Driver for the Maxim DS1WM, a 1-wire bus master ASIC core

Cc: Matt Reimer <mreimer@vpop.net>

[akpm@linux-foundation.org: kconfig update]
Signed-off-by: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 468 insertions, 0 deletions

diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c
new file mode 100644
index 000000000000..763bc73e5070
--- /dev/null
+++ b/drivers/w1/masters/ds1wm.c
@@ -0,0 +1,468 @@
+/*
+ * 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;
+        int             active_high;
+        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->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->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);
+
+        /* Disable interrupts. */
+        ds1wm_write_register(ds1wm_data, DS1WM_INT_EN,
+                             ds1wm_data->active_high ? DS1WM_INTEN_IAS : 0);
+
+        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;
+        ds1wm_data->active_high = (res->flags & IORESOURCE_IRQ_HIGHEDGE) ?
+                1 : 0;
+
+        set_irq_type(ds1wm_data->irq, ds1wm_data->active_high ?
+                        IRQ_TYPE_EDGE_RISING : IRQ_TYPE_EDGE_FALLING);
+
+        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");