i2c: at91: add new driver
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>
Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
[wsa: squashed with the following patches from Ludovic to have some flaws
fixed:
i2c: at91: use managed resources
i2c: at91: add warning about transmission issues for some devices
i2c: at91: use an id table for SoC dependent parameters
]
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
hifive-unleashed-5.1
Nikolaus Voss
Wolfram Sang
parent
a879e9c34b
commit
fac368a040
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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),
|
||||
|
|
|
|||
|
|
@ -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"
|
||||
|
|
|
|||
|
|
@ -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
|
||||
|
|
|
|||
|
|
@ -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");
|
||||
Loading…
Reference in New Issue