Date:	Fri, 20 Mar 2015 13:16:33 +0100
From:	Bert Vermeulen <bert@...t.com>
To:	ralf@...ux-mips.org, broonie@...nel.org, linux-mips@...ux-mips.org,
	linux-kernel@...r.kernel.org, linux-spi@...r.kernel.org
Cc:	Bert Vermeulen <bert@...t.com>
Subject: [PATCH 2/2] spi: Add driver for the CPLD chip on Mikrotik RB4xx boards

The CPLD is connected to the NAND flash chip and five LEDs. Access to
those devices goes via this driver.

Signed-off-by: Bert Vermeulen <bert@...t.com>
---
 arch/mips/include/asm/mach-ath79/rb4xx_cpld.h |  41 ++++
 drivers/spi/Kconfig                           |   8 +
 drivers/spi/Makefile                          |   1 +
 drivers/spi/spi-rb4xx-cpld.c                  | 326 ++++++++++++++++++++++++++
 4 files changed, 376 insertions(+)
 create mode 100644 arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
 create mode 100644 drivers/spi/spi-rb4xx-cpld.c

diff --git a/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h b/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
new file mode 100644
index 0000000..1df5a7e
--- /dev/null
+++ b/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
@@ -0,0 +1,41 @@
+/*
+ * SPI driver definitions for the CPLD chip on the Mikrotik RB4xx boards
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@...nwrt.org>
+ *
+ * This file was based on the patches for Linux 2.6.27.39 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#define CPLD_GPIO_nLED1		0
+#define CPLD_GPIO_nLED2		1
+#define CPLD_GPIO_nLED3		2
+#define CPLD_GPIO_nLED4		3
+#define CPLD_GPIO_FAN		4
+#define CPLD_GPIO_ALE		5
+#define CPLD_GPIO_CLE		6
+#define CPLD_GPIO_nCE		7
+#define CPLD_GPIO_nLED5		8
+
+#define CPLD_NUM_GPIOS		9
+
+#define CPLD_CFG_nLED1		BIT(CPLD_GPIO_nLED1)
+#define CPLD_CFG_nLED2		BIT(CPLD_GPIO_nLED2)
+#define CPLD_CFG_nLED3		BIT(CPLD_GPIO_nLED3)
+#define CPLD_CFG_nLED4		BIT(CPLD_GPIO_nLED4)
+#define CPLD_CFG_FAN		BIT(CPLD_GPIO_FAN)
+#define CPLD_CFG_ALE		BIT(CPLD_GPIO_ALE)
+#define CPLD_CFG_CLE		BIT(CPLD_GPIO_CLE)
+#define CPLD_CFG_nCE		BIT(CPLD_GPIO_nCE)
+#define CPLD_CFG_nLED5		BIT(CPLD_GPIO_nLED5)
+
+struct rb4xx_cpld_platform_data {
+	unsigned	gpio_base;
+};
+
+extern int rb4xx_cpld_read(unsigned char *rx_buf, unsigned cnt);
+extern int rb4xx_cpld_write(const unsigned char *buf, unsigned count);
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index aa76ce5..b32fa6a 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -435,6 +435,14 @@ config SPI_RB4XX
 	help
 	  SPI controller driver for the Mikrotik RB4xx series boards.
 
+config SPI_RB4XX_CPLD
+	tristate "MikroTik RB4XX CPLD driver"
+	depends on ATH79_MACH_RB4XX
+	help
+	  SPI driver for the Xilinx CPLD chip present on the MikroTik
+	  RB4xx boards. It controls CPU access to the NAND flash and
+	  user LEDs.
+
 config SPI_RSPI
 	tristate "Renesas RSPI/QSPI controller"
 	depends on SUPERH || ARCH_SHMOBILE || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 0218f39..c9bbdf9 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_SPI_PXA2XX_PCI)		+= spi-pxa2xx-pci.o
 obj-$(CONFIG_SPI_QUP)			+= spi-qup.o
 obj-$(CONFIG_SPI_ROCKCHIP)		+= spi-rockchip.o
 obj-$(CONFIG_SPI_RB4XX)			+= spi-rb4xx.o
+obj-$(CONFIG_SPI_RB4XX_CPLD)		+= spi-rb4xx-cpld.o
 obj-$(CONFIG_SPI_RSPI)			+= spi-rspi.o
 obj-$(CONFIG_SPI_S3C24XX)		+= spi-s3c24xx-hw.o
 spi-s3c24xx-hw-y			:= spi-s3c24xx.o
diff --git a/drivers/spi/spi-rb4xx-cpld.c b/drivers/spi/spi-rb4xx-cpld.c
new file mode 100644
index 0000000..4e777e2
--- /dev/null
+++ b/drivers/spi/spi-rb4xx-cpld.c
@@ -0,0 +1,326 @@
+/*
+ * SPI driver for the CPLD chip on the Mikrotik RB4xx boards
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@...nwrt.org>
+ *
+ * This file was based on the patches for Linux 2.6.27.39 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/bitops.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+
+#include <asm/mach-ath79/rb4xx_cpld.h>
+
+#define DRV_NAME	"spi-rb4xx-cpld"
+#define DRV_DESC	"RB4xx CPLD driver"
+#define DRV_VERSION	"0.1.0"
+
+#define CPLD_CMD_WRITE_NAND	0x08 /* send cmd, n x send data, send idle */
+#define CPLD_CMD_WRITE_CFG	0x09 /* send cmd, n x send cfg */
+#define CPLD_CMD_READ_NAND	0x0a /* send cmd, send idle, n x read data */
+#define CPLD_CMD_READ_FAST	0x0b /* send cmd, 4 x idle, n x read data */
+#define CPLD_CMD_LED5_ON	0x0c /* send cmd */
+#define CPLD_CMD_LED5_OFF	0x0d /* send cmd */
+
+struct rb4xx_cpld {
+	struct spi_device	*spi;
+	struct mutex		lock;
+	struct gpio_chip	chip;
+	unsigned int		config;
+};
+
+static struct rb4xx_cpld *rb4xx_cpld;
+
+static inline struct rb4xx_cpld *gpio_to_cpld(struct gpio_chip *chip)
+{
+	return container_of(chip, struct rb4xx_cpld, chip);
+}
+
+static int rb4xx_cpld_write_cmd(struct rb4xx_cpld *cpld, unsigned char cmd)
+{
+	struct spi_transfer t[1];
+	struct spi_message m;
+	unsigned char tx_buf[1];
+	int err;
+
+	spi_message_init(&m);
+	memset(&t, 0, sizeof(t));
+
+	t[0].tx_buf = tx_buf;
+	t[0].len = sizeof(tx_buf);
+	spi_message_add_tail(&t[0], &m);
+
+	tx_buf[0] = cmd;
+
+	err = spi_sync(cpld->spi, &m);
+	return err;
+}
+
+static int rb4xx_cpld_write_cfg(struct rb4xx_cpld *cpld, unsigned char config)
+{
+	struct spi_transfer t[1];
+	struct spi_message m;
+	unsigned char cmd[2];
+	int err;
+
+	spi_message_init(&m);
+	memset(&t, 0, sizeof(t));
+
+	t[0].tx_buf = cmd;
+	t[0].len = sizeof(cmd);
+	spi_message_add_tail(&t[0], &m);
+
+	cmd[0] = CPLD_CMD_WRITE_CFG;
+	cmd[1] = config;
+
+	err = spi_sync(cpld->spi, &m);
+	return err;
+}
+
+static int __rb4xx_cpld_change_cfg(struct rb4xx_cpld *cpld, unsigned mask,
+				   unsigned value)
+{
+	unsigned int config;
+	int err;
+
+	config = cpld->config & ~mask;
+	config |= value;
+
+	if ((cpld->config ^ config) & 0xff) {
+		err = rb4xx_cpld_write_cfg(cpld, config);
+		if (err)
+			return err;
+	}
+
+	if ((cpld->config ^ config) & CPLD_CFG_nLED5) {
+		err = rb4xx_cpld_write_cmd(cpld, (value) ? CPLD_CMD_LED5_ON :
+							   CPLD_CMD_LED5_OFF);
+		if (err)
+			return err;
+	}
+
+	cpld->config = config;
+	return 0;
+}
+
+int rb4xx_cpld_read(unsigned char *rx_buf, unsigned count)
+{
+	static const unsigned char cmd[2] = { CPLD_CMD_READ_NAND, 0 };
+	struct spi_transfer t[2] = {
+		{
+			.tx_buf = &cmd,
+			.len = 2,
+		}, {
+			.tx_buf = NULL,
+			.rx_buf = rx_buf,
+			.len = count,
+		},
+	};
+	struct spi_message m;
+
+	if (rb4xx_cpld == NULL)
+		return -ENODEV;
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+	return spi_sync(rb4xx_cpld->spi, &m);
+}
+EXPORT_SYMBOL_GPL(rb4xx_cpld_read);
+
+int rb4xx_cpld_write(const unsigned char *buf, unsigned count)
+{
+	static const unsigned char cmd = CPLD_CMD_WRITE_NAND;
+	struct spi_transfer t[3] = {
+		{
+			.tx_buf = &cmd,
+			.len = 1,
+		}, {
+			.tx_buf = buf,
+			.len = count,
+			.fast_write = 1,
+		}, {
+			.len = 1,
+			.fast_write = 1,
+		},
+	};
+	struct spi_message m;
+
+	if (rb4xx_cpld == NULL)
+		return -ENODEV;
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+	spi_message_add_tail(&t[2], &m);
+	return spi_sync(rb4xx_cpld->spi, &m);
+}
+EXPORT_SYMBOL_GPL(rb4xx_cpld_write);
+
+static int rb4xx_cpld_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+	int ret;
+
+	mutex_lock(&cpld->lock);
+	ret = (cpld->config >> offset) & 1;
+	mutex_unlock(&cpld->lock);
+
+	return ret;
+}
+
+static void rb4xx_cpld_gpio_set(struct gpio_chip *chip, unsigned offset,
+				int value)
+{
+	struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+
+	mutex_lock(&cpld->lock);
+	__rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
+	mutex_unlock(&cpld->lock);
+}
+
+static int rb4xx_cpld_gpio_direction_input(struct gpio_chip *chip,
+					   unsigned offset)
+{
+	return -EOPNOTSUPP;
+}
+
+static int rb4xx_cpld_gpio_direction_output(struct gpio_chip *chip,
+					    unsigned offset,
+					    int value)
+{
+	struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+	int ret;
+
+	mutex_lock(&cpld->lock);
+	ret = __rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
+	mutex_unlock(&cpld->lock);
+
+	return ret;
+}
+
+static int rb4xx_cpld_gpio_init(struct rb4xx_cpld *cpld, unsigned int base)
+{
+	int err;
+
+	/* init config */
+	cpld->config = CPLD_CFG_nLED1 | CPLD_CFG_nLED2 | CPLD_CFG_nLED3 |
+		       CPLD_CFG_nLED4 | CPLD_CFG_nLED5;
+	rb4xx_cpld_write_cfg(cpld, cpld->config);
+
+	/* setup GPIO chip */
+	cpld->chip.label = DRV_NAME;
+
+	cpld->chip.get = rb4xx_cpld_gpio_get;
+	cpld->chip.set = rb4xx_cpld_gpio_set;
+	cpld->chip.direction_input = rb4xx_cpld_gpio_direction_input;
+	cpld->chip.direction_output = rb4xx_cpld_gpio_direction_output;
+
+	cpld->chip.base = base;
+	cpld->chip.ngpio = CPLD_NUM_GPIOS;
+	cpld->chip.can_sleep = 1;
+	cpld->chip.dev = &cpld->spi->dev;
+	cpld->chip.owner = THIS_MODULE;
+
+	err = gpiochip_add(&cpld->chip);
+	if (err)
+		dev_err(&cpld->spi->dev, "adding GPIO chip failed, err=%d\n",
+			err);
+
+	return err;
+}
+
+static int rb4xx_cpld_probe(struct spi_device *spi)
+{
+	struct rb4xx_cpld *cpld;
+	struct rb4xx_cpld_platform_data *pdata;
+	int err;
+
+	pdata = spi->dev.platform_data;
+	if (!pdata) {
+		dev_dbg(&spi->dev, "no platform data\n");
+		return -EINVAL;
+	}
+
+	cpld = kzalloc(sizeof(*cpld), GFP_KERNEL);
+	if (!cpld)
+		return -ENOMEM;
+
+	mutex_init(&cpld->lock);
+	cpld->spi = spi_dev_get(spi);
+	dev_set_drvdata(&spi->dev, cpld);
+
+	spi->mode = SPI_MODE_0;
+	spi->bits_per_word = 8;
+	err = spi_setup(spi);
+	if (err) {
+		dev_err(&spi->dev, "spi_setup failed, err=%d\n", err);
+		goto err_drvdata;
+	}
+
+	err = rb4xx_cpld_gpio_init(cpld, pdata->gpio_base);
+	if (err)
+		goto err_drvdata;
+
+	rb4xx_cpld = cpld;
+
+	return 0;
+
+err_drvdata:
+	dev_set_drvdata(&spi->dev, NULL);
+	kfree(cpld);
+
+	return err;
+}
+
+static int rb4xx_cpld_remove(struct spi_device *spi)
+{
+	struct rb4xx_cpld *cpld;
+
+	rb4xx_cpld = NULL;
+	cpld = dev_get_drvdata(&spi->dev);
+	dev_set_drvdata(&spi->dev, NULL);
+	kfree(cpld);
+
+	return 0;
+}
+
+static struct spi_driver rb4xx_cpld_driver = {
+	.driver = {
+		.name		= DRV_NAME,
+		.bus		= &spi_bus_type,
+		.owner		= THIS_MODULE,
+	},
+	.probe		= rb4xx_cpld_probe,
+	.remove		= rb4xx_cpld_remove,
+};
+
+static int __init rb4xx_cpld_init(void)
+{
+	return spi_register_driver(&rb4xx_cpld_driver);
+}
+module_init(rb4xx_cpld_init);
+
+static void __exit rb4xx_cpld_exit(void)
+{
+	spi_unregister_driver(&rb4xx_cpld_driver);
+}
+module_exit(rb4xx_cpld_exit);
+
+MODULE_DESCRIPTION(DRV_DESC);
+MODULE_VERSION(DRV_VERSION);
+MODULE_AUTHOR("Gabor Juhos <juhosg@...nwrt.org>");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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