+++ /dev/null
---- a/drivers/i2c/busses/Kconfig
-+++ b/drivers/i2c/busses/Kconfig
-@@ -283,7 +283,7 @@ comment "I2C system bus drivers (mostly
-
- 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.
---- a/drivers/i2c/busses/i2c-at91.c
-+++ b/drivers/i2c/busses/i2c-at91.c
-@@ -11,8 +11,18 @@
- 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.
-+
-+ D. Gilbert [20100318 AT91SAM9G20]
-+ - Check for NACK, a NACK will abort current tranfser,
-+ returned as errno=EREMOTEIO unless I2C_M_IGNORE_NAK is set
-+ - Only supports 7 bit I2C device (slave) address
-+ - clockrate adjustable (module_param).
- */
-
-+
-+/* Uncomment following line to see dev_dbg() output in logs */
-+/* #define DEBUG 1 */
-+
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/err.h>
-@@ -32,26 +42,28 @@
- #define TWI_CLOCK 100000 /* Hz. max 400 Kbits/sec */
-
-
-+static unsigned int clockrate = TWI_CLOCK;
-+static unsigned int prev_clockrate = TWI_CLOCK;
- 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.
-+ * Set TWI clock dividers based on clockrate (clock rate for SCL)
- */
--static void __devinit at91_twi_hwinit(void)
-+static void at91_twi_clock_dividers(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 */
-+ if (clockrate < 1000)
-+ clockrate = 1000;
-+ else if (clockrate > 400000)
-+ clockrate = 400000;
-
-- /* Calcuate clock dividers */
-- cdiv = (clk_get_rate(twi_clk) / (2 * TWI_CLOCK)) - 3;
-+ /* Calculate clock dividers */
-+ cdiv = (clk_get_rate(twi_clk) / (2 * clockrate)) - 3;
- cdiv = cdiv + 1; /* round up */
- ckdiv = 0;
- while (cdiv > 255) {
-@@ -61,41 +73,92 @@ static void __devinit at91_twi_hwinit(vo
-
- if (cpu_is_at91rm9200()) { /* AT91RM9200 Errata #22 */
- if (ckdiv > 5) {
-- printk(KERN_ERR "AT91 I2C: Invalid TWI_CLOCK value!\n");
-+ printk(KERN_ERR "i2c-at91: Invalid AT91RM9200 clock rate\n");
- ckdiv = 5;
- }
- }
-+ /* AT91SAM9G20 has 3 bits for ckdiv so it cannot exceed 7 */
-+ if (cpu_is_at91sam9g20()) {
-+ if (ckdiv > 7) {
-+ printk(KERN_ERR "i2c-at91: Invalid AT91SAM9G20 clock "
-+ "rate, ckdiv=%lu\n", ckdiv);
-+ ckdiv = 7;
-+ }
-+ }
-
- at91_twi_write(AT91_TWI_CWGR, (ckdiv << 16) | (cdiv << 8) | cdiv);
-+ prev_clockrate = clockrate;
- }
-
- /*
-- * Poll the i2c status register until the specified bit is set.
-- * Returns 0 if timed out (100 msec).
-+ * Initialize the TWI hardware registers.
- */
--static short at91_poll_status(unsigned long bit)
-+static void __devinit at91_twi_hwinit(void)
- {
-- int loop_cntr = 10000;
-+ at91_twi_write(AT91_TWI_IDR, 0xffffffff); /* Disable all interrupts */
-+ at91_twi_write(AT91_TWI_CR, AT91_TWI_SWRST); /* Reset peripheral */
-+ /* Set Master mode; Atmel suggests disabling slave mode */
-+ at91_twi_write(AT91_TWI_CR, AT91_TWI_MSEN | AT91_TWI_SVDIS);
-
-+ at91_twi_clock_dividers();
-+}
-+
-+/*
-+ * Poll the i2c status register until the specified bit is set or a NACK
-+ * occurs. Returns 0 if timed out (50 msec). If nack_seen_p is non-NULL
-+ * then write 0 to it first, then if the NACK bit is set in the status
-+ * register then write 1 to it and immediately return with a value of 1.
-+ */
-+static short at91_poll_status(unsigned long bit, int * nack_seen_p)
-+{
-+ int loop_cntr = 5000;
-+ unsigned long stat;
-+
-+ if (nack_seen_p)
-+ *nack_seen_p = 0;
-+ if (clockrate <= 20000)
-+ loop_cntr = 100;
- do {
-- udelay(10);
-- } while (!(at91_twi_read(AT91_TWI_SR) & bit) && (--loop_cntr > 0));
-+ if (clockrate <= 20000)
-+ udelay(100);
-+ else if (clockrate <= 100000)
-+ udelay(10);
-+ else
-+ udelay(3);
-+ stat = at91_twi_read(AT91_TWI_SR);
-+ if ((stat & AT91_TWI_NACK) && nack_seen_p) {
-+ *nack_seen_p = 1;
-+ return 1;
-+ }
-+ } while (!(stat & bit) && (--loop_cntr > 0));
-
- return (loop_cntr > 0);
- }
-
- static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
- {
-+ int nack_seen = 0;
-+ int sent_stop = 0;
-+
- /* Send Start */
-- at91_twi_write(AT91_TWI_CR, AT91_TWI_START);
-+ if (1 == length) {
-+ at91_twi_write(AT91_TWI_CR, AT91_TWI_START | AT91_TWI_STOP);
-+ sent_stop = 1;
-+ } else
-+ at91_twi_write(AT91_TWI_CR, AT91_TWI_START);
-
- /* Read data */
- while (length--) {
-- if (!length) /* need to send Stop before reading last byte */
-+ /* send Stop before reading last byte (if not already done) */
-+ if ((0 == length) && (0 == sent_stop))
- at91_twi_write(AT91_TWI_CR, AT91_TWI_STOP);
-- if (!at91_poll_status(AT91_TWI_RXRDY)) {
-+ if (!at91_poll_status(AT91_TWI_RXRDY, &nack_seen)) {
- dev_dbg(&adap->dev, "RXRDY timeout\n");
- return -ETIMEDOUT;
-+ } else if (nack_seen) {
-+ dev_dbg(&adap->dev, "read NACKed\n");
-+ /* NACK supplies Stop */
-+ return -EREMOTEIO;
- }
- *buf++ = (at91_twi_read(AT91_TWI_RHR) & 0xff);
- }
-@@ -105,16 +168,24 @@ static int xfer_read(struct i2c_adapter
-
- static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
- {
-+ int nack_seen = 0;
-+
- /* Load first byte into transmitter */
- at91_twi_write(AT91_TWI_THR, *buf++);
-
-- /* Send Start */
-+ /* Send Start [AT91SAM9G20 does not need this on write] */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_START);
-
- do {
-- if (!at91_poll_status(AT91_TWI_TXRDY)) {
-+ if (!at91_poll_status(AT91_TWI_TXRDY, &nack_seen)) {
- dev_dbg(&adap->dev, "TXRDY timeout\n");
-+ /* Set Master mode again */
-+ at91_twi_write(AT91_TWI_CR, AT91_TWI_MSEN);
- return -ETIMEDOUT;
-+ } else if (nack_seen) {
-+ dev_dbg(&adap->dev, "write NACKed\n");
-+ /* NACK supplies Stop */
-+ return -EREMOTEIO;
- }
-
- length--; /* byte was transmitted */
-@@ -123,7 +194,7 @@ static int xfer_write(struct i2c_adapter
- at91_twi_write(AT91_TWI_THR, *buf++);
- } while (length);
-
-- /* Send Stop */
-+ /* Send Stop [AT91SAM9G20 does not need this on write] */
- at91_twi_write(AT91_TWI_CR, AT91_TWI_STOP);
-
- return 0;
-@@ -136,11 +207,19 @@ static int xfer_write(struct i2c_adapter
- * 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
-+ * [dpg] By 2010 silicon bugs should be fixed, will need IADR for 10 bit device address
- */
- static int at91_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg, int num)
- {
- int i, ret;
-+ int nack_seen = 0;
-
-+ if (prev_clockrate != clockrate) {
-+ dev_dbg(&adap->dev, "at91_xfer: prev_clockrate=%u "
-+ "clockrate=%u, change\n", prev_clockrate, clockrate);
-+ at91_twi_clock_dividers();
-+ msleep(1); /* let things settle */
-+ }
- dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
-
- for (i = 0; i < num; i++) {
-@@ -158,13 +237,23 @@ static int at91_xfer(struct i2c_adapter
- else
- ret = xfer_write(adap, pmsg->buf, pmsg->len);
-
-- if (ret)
-- return ret;
--
-+ if (ret) {
-+ if ((I2C_M_IGNORE_NAK & pmsg->flags) &&
-+ (-EREMOTEIO == ret)) {
-+ dev_dbg(&adap->dev, "transfer "
-+ "NACKed, skip to next\n");
-+ pmsg++;
-+ continue;
-+ } else
-+ return ret;
-+ }
- /* Wait until transfer is finished */
-- if (!at91_poll_status(AT91_TWI_TXCOMP)) {
-+ if (!at91_poll_status(AT91_TWI_TXCOMP, &nack_seen)) {
- dev_dbg(&adap->dev, "TXCOMP timeout\n");
- return -ETIMEDOUT;
-+ } else if (nack_seen) {
-+ dev_dbg(&adap->dev, "TXCOMP NACKed\n");
-+ return -EREMOTEIO;
- }
- }
- dev_dbg(&adap->dev, "transfer complete\n");
-@@ -239,7 +328,8 @@ static int __devinit at91_i2c_probe(stru
- goto fail3;
- }
-
-- dev_info(&pdev->dev, "AT91 i2c bus driver.\n");
-+ dev_info(&pdev->dev, "AT91 TWI (I2C) bus driver [SCL %d Hz]\n",
-+ clockrate);
- return 0;
-
- fail3:
-@@ -295,6 +385,11 @@ static int at91_i2c_resume(struct platfo
- #define at91_i2c_resume NULL
- #endif
-
-+/* I2C clock speed, in Hz 0-400kHz*/
-+module_param(clockrate, uint, S_IRUGO | S_IWUSR);
-+MODULE_PARM_DESC(clockrate,
-+ "SCL clock rate, 1000 to 400000 Hz (def: 100 kHz)");
-+
- /* work with "modprobe at91_i2c" from hotplugging or coldplugging */
- MODULE_ALIAS("platform:at91_i2c");
-
-@@ -323,5 +418,5 @@ module_init(at91_i2c_init);
- module_exit(at91_i2c_exit);
-
- MODULE_AUTHOR("Rick Bronson");
--MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
-+MODULE_DESCRIPTION("I2C (TWI) master driver for Atmel AT91");
- MODULE_LICENSE("GPL");
projects / openwrt.git / blobdiff