path: root/recipes/linux/linux-2.6.34/ts72xx/0018-ts72xx_spi_tmp124.patch

From 314f5d55f44d63c4ff418260580b93727eee00dc Mon Sep 17 00:00:00 2001
From: Matthieu Crapet <mcrapet@gmail.com>
Date: Tue, 22 Jun 2010 15:48:27 +0200
Subject: [PATCH 18/18] ts72xx_spi_tmp124

It's an option. A 3-wire spi temperature sensor can be populated on TS-72XX sbc.
---
 arch/arm/mach-ep93xx/ts72xx.c |   61 ++++++++++++++++
 drivers/spi/Kconfig           |    7 ++
 drivers/spi/Makefile          |    1 +
 drivers/spi/tmp124.c          |  158 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 227 insertions(+), 0 deletions(-)
 create mode 100644 drivers/spi/tmp124.c

diff --git a/arch/arm/mach-ep93xx/ts72xx.c b/arch/arm/mach-ep93xx/ts72xx.c
index 475559e..bf3a666 100644
--- a/arch/arm/mach-ep93xx/ts72xx.c
+++ b/arch/arm/mach-ep93xx/ts72xx.c
@@ -23,7 +23,9 @@
 #include <linux/i2c-gpio.h>
 #include <linux/mtd/nand.h>
 #include <linux/mtd/partitions.h>
+#include <linux/spi/spi.h>
 
+#include <mach/ep93xx_spi.h>
 #include <mach/hardware.h>
 #include <mach/ts72xx.h>
 
@@ -367,6 +369,60 @@ static struct i2c_gpio_platform_data ts72xx_i2c_gpio_data = {
 static struct i2c_board_info __initdata ts72xx_i2c_board_info[] = {
 };
 
+/*************************************************************************
+ * SPI
+ *************************************************************************/
+#if defined(CONFIG_SPI_TMP124) || defined(CONFIG_SPI_TMP124_MODULE)
+
+/* this is our GPIO line used for chip select */
+#define TMP124_CHIP_SELECT_GPIO EP93XX_GPIO_LINE_MCCD2
+
+static int ts72xx_tmp124_setup(struct spi_device *spi)
+{
+	int err;
+
+	err = gpio_request(TMP124_CHIP_SELECT_GPIO, spi->modalias);
+	if (err)
+		return err;
+
+	gpio_direction_output(TMP124_CHIP_SELECT_GPIO, 1);
+
+	return 0;
+}
+
+static void ts72xx_tmp124_cleanup(struct spi_device *spi)
+{
+	gpio_set_value(TMP124_CHIP_SELECT_GPIO, 1);
+	gpio_direction_input(TMP124_CHIP_SELECT_GPIO);
+	gpio_free(TMP124_CHIP_SELECT_GPIO);
+}
+
+static void ts72xx_tmp124_cs_control(struct spi_device *spi, int value)
+{
+	gpio_set_value(TMP124_CHIP_SELECT_GPIO, value);
+}
+
+static struct ep93xx_spi_chip_ops ts72xx_tmp124_ops = {
+	.setup		= ts72xx_tmp124_setup,
+	.cleanup	= ts72xx_tmp124_cleanup,
+	.cs_control	= ts72xx_tmp124_cs_control,
+};
+
+static struct spi_board_info ts72xx_spi_devices[] = {
+	{
+		.modalias		= "tmp124",
+		.max_speed_hz		= 2 * 1000 * 1000,
+		.bus_num		= 0,
+		.chip_select		= 0,
+		.controller_data	= &ts72xx_tmp124_ops,
+	},
+};
+
+static struct ep93xx_spi_info ts72xx_spi_info = {
+	.num_chipselect	= ARRAY_SIZE(ts72xx_spi_devices),
+};
+#endif
+
 static void __init ts72xx_init_machine(void)
 {
 	ep93xx_init_devices();
@@ -380,6 +436,11 @@ static void __init ts72xx_init_machine(void)
 			ts72xx_i2c_board_info,
 			ARRAY_SIZE(ts72xx_i2c_board_info));
 
+	#if defined(CONFIG_SPI_TMP124) || defined(CONFIG_SPI_TMP124_MODULE)
+	ep93xx_register_spi(&ts72xx_spi_info, ts72xx_spi_devices,
+			ARRAY_SIZE(ts72xx_spi_devices));
+	#endif
+
 	if (is_max197_installed()) {
 		platform_device_register(&ts72xx_max197_device);
 	}
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 2b2f4c3..9f40a43 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -372,6 +372,13 @@ config SPI_TLE62X0
 	  sysfs interface, with each line presented as a kind of GPIO
 	  exposing both switch control and diagnostic feedback.
 
+config SPI_TMP124
+	tristate "Texas Instruments TMP1224, TMP124"
+	depends on SPI_MASTER && SYSFS
+	help
+	  SPI driver for TMP12X temperature sensor chips.
+	  This provides a sysfs entry for temperature reading (2�C accurate).
+
 #
 # Add new SPI protocol masters in alphabetical order above this line
 #
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 377f845..2798b38 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -56,6 +56,7 @@ spi_s3c24xx_hw-$(CONFIG_SPI_S3C24XX_FIQ) += spi_s3c24xx_fiq.o
 # SPI protocol drivers (device/link on bus)
 obj-$(CONFIG_SPI_SPIDEV)	+= spidev.o
 obj-$(CONFIG_SPI_TLE62X0)	+= tle62x0.o
+obj-$(CONFIG_SPI_TMP124)	+= tmp124.o
 # 	... add above this line ...
 
 # SPI slave controller drivers (upstream link)
diff --git a/drivers/spi/tmp124.c b/drivers/spi/tmp124.c
new file mode 100644
index 0000000..e41ec8c
--- /dev/null
+++ b/drivers/spi/tmp124.c
@@ -0,0 +1,158 @@
+/*
+ *  TMP124 SPI protocol driver
+ *
+ * (c) Copyright 2008-2010  Matthieu Crapet <mcrapet@gmail.com>
+ * Based on tle62x0.c by Ben Dooks, <ben@simtec.co.uk>
+ *
+ * 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.
+ *
+ * Note: The chip uses a '3-wire SPI' (miso and mosi are the same pin).
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+
+struct tmp124_state {
+	struct spi_device *bus;
+	u8 tx_buff[2];
+	u8 rx_buff[2];
+};
+
+static inline int tmp124_write_then_read(struct tmp124_state *st)
+{
+	struct spi_message msg;
+	struct spi_transfer xfer[2] = {
+		{
+			.tx_buf		= st->tx_buff,
+			.rx_buf		= NULL,
+			.len		= 2,
+		}, {
+			.tx_buf		= NULL,
+			.rx_buf		= st->rx_buff,
+			.len		= 2,
+		}
+	};
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfer[0], &msg);
+	spi_sync(st->bus, &msg);
+
+	/* SPI_3WIRE is not handled by ep93xx_spi, the 2 messages must be
+	 * splitted. We must wait to not confuse driver with read/write. */
+	schedule_timeout(usecs_to_jiffies(1000));
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfer[1], &msg);
+	return spi_sync(st->bus, &msg);
+}
+
+static ssize_t tmp124_temperature_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct tmp124_state *st = dev_get_drvdata(dev);
+	int ret;
+
+	((short *)st->tx_buff)[0] = 0x8000;
+
+	ret = tmp124_write_then_read(st);
+	if (ret < 0) {
+		dev_err(&st->bus->dev, "tmp124_write_then_read\n");
+		ret = 0;
+	} else {
+		signed long val = ((short *)st->rx_buff)[0];
+
+		val = val >> 3;
+
+		/* 2 digit precision (0.0625*100) */
+		val = (val * 50) / 8;
+		ret = snprintf(buf, PAGE_SIZE, "%ld.%02ld\n", val/100, abs(val%100));
+	}
+	return ret;
+}
+
+static DEVICE_ATTR(temperature, S_IRUGO, tmp124_temperature_show, NULL);
+
+static int __devinit tmp124_probe(struct spi_device *spi)
+{
+	struct tmp124_state *st;
+	int ret;
+
+	st = kzalloc(sizeof(struct tmp124_state), GFP_KERNEL);
+	if (st == NULL) {
+		dev_err(&spi->dev, "no memory for device state\n");
+		return -ENOMEM;
+	}
+
+	/* required config */
+	spi->bits_per_word = 16;
+        spi->mode = SPI_MODE_0;
+
+	ret = spi_setup(spi);
+	if (ret) {
+		dev_err(&spi->dev, "setup device\n");
+		goto err;
+	}
+
+	ret = device_create_file(&spi->dev, &dev_attr_temperature);
+	if (ret) {
+		dev_err(&spi->dev, "cannot create temperature attribute\n");
+		goto err;
+	}
+
+	st->bus = spi;
+	spi_set_drvdata(spi, st);
+	return 0;
+
+err:
+	kfree(st);
+	return ret;
+}
+
+static int __devexit tmp124_remove(struct spi_device *spi)
+{
+	struct tmp124_state *st = spi_get_drvdata(spi);
+
+	device_remove_file(&spi->dev, &dev_attr_temperature);
+	kfree(st);
+	return 0;
+}
+
+static struct spi_driver tmp124_driver = {
+	.driver = {
+		.name	= "tmp124",
+		.owner	= THIS_MODULE,
+	},
+	.probe	= tmp124_probe,
+	.remove	= __devexit_p(tmp124_remove),
+};
+
+static __init int tmp124_init(void)
+{
+	return spi_register_driver(&tmp124_driver);
+}
+
+static __exit void tmp124_exit(void)
+{
+	spi_unregister_driver(&tmp124_driver);
+}
+
+module_init(tmp124_init);
+module_exit(tmp124_exit);
+
+MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>");
+MODULE_DESCRIPTION("TMP124 SPI Protocol Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:tmp124");
+MODULE_VERSION("0.2");
-- 
1.7.1