diff options
Diffstat (limited to 'drivers/power/hdq.c')
| -rw-r--r-- | drivers/power/hdq.c | 515 |
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"); |