASK_SCR, 8);
+	SSP_WRITE_BITS(chip->cr0, chip_info->ctrl_len, SSP_CR0_MASK_CSS, 16);
+	SSP_WRITE_BITS(chip->cr0, chip_info->iface, SSP_CR0_MASK_FRF, 21);
+	SSP_WRITE_BITS(chip->cr1, chip_info->lbm, SSP_CR1_MASK_LBM, 0);
+	SSP_WRITE_BITS(chip->cr1, SSP_DISABLED, SSP_CR1_MASK_SSE, 1);
+	SSP_WRITE_BITS(chip->cr1, chip_info->hierarchy, SSP_CR1_MASK_MS, 2);
+	SSP_WRITE_BITS(chip->cr1, chip_info->slave_tx_disable, SSP_CR1_MASK_SOD, 3);
+	SSP_WRITE_BITS(chip->cr1, chip_info->endian_rx, SSP_CR1_MASK_RENDN, 4);
+	SSP_WRITE_BITS(chip->cr1, chip_info->endian_tx, SSP_CR1_MASK_TENDN, 5);
+	SSP_WRITE_BITS(chip->cr1, chip_info->wait_state, SSP_CR1_MASK_MWAIT, 6);
+	SSP_WRITE_BITS(chip->cr1, chip_info->rx_lev_trig, SSP_CR1_MASK_RXIFLSEL, 7);
+	SSP_WRITE_BITS(chip->cr1, chip_info->tx_lev_trig, SSP_CR1_MASK_TXIFLSEL, 10);
+
+	/* Save controller_state */
+	spi_set_ctldata(spi, chip);
+	return status;
+ err_config_params:
+ err_first_setup:
+	kfree(chip);
+	return status;
+}
+
+/**
+ * pl022_cleanup - cleanup function registered to SPI master framework
+ * @spi: spi device which is requesting cleanup
+ *
+ * This function is registered to the SPI framework for this SPI master
+ * controller. It will free the runtime state of chip.
+ */
+static void pl022_cleanup(struct spi_device *spi)
+{
+	struct chip_data *chip = spi_get_ctldata(spi);
+
+	kfree(chip);
+}
+
+
+static int __init
+pl022_probe(struct amba_device *adev, struct amba_id *id)
+{
+	struct device *dev = &adev->dev;
+	struct pl022_ssp_controller *platform_info = adev->dev.platform_data;
+	struct spi_master *master;
+	struct pl022 *pl022 = NULL;	/*Data for this driver */
+	int status = 0;
+
+	dev_info(&adev->dev,
+		 "ARM PL022 driver, device ID: 0x%08x\n", adev->periphid);
+	if (platform_info == NULL) {
+		dev_err(&adev->dev, "probe - no platform data supplied\n");
+		status = -ENODEV;
+		goto err_no_pdata;
+	}
+
+	/* Allocate master with space for data */
+	master = spi_alloc_master(dev, sizeof(struct pl022));
+	if (master == NULL) {
+		dev_err(&adev->dev, "probe - cannot alloc SPI master\n");
+		status = -ENOMEM;
+		goto err_no_master;
+	}
+
+	pl022 = spi_master_get_devdata(master);
+	pl022->master = master;
+	pl022->master_info = platform_info;
+	pl022->adev = adev;
+	pl022->vendor = id->data;
+
+	/*
+	 * Bus Number Which has been Assigned to this SSP controller
+	 * on this board
+	 */
+	master->bus_num = platform_info->bus_id;
+	master->num_chipselect = platform_info->num_chipselect;
+	master->cleanup = pl022_cleanup;
+	master->setup = pl022_setup;
+	master->transfer = pl022_transfer;
+
+	dev_dbg(&adev->dev, "BUSNO: %d\n", master->bus_num);
+
+	/*Get Hold of Device Register Area... */
+	if (request_mem_region(adev->res.start, SZ_4K, "pl022 I/O Area")
+	    == NULL) {
+		status = -EBUSY;
+		goto err_no_ioregion;
+	}
+
+	pl022->virtbase = ioremap(adev->res.start, SZ_4K);
+	if (pl022->virtbase == NULL) {
+		status = -ENOMEM;
+		goto err_no_ioremap;
+	}
+	printk(KERN_INFO "pl022: mapped registers from 0x%08x to %p\n",
+	       adev->res.start, pl022->virtbase);
+
+	pl022->clk = clk_get(&adev->dev, NULL);
+	if (IS_ERR(pl022->clk)) {
+		status = PTR_ERR(pl022->clk);
+		dev_err(&adev->dev, "could not retrieve SSP/SPI bus clock\n");
+		goto err_no_clk;
+	}
+
+	/* Disable SSP */
+	clk_enable(pl022->clk);
+	writew((readw(SSP_CR1(pl022->virtbase)) & (~SSP_CR1_MASK_SSE)),
+	       SSP_CR1(pl022->virtbase));
+	load_ssp_default_config(pl022);
+	clk_disable(pl022->clk);
+
+	status = request_irq(adev->irq[0], pl022_interrupt_handler, 0, "pl022",
+			     pl022);
+	if (status < 0) {
+		dev_err(&adev->dev, "probe - cannot get IRQ (%d)\n", status);
+		goto err_no_irq;
+	}
+	/* Initialize and start queue */
+	status = init_queue(pl022);
+	if (status != 0) {
+		dev_err(&adev->dev, "probe - problem initializing queue\n");
+		goto err_init_queue;
+	}
+	status = start_queue(pl022);
+	if (status != 0) {
+		dev_err(&adev->dev, "probe - problem starting queue\n");
+		goto err_start_queue;
+	}
+	/* Register with the SPI framework */
+	amba_set_drvdata(adev, pl022);
+	status = spi_register_master(master);
+	if (status != 0) {
+		dev_err(&adev->dev,
+			"probe - problem registering spi master\n");
+		goto err_spi_register;
+	}
+	dev_dbg(dev, "probe succeded\n");
+	return 0;
+
+ err_spi_register:
+ err_start_queue:
+ err_init_queue:
+	destroy_queue(pl022);
+	free_irq(adev->irq[0], pl022);
+ err_no_irq:
+	clk_put(pl022->clk);
+ err_no_clk:
+	iounmap(pl022->virtbase);
+ err_no_ioremap:
+	release_mem_region(adev->res.start, SZ_4K);
+ err_no_ioregion:
+	spi_master_put(master);
+ err_no_master:
+ err_no_pdata:
+	return status;
+}
+
+static int __exit
+pl022_remove(struct amba_device *adev)
+{
+	struct pl022 *pl022 = amba_get_drvdata(adev);
+	int status = 0;
+	if (!pl022)
+		return 0;
+
+	/* Remove the queue */
+	status = destroy_queue(pl022);
+	if (status != 0) {
+		dev_err(&adev->dev,
+			"queue remove failed (%d)\n", status);
+		return status;
+	}
+	load_ssp_default_config(pl022);
+	free_irq(adev->irq[0], pl022);
+	clk_disable(pl022->clk);
+	clk_put(pl022->clk);
+	iounmap(pl022->virtbase);
+	release_mem_region(adev->res.start, SZ_4K);
+	tasklet_disable(&pl022->pump_transfers);
+	spi_unregister_master(pl022->master);
+	spi_master_put(pl022->master);
+	amba_set_drvdata(adev, NULL);
+	dev_dbg(&adev->dev, "remove succeded\n");
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int suspend_devices(struct device *dev, void *pm_message)
+{
+	pm_message_t *state = pm_message;
+
+	if (dev->power.power_state.event != state->event) {
+		dev_warn(dev, "pm state does not match request\n");
+		return -EPERM;
+	}
+	return 0;
+}
+
+static int pl022_suspend(struct amba_device *adev, pm_message_t state)
+{
+	struct pl022 *pl022 = amba_get_drvdata(adev);
+	int status = 0;
+
+	/* Check all children (connected SPI chips) for current power state */
+	status = device_for_each_child(&adev->dev, &state, suspend_devices);
+	if (status) {
+		dev_warn(&adev->dev,
+			 "children (SPI chips) not in the same power "
+			 "state, suspend aborted\n");
+		return status;
+	}
+
+	status = stop_queue(pl022);
+	if (status) {
+		dev_warn(&adev->dev, "suspend cannot stop queue\n");
+		return status;
+	}
+
+	clk_enable(pl022->clk);
+	load_ssp_default_config(pl022);
+	clk_disable(pl022->clk);
+	dev_dbg(&adev->dev, "suspended\n");
+	return 0;
+}
+
+static int pl022_resume(struct amba_device *adev)
+{
+	struct pl022 *pl022 = amba_get_drvdata(adev);
+	int status = 0;
+
+	/* Start the queue running */
+	status = start_queue(pl022);
+	if (status)
+		dev_err(&adev->dev, "problem starting queue (%d)\n", status);
+	else
+		dev_dbg(&adev->dev, "resumed\n");
+
+	return status;
+}
+
+#else
+#define pl022_suspend NULL
+#define pl022_resume NULL
+#endif				/* CONFIG_PM */
+
+static struct vendor_data vendor_arm = {
+	.fifodepth = 8,
+	.max_bpw = 16,
+	.unidir = false,
+};
+
+
+static struct vendor_data vendor_st = {
+	.fifodepth = 32,
+	.max_bpw = 32,
+	.unidir = false,
+};
+
+static struct amba_id pl022_ids[] __initdata = {
+	{
+		/*
+		 * ARM PL022 variant, this has a 16bit wide
+		 * and 8 locations deep TX/RX FIFO
+		 */
+		.id	= 0x00041022,
+		.mask	= 0x000fffff,
+		.data	= &vendor_arm,
+	},
+	{
+		/*
+		 * ST Micro derivative, this has 32bit wide
+		 * and 32 locations deep TX/RX FIFO
+		 */
+		.id	= 0x00108022,
+		.mask	= 0xffffffff,
+		.data	= &vendor_st,
+	},
+	{ 0, 0 },
+};
+
+static struct amba_driver pl022_driver = {
+	.drv = {
+		.name	= "ssp-pl022",
+	},
+	.id_table	= pl022_ids,
+	.probe		= pl022_probe,
+	.remove		= __exit_p(pl022_remove),
+	.suspend        = pl022_suspend,
+	.resume         = pl022_resume,
+};
+
+
+static int __init pl022_init(void)
+{
+	return amba_driver_register(&pl022_driver);
+}
+
+module_init(pl022_init);
+
+static void __exit pl022_exit(void)
+{
+	amba_driver_unregister(&pl022_driver);
+}
+
+module_exit(pl022_exit);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij-IzeFyvvaP7pWk0Htik3J/w@public.gmane.org>");
+MODULE_DESCRIPTION("PL022 SSP Controller Driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/amba/pl022.h b/include/linux/amba/pl022.h
new file mode 100644
index 0000000..dcad0ff
--- /dev/null
+++ b/include/linux/amba/pl022.h
@@ -0,0 +1,264 @@
+/*
+ * include/linux/amba/pl022.h
+ *
+ * Copyright (C) 2008-2009 ST-Ericsson AB
+ * Copyright (C) 2006 STMicroelectronics Pvt. Ltd.
+ *
+ * Author: Linus Walleij <linus.walleij-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org>
+ *
+ * Initial version inspired by:
+ *	linux-2.6.17-rc3-mm1/drivers/spi/pxa2xx_spi.c
+ * Initial adoption to PL022 by:
+ *      Sachin Verma <sachin.verma-qxv4g6HH51o@public.gmane.org>
+ *
+ * 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.
+ */
+
+#ifndef _SSP_PL022_H
+#define _SSP_PL022_H
+
+#include <linux/device.h>
+
+/**
+ * whether SSP is in loopback mode or not
+ */
+enum ssp_loopback {
+	LOOPBACK_DISABLED,
+	LOOPBACK_ENABLED
+};
+
+/**
+ * enum ssp_interface - interfaces allowed for this SSP Controller
+ * @SSP_INTERFACE_MOTOROLA_SPI: Motorola Interface
+ * @SSP_INTERFACE_TI_SYNC_SERIAL: Texas Instrument Synchronous Serial
+ * interface
+ * @SSP_INTERFACE_NATIONAL_MICROWIRE: National Semiconductor Microwire
+ * interface
+ * @SSP_INTERFACE_UNIDIRECTIONAL: Unidirectional interface (STn8810
+ * &STn8815 only)
+ */
+enum ssp_interface {
+	SSP_INTERFACE_MOTOROLA_SPI,
+	SSP_INTERFACE_TI_SYNC_SERIAL,
+	SSP_INTERFACE_NATIONAL_MICROWIRE,
+	SSP_INTERFACE_UNIDIRECTIONAL
+};
+
+/**
+ * enum ssp_hierarchy - whether SSP is configured as Master or Slave
+ */
+enum ssp_hierarchy {
+	SSP_MASTER,
+	SSP_SLAVE
+};
+
+/**
+ * enum ssp_clock_params - clock parameters, to set SSP clock at a
+ * desired freq
+ */
+struct ssp_clock_params {
+	u8 cpsdvsr; /* value from 2 to 254 (even only!) */
+	u8 scr;	    /* value from 0 to 255 */
+};
+
+/**
+ * enum ssp_rx_endian - endianess of Rx FIFO Data
+ */
+enum ssp_rx_endian {
+	SSP_RX_MSB,
+	SSP_RX_LSB
+};
+
+/**
+ * enum ssp_tx_endian - endianess of Tx FIFO Data
+ */
+enum ssp_tx_endian {
+	SSP_TX_MSB,
+	SSP_TX_LSB
+};
+
+/**
+ * enum ssp_data_size - number of bits in one data element
+ */
+enum ssp_data_size {
+	SSP_DATA_BITS_4 = 0x03, SSP_DATA_BITS_5, SSP_DATA_BITS_6,
+	SSP_DATA_BITS_7, SSP_DATA_BITS_8, SSP_DATA_BITS_9,
+	SSP_DATA_BITS_10, SSP_DATA_BITS_11, SSP_DATA_BITS_12,
+	SSP_DATA_BITS_13, SSP_DATA_BITS_14, SSP_DATA_BITS_15,
+	SSP_DATA_BITS_16, SSP_DATA_BITS_17, SSP_DATA_BITS_18,
+	SSP_DATA_BITS_19, SSP_DATA_BITS_20, SSP_DATA_BITS_21,
+	SSP_DATA_BITS_22, SSP_DATA_BITS_23, SSP_DATA_BITS_24,
+	SSP_DATA_BITS_25, SSP_DATA_BITS_26, SSP_DATA_BITS_27,
+	SSP_DATA_BITS_28, SSP_DATA_BITS_29, SSP_DATA_BITS_30,
+	SSP_DATA_BITS_31, SSP_DATA_BITS_32
+};
+
+/**
+ * enum ssp_mode - SSP mode of operation (Communication modes)
+ */
+enum ssp_mode {
+	INTERRUPT_TRANSFER,
+	POLLING_TRANSFER,
+	DMA_TRANSFER
+};
+
+/**
+ * enum ssp_rx_level_trig - receive FIFO watermark level which triggers
+ * IT: Interrupt fires when _N_ or more elements in RX FIFO.
+ */
+enum ssp_rx_level_trig {
+	SSP_RX_1_OR_MORE_ELEM,
+	SSP_RX_4_OR_MORE_ELEM,
+	SSP_RX_8_OR_MORE_ELEM,
+	SSP_RX_16_OR_MORE_ELEM,
+	SSP_RX_32_OR_MORE_ELEM
+};
+
+/**
+ * Transmit FIFO watermark level which triggers (IT Interrupt fires
+ * when _N_ or more empty locations in TX FIFO)
+ */
+enum ssp_tx_level_trig {
+	SSP_TX_1_OR_MORE_EMPTY_LOC,
+	SSP_TX_4_OR_MORE_EMPTY_LOC,
+	SSP_TX_8_OR_MORE_EMPTY_LOC,
+	SSP_TX_16_OR_MORE_EMPTY_LOC,
+	SSP_TX_32_OR_MORE_EMPTY_LOC
+};
+
+/**
+ * enum SPI Clock Phase - clock phase (Motorola SPI interface only)
+ * @SSP_CLK_RISING_EDGE: Receive data on rising edge
+ * @SSP_CLK_FALLING_EDGE: Receive data on falling edge
+ */
+enum ssp_spi_clk_phase {
+	SSP_CLK_RISING_EDGE,
+	SSP_CLK_FALLING_EDGE
+};
+
+/**
+ * enum SPI Clock Polarity - clock polarity (Motorola SPI interface only)
+ * @SSP_CLK_POL_IDLE_LOW: Low inactive level
+ * @SSP_CLK_POL_IDLE_HIGH: High inactive level
+ */
+enum ssp_spi_clk_pol {
+	SSP_CLK_POL_IDLE_LOW,
+	SSP_CLK_POL_IDLE_HIGH
+};
+
+/**
+ * Microwire Conrol Lengths Command size in microwire format
+ */
+enum ssp_microwire_ctrl_len {
+	SSP_BITS_4 = 0x03, SSP_BITS_5, SSP_BITS_6,
+	SSP_BITS_7, SSP_BITS_8, SSP_BITS_9,
+	SSP_BITS_10, SSP_BITS_11, SSP_BITS_12,
+	SSP_BITS_13, SSP_BITS_14, SSP_BITS_15,
+	SSP_BITS_16, SSP_BITS_17, SSP_BITS_18,
+	SSP_BITS_19, SSP_BITS_20, SSP_BITS_21,
+	SSP_BITS_22, SSP_BITS_23, SSP_BITS_24,
+	SSP_BITS_25, SSP_BITS_26, SSP_BITS_27,
+	SSP_BITS_28, SSP_BITS_29, SSP_BITS_30,
+	SSP_BITS_31, SSP_BITS_32
+};
+
+/**
+ * enum Microwire Wait State
+ * @SSP_MWIRE_WAIT_ZERO: No wait state inserted after last command bit
+ * @SSP_MWIRE_WAIT_ONE: One wait state inserted after last command bit
+ */
+enum ssp_microwire_wait_state {
+	SSP_MWIRE_WAIT_ZERO,
+	SSP_MWIRE_WAIT_ONE
+};
+
+/**
+ * enum Microwire - whether Full/Half Duplex
+ * @SSP_MICROWIRE_CHANNEL_FULL_DUPLEX: SSPTXD becomes bi-directional,
+ *     SSPRXD not used
+ * @SSP_MICROWIRE_CHANNEL_HALF_DUPLEX: SSPTXD is an output, SSPRXD is
+ *     an input.
+ */
+enum ssp_duplex {
+	SSP_MICROWIRE_CHANNEL_FULL_DUPLEX,
+	SSP_MICROWIRE_CHANNEL_HALF_DUPLEX
+};
+
+/**
+ * CHIP select/deselect commands
+ */
+enum ssp_chip_select {
+	SSP_CHIP_SELECT,
+	SSP_CHIP_DESELECT
+};
+
+
+/**
+ * struct pl022_ssp_master - device.platform_data for SPI controller devices.
+ * @num_chipselect: chipselects are used to distinguish individual
+ *     SPI slaves, and are numbered from zero to num_chipselects - 1.
+ *     each slave has a chipselect signal, but it's common that not
+ *     every chipselect is connected to a slave.
+ * @enable_dma: if true enables DMA driven transfers.
+ */
+struct pl022_ssp_controller {
+	u16 bus_id;
+	u8 num_chipselect;
+	u8 enable_dma:1;
+};
+
+/**
+ * struct ssp_config_chip - spi_board_info.controller_data for SPI
+ * slave devices, copied to spi_device.controller_data.
+ *
+ * @lbm: used for test purpose to internally connect RX and TX
+ * @iface: Interface type(Motorola, TI, Microwire, Universal)
+ * @hierarchy: sets whether interface is master or slave
+ * @slave_tx_disable: SSPTXD is disconnected (in slave mode only)
+ * @clk_freq: Tune freq parameters of SSP(when in master mode)
+ * @endian_rx: Endianess of Data in Rx FIFO
+ * @endian_tx: Endianess of Data in Tx FIFO
+ * @data_size: Width of data element(4 to 32 bits)
+ * @com_mode: communication mode: polling, Interrupt or DMA
+ * @rx_lev_trig: Rx FIFO watermark level (for IT & DMA mode)
+ * @tx_lev_trig: Tx FIFO watermark level (for IT & DMA mode)
+ * @clk_phase: Motorola SPI interface Clock phase
+ * @clk_pol: Motorola SPI interface Clock polarity
+ * @ctrl_len: Microwire interface: Control length
+ * @wait_state: Microwire interface: Wait state
+ * @duplex: Microwire interface: Full/Half duplex
+ * @cs_control: function pointer to board-specific function to
+ * assert/deassert I/O port to control HW generation of devices chip-select.
+ * @dma_xfer_type: Type of DMA xfer (Mem-to-periph or Periph-to-Periph)
+ * @dma_config: DMA configuration for SSP controller and peripheral
+ */
+struct pl022_config_chip {
+	struct device *dev;
+	enum ssp_loopback lbm;
+	enum ssp_interface iface;
+	enum ssp_hierarchy hierarchy;
+	bool slave_tx_disable;
+	struct ssp_clock_params clk_freq;
+	enum ssp_rx_endian endian_rx;
+	enum ssp_tx_endian endian_tx;
+	enum ssp_data_size data_size;
+	enum ssp_mode com_mode;
+	enum ssp_rx_level_trig rx_lev_trig;
+	enum ssp_tx_level_trig tx_lev_trig;
+	enum ssp_spi_clk_phase clk_phase;
+	enum ssp_spi_clk_pol clk_pol;
+	enum ssp_microwire_ctrl_len ctrl_len;
+	enum ssp_microwire_wait_state wait_state;
+	enum ssp_duplex duplex;
+	void (*cs_control) (u32 control);
+};
+
+#endif /* _SSP_PL022_H */
-- 
1.6.2.1

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Re: [PATCH] ARM PL022 SSP/SPI driver v1

[Russell King - ARM Linux]

On Thu, May 28, 2009 at 12:19:15AM +0200, Linus Walleij wrote:
> This adds a driver for the ARM PL022 PrimeCell SSP/SPI
> driver found in the U300 platforms as well as in some
> ARM reference hardware, and in a modified version on the
> Nomadik board.
> 
> Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
> ---
>  drivers/spi/Kconfig        |    9 +
>  drivers/spi/Makefile       |    1 +
>  drivers/spi/amba-pl022.c   | 1887 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/amba/pl022.h |  264 ++++++
>  4 files changed, 2161 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/spi/amba-pl022.c
>  create mode 100644 include/linux/amba/pl022.h
> 
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 83a185d..39cb8cf 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -171,6 +171,15 @@ config SPI_ORION
>  	help
>  	  This enables using the SPI master controller on the Orion chips.
> 
> +config SPI_PL022
> +	tristate "ARM AMBA PL022 SSP controller"
> +	depends on ARM_AMBA && EXPERIMENTAL

Normally, if something depends on EXPERIMENTAL, we put (EXPERIMENTAL) in
the option description.

> +#ifdef CONFIG_PM
> +static int suspend_devices(struct device *dev, void *pm_message)
> +{
> +	pm_message_t *state = pm_message;
> +
> +	if (dev->power.power_state.event != state->event) {
> +		dev_warn(dev, "pm state does not match request\n");
> +		return -EPERM;
> +	}
> +	return 0;
> +}
> +
> +static int pl022_suspend(struct amba_device *adev, pm_message_t state)
> +{
> +	struct pl022 *pl022 = amba_get_drvdata(adev);
> +	int status = 0;
> +
> +	/* Check all children (connected SPI chips) for current power state */
> +	status = device_for_each_child(&adev->dev, &state, suspend_devices);
> +	if (status) {
> +		dev_warn(&adev->dev,
> +			 "children (SPI chips) not in the same power "
> +			 "state, suspend aborted\n");
> +		return status;

Hmm, not sure about this.  The device model guarantees that the children
will have their suspend callbacks called before the parents.  If a child
returns an error from their suspend callback, suspend will be aborted
and the parent's suspend callback won't happen.

Lastly, dev->power.power_state is scheduled for removal...

> +	}
> +
> +	status = stop_queue(pl022);
> +	if (status) {
> +		dev_warn(&adev->dev, "suspend cannot stop queue\n");
> +		return status;
> +	}
> +
> +	clk_enable(pl022->clk);
> +	load_ssp_default_config(pl022);
> +	clk_disable(pl022->clk);
> +	dev_dbg(&adev->dev, "suspended\n");
> +	return 0;
> +}
> +
> +static int pl022_resume(struct amba_device *adev)
> +{
> +	struct pl022 *pl022 = amba_get_drvdata(adev);
> +	int status = 0;
> +
> +	/* Start the queue running */
> +	status = start_queue(pl022);
> +	if (status)
> +		dev_err(&adev->dev, "problem starting queue (%d)\n", status);
> +	else
> +		dev_dbg(&adev->dev, "resumed\n");
> +
> +	return status;
> +}
> +
> +#else
> +#define pl022_suspend NULL
> +#define pl022_resume NULL
> +#endif				/* CONFIG_PM */
> +
> +static struct vendor_data vendor_arm = {
> +	.fifodepth = 8,
> +	.max_bpw = 16,
> +	.unidir = false,
> +};
> +
> +
> +static struct vendor_data vendor_st = {
> +	.fifodepth = 32,
> +	.max_bpw = 32,
> +	.unidir = false,
> +};
> +
> +static struct amba_id pl022_ids[] __initdata = {

This shouldn't be __initdata - it can be referenced at runtime.

> +#ifndef _SSP_PL022_H
> +#define _SSP_PL022_H
> +
> +#include <linux/device.h>

Instead, use a forward declaration:

struct device;

to shut up the warnings about that missing.  Including header files to
shut those warnings up eventually gets us into treacherous water.

I've not reviewed the SSP code itself - it's something I'm far from
knowledgeable of.

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Re: [spi-devel-general] [PATCH] ARM PL022 SSP/SPI driver v1

[Baruch Siach]

Hi Linus,

This drivers looks like a nice piece of code.

Below are some small comments, FWIW.

On Thu, May 28, 2009 at 12:19:15AM +0200, Linus Walleij wrote:
> This adds a driver for the ARM PL022 PrimeCell SSP/SPI
> driver found in the U300 platforms as well as in some
> ARM reference hardware, and in a modified version on the
> Nomadik board.
> 
> Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
> ---
>  drivers/spi/Kconfig        |    9 +
>  drivers/spi/Makefile       |    1 +
>  drivers/spi/amba-pl022.c   | 1887 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/amba/pl022.h |  264 ++++++

Why include/linux/amba/? There's nothing AMBA specific in this header. IMO 
include/linux/spi is a better place for this header.

>  4 files changed, 2161 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/spi/amba-pl022.c
>  create mode 100644 include/linux/amba/pl022.h
> 
> ...
>
> +/**
> + * struct chip_data - To maintain runtime state of SSP for each client chip
> + * @cr0: Value of control register CR0 of SSP
> + * @cr1: Value of control register CR1 of SSP
> + * @dmacr: Value of DMA control Register of SSP
> + * @cpsr: Value of Clock prescale register
> + * @n_bytes: how many bytes(power of 2) reqd for a given data width of client
> + * @enable_dma: Whether to enable DMA or not
> + * @write: function ptr to be used to write when doing xfer for this chip
> + * @read: function ptr to be used to read when doing xfer for this chip
> + * @cs_control: chip select callback provided by chip
> + * @xfer_type: polling/interrupt/DMA
> + *
> + * Runtime state of the SSP controller, maintained per chip,
> + * This would be set according to the current message that would be served
> + */
> +struct chip_data {
> +	u16 cr0;
> +	u16 cr1;
> +	u16 dmacr;
> +	u16 cpsr;
> +	u8 n_bytes;
> +	u8 enable_dma:1;
> +	enum ssp_reading read;
> +	enum ssp_writing write;
> +	void (*cs_control) (u32 command);

Isn't there a way for the PL022 block itself to control the chip select? In 
case there isn't one, IMHO you should provide simple way to use the generic 
GPIO API for chip select. See for example drivers/spi/atmel_spi.c, and my 
DesignWare driver that you reviewed.

> ...
> 
> +/**
> + * pl022_interrupt_handler - Interrupt handler for SSP controller
> + *
> + * This function handles interrupts generated for an interrupt based transfer.
> + * If a receive overrun (ROR) interrupt is there then we disable SSP, flag the
> + * current message's state as ERROR_STATE and schedule the tasklet
> + * pump_transfers which will do the postprocessing of the current message by
> + * calling giveback(). Otherwise it reads data from Rx FIFO till there is no
> + * more data, and writes data in Tx FIFO till it is not full. If we complete
                                                       ^^^
Typo?

> + * the transfer we move to the next transfer and schedule the tasklet.
> + */
>
> ...
>
> +static int pl022_setup(struct spi_device *spi)
> +{
> +	struct pl022_config_chip *chip_info;
> +	struct chip_data *chip;
> +	int status = 0;
> +	struct pl022 *pl022 = spi_master_get_devdata(spi->master);
>
> ...
>
> +	/* Save controller_state */
> +	spi_set_ctldata(spi, chip);
> +	return status;
> + err_config_params:
> + err_first_setup:
> +	kfree(chip);

You should probably also spi_set_ctldata(spi, NULL), so that next time 
pl022_setup() won't attempt to access freed memory on the same SPI device.

> +	return status;
> +}
>
> ...

baruch

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=}------------------------------------------------ooO--U--Ooo------------{=
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Re: [spi-devel-general] [PATCH] ARM PL022 SSP/SPI driver v1

[Russell King - ARM Linux]

On Mon, Jun 01, 2009 at 07:31:01AM +0300, Baruch Siach wrote:
> Why include/linux/amba/? There's nothing AMBA specific in this header. IMO 
> include/linux/spi is a better place for this header.

Because that's where AMBA primecell headers go.

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Re: [spi-devel-general] [PATCH] ARM PL022 SSP/SPI driver v1

[Linus Walleij]

Thanks for your helpful review Baruch, I've fixed most things I think...

2009/6/1 Baruch Siach <baruch@tkos.co.il>:

>> +/**
>> + * struct chip_data - To maintain runtime state of SSP for each client chip
>> + * @cr0: Value of control register CR0 of SSP
>> + * @cr1: Value of control register CR1 of SSP
>> + * @dmacr: Value of DMA control Register of SSP
>> + * @cpsr: Value of Clock prescale register
>> + * @n_bytes: how many bytes(power of 2) reqd for a given data width of client
>> + * @enable_dma: Whether to enable DMA or not
>> + * @write: function ptr to be used to write when doing xfer for this chip
>> + * @read: function ptr to be used to read when doing xfer for this chip
>> + * @cs_control: chip select callback provided by chip
>> + * @xfer_type: polling/interrupt/DMA
>> + *
>> + * Runtime state of the SSP controller, maintained per chip,
>> + * This would be set according to the current message that would be served
>> + */
>> +struct chip_data {
>> +     u16 cr0;
>> +     u16 cr1;
>> +     u16 dmacr;
>> +     u16 cpsr;
>> +     u8 n_bytes;
>> +     u8 enable_dma:1;
>> +     enum ssp_reading read;
>> +     enum ssp_writing write;
>> +     void (*cs_control) (u32 command);
>
> Isn't there a way for the PL022 block itself to control the chip select?

Sadly no. Or rather, I think most SoC designers want to be free to
implement that themselves any way they choose.

> In
> case there isn't one, IMHO you should provide simple way to use the generic
> GPIO API for chip select. See for example drivers/spi/atmel_spi.c, and my
> DesignWare driver that you reviewed.

Yep I saw that, the problem is that the PL022 is synthesized in many many
designs, and the ways of doing chip select does not have to be GPIO pins
actually.

For this particular chip I have a dummy chip driver that does not connect
anywhere, it puts the chip into loopback mode so you can test the driver by
bombing it with a few transactions. It uses  a NULL CS function so nothing
really happens when the chip select callback is called on this chip.

I can think of a few other strange ways of activating chip selects too, like
writing I2C registers in some other off-mainchip subchip etc so I think
I'd better leave this open and each platform can decide for itself how
to implement it, generic GPIO being one way.

Linus Walleij

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