w1: complete the 1-wire (w1) ds1wm driver search algorithm
This adds multi-slave support of the w1 bus for the ds1wm Synthesizable
1-Wire Bus Master. Also many fixes and tweaks based on the rev3 of the
datasheet http://datasheets.maxim-ic.com/en/ds/DS1WM.pdf
Signed-off-by: Jean-François Dagenais <dagenaisj@sonatest.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
Cc: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c
index 0855d6cc..ad57593 100644
--- a/drivers/w1/masters/ds1wm.c
+++ b/drivers/w1/masters/ds1wm.c
@@ -33,6 +33,7 @@
#define DS1WM_INT 0x02 /* R/W interrupt status */
#define DS1WM_INT_EN 0x03 /* R/W interrupt enable */
#define DS1WM_CLKDIV 0x04 /* R/W 5 bits of divisor and pre-scale */
+#define DS1WM_CNTRL 0x05 /* R/W master control register (not used yet) */
#define DS1WM_CMD_1W_RESET (1 << 0) /* force reset on 1-wire bus */
#define DS1WM_CMD_SRA (1 << 1) /* enable Search ROM accelerator mode */
@@ -56,6 +57,7 @@
#define DS1WM_INTEN_ERSRF (1 << 5) /* enable rx shift register full int */
#define DS1WM_INTEN_DQO (1 << 6) /* enable direct bus driving ops */
+#define DS1WM_INTEN_NOT_IAS (~DS1WM_INTEN_IAS) /* all but INTR active state */
#define DS1WM_TIMEOUT (HZ * 5)
@@ -63,41 +65,50 @@
unsigned long freq;
unsigned long divisor;
} freq[] = {
- { 4000000, 0x8 },
- { 5000000, 0x2 },
- { 6000000, 0x5 },
- { 7000000, 0x3 },
- { 8000000, 0xc },
- { 10000000, 0x6 },
- { 12000000, 0x9 },
- { 14000000, 0x7 },
- { 16000000, 0x10 },
- { 20000000, 0xa },
- { 24000000, 0xd },
- { 28000000, 0xb },
- { 32000000, 0x14 },
- { 40000000, 0xe },
- { 48000000, 0x11 },
- { 56000000, 0xf },
- { 64000000, 0x18 },
- { 80000000, 0x12 },
- { 96000000, 0x15 },
- { 112000000, 0x13 },
- { 128000000, 0x1c },
+ { 1000000, 0x80 },
+ { 2000000, 0x84 },
+ { 3000000, 0x81 },
+ { 4000000, 0x88 },
+ { 5000000, 0x82 },
+ { 6000000, 0x85 },
+ { 7000000, 0x83 },
+ { 8000000, 0x8c },
+ { 10000000, 0x86 },
+ { 12000000, 0x89 },
+ { 14000000, 0x87 },
+ { 16000000, 0x90 },
+ { 20000000, 0x8a },
+ { 24000000, 0x8d },
+ { 28000000, 0x8b },
+ { 32000000, 0x94 },
+ { 40000000, 0x8e },
+ { 48000000, 0x91 },
+ { 56000000, 0x8f },
+ { 64000000, 0x98 },
+ { 80000000, 0x92 },
+ { 96000000, 0x95 },
+ { 112000000, 0x93 },
+ { 128000000, 0x9c },
+/* you can continue this table, consult the OPERATION - CLOCK DIVISOR
+ section of the ds1wm spec sheet. */
};
struct ds1wm_data {
- void __iomem *map;
- int bus_shift; /* # of shifts to calc register offsets */
+ void __iomem *map;
+ int bus_shift; /* # of shifts to calc register offsets */
struct platform_device *pdev;
- const struct mfd_cell *cell;
- int irq;
- int active_high;
- int slave_present;
- void *reset_complete;
- void *read_complete;
- void *write_complete;
- u8 read_byte; /* last byte received */
+ const struct mfd_cell *cell;
+ int irq;
+ int slave_present;
+ void *reset_complete;
+ void *read_complete;
+ void *write_complete;
+ int read_error;
+ /* last byte received */
+ u8 read_byte;
+ /* byte to write that makes all intr disabled, */
+ /* considering active_state (IAS) (optimization) */
+ u8 int_en_reg_none;
};
static inline void ds1wm_write_register(struct ds1wm_data *ds1wm_data, u32 reg,
@@ -115,23 +126,39 @@
static irqreturn_t ds1wm_isr(int isr, void *data)
{
struct ds1wm_data *ds1wm_data = data;
- u8 intr = ds1wm_read_register(ds1wm_data, DS1WM_INT);
+ u8 intr;
+ u8 inten = ds1wm_read_register(ds1wm_data, DS1WM_INT_EN);
+ /* if no bits are set in int enable register (except the IAS)
+ than go no further, reading the regs below has side effects */
+ if (!(inten & DS1WM_INTEN_NOT_IAS))
+ return IRQ_NONE;
+
+ ds1wm_write_register(ds1wm_data,
+ DS1WM_INT_EN, ds1wm_data->int_en_reg_none);
+
+ /* this read action clears the INTR and certain flags in ds1wm */
+ intr = ds1wm_read_register(ds1wm_data, DS1WM_INT);
ds1wm_data->slave_present = (intr & DS1WM_INT_PDR) ? 0 : 1;
- if ((intr & DS1WM_INT_PD) && ds1wm_data->reset_complete)
- complete(ds1wm_data->reset_complete);
-
- if ((intr & DS1WM_INT_TSRE) && ds1wm_data->write_complete)
+ if ((intr & DS1WM_INT_TSRE) && ds1wm_data->write_complete) {
+ inten &= ~DS1WM_INTEN_ETMT;
complete(ds1wm_data->write_complete);
-
+ }
if (intr & DS1WM_INT_RBF) {
+ /* this read clears the RBF flag */
ds1wm_data->read_byte = ds1wm_read_register(ds1wm_data,
- DS1WM_DATA);
+ DS1WM_DATA);
+ inten &= ~DS1WM_INTEN_ERBF;
if (ds1wm_data->read_complete)
complete(ds1wm_data->read_complete);
}
+ if ((intr & DS1WM_INT_PD) && ds1wm_data->reset_complete) {
+ inten &= ~DS1WM_INTEN_EPD;
+ complete(ds1wm_data->reset_complete);
+ }
+ ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, inten);
return IRQ_HANDLED;
}
@@ -142,33 +169,19 @@
ds1wm_data->reset_complete = &reset_done;
+ /* enable Presence detect only */
ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_EPD |
- (ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));
+ ds1wm_data->int_en_reg_none);
ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_1W_RESET);
timeleft = wait_for_completion_timeout(&reset_done, DS1WM_TIMEOUT);
ds1wm_data->reset_complete = NULL;
if (!timeleft) {
- dev_err(&ds1wm_data->pdev->dev, "reset failed\n");
+ dev_err(&ds1wm_data->pdev->dev, "reset failed, timed out\n");
return 1;
}
- /* Wait for the end of the reset. According to the specs, the time
- * from when the interrupt is asserted to the end of the reset is:
- * tRSTH - tPDH - tPDL - tPDI
- * 625 us - 60 us - 240 us - 100 ns = 324.9 us
- *
- * We'll wait a bit longer just to be sure.
- * Was udelay(500), but if it is going to busywait the cpu that long,
- * might as well come back later.
- */
- msleep(1);
-
- ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
- DS1WM_INTEN_ERBF | DS1WM_INTEN_ETMT | DS1WM_INTEN_EPD |
- (ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0));
-
if (!ds1wm_data->slave_present) {
dev_dbg(&ds1wm_data->pdev->dev, "reset: no devices found\n");
return 1;
@@ -179,26 +192,47 @@
static int ds1wm_write(struct ds1wm_data *ds1wm_data, u8 data)
{
+ unsigned long timeleft;
DECLARE_COMPLETION_ONSTACK(write_done);
ds1wm_data->write_complete = &write_done;
+ ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
+ ds1wm_data->int_en_reg_none | DS1WM_INTEN_ETMT);
+
ds1wm_write_register(ds1wm_data, DS1WM_DATA, data);
- wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);
+ timeleft = wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);
+
ds1wm_data->write_complete = NULL;
+ if (!timeleft) {
+ dev_err(&ds1wm_data->pdev->dev, "write failed, timed out\n");
+ return -ETIMEDOUT;
+ }
return 0;
}
-static int ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
+static u8 ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
{
+ unsigned long timeleft;
+ u8 intEnable = DS1WM_INTEN_ERBF | ds1wm_data->int_en_reg_none;
DECLARE_COMPLETION_ONSTACK(read_done);
+
+ ds1wm_read_register(ds1wm_data, DS1WM_DATA);
+
ds1wm_data->read_complete = &read_done;
+ ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, intEnable);
- ds1wm_write(ds1wm_data, write_data);
- wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);
+ ds1wm_write_register(ds1wm_data, DS1WM_DATA, write_data);
+ timeleft = wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);
+
ds1wm_data->read_complete = NULL;
-
+ if (!timeleft) {
+ dev_err(&ds1wm_data->pdev->dev, "read failed, timed out\n");
+ ds1wm_data->read_error = -ETIMEDOUT;
+ return 0xFF;
+ }
+ ds1wm_data->read_error = 0;
return ds1wm_data->read_byte;
}
@@ -206,8 +240,8 @@
{
int i;
- for (i = 0; i < ARRAY_SIZE(freq); i++)
- if (gclk <= freq[i].freq)
+ for (i = ARRAY_SIZE(freq)-1; i >= 0; --i)
+ if (gclk >= freq[i].freq)
return freq[i].divisor;
return 0;
@@ -222,6 +256,8 @@
ds1wm_data->cell->enable(ds1wm_data->pdev);
divisor = ds1wm_find_divisor(plat->clock_rate);
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "found divisor 0x%x for clock %d\n", divisor, plat->clock_rate);
if (divisor == 0) {
dev_err(&ds1wm_data->pdev->dev,
"no suitable divisor for %dHz clock\n",
@@ -242,7 +278,7 @@
/* Disable interrupts. */
ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
- ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0);
+ ds1wm_data->int_en_reg_none);
if (ds1wm_data->cell->disable)
ds1wm_data->cell->disable(ds1wm_data->pdev);
@@ -279,41 +315,121 @@
{
struct ds1wm_data *ds1wm_data = data;
int i;
- unsigned long long rom_id;
+ int ms_discrep_bit = -1;
+ u64 r = 0; /* holds the progress of the search */
+ u64 r_prime, d;
+ unsigned slaves_found = 0;
+ unsigned int pass = 0;
- /* XXX We need to iterate for multiple devices per the DS1WM docs.
- * See http://www.maxim-ic.com/appnotes.cfm/appnote_number/120. */
- if (ds1wm_reset(ds1wm_data))
- return;
+ dev_dbg(&ds1wm_data->pdev->dev, "search begin\n");
+ while (true) {
+ ++pass;
+ if (pass > 100) {
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "too many attempts (100), search aborted\n");
+ return;
+ }
- ds1wm_write(ds1wm_data, search_type);
- ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);
+ if (ds1wm_reset(ds1wm_data)) {
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d reset error (or no slaves)\n", pass);
+ break;
+ }
- for (rom_id = 0, i = 0; i < 16; i++) {
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d r : %0#18llx writing SEARCH_ROM\n", pass, r);
+ ds1wm_write(ds1wm_data, search_type);
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d entering ASM\n", pass);
+ ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d begining nibble loop\n", pass);
- unsigned char resp, r, d;
+ r_prime = 0;
+ d = 0;
+ /* we work one nibble at a time */
+ /* each nibble is interleaved to form a byte */
+ for (i = 0; i < 16; i++) {
- resp = ds1wm_read(ds1wm_data, 0x00);
+ unsigned char resp, _r, _r_prime, _d;
- r = ((resp & 0x02) >> 1) |
- ((resp & 0x08) >> 2) |
- ((resp & 0x20) >> 3) |
- ((resp & 0x80) >> 4);
+ _r = (r >> (4*i)) & 0xf;
+ _r = ((_r & 0x1) << 1) |
+ ((_r & 0x2) << 2) |
+ ((_r & 0x4) << 3) |
+ ((_r & 0x8) << 4);
- d = ((resp & 0x01) >> 0) |
- ((resp & 0x04) >> 1) |
- ((resp & 0x10) >> 2) |
- ((resp & 0x40) >> 3);
+ /* writes _r, then reads back: */
+ resp = ds1wm_read(ds1wm_data, _r);
- rom_id |= (unsigned long long) r << (i * 4);
+ if (ds1wm_data->read_error) {
+ dev_err(&ds1wm_data->pdev->dev,
+ "pass: %d nibble: %d read error\n", pass, i);
+ break;
+ }
- }
- dev_dbg(&ds1wm_data->pdev->dev, "found 0x%08llX\n", rom_id);
+ _r_prime = ((resp & 0x02) >> 1) |
+ ((resp & 0x08) >> 2) |
+ ((resp & 0x20) >> 3) |
+ ((resp & 0x80) >> 4);
- ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
- ds1wm_reset(ds1wm_data);
+ _d = ((resp & 0x01) >> 0) |
+ ((resp & 0x04) >> 1) |
+ ((resp & 0x10) >> 2) |
+ ((resp & 0x40) >> 3);
- slave_found(master_dev, rom_id);
+ r_prime |= (unsigned long long) _r_prime << (i * 4);
+ d |= (unsigned long long) _d << (i * 4);
+
+ }
+ if (ds1wm_data->read_error) {
+ dev_err(&ds1wm_data->pdev->dev,
+ "pass: %d read error, retrying\n", pass);
+ break;
+ }
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d r\': %0#18llx d:%0#18llx\n",
+ pass, r_prime, d);
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d nibble loop complete, exiting ASM\n", pass);
+ ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d resetting bus\n", pass);
+ ds1wm_reset(ds1wm_data);
+ if ((r_prime & ((u64)1 << 63)) && (d & ((u64)1 << 63))) {
+ dev_err(&ds1wm_data->pdev->dev,
+ "pass: %d bus error, retrying\n", pass);
+ continue; /* start over */
+ }
+
+
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d found %0#18llx\n", pass, r_prime);
+ slave_found(master_dev, r_prime);
+ ++slaves_found;
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d complete, preparing next pass\n", pass);
+
+ /* any discrepency found which we already choose the
+ '1' branch is now is now irrelevant we reveal the
+ next branch with this: */
+ d &= ~r;
+ /* find last bit set, i.e. the most signif. bit set */
+ ms_discrep_bit = fls64(d) - 1;
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d new d:%0#18llx MS discrep bit:%d\n",
+ pass, d, ms_discrep_bit);
+
+ /* prev_ms_discrep_bit = ms_discrep_bit;
+ prepare for next ROM search: */
+ if (ms_discrep_bit == -1)
+ break;
+
+ r = (r & ~(~0ull << (ms_discrep_bit))) | 1 << ms_discrep_bit;
+ } /* end while true */
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "pass: %d total: %d search done ms d bit pos: %d\n", pass,
+ slaves_found, ms_discrep_bit);
}
/* --------------------------------------------------------------------- */
@@ -373,15 +489,15 @@
goto err1;
}
ds1wm_data->irq = res->start;
- ds1wm_data->active_high = plat->active_high;
+ ds1wm_data->int_en_reg_none = (plat->active_high ? DS1WM_INTEN_IAS : 0);
if (res->flags & IORESOURCE_IRQ_HIGHEDGE)
irq_set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_RISING);
if (res->flags & IORESOURCE_IRQ_LOWEDGE)
irq_set_irq_type(ds1wm_data->irq, IRQ_TYPE_EDGE_FALLING);
- ret = request_irq(ds1wm_data->irq, ds1wm_isr, IRQF_DISABLED,
- "ds1wm", ds1wm_data);
+ ret = request_irq(ds1wm_data->irq, ds1wm_isr,
+ IRQF_DISABLED | IRQF_SHARED, "ds1wm", ds1wm_data);
if (ret)
goto err1;
@@ -468,5 +584,6 @@
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
- "Matt Reimer <mreimer@vpop.net>");
+ "Matt Reimer <mreimer@vpop.net>,"
+ "Jean-Francois Dagenais <dagenaisj@sonatest.com>");
MODULE_DESCRIPTION("DS1WM w1 busmaster driver");