spi/spi-fsl-spi: Add support for Aeroflex Gaisler GRLIB cores normally running on SPARC

This adds support for the mostly register-compatible SPICTRL cores from the
GRLIB VHDL IP core library from Aeroflex Gaisler. They are normally running on
SPARC. A different entry in of_fsl_spi_match matches this core and indicates a
different hardware type that is used to set up different function pointers and
special cases.

The GRLIB core operates in cpu mode. The number of bits per word might be
limited. There might be native chipselects selected via a slave select
register. These differences to the FSL type cores, if present, are indicated by
a capabilities register. Other register and function differences exists but are
not relevant to the driver.

Acked-by: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 86 insertions, 12 deletions

diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
index 7eff63a284f..6846459e5c9 100644
--- a/drivers/spi/spi-fsl-spi.c
+++ b/drivers/spi/spi-fsl-spi.c
@@ -10,6 +10,10 @@
  * Copyright (c) 2009  MontaVista Software, Inc.
  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
  *
+ * GRLIB support:
+ * Copyright (c) 2012 Aeroflex Gaisler AB.
+ * Author: Andreas Larsson <andreas@gaisler.com>
+ *
  * 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
@@ -40,6 +44,7 @@
 #include "spi-fsl-spi.h"
 
 #define TYPE_FSL	0
+#define TYPE_GRLIB	1
 
 struct fsl_spi_match_data {
 	int type;
@@ -49,11 +54,19 @@ static struct fsl_spi_match_data of_fsl_spi_fsl_config = {
 	.type = TYPE_FSL,
 };
 
+static struct fsl_spi_match_data of_fsl_spi_grlib_config = {
+	.type = TYPE_GRLIB,
+};
+
 static struct of_device_id of_fsl_spi_match[] = {
 	{
 		.compatible = "fsl,spi",
 		.data = &of_fsl_spi_fsl_config,
 	},
+	{
+		.compatible = "aeroflexgaisler,spictrl",
+		.data = &of_fsl_spi_grlib_config,
+	},
 	{}
 };
 MODULE_DEVICE_TABLE(of, of_fsl_spi_match);
@@ -141,6 +154,21 @@ static void fsl_spi_qe_cpu_set_shifts(u32 *rx_shift, u32 *tx_shift,
 	}
 }
 
+static void fsl_spi_grlib_set_shifts(u32 *rx_shift, u32 *tx_shift,
+				     int bits_per_word, int msb_first)
+{
+	*rx_shift = 0;
+	*tx_shift = 0;
+	if (bits_per_word <= 16) {
+		if (msb_first) {
+			*rx_shift = 16; /* LSB in bit 16 */
+			*tx_shift = 32 - bits_per_word; /* MSB in bit 31 */
+		} else {
+			*rx_shift = 16 - bits_per_word; /* MSB in bit 15 */
+		}
+	}
+}
+
 static int mspi_apply_cpu_mode_quirks(struct spi_mpc8xxx_cs *cs,
 				struct spi_device *spi,
 				struct mpc8xxx_spi *mpc8xxx_spi,
@@ -494,6 +522,42 @@ static void fsl_spi_remove(struct mpc8xxx_spi *mspi)
 	fsl_spi_cpm_free(mspi);
 }
 
+static void fsl_spi_grlib_cs_control(struct spi_device *spi, bool on)
+{
+	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
+	struct fsl_spi_reg *reg_base = mpc8xxx_spi->reg_base;
+	u32 slvsel;
+	u16 cs = spi->chip_select;
+
+	slvsel = mpc8xxx_spi_read_reg(&reg_base->slvsel);
+	slvsel = on ? (slvsel | (1 << cs)) : (slvsel & ~(1 << cs));
+	mpc8xxx_spi_write_reg(&reg_base->slvsel, slvsel);
+}
+
+static void fsl_spi_grlib_probe(struct device *dev)
+{
+	struct fsl_spi_platform_data *pdata = dev->platform_data;
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(master);
+	struct fsl_spi_reg *reg_base = mpc8xxx_spi->reg_base;
+	int mbits;
+	u32 capabilities;
+
+	capabilities = mpc8xxx_spi_read_reg(&reg_base->cap);
+
+	mpc8xxx_spi->set_shifts = fsl_spi_grlib_set_shifts;
+	mbits = SPCAP_MAXWLEN(capabilities);
+	if (mbits)
+		mpc8xxx_spi->max_bits_per_word = mbits + 1;
+
+	master->num_chipselect = 1; /* Allow for an always selected chip */
+	if (SPCAP_SSEN(capabilities)) {
+		master->num_chipselect = SPCAP_SSSZ(capabilities);
+		mpc8xxx_spi_write_reg(&reg_base->slvsel, 0xffffffff);
+	}
+	pdata->cs_control = fsl_spi_grlib_cs_control;
+}
+
 static struct spi_master * fsl_spi_probe(struct device *dev,
 		struct resource *mem, unsigned int irq)
 {
@@ -528,6 +592,15 @@ static struct spi_master * fsl_spi_probe(struct device *dev,
 	if (ret)
 		goto err_cpm_init;
 
+	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
+	if (mpc8xxx_spi->reg_base == NULL) {
+		ret = -ENOMEM;
+		goto err_ioremap;
+	}
+
+	if (mpc8xxx_spi->type == TYPE_GRLIB)
+		fsl_spi_grlib_probe(dev);
+
 	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE)
 		mpc8xxx_spi->set_shifts = fsl_spi_qe_cpu_set_shifts;
 
@@ -536,12 +609,6 @@ static struct spi_master * fsl_spi_probe(struct device *dev,
 		mpc8xxx_spi->set_shifts(&mpc8xxx_spi->rx_shift,
 					&mpc8xxx_spi->tx_shift, 8, 1);
 
-	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
-	if (mpc8xxx_spi->reg_base == NULL) {
-		ret = -ENOMEM;
-		goto err_ioremap;
-	}
-
 	/* Register for SPI Interrupt */
 	ret = request_irq(mpc8xxx_spi->irq, fsl_spi_irq,
 			  0, "fsl_spi", mpc8xxx_spi);
@@ -706,16 +773,19 @@ static int of_fsl_spi_probe(struct platform_device *ofdev)
 	struct device_node *np = ofdev->dev.of_node;
 	struct spi_master *master;
 	struct resource mem;
-	int irq;
+	int irq, type;
 	int ret = -ENOMEM;
 
 	ret = of_mpc8xxx_spi_probe(ofdev);
 	if (ret)
 		return ret;
 
-	ret = of_fsl_spi_get_chipselects(dev);
-	if (ret)
-		goto err;
+	type = fsl_spi_get_type(&ofdev->dev);
+	if (type == TYPE_FSL) {
+		ret = of_fsl_spi_get_chipselects(dev);
+		if (ret)
+			goto err;
+	}
 
 	ret = of_address_to_resource(np, 0, &mem);
 	if (ret)
@@ -736,18 +806,22 @@ static int of_fsl_spi_probe(struct platform_device *ofdev)
 	return 0;
 
 err:
-	of_fsl_spi_free_chipselects(dev);
+	if (type == TYPE_FSL)
+		of_fsl_spi_free_chipselects(dev);
 	return ret;
 }
 
 static int of_fsl_spi_remove(struct platform_device *ofdev)
 {
+	struct spi_master *master = dev_get_drvdata(&ofdev->dev);
+	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(master);
 	int ret;
 
 	ret = mpc8xxx_spi_remove(&ofdev->dev);
 	if (ret)
 		return ret;
-	of_fsl_spi_free_chipselects(&ofdev->dev);
+	if (mpc8xxx_spi->type == TYPE_FSL)
+		of_fsl_spi_free_chipselects(&ofdev->dev);
 	return 0;
 }