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SubjectRe: [2/2] Driver for the Maxim DS1WM, a 1-wire bus master ASIC core.
Date
On Apr 25, 2007, at 5:46 PM, Andrew Morton wrote:

> On Tue, 24 Apr 2007 14:02:03 +0400 Evgeniy Polyakov
> <johnpol@2ka.mipt.ru> wrote:
>
>> +#define DS1WM_CMD_1W_RESET 1 << 0 /* force reset on 1-wire bus */
>> +#define DS1WM_CMD_SRA 1 << 1 /* enable Search ROM accelerator
>> mode */
>> +#define DS1WM_CMD_DQ_OUTPUT 1 << 2 /* write only - forces bus low */
>> +#define DS1WM_CMD_DQ_INPUT 1 << 3 /* read only - reflects state
>> of bus */
>> +
>> +#define DS1WM_INT_PD 1 << 0 /* presence detect */
>> +#define DS1WM_INT_PDR 1 << 1 /* presence detect result */
>> +#define DS1WM_INT_TBE 1 << 2 /* tx buffer empty */
>> +#define DS1WM_INT_TSRE 1 << 3 /* tx shift register empty */
>> +#define DS1WM_INT_RBF 1 << 4 /* rx buffer full */
>> +#define DS1WM_INT_RSRF 1 << 5 /* rx shift register full */
>> +
>> +#define DS1WM_INTEN_EPD 1 << 0 /* enable presence detect int */
>> +#define DS1WM_INTEN_IAS 1 << 1 /* INTR active state */
>> +#define DS1WM_INTEN_ETBE 1 << 2 /* enable tx buffer empty int */
>> +#define DS1WM_INTEN_ETMT 1 << 3 /* enable tx shift register
>> empty int */
>> +#define DS1WM_INTEN_ERBF 1 << 4 /* enable rx buffer full int */
>> +#define DS1WM_INTEN_ERSRF 1 << 5 /* enable rx shift register
>> full int */
>> +#define DS1WM_INTEN_DQO 1 << 6 /* enable direct bus driving ops
>> + (undocumented), Szabolcs Gyurko */
>
> These macros are very dangerous - please parenthesise them all.

(and several other helpful suggestions...)

Thanks for your review Andrew. I made all the code changes you
suggested in the attached patch.

Matt
From b1f6ac622b85cbc08b96dbff3ccb5e0b3a8e1ad0 Mon Sep 17 00:00:00 2001
From: Matt Reimer <mreimer@vpop.net>
Date: Thu, 26 Apr 2007 09:39:30 -0700
Subject: [PATCH] w1 driver for Maxim DS1WM

Implements a driver for the Maxim DS1WM ASIC core, used in most HP
iPAQs.

Signed-off-by: Matt Reimer <mreimer@vpop.net>
---
drivers/w1/masters/Kconfig | 8 +
drivers/w1/masters/Makefile | 2 +-
drivers/w1/masters/ds1wm.c | 461 +++++++++++++++++++++++++++++++++++++++++++
include/linux/ds1wm.h | 12 ++
4 files changed, 482 insertions(+), 1 deletions(-)
create mode 100644 drivers/w1/masters/ds1wm.c
create mode 100644 include/linux/ds1wm.h
diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
index 2fb4255..ca44f9e 100644
--- a/drivers/w1/masters/Kconfig
+++ b/drivers/w1/masters/Kconfig
@@ -35,5 +35,13 @@ config W1_MASTER_DS2482
This driver can also be built as a module. If so, the module
will be called ds2482.

+config W1_DS1WM
+ tristate "Maxim DS1WM 1-wire busmaster"
+ depends on W1
+ help
+ Say Y here to enable the DS1WM 1-wire driver, such as that
+ in HP iPAQ devices like h5xxx, h2200, and ASIC3-based like
+ hx4700.
+
endmenu

diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
index 4cee256..a9e45fb 100644
--- a/drivers/w1/masters/Makefile
+++ b/drivers/w1/masters/Makefile
@@ -5,4 +5,4 @@
obj-$(CONFIG_W1_MASTER_MATROX) += matrox_w1.o
obj-$(CONFIG_W1_MASTER_DS2490) += ds2490.o
obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o
-
+obj-$(CONFIG_W1_DS1WM) += ds1wm.o
diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c
new file mode 100644
index 0000000..3f984f5
--- /dev/null
+++ b/drivers/w1/masters/ds1wm.c
@@ -0,0 +1,461 @@
+/*
+ * 1-wire busmaster driver for DS1WM and ASICs with embedded DS1WMs
+ * such as HP iPAQs (including h5xxx, h2200, and devices with ASIC3
+ * like hx4700).
+ *
+ * Copyright (c) 2004-2005, Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
+ * Copyright (c) 2004-2007, Matt Reimer <mreimer@vpop.net>
+ *
+ * Use consistent with the GNU GPL is permitted,
+ * provided that this copyright notice is
+ * preserved in its entirety in all copies and derived works.
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/ds1wm.h>
+
+#include <asm/io.h>
+
+#include "../w1.h"
+#include "../w1_int.h"
+
+
+#define DS1WM_CMD 0x00 /* R/W 4 bits command */
+#define DS1WM_DATA 0x01 /* R/W 8 bits, transmit/receive buffer */
+#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_CMD_1W_RESET (1 << 0) /* force reset on 1-wire bus */
+#define DS1WM_CMD_SRA (1 << 1) /* enable Search ROM accelerator mode */
+#define DS1WM_CMD_DQ_OUTPUT (1 << 2) /* write only - forces bus low */
+#define DS1WM_CMD_DQ_INPUT (1 << 3) /* read only - reflects state of bus */
+#define DS1WM_CMD_RST (1 << 5) /* software reset */
+#define DS1WM_CMD_OD (1 << 7) /* overdrive */
+
+#define DS1WM_INT_PD (1 << 0) /* presence detect */
+#define DS1WM_INT_PDR (1 << 1) /* presence detect result */
+#define DS1WM_INT_TBE (1 << 2) /* tx buffer empty */
+#define DS1WM_INT_TSRE (1 << 3) /* tx shift register empty */
+#define DS1WM_INT_RBF (1 << 4) /* rx buffer full */
+#define DS1WM_INT_RSRF (1 << 5) /* rx shift register full */
+
+#define DS1WM_INTEN_EPD (1 << 0) /* enable presence detect int */
+#define DS1WM_INTEN_IAS (1 << 1) /* INTR active state */
+#define DS1WM_INTEN_ETBE (1 << 2) /* enable tx buffer empty int */
+#define DS1WM_INTEN_ETMT (1 << 3) /* enable tx shift register empty int */
+#define DS1WM_INTEN_ERBF (1 << 4) /* enable rx buffer full int */
+#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_TIMEOUT (HZ * 5)
+
+static struct {
+ 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 },
+};
+
+struct ds1wm_data {
+ void *map;
+ int bus_shift; /* # of shifts to calc register offsets */
+ struct platform_device *pdev;
+ struct ds1wm_platform_data *pdata;
+ int irq;
+ struct clk *clk;
+ int slave_present;
+ void *reset_complete;
+ void *read_complete;
+ void *write_complete;
+ u8 read_byte; /* last byte received */
+};
+
+static inline void ds1wm_write_register(struct ds1wm_data *ds1wm_data, u32 reg,
+ u8 val)
+{
+ __raw_writeb(val, ds1wm_data->map + (reg << ds1wm_data->bus_shift));
+}
+
+static inline u8 ds1wm_read_register(struct ds1wm_data *ds1wm_data, u32 reg)
+{
+ return __raw_readb(ds1wm_data->map + (reg << ds1wm_data->bus_shift));
+}
+
+
+static irqreturn_t ds1wm_isr(int isr, void *data)
+{
+ struct ds1wm_data *ds1wm_data = data;
+ u8 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)
+ complete(ds1wm_data->write_complete);
+
+ if (intr & DS1WM_INT_RBF) {
+ ds1wm_data->read_byte = ds1wm_read_register(ds1wm_data,
+ DS1WM_DATA);
+ if (ds1wm_data->read_complete)
+ complete(ds1wm_data->read_complete);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int ds1wm_reset(struct ds1wm_data *ds1wm_data)
+{
+ unsigned long timeleft;
+ DECLARE_COMPLETION_ONSTACK(reset_done);
+
+ ds1wm_data->reset_complete = &reset_done;
+
+ ds1wm_write_register(ds1wm_data, DS1WM_INT_EN, DS1WM_INTEN_EPD |
+ (ds1wm_data->pdata->active_high ? DS1WM_INTEN_IAS : 0));
+
+ 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_dbg(&ds1wm_data->pdev->dev, "reset failed\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.
+ */
+ udelay(500);
+
+ ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
+ DS1WM_INTEN_ERBF | DS1WM_INTEN_ETMT | DS1WM_INTEN_EPD |
+ (ds1wm_data->pdata->active_high ? DS1WM_INTEN_IAS : 0));
+
+ if (!ds1wm_data->slave_present) {
+ dev_dbg(&ds1wm_data->pdev->dev, "reset: no devices found\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+static int ds1wm_write(struct ds1wm_data *ds1wm_data, u8 data)
+{
+ DECLARE_COMPLETION_ONSTACK(write_done);
+ ds1wm_data->write_complete = &write_done;
+
+ ds1wm_write_register(ds1wm_data, DS1WM_DATA, data);
+
+ wait_for_completion_timeout(&write_done, DS1WM_TIMEOUT);
+ ds1wm_data->write_complete = NULL;
+
+ return 0;
+}
+
+static int ds1wm_read(struct ds1wm_data *ds1wm_data, unsigned char write_data)
+{
+ DECLARE_COMPLETION_ONSTACK(read_done);
+ ds1wm_data->read_complete = &read_done;
+
+ ds1wm_write(ds1wm_data, write_data);
+ wait_for_completion_timeout(&read_done, DS1WM_TIMEOUT);
+ ds1wm_data->read_complete = NULL;
+
+ return ds1wm_data->read_byte;
+}
+
+static int ds1wm_find_divisor(int gclk)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(freq); i++)
+ if (gclk <= freq[i].freq)
+ return freq[i].divisor;
+
+ return 0;
+}
+
+static void ds1wm_up(struct ds1wm_data *ds1wm_data)
+{
+ int gclk, divisor;
+
+ if (ds1wm_data->pdata->enable)
+ ds1wm_data->pdata->enable(ds1wm_data->pdev);
+
+ gclk = clk_get_rate(ds1wm_data->clk);
+ clk_enable(ds1wm_data->clk);
+ divisor = ds1wm_find_divisor(gclk);
+ if (divisor == 0) {
+ dev_err(&ds1wm_data->pdev->dev,
+ "no suitable divisor for %dHz clock\n", gclk);
+ return;
+ }
+ ds1wm_write_register(ds1wm_data, DS1WM_CLKDIV, divisor);
+
+ /* Let the w1 clock stabilize. */
+ msleep(1);
+
+ ds1wm_reset(ds1wm_data);
+}
+
+static void ds1wm_down(struct ds1wm_data *ds1wm_data)
+{
+ ds1wm_reset(ds1wm_data);
+
+ if (ds1wm_data->pdata->disable)
+ ds1wm_data->pdata->disable(ds1wm_data->pdev);
+
+ clk_disable(ds1wm_data->clk);
+}
+
+/* --------------------------------------------------------------------- */
+/* w1 methods */
+
+static u8 ds1wm_read_byte(void *data)
+{
+ struct ds1wm_data *ds1wm_data = data;
+
+ return ds1wm_read(ds1wm_data, 0xff);
+}
+
+static void ds1wm_write_byte(void *data, u8 byte)
+{
+ struct ds1wm_data *ds1wm_data = data;
+
+ ds1wm_write(ds1wm_data, byte);
+}
+
+static u8 ds1wm_reset_bus(void *data)
+{
+ struct ds1wm_data *ds1wm_data = data;
+
+ ds1wm_reset(ds1wm_data);
+
+ return 0;
+}
+
+static void ds1wm_search(void *data, u8 search_type,
+ w1_slave_found_callback slave_found)
+{
+ struct ds1wm_data *ds1wm_data = data;
+ int i;
+ unsigned long long rom_id;
+
+ /* 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;
+
+ ds1wm_write(ds1wm_data, search_type);
+ ds1wm_write_register(ds1wm_data, DS1WM_CMD, DS1WM_CMD_SRA);
+
+ for (rom_id = 0, i = 0; i < 16; i++) {
+
+ unsigned char resp, r, d;
+
+ resp = ds1wm_read(ds1wm_data, 0x00);
+
+ r = ((resp & 0x02) >> 1) |
+ ((resp & 0x08) >> 2) |
+ ((resp & 0x20) >> 3) |
+ ((resp & 0x80) >> 4);
+
+ d = ((resp & 0x01) >> 0) |
+ ((resp & 0x04) >> 1) |
+ ((resp & 0x10) >> 2) |
+ ((resp & 0x40) >> 3);
+
+ rom_id |= (unsigned long long) r << (i * 4);
+
+ }
+ dev_dbg(&ds1wm_data->pdev->dev, "found 0x%08llX", rom_id);
+
+ ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
+ ds1wm_reset(ds1wm_data);
+
+ slave_found(ds1wm_data, rom_id);
+}
+
+/* --------------------------------------------------------------------- */
+
+static struct w1_bus_master ds1wm_master = {
+ .read_byte = ds1wm_read_byte,
+ .write_byte = ds1wm_write_byte,
+ .reset_bus = ds1wm_reset_bus,
+ .search = ds1wm_search,
+};
+
+static int ds1wm_probe(struct platform_device *pdev)
+{
+ struct ds1wm_data *ds1wm_data;
+ struct ds1wm_platform_data *plat;
+ struct resource *res;
+ int ret;
+
+ if (!pdev)
+ return -ENODEV;
+
+ ds1wm_data = kzalloc(sizeof (*ds1wm_data), GFP_KERNEL);
+ if (!ds1wm_data)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, ds1wm_data);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ ret = -ENXIO;
+ goto err0;
+ }
+ ds1wm_data->map = ioremap(res->start, res->end - res->start + 1);
+ if (!ds1wm_data->map) {
+ ret = -ENOMEM;
+ goto err0;
+ }
+ plat = pdev->dev.platform_data;
+ ds1wm_data->bus_shift = plat->bus_shift;
+ ds1wm_data->pdev = pdev;
+ ds1wm_data->pdata = plat;
+
+ res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ if (!res) {
+ ret = -ENXIO;
+ goto err1;
+ }
+ ds1wm_data->irq = res->start;
+
+ set_irq_type(ds1wm_data->irq, res->flags & IORESOURCE_IRQ_LOWEDGE ?
+ IRQ_TYPE_EDGE_FALLING : IRQ_TYPE_EDGE_RISING);
+
+ ret = request_irq(ds1wm_data->irq, ds1wm_isr, IRQF_DISABLED,
+ "ds1wm", ds1wm_data);
+ if (ret)
+ goto err1;
+
+ ds1wm_data->clk = clk_get(&pdev->dev, "ds1wm");
+ if (!ds1wm_data->clk) {
+ ret = -ENOENT;
+ goto err2;
+ }
+
+ ds1wm_up(ds1wm_data);
+
+ ds1wm_master.data = (void *)ds1wm_data;
+
+ ret = w1_add_master_device(&ds1wm_master);
+ if (ret)
+ goto err3;
+
+ return 0;
+
+err3:
+ ds1wm_down(ds1wm_data);
+ clk_put(ds1wm_data->clk);
+err2:
+ free_irq(ds1wm_data->irq, ds1wm_data);
+err1:
+ iounmap(ds1wm_data->map);
+err0:
+ kfree(ds1wm_data);
+
+ return ret;
+}
+
+#ifdef CONFIG_PM
+static int ds1wm_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
+
+ ds1wm_down(ds1wm_data);
+
+ return 0;
+}
+
+static int ds1wm_resume(struct platform_device *pdev)
+{
+ struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
+
+ ds1wm_up(ds1wm_data);
+
+ return 0;
+}
+#else
+#define ds1wm_suspend NULL
+#define ds1wm_resume NULL
+#endif
+
+static int ds1wm_remove(struct platform_device *pdev)
+{
+ struct ds1wm_data *ds1wm_data = platform_get_drvdata(pdev);
+
+ w1_remove_master_device(&ds1wm_master);
+ ds1wm_down(ds1wm_data);
+ clk_put(ds1wm_data->clk);
+ free_irq(ds1wm_data->irq, ds1wm_data);
+ iounmap(ds1wm_data->map);
+ kfree(ds1wm_data);
+
+ return 0;
+}
+
+static struct platform_driver ds1wm_driver = {
+ .driver = {
+ .name = "ds1wm",
+ },
+ .probe = ds1wm_probe,
+ .remove = ds1wm_remove,
+ .suspend = ds1wm_suspend,
+ .resume = ds1wm_resume
+};
+
+static int __init ds1wm_init(void)
+{
+ printk("DS1WM w1 busmaster driver - (c) 2004 Szabolcs Gyurko\n");
+ return platform_driver_register(&ds1wm_driver);
+}
+
+static void __exit ds1wm_exit(void)
+{
+ platform_driver_unregister(&ds1wm_driver);
+}
+
+module_init(ds1wm_init);
+module_exit(ds1wm_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
+ "Matt Reimer <mreimer@vpop.net>");
+MODULE_DESCRIPTION("DS1WM w1 busmaster driver");
diff --git a/include/linux/ds1wm.h b/include/linux/ds1wm.h
new file mode 100644
index 0000000..feeb64d
--- /dev/null
+++ b/include/linux/ds1wm.h
@@ -0,0 +1,12 @@
+/* platform data for the DS1WM driver */
+
+struct ds1wm_platform_data {
+ int bus_shift; /* number of shifts needed to calculate the
+ * offset between DS1WM registers;
+ * e.g. on h5xxx and h2200 this is 2
+ * (registers aligned to 4-byte boundaries),
+ * while on hx4700 this is 1 */
+ int active_high; /* interrupt polarity, passed to DS1WM as IAS bit */
+ void (*enable)(struct platform_device *pdev);
+ void (*disable)(struct platform_device *pdev);
+};
--
1.5.1.1
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