diff options
Diffstat (limited to 'drivers/mfd/wm831x-auxadc.c')
| -rw-r--r-- | drivers/mfd/wm831x-auxadc.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/drivers/mfd/wm831x-auxadc.c b/drivers/mfd/wm831x-auxadc.c new file mode 100644 index 000000000000..2fc9531b243d --- /dev/null +++ b/drivers/mfd/wm831x-auxadc.c @@ -0,0 +1,199 @@ +/* + * wm831x-auxadc.c -- AUXADC for Wolfson WM831x PMICs + * + * Copyright 2009-2011 Wolfson Microelectronics PLC. + * + * Author: Mark Brown <broonie@opensource.wolfsonmicro.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/mfd/core.h> +#include <linux/slab.h> + +#include <linux/mfd/wm831x/core.h> +#include <linux/mfd/wm831x/pdata.h> +#include <linux/mfd/wm831x/irq.h> +#include <linux/mfd/wm831x/auxadc.h> +#include <linux/mfd/wm831x/otp.h> +#include <linux/mfd/wm831x/regulator.h> + +/** + * wm831x_auxadc_read: Read a value from the WM831x AUXADC + * + * @wm831x: Device to read from. + * @input: AUXADC input to read. + */ +int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input) +{ + int ret, src, irq_masked, timeout; + + /* Are we using the interrupt? */ + irq_masked = wm831x_reg_read(wm831x, WM831X_INTERRUPT_STATUS_1_MASK); + irq_masked &= WM831X_AUXADC_DATA_EINT; + + mutex_lock(&wm831x->auxadc_lock); + + ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, + WM831X_AUX_ENA, WM831X_AUX_ENA); + if (ret < 0) { + dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n", ret); + goto out; + } + + /* We force a single source at present */ + src = input; + ret = wm831x_reg_write(wm831x, WM831X_AUXADC_SOURCE, + 1 << src); + if (ret < 0) { + dev_err(wm831x->dev, "Failed to set AUXADC source: %d\n", ret); + goto out; + } + + /* Clear any notification from a very late arriving interrupt */ + try_wait_for_completion(&wm831x->auxadc_done); + + ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, + WM831X_AUX_CVT_ENA, WM831X_AUX_CVT_ENA); + if (ret < 0) { + dev_err(wm831x->dev, "Failed to start AUXADC: %d\n", ret); + goto disable; + } + + if (irq_masked) { + /* If we're not using interrupts then poll the + * interrupt status register */ + timeout = 5; + while (timeout) { + msleep(1); + + ret = wm831x_reg_read(wm831x, + WM831X_INTERRUPT_STATUS_1); + if (ret < 0) { + dev_err(wm831x->dev, + "ISR 1 read failed: %d\n", ret); + goto disable; + } + + /* Did it complete? */ + if (ret & WM831X_AUXADC_DATA_EINT) { + wm831x_reg_write(wm831x, + WM831X_INTERRUPT_STATUS_1, + WM831X_AUXADC_DATA_EINT); + break; + } else { + dev_err(wm831x->dev, + "AUXADC conversion timeout\n"); + ret = -EBUSY; + goto disable; + } + } + + ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA); + if (ret < 0) { + dev_err(wm831x->dev, + "Failed to read AUXADC data: %d\n", ret); + goto disable; + } + + wm831x->auxadc_data = ret; + + } else { + /* If we are using interrupts then wait for the + * interrupt to complete. Use an extremely long + * timeout to handle situations with heavy load where + * the notification of the interrupt may be delayed by + * threaded IRQ handling. */ + if (!wait_for_completion_timeout(&wm831x->auxadc_done, + msecs_to_jiffies(500))) { + dev_err(wm831x->dev, "Timed out waiting for AUXADC\n"); + ret = -EBUSY; + goto disable; + } + } + + src = ((wm831x->auxadc_data & WM831X_AUX_DATA_SRC_MASK) + >> WM831X_AUX_DATA_SRC_SHIFT) - 1; + + if (src == 14) + src = WM831X_AUX_CAL; + + if (src != input) { + dev_err(wm831x->dev, "Data from source %d not %d\n", + src, input); + ret = -EINVAL; + } else { + ret = wm831x->auxadc_data & WM831X_AUX_DATA_MASK; + } + +disable: + wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0); +out: + mutex_unlock(&wm831x->auxadc_lock); + return ret; +} +EXPORT_SYMBOL_GPL(wm831x_auxadc_read); + +static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data) +{ + struct wm831x *wm831x = irq_data; + int ret; + + ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA); + if (ret < 0) { + dev_err(wm831x->dev, + "Failed to read AUXADC data: %d\n", ret); + wm831x->auxadc_data = 0xffff; + } else { + wm831x->auxadc_data = ret; + } + + complete(&wm831x->auxadc_done); + + return IRQ_HANDLED; +} + +/** + * wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC + * + * @wm831x: Device to read from. + * @input: AUXADC input to read. + */ +int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input) +{ + int ret; + + ret = wm831x_auxadc_read(wm831x, input); + if (ret < 0) + return ret; + + ret *= 1465; + + return ret; +} +EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv); + +void wm831x_auxadc_init(struct wm831x *wm831x) +{ + int ret; + + mutex_init(&wm831x->auxadc_lock); + init_completion(&wm831x->auxadc_done); + + if (wm831x->irq_base) { + ret = request_threaded_irq(wm831x->irq_base + + WM831X_IRQ_AUXADC_DATA, + NULL, wm831x_auxadc_irq, 0, + "auxadc", wm831x); + if (ret < 0) + dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n", + ret); + } +} |