* [PATCH v10 1/4] drivers/i2c/busses/i2c-at91.c: remove broken driver
2012-04-20 10:13 [PATCH v10 0/4] AT91: replace broken TWI driver i2c-at91.c Nikolaus Voss
@ 2011-11-08 10:49 ` Nikolaus Voss
2011-11-08 10:49 ` [PATCH v10 3/4] drivers/i2c/busses/i2c-at91.c: add new driver Nikolaus Voss
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Nikolaus Voss @ 2011-11-08 10:49 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, linux-i2c
Cc: nicolas.ferre, ben-linux, balbi, h.feurstein, rmallon,
adrian.yanes
Signed-off-by: Nikolaus Voss <n.voss@weinmann.de>
---
arch/arm/mach-at91/include/mach/at91_twi.h | 68 ------
drivers/i2c/busses/Makefile | 1 -
drivers/i2c/busses/i2c-at91.c | 314 ----------------------------
3 files changed, 0 insertions(+), 383 deletions(-)
delete mode 100644 arch/arm/mach-at91/include/mach/at91_twi.h
delete mode 100644 drivers/i2c/busses/i2c-at91.c
diff --git a/arch/arm/mach-at91/include/mach/at91_twi.h b/arch/arm/mach-at91/include/mach/at91_twi.h
deleted file mode 100644
index bb2880f..0000000
--- a/arch/arm/mach-at91/include/mach/at91_twi.h
+++ /dev/null
@@ -1,68 +0,0 @@
-/*
- * arch/arm/mach-at91/include/mach/at91_twi.h
- *
- * Copyright (C) 2005 Ivan Kokshaysky
- * Copyright (C) SAN People
- *
- * Two-wire Interface (TWI) registers.
- * Based on AT91RM9200 datasheet revision E.
- *
- * 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.
- */
-
-#ifndef AT91_TWI_H
-#define AT91_TWI_H
-
-#define AT91_TWI_CR 0x00 /* Control Register */
-#define AT91_TWI_START (1 << 0) /* Send a Start Condition */
-#define AT91_TWI_STOP (1 << 1) /* Send a Stop Condition */
-#define AT91_TWI_MSEN (1 << 2) /* Master Transfer Enable */
-#define AT91_TWI_MSDIS (1 << 3) /* Master Transfer Disable */
-#define AT91_TWI_SVEN (1 << 4) /* Slave Transfer Enable [SAM9260 only] */
-#define AT91_TWI_SVDIS (1 << 5) /* Slave Transfer Disable [SAM9260 only] */
-#define AT91_TWI_SWRST (1 << 7) /* Software Reset */
-
-#define AT91_TWI_MMR 0x04 /* Master Mode Register */
-#define AT91_TWI_IADRSZ (3 << 8) /* Internal Device Address Size */
-#define AT91_TWI_IADRSZ_NO (0 << 8)
-#define AT91_TWI_IADRSZ_1 (1 << 8)
-#define AT91_TWI_IADRSZ_2 (2 << 8)
-#define AT91_TWI_IADRSZ_3 (3 << 8)
-#define AT91_TWI_MREAD (1 << 12) /* Master Read Direction */
-#define AT91_TWI_DADR (0x7f << 16) /* Device Address */
-
-#define AT91_TWI_SMR 0x08 /* Slave Mode Register [SAM9260 only] */
-#define AT91_TWI_SADR (0x7f << 16) /* Slave Address */
-
-#define AT91_TWI_IADR 0x0c /* Internal Address Register */
-
-#define AT91_TWI_CWGR 0x10 /* Clock Waveform Generator Register */
-#define AT91_TWI_CLDIV (0xff << 0) /* Clock Low Divisor */
-#define AT91_TWI_CHDIV (0xff << 8) /* Clock High Divisor */
-#define AT91_TWI_CKDIV (7 << 16) /* Clock Divider */
-
-#define AT91_TWI_SR 0x20 /* Status Register */
-#define AT91_TWI_TXCOMP (1 << 0) /* Transmission Complete */
-#define AT91_TWI_RXRDY (1 << 1) /* Receive Holding Register Ready */
-#define AT91_TWI_TXRDY (1 << 2) /* Transmit Holding Register Ready */
-#define AT91_TWI_SVREAD (1 << 3) /* Slave Read [SAM9260 only] */
-#define AT91_TWI_SVACC (1 << 4) /* Slave Access [SAM9260 only] */
-#define AT91_TWI_GACC (1 << 5) /* General Call Access [SAM9260 only] */
-#define AT91_TWI_OVRE (1 << 6) /* Overrun Error [AT91RM9200 only] */
-#define AT91_TWI_UNRE (1 << 7) /* Underrun Error [AT91RM9200 only] */
-#define AT91_TWI_NACK (1 << 8) /* Not Acknowledged */
-#define AT91_TWI_ARBLST (1 << 9) /* Arbitration Lost [SAM9260 only] */
-#define AT91_TWI_SCLWS (1 << 10) /* Clock Wait State [SAM9260 only] */
-#define AT91_TWI_EOSACC (1 << 11) /* End of Slave Address [SAM9260 only] */
-
-#define AT91_TWI_IER 0x24 /* Interrupt Enable Register */
-#define AT91_TWI_IDR 0x28 /* Interrupt Disable Register */
-#define AT91_TWI_IMR 0x2c /* Interrupt Mask Register */
-#define AT91_TWI_RHR 0x30 /* Receive Holding Register */
-#define AT91_TWI_THR 0x34 /* Transmit Holding Register */
-
-#endif
-
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index fba6da6..e8a1852 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -28,7 +28,6 @@ obj-$(CONFIG_I2C_HYDRA) += i2c-hydra.o
obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
# Embedded system I2C/SMBus host controller drivers
-obj-$(CONFIG_I2C_AT91) += i2c-at91.o
obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o
obj-$(CONFIG_I2C_CPM) += i2c-cpm.o
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
deleted file mode 100644
index 1679dee..0000000
--- a/drivers/i2c/busses/i2c-at91.c
+++ /dev/null
@@ -1,314 +0,0 @@
-/*
- i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
-
- Copyright (C) 2004 Rick Bronson
- Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
-
- Borrowed heavily from original work by:
- Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.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 option) any later version.
-*/
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/err.h>
-#include <linux/slab.h>
-#include <linux/types.h>
-#include <linux/delay.h>
-#include <linux/i2c.h>
-#include <linux/init.h>
-#include <linux/clk.h>
-#include <linux/platform_device.h>
-#include <linux/io.h>
-
-#include <mach/at91_twi.h>
-#include <mach/board.h>
-#include <mach/cpu.h>
-
-#define TWI_CLOCK 100000 /* Hz. max 400 Kbits/sec */
-
-
-static struct clk *twi_clk;
-static void __iomem *twi_base;
-
-#define at91_twi_read(reg) __raw_readl(twi_base + (reg))
-#define at91_twi_write(reg, val) __raw_writel((val), twi_base + (reg))
-
-
-/*
- * Initialize the TWI hardware registers.
- */
-static void __devinit at91_twi_hwinit(void)
-{
- unsigned long cdiv, ckdiv;
-
- at91_twi_write(AT91_TWI_IDR, 0xffffffff); /* Disable all interrupts */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_SWRST); /* Reset peripheral */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_MSEN); /* Set Master mode */
-
- /* Calcuate clock dividers */
- cdiv = (clk_get_rate(twi_clk) / (2 * TWI_CLOCK)) - 3;
- cdiv = cdiv + 1; /* round up */
- ckdiv = 0;
- while (cdiv > 255) {
- ckdiv++;
- cdiv = cdiv >> 1;
- }
-
- if (cpu_is_at91rm9200()) { /* AT91RM9200 Errata #22 */
- if (ckdiv > 5) {
- printk(KERN_ERR "AT91 I2C: Invalid TWI_CLOCK value!\n");
- ckdiv = 5;
- }
- }
-
- at91_twi_write(AT91_TWI_CWGR, (ckdiv << 16) | (cdiv << 8) | cdiv);
-}
-
-/*
- * Poll the i2c status register until the specified bit is set.
- * Returns 0 if timed out (100 msec).
- */
-static short at91_poll_status(unsigned long bit)
-{
- int loop_cntr = 10000;
-
- do {
- udelay(10);
- } while (!(at91_twi_read(AT91_TWI_SR) & bit) && (--loop_cntr > 0));
-
- return (loop_cntr > 0);
-}
-
-static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
-{
- /* Send Start */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_START);
-
- /* Read data */
- while (length--) {
- if (!length) /* need to send Stop before reading last byte */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_STOP);
- if (!at91_poll_status(AT91_TWI_RXRDY)) {
- dev_dbg(&adap->dev, "RXRDY timeout\n");
- return -ETIMEDOUT;
- }
- *buf++ = (at91_twi_read(AT91_TWI_RHR) & 0xff);
- }
-
- return 0;
-}
-
-static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
-{
- /* Load first byte into transmitter */
- at91_twi_write(AT91_TWI_THR, *buf++);
-
- /* Send Start */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_START);
-
- do {
- if (!at91_poll_status(AT91_TWI_TXRDY)) {
- dev_dbg(&adap->dev, "TXRDY timeout\n");
- return -ETIMEDOUT;
- }
-
- length--; /* byte was transmitted */
-
- if (length > 0) /* more data to send? */
- at91_twi_write(AT91_TWI_THR, *buf++);
- } while (length);
-
- /* Send Stop */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_STOP);
-
- return 0;
-}
-
-/*
- * Generic i2c master transfer entrypoint.
- *
- * Note: We do not use Atmel's feature of storing the "internal device address".
- * Instead the "internal device address" has to be written using a separate
- * i2c message.
- * http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html
- */
-static int at91_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg, int num)
-{
- int i, ret;
-
- dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
-
- for (i = 0; i < num; i++) {
- dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
- pmsg->flags & I2C_M_RD ? "read" : "writ",
- pmsg->len, pmsg->len > 1 ? "s" : "",
- pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr);
-
- at91_twi_write(AT91_TWI_MMR, (pmsg->addr << 16)
- | ((pmsg->flags & I2C_M_RD) ? AT91_TWI_MREAD : 0));
-
- if (pmsg->len && pmsg->buf) { /* sanity check */
- if (pmsg->flags & I2C_M_RD)
- ret = xfer_read(adap, pmsg->buf, pmsg->len);
- else
- ret = xfer_write(adap, pmsg->buf, pmsg->len);
-
- if (ret)
- return ret;
-
- /* Wait until transfer is finished */
- if (!at91_poll_status(AT91_TWI_TXCOMP)) {
- dev_dbg(&adap->dev, "TXCOMP timeout\n");
- return -ETIMEDOUT;
- }
- }
- dev_dbg(&adap->dev, "transfer complete\n");
- pmsg++; /* next message */
- }
- return i;
-}
-
-/*
- * Return list of supported functionality.
- */
-static u32 at91_func(struct i2c_adapter *adapter)
-{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
-}
-
-static struct i2c_algorithm at91_algorithm = {
- .master_xfer = at91_xfer,
- .functionality = at91_func,
-};
-
-/*
- * Main initialization routine.
- */
-static int __devinit at91_i2c_probe(struct platform_device *pdev)
-{
- struct i2c_adapter *adapter;
- struct resource *res;
- int rc;
-
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!res)
- return -ENXIO;
-
- if (!request_mem_region(res->start, resource_size(res), "at91_i2c"))
- return -EBUSY;
-
- twi_base = ioremap(res->start, resource_size(res));
- if (!twi_base) {
- rc = -ENOMEM;
- goto fail0;
- }
-
- twi_clk = clk_get(NULL, "twi_clk");
- if (IS_ERR(twi_clk)) {
- dev_err(&pdev->dev, "no clock defined\n");
- rc = -ENODEV;
- goto fail1;
- }
-
- adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
- if (adapter == NULL) {
- dev_err(&pdev->dev, "can't allocate inteface!\n");
- rc = -ENOMEM;
- goto fail2;
- }
- snprintf(adapter->name, sizeof(adapter->name), "AT91");
- adapter->algo = &at91_algorithm;
- adapter->class = I2C_CLASS_HWMON;
- adapter->dev.parent = &pdev->dev;
- /* adapter->id == 0 ... only one TWI controller for now */
-
- platform_set_drvdata(pdev, adapter);
-
- clk_enable(twi_clk); /* enable peripheral clock */
- at91_twi_hwinit(); /* initialize TWI controller */
-
- rc = i2c_add_numbered_adapter(adapter);
- if (rc) {
- dev_err(&pdev->dev, "Adapter %s registration failed\n",
- adapter->name);
- goto fail3;
- }
-
- dev_info(&pdev->dev, "AT91 i2c bus driver.\n");
- return 0;
-
-fail3:
- platform_set_drvdata(pdev, NULL);
- kfree(adapter);
- clk_disable(twi_clk);
-fail2:
- clk_put(twi_clk);
-fail1:
- iounmap(twi_base);
-fail0:
- release_mem_region(res->start, resource_size(res));
-
- return rc;
-}
-
-static int __devexit at91_i2c_remove(struct platform_device *pdev)
-{
- struct i2c_adapter *adapter = platform_get_drvdata(pdev);
- struct resource *res;
- int rc;
-
- rc = i2c_del_adapter(adapter);
- platform_set_drvdata(pdev, NULL);
-
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- iounmap(twi_base);
- release_mem_region(res->start, resource_size(res));
-
- clk_disable(twi_clk); /* disable peripheral clock */
- clk_put(twi_clk);
-
- return rc;
-}
-
-#ifdef CONFIG_PM
-
-/* NOTE: could save a few mA by keeping clock off outside of at91_xfer... */
-
-static int at91_i2c_suspend(struct platform_device *pdev, pm_message_t mesg)
-{
- clk_disable(twi_clk);
- return 0;
-}
-
-static int at91_i2c_resume(struct platform_device *pdev)
-{
- return clk_enable(twi_clk);
-}
-
-#else
-#define at91_i2c_suspend NULL
-#define at91_i2c_resume NULL
-#endif
-
-static struct platform_driver at91_i2c_driver = {
- .probe = at91_i2c_probe,
- .remove = __devexit_p(at91_i2c_remove),
- .suspend = at91_i2c_suspend,
- .resume = at91_i2c_resume,
- .driver = {
- .name = "at91_i2c",
- .owner = THIS_MODULE,
- },
-};
-
-module_platform_driver(at91_i2c_driver);
-
-MODULE_AUTHOR("Rick Bronson");
-MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:at91_i2c");
--
1.7.5.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v10 3/4] drivers/i2c/busses/i2c-at91.c: add new driver
2012-04-20 10:13 [PATCH v10 0/4] AT91: replace broken TWI driver i2c-at91.c Nikolaus Voss
2011-11-08 10:49 ` [PATCH v10 1/4] drivers/i2c/busses/i2c-at91.c: remove broken driver Nikolaus Voss
@ 2011-11-08 10:49 ` Nikolaus Voss
[not found] ` <cover.1334916810.git.n.voss-+umVssTZoCsb1SvskN2V4Q@public.gmane.org>
2011-11-08 11:11 ` [PATCH v10 4/4] G45 TWI: remove open drain setting for twi function gpios Nikolaus Voss
3 siblings, 0 replies; 5+ messages in thread
From: Nikolaus Voss @ 2011-11-08 10:49 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, linux-i2c
Cc: nicolas.ferre, ben-linux, balbi, h.feurstein, rmallon,
adrian.yanes
This driver has the following properties compared to the old driver:
1. Support for multiple interfaces.
2. Interrupt driven I/O as opposed to polling/busy waiting.
3. Support for _one_ repeated start (Sr) condition, which is enough
for most real-world applications including all SMBus transfer types.
(The hardware does not support issuing arbitrary Sr conditions on the
bus.)
testing: SoC: at91sam9g45
- BQ20Z80 battery SMBus client.
- on a 2.6.38 kernel with several i2c clients (temp-sensor,
audio-codec, touchscreen-controller, w1-bridge, io-expanders)
Signed-off-by: Nikolaus Voss <n.voss@weinmann.de>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Tested-by: Hubert Feurstein <h.feurstein@gmail.com>
---
v10: - applied fix for RXRDY overrun bug submitted by Hubert Feurstein
- applied fix for calculating twi_clk
v9: - merge i2c-at91.c patches to single patch
- rewrite cwgr reg after timeout
v8: - remove local include
- remove cpu_is_rm9200() and put twi hw bug info in platform_device
- use readl/writel_relaxed instead of __raw_readl/writel
v7: i) fix bug if internal address > 1 byte
ii) send stop when len == 1 (both reported by Carsten Behling)
v6: support for I2C_SMBUS_BLOCK_DATA transfers.
Better use of clk_(un)prepare().
More sensible transfer timeout.
v5: Another round of review comments from Ryan Mallon, Felipe Balbi
and Russell King: convert twi clk to use .dev_id, cleanups
v4: Integrated more review comments from Ryan Mallon and Felipe Balbi:
Moved register include file to local include, code cleanups
v3: Integrated review comments from Ryan Mallon and Felipe Balbi
v2: Fixed whitespace issue
arch/arm/mach-at91/at91rm9200_devices.c | 9 +
drivers/i2c/busses/Kconfig | 11 +-
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-at91.c | 477 +++++++++++++++++++++++++++++++
4 files changed, 491 insertions(+), 7 deletions(-)
create mode 100644 drivers/i2c/busses/i2c-at91.c
diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c
index 97676bd..0912f29 100644
--- a/arch/arm/mach-at91/at91rm9200_devices.c
+++ b/arch/arm/mach-at91/at91rm9200_devices.c
@@ -493,9 +493,18 @@ static struct resource twi_resources[] = {
},
};
+static const struct platform_device_id twi_id = {
+ /*
+ * driver_data is "1" for hardware with ckdiv upper limit == 5
+ * (AT91RM9200 erratum 22), "0" for twi modules without this bug
+ */
+ .driver_data = 1,
+};
+
static struct platform_device at91rm9200_twi_device = {
.name = "at91_i2c",
.id = -1,
+ .id_entry = &twi_id,
.resource = twi_resources,
.num_resources = ARRAY_SIZE(twi_resources),
};
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3101dd5..92158df 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -285,18 +285,15 @@ comment "I2C system bus drivers (mostly embedded / system-on-chip)"
config I2C_AT91
tristate "Atmel AT91 I2C Two-Wire interface (TWI)"
- depends on ARCH_AT91 && EXPERIMENTAL && BROKEN
+ depends on ARCH_AT91 && EXPERIMENTAL
help
This supports the use of the I2C interface on Atmel AT91
processors.
- This driver is BROKEN because the controller which it uses
- will easily trigger RX overrun and TX underrun errors. Using
- low I2C clock rates may partially work around those issues
- on some systems. Another serious problem is that there is no
- documented way to issue repeated START conditions, as needed
+ A serious problem is that there is no documented way to issue
+ repeated START conditions for more than two messages, as needed
to support combined I2C messages. Use the i2c-gpio driver
- unless your system can cope with those limitations.
+ unless your system can cope with this limitation.
config I2C_AU1550
tristate "Au1550/Au1200/Au1300 SMBus interface"
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index e8a1852..fba6da6 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_I2C_HYDRA) += i2c-hydra.o
obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
# Embedded system I2C/SMBus host controller drivers
+obj-$(CONFIG_I2C_AT91) += i2c-at91.o
obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o
obj-$(CONFIG_I2C_CPM) += i2c-cpm.o
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
new file mode 100644
index 0000000..e1876a4
--- /dev/null
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -0,0 +1,477 @@
+/*
+ * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
+ *
+ * Copyright (C) 2011 Weinmann Medical GmbH
+ * Author: Nikolaus Voss <n.voss@weinmann.de>
+ *
+ * Evolved from original work by:
+ * Copyright (C) 2004 Rick Bronson
+ * Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
+ *
+ * Borrowed heavily from original work by:
+ * Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.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 option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define TWI_CLK_HZ 100000 /* max 400 Kbits/s */
+#define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
+
+/* AT91 TWI register definitions */
+#define AT91_TWI_CR 0x0000 /* Control Register */
+#define AT91_TWI_START 0x0001 /* Send a Start Condition */
+#define AT91_TWI_STOP 0x0002 /* Send a Stop Condition */
+#define AT91_TWI_MSEN 0x0004 /* Master Transfer Enable */
+#define AT91_TWI_SVDIS 0x0020 /* Slave Transfer Disable */
+#define AT91_TWI_SWRST 0x0080 /* Software Reset */
+
+#define AT91_TWI_MMR 0x0004 /* Master Mode Register */
+#define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */
+#define AT91_TWI_MREAD 0x1000 /* Master Read Direction */
+
+#define AT91_TWI_IADR 0x000c /* Internal Address Register */
+
+#define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
+
+#define AT91_TWI_SR 0x0020 /* Status Register */
+#define AT91_TWI_TXCOMP 0x0001 /* Transmission Complete */
+#define AT91_TWI_RXRDY 0x0002 /* Receive Holding Register Ready */
+#define AT91_TWI_TXRDY 0x0004 /* Transmit Holding Register Ready */
+
+#define AT91_TWI_OVRE 0x0040 /* Overrun Error */
+#define AT91_TWI_UNRE 0x0080 /* Underrun Error */
+#define AT91_TWI_NACK 0x0100 /* Not Acknowledged */
+
+#define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
+#define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
+#define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
+#define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
+#define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
+
+struct at91_twi_dev {
+ struct device *dev;
+ void __iomem *base;
+ struct completion cmd_complete;
+ struct clk *clk;
+ u8 *buf;
+ size_t buf_len;
+ struct i2c_msg *msg;
+ int irq;
+ unsigned transfer_status;
+ struct i2c_adapter adapter;
+ bool is_rm9200;
+ unsigned twi_cwgr_reg;
+};
+
+static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
+{
+ return readl_relaxed(dev->base + reg);
+}
+
+static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
+{
+ writel_relaxed(val, dev->base + reg);
+}
+
+static void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
+{
+ at91_twi_write(dev, AT91_TWI_IDR,
+ AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY);
+}
+
+static void at91_init_twi_bus(struct at91_twi_dev *dev)
+{
+ at91_disable_twi_interrupts(dev);
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
+ at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
+}
+
+/*
+ * Calculate symmetric clock as stated in datasheet:
+ * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
+ * where offset := 3 for RM9200 and offset := 4 for all others
+ *
+ * NOTE: on G45 real offset seems to be 27. Contacted atmel support for
+ * clarification.
+ */
+static void __devinit at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
+{
+ const int offset = dev->is_rm9200 ? 3 : 4;
+ const int div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
+ 2 * twi_clk) - offset);
+ int ckdiv = fls(div >> 8);
+ int cdiv = div >> ckdiv;
+
+ if (dev->is_rm9200 && (ckdiv > 5)) {
+ dev_warn(dev->dev, "AT91RM9200 erratum 22: using ckdiv = 5.\n");
+ ckdiv = 5;
+ cdiv = 255;
+ } else if (ckdiv > 7) {
+ dev_warn(dev->dev, "%d exceeds 3 bits for ckdiv, limiting.\n",
+ ckdiv);
+ ckdiv = 7;
+ cdiv = 255;
+ }
+
+ dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv;
+ dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv);
+}
+
+static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
+{
+ if (dev->buf_len <= 0)
+ return;
+
+ at91_twi_write(dev, AT91_TWI_THR, *dev->buf);
+
+ /* send stop when last byte has been written */
+ if (--dev->buf_len == 0)
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
+
+ dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len);
+
+ ++dev->buf;
+}
+
+static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
+{
+ if (dev->buf_len <= 0)
+ return;
+
+ *dev->buf = at91_twi_read(dev, AT91_TWI_RHR) & 0xff;
+ --dev->buf_len;
+
+ /* handle I2C_SMBUS_BLOCK_DATA */
+ if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) {
+ dev->msg->flags &= ~I2C_M_RECV_LEN;
+ dev->buf_len += *dev->buf;
+ dev->msg->len = dev->buf_len + 1;
+ dev_dbg(dev->dev, "received block length %d\n", dev->buf_len);
+ }
+
+ /* send stop if second but last byte has been read */
+ if (dev->buf_len == 1)
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
+
+ dev_dbg(dev->dev, "read 0x%x, to go %d\n", *dev->buf, dev->buf_len);
+
+ ++dev->buf;
+}
+
+static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
+{
+ struct at91_twi_dev *dev = dev_id;
+ const unsigned status = at91_twi_read(dev, AT91_TWI_SR);
+ const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
+
+ if (!irqstatus)
+ return IRQ_NONE;
+ else if (irqstatus & AT91_TWI_RXRDY)
+ at91_twi_read_next_byte(dev);
+ else if (irqstatus & AT91_TWI_TXRDY)
+ at91_twi_write_next_byte(dev);
+
+ if (irqstatus & AT91_TWI_TXCOMP) {
+ at91_disable_twi_interrupts(dev);
+ dev->transfer_status = status;
+ complete(&dev->cmd_complete);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int at91_do_twi_transfer(struct at91_twi_dev *dev)
+{
+ int ret;
+
+ dev_dbg(dev->dev, "transfer: %s %d bytes.\n",
+ (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
+
+ INIT_COMPLETION(dev->cmd_complete);
+ if (dev->msg->flags & I2C_M_RD) {
+ unsigned start_flags = AT91_TWI_START;
+
+ if (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY) {
+ dev_err(dev->dev, "RXRDY still set!");
+ at91_twi_read(dev, AT91_TWI_RHR);
+ }
+
+ /* if only one byte is to be read, immediately stop transfer */
+ if (dev->buf_len <= 1 && !(dev->msg->flags & I2C_M_RECV_LEN))
+ start_flags |= AT91_TWI_STOP;
+ at91_twi_write(dev, AT91_TWI_CR, start_flags);
+ at91_twi_write(dev, AT91_TWI_IER,
+ AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
+ } else {
+ at91_twi_write_next_byte(dev);
+ at91_twi_write(dev, AT91_TWI_IER,
+ AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
+ }
+
+ ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
+ dev->adapter.timeout);
+ if (ret == 0) {
+ dev_err(dev->dev, "controller timed out\n");
+ at91_init_twi_bus(dev);
+ return -ETIMEDOUT;
+ }
+ if (dev->transfer_status & AT91_TWI_NACK) {
+ dev_dbg(dev->dev, "received nack\n");
+ return -EREMOTEIO;
+ }
+ if (dev->transfer_status & AT91_TWI_OVRE) {
+ dev_err(dev->dev, "overrun while reading\n");
+ return -EIO;
+ }
+ dev_dbg(dev->dev, "transfer complete\n");
+
+ return 0;
+}
+
+static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
+{
+ struct at91_twi_dev *dev = i2c_get_adapdata(adap);
+ int ret;
+ unsigned int_addr_flag = 0;
+ struct i2c_msg *m_start = msg;
+
+ dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
+
+ /*
+ * The hardware can handle at most two messages concatenated by a
+ * repeated start via it's internal address feature.
+ */
+ if (num > 2) {
+ dev_err(dev->dev,
+ "cannot handle more than two concatenated messages.\n");
+ return 0;
+ } else if (num == 2) {
+ int internal_address = 0;
+ int i;
+
+ if (msg->flags & I2C_M_RD) {
+ dev_err(dev->dev, "first transfer must be write.\n");
+ return -EINVAL;
+ }
+ if (msg->len > 3) {
+ dev_err(dev->dev, "first message size must be <= 3.\n");
+ return -EINVAL;
+ }
+
+ /* 1st msg is put into the internal address, start with 2nd */
+ m_start = &msg[1];
+ for (i = 0; i < msg->len; ++i) {
+ const unsigned addr = msg->buf[msg->len - 1 - i];
+
+ internal_address |= addr << (8 * i);
+ int_addr_flag += AT91_TWI_IADRSZ_1;
+ }
+ at91_twi_write(dev, AT91_TWI_IADR, internal_address);
+ }
+
+ at91_twi_write(dev, AT91_TWI_MMR, (m_start->addr << 16) | int_addr_flag
+ | ((m_start->flags & I2C_M_RD) ? AT91_TWI_MREAD : 0));
+
+ dev->buf_len = m_start->len;
+ dev->buf = m_start->buf;
+ dev->msg = m_start;
+
+ ret = at91_do_twi_transfer(dev);
+
+ return (ret < 0) ? ret : num;
+}
+
+static u32 at91_twi_func(struct i2c_adapter *adapter)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
+ | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
+}
+
+static struct i2c_algorithm at91_twi_algorithm = {
+ .master_xfer = at91_twi_xfer,
+ .functionality = at91_twi_func,
+};
+
+static int __devinit at91_twi_probe(struct platform_device *pdev)
+{
+ struct at91_twi_dev *dev;
+ struct resource *mem, *ioarea;
+ int irq, rc;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!mem)
+ return -ENODEV;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ioarea = request_mem_region(mem->start, resource_size(mem), pdev->name);
+ if (!ioarea)
+ return -EBUSY;
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev) {
+ rc = -ENOMEM;
+ goto err_release_region;
+ }
+
+ if (pdev->id_entry && pdev->id_entry->driver_data == 1)
+ dev->is_rm9200 = 1;
+
+ init_completion(&dev->cmd_complete);
+
+ dev->dev = &pdev->dev;
+ dev->irq = irq;
+ platform_set_drvdata(pdev, dev);
+
+ dev->clk = clk_get(dev->dev, NULL);
+ if (IS_ERR(dev->clk)) {
+ dev_err(dev->dev, "no clock defined\n");
+ rc = -ENODEV;
+ goto err_free_mem;
+ }
+ clk_prepare(dev->clk);
+ clk_enable(dev->clk);
+
+ dev->base = ioremap(mem->start, resource_size(mem));
+ if (!dev->base) {
+ rc = -EBUSY;
+ goto err_mem_ioremap;
+ }
+
+ at91_calc_twi_clock(dev, TWI_CLK_HZ);
+ at91_init_twi_bus(dev);
+
+ rc = request_irq(dev->irq, atmel_twi_interrupt, 0,
+ dev_name(dev->dev), dev);
+ if (rc) {
+ dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
+ goto err_unuse_clocks;
+ }
+
+ snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
+ i2c_set_adapdata(&dev->adapter, dev);
+ dev->adapter.owner = THIS_MODULE;
+ dev->adapter.class = I2C_CLASS_HWMON;
+ dev->adapter.algo = &at91_twi_algorithm;
+ dev->adapter.dev.parent = dev->dev;
+ dev->adapter.nr = pdev->id;
+ dev->adapter.timeout = AT91_I2C_TIMEOUT;
+
+ rc = i2c_add_numbered_adapter(&dev->adapter);
+ if (rc) {
+ dev_err(dev->dev, "Adapter %s registration failed\n",
+ dev->adapter.name);
+ goto err_free_irq;
+ }
+
+ dev_info(dev->dev, "AT91 i2c bus driver.\n");
+ return 0;
+
+err_free_irq:
+ free_irq(dev->irq, dev);
+err_unuse_clocks:
+ iounmap(dev->base);
+err_mem_ioremap:
+ clk_disable(dev->clk);
+ clk_unprepare(dev->clk);
+ clk_put(dev->clk);
+err_free_mem:
+ kfree(dev);
+err_release_region:
+ release_mem_region(mem->start, resource_size(mem));
+
+ return rc;
+}
+
+static int __devexit at91_twi_remove(struct platform_device *pdev)
+{
+ struct at91_twi_dev *dev = platform_get_drvdata(pdev);
+ struct resource *mem;
+ int rc;
+
+ rc = i2c_del_adapter(&dev->adapter);
+ clk_disable(dev->clk);
+ clk_unprepare(dev->clk);
+ clk_put(dev->clk);
+ free_irq(dev->irq, dev);
+ iounmap(dev->base);
+ kfree(dev);
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ release_mem_region(mem->start, resource_size(mem));
+
+ return rc;
+}
+
+#ifdef CONFIG_PM
+
+static int at91_twi_runtime_suspend(struct device *dev)
+{
+ struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
+
+ clk_disable(twi_dev->clk);
+
+ return 0;
+}
+
+static int at91_twi_runtime_resume(struct device *dev)
+{
+ struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
+
+ return clk_enable(twi_dev->clk);
+}
+
+static const struct dev_pm_ops at91_twi_pm = {
+ .runtime_suspend = at91_twi_runtime_suspend,
+ .runtime_resume = at91_twi_runtime_resume,
+};
+
+#define at91_twi_pm_ops (&at91_twi_pm)
+#else
+#define at91_twi_pm_ops NULL
+#endif
+
+static struct platform_driver at91_twi_driver = {
+ .probe = at91_twi_probe,
+ .remove = __devexit_p(at91_twi_remove),
+ .driver = {
+ .name = "at91_i2c",
+ .owner = THIS_MODULE,
+ .pm = at91_twi_pm_ops,
+ },
+};
+
+static int __init at91_twi_init(void)
+{
+ return platform_driver_register(&at91_twi_driver);
+}
+
+static void __exit at91_twi_exit(void)
+{
+ platform_driver_unregister(&at91_twi_driver);
+}
+
+subsys_initcall(at91_twi_init);
+module_exit(at91_twi_exit);
+
+MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
+MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:at91_i2c");
--
1.7.5.4
^ permalink raw reply related [flat|nested] 5+ messages in thread