i2c: octeon: Cleanup i2c-octeon driver
Cleanup only without functional change.
- removed DRV_VERSION
- defines: use defines instead of plain values,
use BIT_ULL macro, add comments
- rename waitqueue return value to time_left
- sort local variables by length
- fix indentation and whitespace errors
- make function return void if the result is not used
(octeon_i2c_stop, octeon_i2c_set_clock)
- remove debug code from octeon_i2c_stop
- renamed some functions for readability
- update copyright
Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index 4a08418..9787379 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -2,7 +2,7 @@
* (C) Copyright 2009-2010
* Nokia Siemens Networks, michael.lawnick.ext@nsn.com
*
- * Portions Copyright (C) 2010, 2011 Cavium Networks, Inc.
+ * Portions Copyright (C) 2010 - 2016 Cavium, Inc.
*
* This is a driver for the i2c adapter in Cavium Networks' OCTEON processors.
*
@@ -26,39 +26,48 @@
#define DRV_NAME "i2c-octeon"
-/* The previous out-of-tree version was implicitly version 1.0. */
-#define DRV_VERSION "2.0"
-
-/* register offsets */
-#define SW_TWSI 0x00
-#define TWSI_INT 0x10
+/* Register offsets */
+#define SW_TWSI 0x00
+#define TWSI_INT 0x10
/* Controller command patterns */
-#define SW_TWSI_V 0x8000000000000000ull
-#define SW_TWSI_EOP_TWSI_DATA 0x0C00000100000000ull
-#define SW_TWSI_EOP_TWSI_CTL 0x0C00000200000000ull
-#define SW_TWSI_EOP_TWSI_CLKCTL 0x0C00000300000000ull
-#define SW_TWSI_EOP_TWSI_STAT 0x0C00000300000000ull
-#define SW_TWSI_EOP_TWSI_RST 0x0C00000700000000ull
-#define SW_TWSI_OP_TWSI_CLK 0x0800000000000000ull
-#define SW_TWSI_R 0x0100000000000000ull
+#define SW_TWSI_V BIT_ULL(63) /* Valid bit */
+#define SW_TWSI_R BIT_ULL(56) /* Result or read bit */
+
+/* Controller opcode word (bits 60:57) */
+#define SW_TWSI_OP_SHIFT 57
+#define SW_TWSI_OP_TWSI_CLK (4ULL << SW_TWSI_OP_SHIFT)
+#define SW_TWSI_OP_EOP (6ULL << SW_TWSI_OP_SHIFT) /* Extended opcode */
+
+/* Controller extended opcode word (bits 34:32) */
+#define SW_TWSI_EOP_SHIFT 32
+#define SW_TWSI_EOP_TWSI_DATA (SW_TWSI_OP_EOP | 1ULL << SW_TWSI_EOP_SHIFT)
+#define SW_TWSI_EOP_TWSI_CTL (SW_TWSI_OP_EOP | 2ULL << SW_TWSI_EOP_SHIFT)
+#define SW_TWSI_EOP_TWSI_CLKCTL (SW_TWSI_OP_EOP | 3ULL << SW_TWSI_EOP_SHIFT)
+#define SW_TWSI_EOP_TWSI_STAT (SW_TWSI_OP_EOP | 3ULL << SW_TWSI_EOP_SHIFT)
+#define SW_TWSI_EOP_TWSI_RST (SW_TWSI_OP_EOP | 7ULL << SW_TWSI_EOP_SHIFT)
/* Controller command and status bits */
-#define TWSI_CTL_CE 0x80
-#define TWSI_CTL_ENAB 0x40
-#define TWSI_CTL_STA 0x20
-#define TWSI_CTL_STP 0x10
-#define TWSI_CTL_IFLG 0x08
-#define TWSI_CTL_AAK 0x04
+#define TWSI_CTL_CE 0x80
+#define TWSI_CTL_ENAB 0x40 /* Bus enable */
+#define TWSI_CTL_STA 0x20 /* Master-mode start, HW clears when done */
+#define TWSI_CTL_STP 0x10 /* Master-mode stop, HW clears when done */
+#define TWSI_CTL_IFLG 0x08 /* HW event, SW writes 0 to ACK */
+#define TWSI_CTL_AAK 0x04 /* Assert ACK */
/* Some status values */
-#define STAT_START 0x08
-#define STAT_RSTART 0x10
-#define STAT_TXADDR_ACK 0x18
-#define STAT_TXDATA_ACK 0x28
-#define STAT_RXADDR_ACK 0x40
-#define STAT_RXDATA_ACK 0x50
-#define STAT_IDLE 0xF8
+#define STAT_START 0x08
+#define STAT_RSTART 0x10
+#define STAT_TXADDR_ACK 0x18
+#define STAT_TXDATA_ACK 0x28
+#define STAT_RXADDR_ACK 0x40
+#define STAT_RXDATA_ACK 0x50
+#define STAT_IDLE 0xF8
+
+/* TWSI_INT values */
+#define TWSI_INT_CORE_EN BIT_ULL(6)
+#define TWSI_INT_SDA_OVR BIT_ULL(8)
+#define TWSI_INT_SCL_OVR BIT_ULL(9)
struct octeon_i2c {
wait_queue_head_t queue;
@@ -80,9 +89,7 @@
*
* The I2C core registers are accessed indirectly via the SW_TWSI CSR.
*/
-static void octeon_i2c_write_sw(struct octeon_i2c *i2c,
- u64 eop_reg,
- u8 data)
+static void octeon_i2c_write_sw(struct octeon_i2c *i2c, u64 eop_reg, u8 data)
{
u64 tmp;
@@ -93,7 +100,7 @@
}
/**
- * octeon_i2c_read_sw - write an I2C core register
+ * octeon_i2c_read_sw - read lower bits of an I2C core register
* @i2c: The struct octeon_i2c
* @eop_reg: Register selector
*
@@ -133,12 +140,13 @@
*/
static void octeon_i2c_int_enable(struct octeon_i2c *i2c)
{
- octeon_i2c_write_int(i2c, 0x40);
+ octeon_i2c_write_int(i2c, TWSI_INT_CORE_EN);
}
/* disable the CORE interrupt */
static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
{
+ /* clear TS/ST/IFLG events */
octeon_i2c_write_int(i2c, 0);
}
@@ -154,17 +162,19 @@
int i;
dev_dbg(i2c->dev, "%s\n", __func__);
+
for (i = 0; i < 9; i++) {
- octeon_i2c_write_int(i2c, 0x0);
+ octeon_i2c_write_int(i2c, 0);
udelay(5);
- octeon_i2c_write_int(i2c, 0x200);
+ octeon_i2c_write_int(i2c, TWSI_INT_SCL_OVR);
udelay(5);
}
- octeon_i2c_write_int(i2c, 0x300);
+ /* hand-crank a STOP */
+ octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR | TWSI_INT_SCL_OVR);
udelay(5);
- octeon_i2c_write_int(i2c, 0x100);
+ octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR);
udelay(5);
- octeon_i2c_write_int(i2c, 0x0);
+ octeon_i2c_write_int(i2c, 0);
}
/* interrupt service routine */
@@ -192,17 +202,13 @@
*/
static int octeon_i2c_wait(struct octeon_i2c *i2c)
{
- long result;
+ long time_left;
octeon_i2c_int_enable(i2c);
-
- result = wait_event_timeout(i2c->queue,
- octeon_i2c_test_iflg(i2c),
- i2c->adap.timeout);
-
+ time_left = wait_event_timeout(i2c->queue, octeon_i2c_test_iflg(i2c),
+ i2c->adap.timeout);
octeon_i2c_int_disable(i2c);
-
- if (result == 0) {
+ if (!time_left) {
dev_dbg(i2c->dev, "%s: timeout\n", __func__);
return -ETIMEDOUT;
}
@@ -218,11 +224,11 @@
*/
static int octeon_i2c_start(struct octeon_i2c *i2c)
{
- u8 data;
int result;
+ u8 data;
octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
- TWSI_CTL_ENAB | TWSI_CTL_STA);
+ TWSI_CTL_ENAB | TWSI_CTL_STA);
result = octeon_i2c_wait(i2c);
if (result) {
@@ -235,7 +241,6 @@
octeon_i2c_unblock(i2c);
octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
TWSI_CTL_ENAB | TWSI_CTL_STA);
-
result = octeon_i2c_wait(i2c);
}
if (result)
@@ -251,26 +256,11 @@
return 0;
}
-/**
- * octeon_i2c_stop - send STOP to the bus
- * @i2c: The struct octeon_i2c
- *
- * Returns 0 on success, otherwise a negative errno.
- */
-static int octeon_i2c_stop(struct octeon_i2c *i2c)
+/* send STOP to the bus */
+static void octeon_i2c_stop(struct octeon_i2c *i2c)
{
- u8 data;
-
octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
TWSI_CTL_ENAB | TWSI_CTL_STP);
-
- data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
-
- if (data != STAT_IDLE) {
- dev_err(i2c->dev, "%s: bad status(0x%x)\n", __func__, data);
- return -EIO;
- }
- return 0;
}
/**
@@ -303,6 +293,7 @@
for (i = 0; i < length; i++) {
tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
+
if ((tmp != STAT_TXADDR_ACK) && (tmp != STAT_TXDATA_ACK)) {
dev_err(i2c->dev,
"%s: bad status before write (0x%x)\n",
@@ -345,7 +336,7 @@
if (result)
return result;
- octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, (target<<1) | 1);
+ octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, (target << 1) | 1);
octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
result = octeon_i2c_wait(i2c);
@@ -354,6 +345,7 @@
for (i = 0; i < length; i++) {
tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
+
if ((tmp != STAT_RXDATA_ACK) && (tmp != STAT_RXADDR_ACK)) {
dev_err(i2c->dev,
"%s: bad status before read (0x%x)\n",
@@ -361,12 +353,12 @@
return -EIO;
}
- if (i+1 < length)
+ if (i + 1 < length)
octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
- TWSI_CTL_ENAB | TWSI_CTL_AAK);
+ TWSI_CTL_ENAB | TWSI_CTL_AAK);
else
octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
- TWSI_CTL_ENAB);
+ TWSI_CTL_ENAB);
result = octeon_i2c_wait(i2c);
if (result)
@@ -385,27 +377,25 @@
*
* Returns the number of messages processed, or a negative errno on failure.
*/
-static int octeon_i2c_xfer(struct i2c_adapter *adap,
- struct i2c_msg *msgs,
+static int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
- struct i2c_msg *pmsg;
- int i;
- int ret = 0;
struct octeon_i2c *i2c = i2c_get_adapdata(adap);
+ int i, ret = 0;
for (i = 0; ret == 0 && i < num; i++) {
- pmsg = &msgs[i];
+ struct i2c_msg *pmsg = &msgs[i];
+
dev_dbg(i2c->dev,
"Doing %s %d byte(s) to/from 0x%02x - %d of %d messages\n",
pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->len, pmsg->addr, i + 1, num);
if (pmsg->flags & I2C_M_RD)
ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf,
- pmsg->len);
+ pmsg->len);
else
ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf,
- pmsg->len);
+ pmsg->len);
}
octeon_i2c_stop(i2c);
@@ -430,7 +420,7 @@
};
/* calculate and set clock divisors */
-static int octeon_i2c_setclock(struct octeon_i2c *i2c)
+static void octeon_i2c_set_clock(struct octeon_i2c *i2c)
{
int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;
@@ -438,8 +428,7 @@
for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
/*
* An mdiv value of less than 2 seems to not work well
- * with ds1337 RTCs, so we constrain it to larger
- * values.
+ * with ds1337 RTCs, so we constrain it to larger values.
*/
for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {
/*
@@ -449,6 +438,7 @@
tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;
tclk *= (1 << ndiv_idx);
thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
+
for (inc = 0; inc <= 1; inc++) {
thp_idx = thp_base + inc;
if (thp_idx < 5 || thp_idx > 0xff)
@@ -469,11 +459,9 @@
}
octeon_i2c_write_sw(i2c, SW_TWSI_OP_TWSI_CLK, thp);
octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv);
-
- return 0;
}
-static int octeon_i2c_initlowlevel(struct octeon_i2c *i2c)
+static int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c)
{
u8 status;
int tries;
@@ -496,9 +484,10 @@
static int octeon_i2c_probe(struct platform_device *pdev)
{
- int irq, result = 0;
- struct octeon_i2c *i2c;
+ struct device_node *node = pdev->dev.of_node;
struct resource *res_mem;
+ struct octeon_i2c *i2c;
+ int irq, result = 0;
/* All adaptors have an irq. */
irq = platform_get_irq(pdev, 0);
@@ -507,7 +496,6 @@
i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c) {
- dev_err(&pdev->dev, "kzalloc failed\n");
result = -ENOMEM;
goto out;
}
@@ -528,10 +516,8 @@
* "clock-frequency". Try the official one first and then
* fall back if it doesn't exist.
*/
- if (of_property_read_u32(pdev->dev.of_node,
- "clock-frequency", &i2c->twsi_freq) &&
- of_property_read_u32(pdev->dev.of_node,
- "clock-rate", &i2c->twsi_freq)) {
+ if (of_property_read_u32(node, "clock-frequency", &i2c->twsi_freq) &&
+ of_property_read_u32(node, "clock-rate", &i2c->twsi_freq)) {
dev_err(i2c->dev,
"no I2C 'clock-rate' or 'clock-frequency' property\n");
result = -ENXIO;
@@ -541,7 +527,7 @@
i2c->sys_freq = octeon_get_io_clock_rate();
if (!devm_request_mem_region(&pdev->dev, i2c->twsi_phys, i2c->regsize,
- res_mem->name)) {
+ res_mem->name)) {
dev_err(i2c->dev, "request_mem_region failed\n");
goto out;
}
@@ -558,21 +544,17 @@
goto out;
}
- result = octeon_i2c_initlowlevel(i2c);
+ result = octeon_i2c_init_lowlevel(i2c);
if (result) {
dev_err(i2c->dev, "init low level failed\n");
goto out;
}
- result = octeon_i2c_setclock(i2c);
- if (result) {
- dev_err(i2c->dev, "clock init failed\n");
- goto out;
- }
+ octeon_i2c_set_clock(i2c);
i2c->adap = octeon_i2c_ops;
i2c->adap.dev.parent = &pdev->dev;
- i2c->adap.dev.of_node = pdev->dev.of_node;
+ i2c->adap.dev.of_node = node;
i2c_set_adapdata(&i2c->adap, i2c);
platform_set_drvdata(pdev, i2c);
@@ -581,8 +563,7 @@
dev_err(i2c->dev, "failed to add adapter\n");
goto out;
}
- dev_info(i2c->dev, "version %s\n", DRV_VERSION);
-
+ dev_info(i2c->dev, "probed\n");
return 0;
out:
@@ -597,10 +578,8 @@
return 0;
};
-static struct of_device_id octeon_i2c_match[] = {
- {
- .compatible = "cavium,octeon-3860-twsi",
- },
+static const struct of_device_id octeon_i2c_match[] = {
+ { .compatible = "cavium,octeon-3860-twsi", },
{},
};
MODULE_DEVICE_TABLE(of, octeon_i2c_match);
@@ -619,4 +598,3 @@
MODULE_AUTHOR("Michael Lawnick <michael.lawnick.ext@nsn.com>");
MODULE_DESCRIPTION("I2C-Bus adapter for Cavium OCTEON processors");
MODULE_LICENSE("GPL");
-MODULE_VERSION(DRV_VERSION);