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path: root/drivers/power/hdq.c
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-rw-r--r--drivers/power/hdq.c515
1 files changed, 515 insertions, 0 deletions
diff --git a/drivers/power/hdq.c b/drivers/power/hdq.c
new file mode 100644
index 00000000000..f03fabfb1aa
--- /dev/null
+++ b/drivers/power/hdq.c
@@ -0,0 +1,515 @@
+/*
+ * HDQ generic GPIO bitbang driver using FIQ
+ *
+ * (C) 2006-2007 by Openmoko, Inc.
+ * Author: Andy Green <andy@openmoko.com>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/hdq.h>
+
+#define HDQ_READ 0
+#define HDQ_WRITE 0x80
+
+enum hdq_bitbang_states {
+ HDQB_IDLE = 0,
+ HDQB_TX_BREAK,
+ HDQB_TX_BREAK_RECOVERY,
+ HDQB_ADS_CALC,
+ HDQB_ADS_LOW,
+ HDQB_ADS_HIGH,
+ HDQB_WAIT_RX,
+ HDQB_DATA_RX_LOW,
+ HDQB_DATA_RX_HIGH,
+ HDQB_WAIT_TX,
+};
+
+static struct hdq_priv {
+ u8 hdq_probed; /* nonzero after HDQ driver probed */
+ struct mutex hdq_lock; /* if you want to use hdq, you have to take lock */
+ unsigned long hdq_gpio_pin; /* GTA02 = GPD14 which pin to meddle with */
+ u8 hdq_ads; /* b7..b6 = register address, b0 = r/w */
+ u8 hdq_tx_data; /* data to tx for write action */
+ u8 hdq_rx_data; /* data received in read action */
+ u8 hdq_request_ctr; /* incremented by "user" to request a transfer */
+ u8 hdq_transaction_ctr; /* incremented after each transfer */
+ u8 hdq_error; /* 0 = no error */
+ u8 hdq_ctr;
+ u8 hdq_ctr2;
+ u8 hdq_bit;
+ u8 hdq_shifter;
+ u8 hdq_tx_data_done;
+ enum hdq_bitbang_states hdq_state;
+ int reported_error;
+
+ struct hdq_platform_data *pdata;
+} hdq_priv;
+
+
+static void hdq_bad(void)
+{
+ if (!hdq_priv.reported_error)
+ printk(KERN_ERR "HDQ error: %d\n", hdq_priv.hdq_error);
+ hdq_priv.reported_error = 1;
+}
+
+static void hdq_good(void)
+{
+ if (hdq_priv.reported_error)
+ printk(KERN_INFO "HDQ responds again\n");
+ hdq_priv.reported_error = 0;
+}
+
+int hdq_fiq_handler(void)
+{
+ if (!hdq_priv.hdq_probed)
+ return 0;
+
+ switch (hdq_priv.hdq_state) {
+ case HDQB_IDLE:
+ if (hdq_priv.hdq_request_ctr == hdq_priv.hdq_transaction_ctr)
+ break;
+ hdq_priv.hdq_ctr = 250 / HDQ_SAMPLE_PERIOD_US;
+ hdq_priv.pdata->gpio_set(0);
+ hdq_priv.pdata->gpio_dir_out();
+ hdq_priv.hdq_tx_data_done = 0;
+ hdq_priv.hdq_state = HDQB_TX_BREAK;
+ break;
+
+ case HDQB_TX_BREAK: /* issue low for > 190us */
+ if (--hdq_priv.hdq_ctr == 0) {
+ hdq_priv.hdq_ctr = 60 / HDQ_SAMPLE_PERIOD_US;
+ hdq_priv.hdq_state = HDQB_TX_BREAK_RECOVERY;
+ hdq_priv.pdata->gpio_set(1);
+ }
+ break;
+
+ case HDQB_TX_BREAK_RECOVERY: /* issue low for > 40us */
+ if (--hdq_priv.hdq_ctr)
+ break;
+ hdq_priv.hdq_shifter = hdq_priv.hdq_ads;
+ hdq_priv.hdq_bit = 8; /* 8 bits of ads / rw */
+ hdq_priv.hdq_tx_data_done = 0; /* doing ads */
+ /* fallthru on last one */
+ case HDQB_ADS_CALC:
+ if (hdq_priv.hdq_shifter & 1)
+ hdq_priv.hdq_ctr = 50 / HDQ_SAMPLE_PERIOD_US;
+ else
+ hdq_priv.hdq_ctr = 120 / HDQ_SAMPLE_PERIOD_US;
+ /* carefully precompute the other phase length */
+ hdq_priv.hdq_ctr2 = (210 - (hdq_priv.hdq_ctr * HDQ_SAMPLE_PERIOD_US)) /
+ HDQ_SAMPLE_PERIOD_US;
+ hdq_priv.hdq_state = HDQB_ADS_LOW;
+ hdq_priv.hdq_shifter >>= 1;
+ hdq_priv.hdq_bit--;
+ hdq_priv.pdata->gpio_set(0);
+ break;
+
+ case HDQB_ADS_LOW:
+ if (--hdq_priv.hdq_ctr)
+ break;
+ hdq_priv.pdata->gpio_set(1);
+ hdq_priv.hdq_state = HDQB_ADS_HIGH;
+ break;
+
+ case HDQB_ADS_HIGH:
+ if (--hdq_priv.hdq_ctr2 > 1) /* account for HDQB_ADS_CALC */
+ break;
+ if (hdq_priv.hdq_bit) { /* more bits to do */
+ hdq_priv.hdq_state = HDQB_ADS_CALC;
+ break;
+ }
+ /* no more bits, wait it out until hdq_priv.hdq_ctr2 exhausted */
+ if (hdq_priv.hdq_ctr2)
+ break;
+ /* ok no more bits and very last state */
+ hdq_priv.hdq_ctr = 60 / HDQ_SAMPLE_PERIOD_US;
+ /* FIXME 0 = read */
+ if (hdq_priv.hdq_ads & 0x80) { /* write the byte out */
+ /* set delay before payload */
+ hdq_priv.hdq_ctr = 300 / HDQ_SAMPLE_PERIOD_US;
+ /* already high, no need to write */
+ hdq_priv.hdq_state = HDQB_WAIT_TX;
+ break;
+ }
+ /* read the next byte */
+ hdq_priv.hdq_bit = 8; /* 8 bits of data */
+ hdq_priv.hdq_ctr = 2500 / HDQ_SAMPLE_PERIOD_US;
+ hdq_priv.hdq_state = HDQB_WAIT_RX;
+ hdq_priv.pdata->gpio_dir_in();
+ break;
+
+ case HDQB_WAIT_TX: /* issue low for > 40us */
+ if (--hdq_priv.hdq_ctr)
+ break;
+ if (!hdq_priv.hdq_tx_data_done) { /* was that the data sent? */
+ hdq_priv.hdq_tx_data_done++;
+ hdq_priv.hdq_shifter = hdq_priv.hdq_tx_data;
+ hdq_priv.hdq_bit = 8; /* 8 bits of data */
+ hdq_priv.hdq_state = HDQB_ADS_CALC; /* start sending */
+ break;
+ }
+ hdq_priv.hdq_error = 0;
+ hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+ hdq_priv.hdq_state = HDQB_IDLE; /* all tx is done */
+ /* idle in input mode, it's pulled up by 10K */
+ hdq_priv.pdata->gpio_dir_in();
+ break;
+
+ case HDQB_WAIT_RX: /* wait for battery to talk to us */
+ if (hdq_priv.pdata->gpio_get() == 0) {
+ /* it talks to us! */
+ hdq_priv.hdq_ctr2 = 1;
+ hdq_priv.hdq_bit = 8; /* 8 bits of data */
+ /* timeout */
+ hdq_priv.hdq_ctr = 500 / HDQ_SAMPLE_PERIOD_US;
+ hdq_priv.hdq_state = HDQB_DATA_RX_LOW;
+ break;
+ }
+ if (--hdq_priv.hdq_ctr == 0) { /* timed out, error */
+ hdq_priv.hdq_error = 1;
+ hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+ hdq_priv.hdq_state = HDQB_IDLE; /* abort */
+ }
+ break;
+
+ /*
+ * HDQ basically works by measuring the low time of the bit cell
+ * 32-50us --> '1', 80 - 145us --> '0'
+ */
+
+ case HDQB_DATA_RX_LOW:
+ if (hdq_priv.pdata->gpio_get()) {
+ hdq_priv.hdq_rx_data >>= 1;
+ if (hdq_priv.hdq_ctr2 <= (65 / HDQ_SAMPLE_PERIOD_US))
+ hdq_priv.hdq_rx_data |= 0x80;
+
+ if (--hdq_priv.hdq_bit == 0) {
+ hdq_priv.hdq_error = 0;
+ hdq_priv.hdq_transaction_ctr =
+ hdq_priv.hdq_request_ctr;
+
+ hdq_priv.hdq_state = HDQB_IDLE;
+ } else
+ hdq_priv.hdq_state = HDQB_DATA_RX_HIGH;
+ /* timeout */
+ hdq_priv.hdq_ctr = 1000 / HDQ_SAMPLE_PERIOD_US;
+ hdq_priv.hdq_ctr2 = 1;
+ break;
+ }
+ hdq_priv.hdq_ctr2++;
+ if (--hdq_priv.hdq_ctr)
+ break;
+ /* timed out, error */
+ hdq_priv.hdq_error = 2;
+ hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+ hdq_priv.hdq_state = HDQB_IDLE; /* abort */
+ break;
+
+ case HDQB_DATA_RX_HIGH:
+ if (!hdq_priv.pdata->gpio_get()) {
+ /* it talks to us! */
+ hdq_priv.hdq_ctr2 = 1;
+ /* timeout */
+ hdq_priv.hdq_ctr = 400 / HDQ_SAMPLE_PERIOD_US;
+ hdq_priv.hdq_state = HDQB_DATA_RX_LOW;
+ break;
+ }
+ if (--hdq_priv.hdq_ctr)
+ break;
+ /* timed out, error */
+ hdq_priv.hdq_error = 3;
+ hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
+
+ /* we're in input mode already */
+ hdq_priv.hdq_state = HDQB_IDLE; /* abort */
+ break;
+ }
+
+ /* Are we interested in keeping the FIQ source alive ? */
+ if (hdq_priv.hdq_state != HDQB_IDLE)
+ return 1;
+ else
+ return 0;
+}
+static int fiq_busy(void)
+{
+ int request = (volatile u8)hdq_priv.hdq_request_ctr;
+ int transact = (volatile u8)hdq_priv.hdq_transaction_ctr;
+
+
+ return (request != transact);
+}
+
+int hdq_initialized(void)
+{
+ return hdq_priv.hdq_probed;
+}
+EXPORT_SYMBOL_GPL(hdq_initialized);
+
+int hdq_read(int address)
+{
+ int count_sleeps = 5;
+ int ret = -ETIME;
+
+ if (!hdq_priv.hdq_probed)
+ return -EINVAL;
+
+ mutex_lock(&hdq_priv.hdq_lock);
+
+ hdq_priv.hdq_error = 0;
+ hdq_priv.hdq_ads = address | HDQ_READ;
+ hdq_priv.hdq_request_ctr++;
+ hdq_priv.pdata->kick_fiq();
+ /*
+ * FIQ takes care of it while we block our calling process
+ * But we're not spinning -- other processes run normally while
+ * we wait for the result
+ */
+ while (count_sleeps--) {
+ msleep(10); /* valid transaction always completes in < 10ms */
+
+ if (fiq_busy())
+ continue;
+
+ if (hdq_priv.hdq_error) {
+ hdq_bad();
+ goto done; /* didn't see a response in good time */
+ }
+ hdq_good();
+
+ ret = hdq_priv.hdq_rx_data;
+ goto done;
+ }
+
+done:
+ mutex_unlock(&hdq_priv.hdq_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(hdq_read);
+
+int hdq_write(int address, u8 data)
+{
+ int count_sleeps = 5;
+ int ret = -ETIME;
+
+ if (!hdq_priv.hdq_probed)
+ return -EINVAL;
+
+ mutex_lock(&hdq_priv.hdq_lock);
+
+ hdq_priv.hdq_error = 0;
+ hdq_priv.hdq_ads = address | HDQ_WRITE;
+ hdq_priv.hdq_tx_data = data;
+ hdq_priv.hdq_request_ctr++;
+ hdq_priv.pdata->kick_fiq();
+ /*
+ * FIQ takes care of it while we block our calling process
+ * But we're not spinning -- other processes run normally while
+ * we wait for the result
+ */
+ while (count_sleeps--) {
+ msleep(10); /* valid transaction always completes in < 10ms */
+
+ if (fiq_busy())
+ continue; /* something bad with FIQ */
+
+ if (hdq_priv.hdq_error) {
+ hdq_bad();
+ goto done; /* didn't see a response in good time */
+ }
+ hdq_good();
+
+ ret = 0;
+ goto done;
+ }
+
+done:
+ mutex_unlock(&hdq_priv.hdq_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(hdq_write);
+
+/* sysfs */
+
+static ssize_t hdq_sysfs_dump(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ int n;
+ int v;
+ u8 u8a[128]; /* whole address space for HDQ */
+ char *end = buf;
+
+ if (!hdq_priv.hdq_probed)
+ return -EINVAL;
+
+ /* the dump does not take care about 16 bit regs, because at this
+ * bus level we don't know about the chip details
+ */
+ for (n = 0; n < sizeof(u8a); n++) {
+ v = hdq_read(n);
+ if (v < 0)
+ goto bail;
+ u8a[n] = v;
+ }
+
+ for (n = 0; n < sizeof(u8a); n += 16) {
+ hex_dump_to_buffer(u8a + n, sizeof(u8a), 16, 1, end, 4096, 0);
+ end += strlen(end);
+ *end++ = '\n';
+ *end = '\0';
+ }
+ return (end - buf);
+
+bail:
+ return sprintf(buf, "ERROR %d\n", v);
+}
+
+/* you write by <address> <data>, eg, "34 128" */
+
+#define atoi(str) simple_strtoul(((str != NULL) ? str : ""), NULL, 0)
+
+static ssize_t hdq_sysfs_write(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ const char *end = buf + count;
+ int address = atoi(buf);
+
+ if (!hdq_priv.hdq_probed)
+ return -EINVAL;
+
+ while ((buf != end) && (*buf != ' '))
+ buf++;
+ if (buf >= end)
+ return 0;
+ while ((buf < end) && (*buf == ' '))
+ buf++;
+ if (buf >= end)
+ return 0;
+
+ hdq_write(address, atoi(buf));
+
+ return count;
+}
+
+static DEVICE_ATTR(dump, 0400, hdq_sysfs_dump, NULL);
+static DEVICE_ATTR(write, 0600, NULL, hdq_sysfs_write);
+
+static struct attribute *hdq_sysfs_entries[] = {
+ &dev_attr_dump.attr,
+ &dev_attr_write.attr,
+ NULL
+};
+
+static struct attribute_group hdq_attr_group = {
+ .name = "hdq",
+ .attrs = hdq_sysfs_entries,
+};
+
+
+#ifdef CONFIG_PM
+static int hdq_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ /* after 18s of this, the battery monitor will also go to sleep */
+ hdq_priv.pdata->gpio_dir_in();
+ hdq_priv.pdata->disable_fiq();
+ return 0;
+}
+
+static int hdq_resume(struct platform_device *pdev)
+{
+ hdq_priv.pdata->gpio_set(1);
+ hdq_priv.pdata->gpio_dir_out();
+ hdq_priv.pdata->enable_fiq();
+ return 0;
+}
+#endif
+
+static int __init hdq_probe(struct platform_device *pdev)
+{
+ struct resource *r = platform_get_resource(pdev, 0, 0);
+ int ret;
+ struct hdq_platform_data *pdata = pdev->dev.platform_data;
+
+ if (!r || !pdata)
+ return -EINVAL;
+
+ platform_set_drvdata(pdev, NULL);
+
+ mutex_init(&hdq_priv.hdq_lock);
+
+ /* set our HDQ comms pin from the platform data */
+ hdq_priv.hdq_gpio_pin = r->start;
+ hdq_priv.pdata = pdata;
+
+ hdq_priv.pdata->gpio_set(1);
+ hdq_priv.pdata->gpio_dir_out();
+
+ /* Initialize FIQ */
+ if (hdq_priv.pdata->enable_fiq() < 0) {
+ dev_err(&pdev->dev, "Could not enable FIQ source\n");
+ return -EINVAL;
+ }
+
+ ret = sysfs_create_group(&pdev->dev.kobj, &hdq_attr_group);
+ if (ret)
+ return ret;
+
+ hdq_priv.hdq_probed = 1; /* we are ready to do stuff now */
+
+ /*
+ * if wanted, users can defer registration of devices
+ * that depend on HDQ until after we register, and can use our
+ * device as parent so suspend-resume ordering is correct
+ */
+ if (pdata->attach_child_devices)
+ (pdata->attach_child_devices)(&pdev->dev);
+
+ hdq_priv.pdata = pdata;
+
+ return 0;
+}
+
+static int hdq_remove(struct platform_device *pdev)
+{
+ sysfs_remove_group(&pdev->dev.kobj, &hdq_attr_group);
+ return 0;
+}
+
+static struct platform_driver hdq_driver = {
+ .probe = hdq_probe,
+ .remove = hdq_remove,
+#ifdef CONFIG_PM
+ .suspend = hdq_suspend,
+ .resume = hdq_resume,
+#endif
+ .driver = {
+ .name = "hdq",
+ },
+};
+
+static int __init hdq_init(void)
+{
+ return platform_driver_register(&hdq_driver);
+}
+
+static void __exit hdq_exit(void)
+{
+ platform_driver_unregister(&hdq_driver);
+}
+
+module_init(hdq_init);
+module_exit(hdq_exit);
+
+MODULE_AUTHOR("Andy Green <andy@openmoko.com>");
+MODULE_DESCRIPTION("HDQ driver");