diff options
Diffstat (limited to 'drivers/char/ds1620.c')
| -rw-r--r-- | drivers/char/ds1620.c | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/drivers/char/ds1620.c b/drivers/char/ds1620.c new file mode 100644 index 000000000..cf89a9631 --- /dev/null +++ b/drivers/char/ds1620.c @@ -0,0 +1,424 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/drivers/char/ds1620.c: Dallas Semiconductors DS1620 + * thermometer driver (as used in the Rebel.com NetWinder) + */ +#include <linux/module.h> +#include <linux/miscdevice.h> +#include <linux/delay.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/capability.h> +#include <linux/init.h> +#include <linux/mutex.h> + +#include <mach/hardware.h> +#include <asm/mach-types.h> +#include <linux/uaccess.h> +#include <asm/therm.h> + +#ifdef CONFIG_PROC_FS +/* define for /proc interface */ +#define THERM_USE_PROC +#endif + +/* Definitions for DS1620 chip */ +#define THERM_START_CONVERT 0xee +#define THERM_RESET 0xaf +#define THERM_READ_CONFIG 0xac +#define THERM_READ_TEMP 0xaa +#define THERM_READ_TL 0xa2 +#define THERM_READ_TH 0xa1 +#define THERM_WRITE_CONFIG 0x0c +#define THERM_WRITE_TL 0x02 +#define THERM_WRITE_TH 0x01 + +#define CFG_CPU 2 +#define CFG_1SHOT 1 + +static DEFINE_MUTEX(ds1620_mutex); +static const char *fan_state[] = { "off", "on", "on (hardwired)" }; + +/* + * Start of NetWinder specifics + * Note! We have to hold the gpio lock with IRQs disabled over the + * whole of our transaction to the Dallas chip, since there is a + * chance that the WaveArtist driver could touch these bits to + * enable or disable the speaker. + */ +extern unsigned int system_rev; + +static inline void netwinder_ds1620_set_clk(int clk) +{ + nw_gpio_modify_op(GPIO_DSCLK, clk ? GPIO_DSCLK : 0); +} + +static inline void netwinder_ds1620_set_data(int dat) +{ + nw_gpio_modify_op(GPIO_DATA, dat ? GPIO_DATA : 0); +} + +static inline int netwinder_ds1620_get_data(void) +{ + return nw_gpio_read() & GPIO_DATA; +} + +static inline void netwinder_ds1620_set_data_dir(int dir) +{ + nw_gpio_modify_io(GPIO_DATA, dir ? GPIO_DATA : 0); +} + +static inline void netwinder_ds1620_reset(void) +{ + nw_cpld_modify(CPLD_DS_ENABLE, 0); + nw_cpld_modify(CPLD_DS_ENABLE, CPLD_DS_ENABLE); +} + +static inline void netwinder_lock(unsigned long *flags) +{ + raw_spin_lock_irqsave(&nw_gpio_lock, *flags); +} + +static inline void netwinder_unlock(unsigned long *flags) +{ + raw_spin_unlock_irqrestore(&nw_gpio_lock, *flags); +} + +static inline void netwinder_set_fan(int i) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&nw_gpio_lock, flags); + nw_gpio_modify_op(GPIO_FAN, i ? GPIO_FAN : 0); + raw_spin_unlock_irqrestore(&nw_gpio_lock, flags); +} + +static inline int netwinder_get_fan(void) +{ + if ((system_rev & 0xf000) == 0x4000) + return FAN_ALWAYS_ON; + + return (nw_gpio_read() & GPIO_FAN) ? FAN_ON : FAN_OFF; +} + +/* + * End of NetWinder specifics + */ + +static void ds1620_send_bits(int nr, int value) +{ + int i; + + for (i = 0; i < nr; i++) { + netwinder_ds1620_set_data(value & 1); + netwinder_ds1620_set_clk(0); + udelay(1); + netwinder_ds1620_set_clk(1); + udelay(1); + + value >>= 1; + } +} + +static unsigned int ds1620_recv_bits(int nr) +{ + unsigned int value = 0, mask = 1; + int i; + + netwinder_ds1620_set_data(0); + + for (i = 0; i < nr; i++) { + netwinder_ds1620_set_clk(0); + udelay(1); + + if (netwinder_ds1620_get_data()) + value |= mask; + + mask <<= 1; + + netwinder_ds1620_set_clk(1); + udelay(1); + } + + return value; +} + +static void ds1620_out(int cmd, int bits, int value) +{ + unsigned long flags; + + netwinder_lock(&flags); + netwinder_ds1620_set_clk(1); + netwinder_ds1620_set_data_dir(0); + netwinder_ds1620_reset(); + + udelay(1); + + ds1620_send_bits(8, cmd); + if (bits) + ds1620_send_bits(bits, value); + + udelay(1); + + netwinder_ds1620_reset(); + netwinder_unlock(&flags); + + msleep(20); +} + +static unsigned int ds1620_in(int cmd, int bits) +{ + unsigned long flags; + unsigned int value; + + netwinder_lock(&flags); + netwinder_ds1620_set_clk(1); + netwinder_ds1620_set_data_dir(0); + netwinder_ds1620_reset(); + + udelay(1); + + ds1620_send_bits(8, cmd); + + netwinder_ds1620_set_data_dir(1); + value = ds1620_recv_bits(bits); + + netwinder_ds1620_reset(); + netwinder_unlock(&flags); + + return value; +} + +static int cvt_9_to_int(unsigned int val) +{ + if (val & 0x100) + val |= 0xfffffe00; + + return val; +} + +static void ds1620_write_state(struct therm *therm) +{ + ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU); + ds1620_out(THERM_WRITE_TL, 9, therm->lo); + ds1620_out(THERM_WRITE_TH, 9, therm->hi); + ds1620_out(THERM_START_CONVERT, 0, 0); +} + +static void ds1620_read_state(struct therm *therm) +{ + therm->lo = cvt_9_to_int(ds1620_in(THERM_READ_TL, 9)); + therm->hi = cvt_9_to_int(ds1620_in(THERM_READ_TH, 9)); +} + +static int ds1620_open(struct inode *inode, struct file *file) +{ + return stream_open(inode, file); +} + +static ssize_t +ds1620_read(struct file *file, char __user *buf, size_t count, loff_t *ptr) +{ + signed int cur_temp; + signed char cur_temp_degF; + + cur_temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)) >> 1; + + /* convert to Fahrenheit, as per wdt.c */ + cur_temp_degF = (cur_temp * 9) / 5 + 32; + + if (copy_to_user(buf, &cur_temp_degF, 1)) + return -EFAULT; + + return 1; +} + +static int +ds1620_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct therm therm; + union { + struct therm __user *therm; + int __user *i; + } uarg; + int i; + + uarg.i = (int __user *)arg; + + switch(cmd) { + case CMD_SET_THERMOSTATE: + case CMD_SET_THERMOSTATE2: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (cmd == CMD_SET_THERMOSTATE) { + if (get_user(therm.hi, uarg.i)) + return -EFAULT; + therm.lo = therm.hi - 3; + } else { + if (copy_from_user(&therm, uarg.therm, sizeof(therm))) + return -EFAULT; + } + + therm.lo <<= 1; + therm.hi <<= 1; + + ds1620_write_state(&therm); + break; + + case CMD_GET_THERMOSTATE: + case CMD_GET_THERMOSTATE2: + ds1620_read_state(&therm); + + therm.lo >>= 1; + therm.hi >>= 1; + + if (cmd == CMD_GET_THERMOSTATE) { + if (put_user(therm.hi, uarg.i)) + return -EFAULT; + } else { + if (copy_to_user(uarg.therm, &therm, sizeof(therm))) + return -EFAULT; + } + break; + + case CMD_GET_TEMPERATURE: + case CMD_GET_TEMPERATURE2: + i = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); + + if (cmd == CMD_GET_TEMPERATURE) + i >>= 1; + + return put_user(i, uarg.i) ? -EFAULT : 0; + + case CMD_GET_STATUS: + i = ds1620_in(THERM_READ_CONFIG, 8) & 0xe3; + + return put_user(i, uarg.i) ? -EFAULT : 0; + + case CMD_GET_FAN: + i = netwinder_get_fan(); + + return put_user(i, uarg.i) ? -EFAULT : 0; + + case CMD_SET_FAN: + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (get_user(i, uarg.i)) + return -EFAULT; + + netwinder_set_fan(i); + break; + + default: + return -ENOIOCTLCMD; + } + + return 0; +} + +static long +ds1620_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int ret; + + mutex_lock(&ds1620_mutex); + ret = ds1620_ioctl(file, cmd, arg); + mutex_unlock(&ds1620_mutex); + + return ret; +} + +#ifdef THERM_USE_PROC +static int ds1620_proc_therm_show(struct seq_file *m, void *v) +{ + struct therm th; + int temp; + + ds1620_read_state(&th); + temp = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); + + seq_printf(m, "Thermostat: HI %i.%i, LOW %i.%i; temperature: %i.%i C, fan %s\n", + th.hi >> 1, th.hi & 1 ? 5 : 0, + th.lo >> 1, th.lo & 1 ? 5 : 0, + temp >> 1, temp & 1 ? 5 : 0, + fan_state[netwinder_get_fan()]); + return 0; +} +#endif + +static const struct file_operations ds1620_fops = { + .owner = THIS_MODULE, + .open = ds1620_open, + .read = ds1620_read, + .unlocked_ioctl = ds1620_unlocked_ioctl, + .llseek = no_llseek, +}; + +static struct miscdevice ds1620_miscdev = { + TEMP_MINOR, + "temp", + &ds1620_fops +}; + +static int __init ds1620_init(void) +{ + int ret; + struct therm th, th_start; + + if (!machine_is_netwinder()) + return -ENODEV; + + ds1620_out(THERM_RESET, 0, 0); + ds1620_out(THERM_WRITE_CONFIG, 8, CFG_CPU); + ds1620_out(THERM_START_CONVERT, 0, 0); + + /* + * Trigger the fan to start by setting + * temperature high point low. This kicks + * the fan into action. + */ + ds1620_read_state(&th); + th_start.lo = 0; + th_start.hi = 1; + ds1620_write_state(&th_start); + + msleep(2000); + + ds1620_write_state(&th); + + ret = misc_register(&ds1620_miscdev); + if (ret < 0) + return ret; + +#ifdef THERM_USE_PROC + if (!proc_create_single("therm", 0, NULL, ds1620_proc_therm_show)) + printk(KERN_ERR "therm: unable to register /proc/therm\n"); +#endif + + ds1620_read_state(&th); + ret = cvt_9_to_int(ds1620_in(THERM_READ_TEMP, 9)); + + printk(KERN_INFO "Thermostat: high %i.%i, low %i.%i, " + "current %i.%i C, fan %s.\n", + th.hi >> 1, th.hi & 1 ? 5 : 0, + th.lo >> 1, th.lo & 1 ? 5 : 0, + ret >> 1, ret & 1 ? 5 : 0, + fan_state[netwinder_get_fan()]); + + return 0; +} + +static void __exit ds1620_exit(void) +{ +#ifdef THERM_USE_PROC + remove_proc_entry("therm", NULL); +#endif + misc_deregister(&ds1620_miscdev); +} + +module_init(ds1620_init); +module_exit(ds1620_exit); + +MODULE_LICENSE("GPL"); |