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-rw-r--r--arch/arm/mach-at91/at91rm9200.c2
-rw-r--r--arch/arm/mach-at91/at91rm9200_devices.c2
-rw-r--r--arch/arm/mach-at91/at91sam9260.c3
-rw-r--r--arch/arm/mach-at91/at91sam9260_devices.c8
-rw-r--r--arch/arm/mach-at91/at91sam9261.c3
-rw-r--r--arch/arm/mach-at91/at91sam9261_devices.c8
-rw-r--r--arch/arm/mach-at91/at91sam9263.c2
-rw-r--r--arch/arm/mach-at91/at91sam9263_devices.c2
-rw-r--r--arch/arm/mach-at91/at91sam9g45.c4
-rw-r--r--arch/arm/mach-at91/at91sam9g45_devices.c4
-rw-r--r--arch/arm/mach-at91/at91sam9rl.c4
-rw-r--r--arch/arm/mach-at91/at91sam9rl_devices.c2
-rw-r--r--drivers/i2c/busses/Kconfig17
-rw-r--r--drivers/i2c/busses/Makefile1
-rw-r--r--drivers/i2c/busses/i2c-at91.c505
15 files changed, 545 insertions, 22 deletions
diff --git a/arch/arm/mach-at91/at91rm9200.c b/arch/arm/mach-at91/at91rm9200.c
index f2112f9c1800..b4f0565aff63 100644
--- a/arch/arm/mach-at91/at91rm9200.c
+++ b/arch/arm/mach-at91/at91rm9200.c
@@ -187,7 +187,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
CLKDEV_CON_DEV_ID("pclk", "ssc.0", &ssc0_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.1", &ssc1_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.2", &ssc2_clk),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c", &twi_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91rm9200", &twi_clk),
/* fake hclk clock */
CLKDEV_CON_DEV_ID("hclk", "at91_ohci", &ohci_clk),
CLKDEV_CON_ID("pioA", &pioA_clk),
diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c
index 01fb7325fecc..0b972f2e57eb 100644
--- a/arch/arm/mach-at91/at91rm9200_devices.c
+++ b/arch/arm/mach-at91/at91rm9200_devices.c
@@ -495,7 +495,7 @@ static struct resource twi_resources[] = {
};
static struct platform_device at91rm9200_twi_device = {
- .name = "at91_i2c",
+ .name = "i2c-at91rm9200",
.id = -1,
.resource = twi_resources,
.num_resources = ARRAY_SIZE(twi_resources),
diff --git a/arch/arm/mach-at91/at91sam9260.c b/arch/arm/mach-at91/at91sam9260.c
index 57c79eed5fd0..5bd19a442365 100644
--- a/arch/arm/mach-at91/at91sam9260.c
+++ b/arch/arm/mach-at91/at91sam9260.c
@@ -211,7 +211,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
CLKDEV_CON_DEV_ID("t1_clk", "atmel_tcb.1", &tc4_clk),
CLKDEV_CON_DEV_ID("t2_clk", "atmel_tcb.1", &tc5_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.0", &ssc_clk),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c", &twi_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9260", &twi_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9g20", &twi_clk),
/* more usart lookup table for DT entries */
CLKDEV_CON_DEV_ID("usart", "fffff200.serial", &mck),
CLKDEV_CON_DEV_ID("usart", "fffb0000.serial", &usart0_clk),
diff --git a/arch/arm/mach-at91/at91sam9260_devices.c b/arch/arm/mach-at91/at91sam9260_devices.c
index bce572a530ef..95fc23aab432 100644
--- a/arch/arm/mach-at91/at91sam9260_devices.c
+++ b/arch/arm/mach-at91/at91sam9260_devices.c
@@ -503,7 +503,6 @@ static struct resource twi_resources[] = {
};
static struct platform_device at91sam9260_twi_device = {
- .name = "at91_i2c",
.id = -1,
.resource = twi_resources,
.num_resources = ARRAY_SIZE(twi_resources),
@@ -511,6 +510,13 @@ static struct platform_device at91sam9260_twi_device = {
void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices)
{
+ /* IP version is not the same on 9260 and g20 */
+ if (cpu_is_at91sam9g20()) {
+ at91sam9260_twi_device.name = "i2c-at91sam9g20";
+ } else {
+ at91sam9260_twi_device.name = "i2c-at91sam9260";
+ }
+
/* pins used for TWI interface */
at91_set_A_periph(AT91_PIN_PA23, 0); /* TWD */
at91_set_multi_drive(AT91_PIN_PA23, 1);
diff --git a/arch/arm/mach-at91/at91sam9261.c b/arch/arm/mach-at91/at91sam9261.c
index 71ca1e06a16f..8d999eb1a137 100644
--- a/arch/arm/mach-at91/at91sam9261.c
+++ b/arch/arm/mach-at91/at91sam9261.c
@@ -178,7 +178,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
CLKDEV_CON_DEV_ID("pclk", "ssc.1", &ssc1_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.2", &ssc2_clk),
CLKDEV_CON_DEV_ID("hclk", "at91_ohci", &hck0),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c", &twi_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9261", &twi_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9g10", &twi_clk),
CLKDEV_CON_ID("pioA", &pioA_clk),
CLKDEV_CON_ID("pioB", &pioB_clk),
CLKDEV_CON_ID("pioC", &pioC_clk),
diff --git a/arch/arm/mach-at91/at91sam9261_devices.c b/arch/arm/mach-at91/at91sam9261_devices.c
index bc2590d712d0..29188ef7422b 100644
--- a/arch/arm/mach-at91/at91sam9261_devices.c
+++ b/arch/arm/mach-at91/at91sam9261_devices.c
@@ -317,7 +317,6 @@ static struct resource twi_resources[] = {
};
static struct platform_device at91sam9261_twi_device = {
- .name = "at91_i2c",
.id = -1,
.resource = twi_resources,
.num_resources = ARRAY_SIZE(twi_resources),
@@ -325,6 +324,13 @@ static struct platform_device at91sam9261_twi_device = {
void __init at91_add_device_i2c(struct i2c_board_info *devices, int nr_devices)
{
+ /* IP version is not the same on 9261 and g10 */
+ if (cpu_is_at91sam9g10()) {
+ at91sam9261_twi_device.name = "i2c-at91sam9g10";
+ } else {
+ at91sam9261_twi_device.name = "i2c-at91sam9261";
+ }
+
/* pins used for TWI interface */
at91_set_A_periph(AT91_PIN_PA7, 0); /* TWD */
at91_set_multi_drive(AT91_PIN_PA7, 1);
diff --git a/arch/arm/mach-at91/at91sam9263.c b/arch/arm/mach-at91/at91sam9263.c
index 2a08305b6571..e6b595658e75 100644
--- a/arch/arm/mach-at91/at91sam9263.c
+++ b/arch/arm/mach-at91/at91sam9263.c
@@ -193,7 +193,7 @@ static struct clk_lookup periph_clocks_lookups[] = {
CLKDEV_CON_DEV_ID("spi_clk", "atmel_spi.0", &spi0_clk),
CLKDEV_CON_DEV_ID("spi_clk", "atmel_spi.1", &spi1_clk),
CLKDEV_CON_DEV_ID("t0_clk", "atmel_tcb.0", &tcb_clk),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c", &twi_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9260", &twi_clk),
/* fake hclk clock */
CLKDEV_CON_DEV_ID("hclk", "at91_ohci", &ohci_clk),
CLKDEV_CON_ID("pioA", &pioA_clk),
diff --git a/arch/arm/mach-at91/at91sam9263_devices.c b/arch/arm/mach-at91/at91sam9263_devices.c
index 9b6ca734f1a9..3f5288ea64b9 100644
--- a/arch/arm/mach-at91/at91sam9263_devices.c
+++ b/arch/arm/mach-at91/at91sam9263_devices.c
@@ -574,7 +574,7 @@ static struct resource twi_resources[] = {
};
static struct platform_device at91sam9263_twi_device = {
- .name = "at91_i2c",
+ .name = "i2c-at91sam9260",
.id = -1,
.resource = twi_resources,
.num_resources = ARRAY_SIZE(twi_resources),
diff --git a/arch/arm/mach-at91/at91sam9g45.c b/arch/arm/mach-at91/at91sam9g45.c
index ddf3d3707c54..858f032e5102 100644
--- a/arch/arm/mach-at91/at91sam9g45.c
+++ b/arch/arm/mach-at91/at91sam9g45.c
@@ -237,8 +237,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
CLKDEV_CON_DEV_ID("spi_clk", "atmel_spi.1", &spi1_clk),
CLKDEV_CON_DEV_ID("t0_clk", "atmel_tcb.0", &tcb0_clk),
CLKDEV_CON_DEV_ID("t0_clk", "atmel_tcb.1", &tcb0_clk),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c.0", &twi0_clk),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c.1", &twi1_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9g10.0", &twi0_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9g10.1", &twi1_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.0", &ssc0_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.1", &ssc1_clk),
CLKDEV_CON_DEV_ID(NULL, "atmel-trng", &trng_clk),
diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
index 1b47319ca00b..ac1b0f8c3b31 100644
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -653,7 +653,7 @@ static struct resource twi0_resources[] = {
};
static struct platform_device at91sam9g45_twi0_device = {
- .name = "at91_i2c",
+ .name = "i2c-at91sam9g10",
.id = 0,
.resource = twi0_resources,
.num_resources = ARRAY_SIZE(twi0_resources),
@@ -673,7 +673,7 @@ static struct resource twi1_resources[] = {
};
static struct platform_device at91sam9g45_twi1_device = {
- .name = "at91_i2c",
+ .name = "i2c-at91sam9g10",
.id = 1,
.resource = twi1_resources,
.num_resources = ARRAY_SIZE(twi1_resources),
diff --git a/arch/arm/mach-at91/at91sam9rl.c b/arch/arm/mach-at91/at91sam9rl.c
index bf79c1fd5939..72e908412222 100644
--- a/arch/arm/mach-at91/at91sam9rl.c
+++ b/arch/arm/mach-at91/at91sam9rl.c
@@ -186,8 +186,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
CLKDEV_CON_DEV_ID("t2_clk", "atmel_tcb.0", &tc2_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.0", &ssc0_clk),
CLKDEV_CON_DEV_ID("pclk", "ssc.1", &ssc1_clk),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c.0", &twi0_clk),
- CLKDEV_CON_DEV_ID(NULL, "at91_i2c.1", &twi1_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9g20.0", &twi0_clk),
+ CLKDEV_CON_DEV_ID(NULL, "i2c-at91sam9g20.1", &twi1_clk),
CLKDEV_CON_ID("pioA", &pioA_clk),
CLKDEV_CON_ID("pioB", &pioB_clk),
CLKDEV_CON_ID("pioC", &pioC_clk),
diff --git a/arch/arm/mach-at91/at91sam9rl_devices.c b/arch/arm/mach-at91/at91sam9rl_devices.c
index b3d365dadef5..0794954953e5 100644
--- a/arch/arm/mach-at91/at91sam9rl_devices.c
+++ b/arch/arm/mach-at91/at91sam9rl_devices.c
@@ -346,7 +346,7 @@ static struct resource twi_resources[] = {
};
static struct platform_device at91sam9rl_twi_device = {
- .name = "at91_i2c",
+ .name = "i2c-at91sam9g20",
.id = -1,
.resource = twi_resources,
.num_resources = ARRAY_SIZE(twi_resources),
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index b4aaa1bd6728..da77c37caf1e 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -290,18 +290,21 @@ 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.
+
+ Caution! at91rm9200, at91sam9261, at91sam9260, at91sam9263 devices
+ don't have clock stretching in transmission mode. For that reason,
+ you can encounter underrun issues causing premature stop sendings if
+ the latency to fill the transmission register is too long. If you
+ are facing this situation, use the i2c-gpio driver.
config I2C_AU1550
tristate "Au1550/Au1200/Au1300 SMBus interface"
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 4f46873282b8..ce3c2be7fb40 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 000000000000..78bcad031d6a
--- /dev/null
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -0,0 +1,505 @@
+/*
+ * 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_pdata {
+ unsigned clk_max_div;
+ unsigned clk_offset;
+ bool has_unre_flag;
+};
+
+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;
+ unsigned twi_cwgr_reg;
+ struct at91_twi_pdata *pdata;
+};
+
+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))
+ */
+static void __devinit at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
+{
+ int ckdiv, cdiv, div;
+ struct at91_twi_pdata *pdata = dev->pdata;
+ int offset = pdata->clk_offset;
+ int max_ckdiv = pdata->clk_max_div;
+
+ div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
+ 2 * twi_clk) - offset);
+ ckdiv = fls(div >> 8);
+ cdiv = div >> ckdiv;
+
+ if (ckdiv > max_ckdiv) {
+ dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
+ ckdiv, max_ckdiv);
+ ckdiv = max_ckdiv;
+ 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);
+
+ /* catch error flags */
+ dev->transfer_status |= status;
+
+ if (irqstatus & AT91_TWI_TXCOMP) {
+ at91_disable_twi_interrupts(dev);
+ complete(&dev->cmd_complete);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int at91_do_twi_transfer(struct at91_twi_dev *dev)
+{
+ int ret;
+ bool has_unre_flag = dev->pdata->has_unre_flag;
+
+ 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);
+ dev->transfer_status = 0;
+ 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;
+ }
+ if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) {
+ dev_err(dev->dev, "underrun while writing\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 struct at91_twi_pdata at91rm9200_config = {
+ .clk_max_div = 5,
+ .clk_offset = 3,
+ .has_unre_flag = true,
+};
+
+static struct at91_twi_pdata at91sam9261_config = {
+ .clk_max_div = 5,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+};
+
+static struct at91_twi_pdata at91sam9260_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+};
+
+static struct at91_twi_pdata at91sam9g20_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+};
+
+static struct at91_twi_pdata at91sam9g10_config = {
+ .clk_max_div = 7,
+ .clk_offset = 4,
+ .has_unre_flag = false,
+};
+
+static const struct platform_device_id at91_twi_devtypes[] = {
+ {
+ .name = "i2c-at91rm9200",
+ .driver_data = (unsigned long) &at91rm9200_config,
+ }, {
+ .name = "i2c-at91sam9261",
+ .driver_data = (unsigned long) &at91sam9261_config,
+ }, {
+ .name = "i2c-at91sam9260",
+ .driver_data = (unsigned long) &at91sam9260_config,
+ }, {
+ .name = "i2c-at91sam9g20",
+ .driver_data = (unsigned long) &at91sam9g20_config,
+ }, {
+ .name = "i2c-at91sam9g10",
+ .driver_data = (unsigned long) &at91sam9g10_config,
+ }, {
+ /* sentinel */
+ }
+};
+
+static int __devinit at91_twi_probe(struct platform_device *pdev)
+{
+ struct at91_twi_dev *dev;
+ struct resource *mem;
+ int rc;
+
+ dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
+ init_completion(&dev->cmd_complete);
+ dev->dev = &pdev->dev;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!mem)
+ return -ENODEV;
+
+ dev->pdata = at91_twi_get_driver_data(pdev);
+ if (!dev->pdata)
+ return -ENODEV;
+
+ dev->base = devm_request_and_ioremap(&pdev->dev, mem);
+ if (!dev->base)
+ return -EBUSY;
+
+ dev->irq = platform_get_irq(pdev, 0);
+ if (dev->irq < 0)
+ return dev->irq;
+
+ rc = devm_request_irq(&pdev->dev, 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);
+ return rc;
+ }
+
+ platform_set_drvdata(pdev, dev);
+
+ dev->clk = devm_clk_get(dev->dev, NULL);
+ if (IS_ERR(dev->clk)) {
+ dev_err(dev->dev, "no clock defined\n");
+ return -ENODEV;
+ }
+ clk_prepare_enable(dev->clk);
+
+ at91_calc_twi_clock(dev, TWI_CLK_HZ);
+ at91_init_twi_bus(dev);
+
+ 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);
+ clk_disable_unprepare(dev->clk);
+ return rc;
+ }
+
+ dev_info(dev->dev, "AT91 i2c bus driver.\n");
+ return 0;
+}
+
+static int __devexit at91_twi_remove(struct platform_device *pdev)
+{
+ struct at91_twi_dev *dev = platform_get_drvdata(pdev);
+ int rc;
+
+ rc = i2c_del_adapter(&dev->adapter);
+ clk_disable_unprepare(dev->clk);
+
+ 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),
+ .id_table = at91_twi_devtypes,
+ .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");
generated by cgit (git 2.34.1) at 2024-06-09 01:27:27 +0000