diff options
Diffstat (limited to 'drivers/mfd/ab8500-gpadc.c')
| -rw-r--r-- | drivers/mfd/ab8500-gpadc.c | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/drivers/mfd/ab8500-gpadc.c b/drivers/mfd/ab8500-gpadc.c new file mode 100644 index 00000000000..19339bc439c --- /dev/null +++ b/drivers/mfd/ab8500-gpadc.c @@ -0,0 +1,296 @@ +/* + * Copyright (C) ST-Ericsson SA 2010 + * + * License Terms: GNU General Public License v2 + * Author: Arun R Murthy <arun.murthy@stericsson.com> + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/interrupt.h> +#include <linux/spinlock.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/completion.h> +#include <linux/regulator/consumer.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/mfd/ab8500.h> +#include <linux/mfd/abx500.h> +#include <linux/mfd/ab8500-gpadc.h> + +/* + * GPADC register offsets + * Bank : 0x0A + */ +#define AB8500_GPADC_CTRL1_REG 0x00 +#define AB8500_GPADC_CTRL2_REG 0x01 +#define AB8500_GPADC_CTRL3_REG 0x02 +#define AB8500_GPADC_AUTO_TIMER_REG 0x03 +#define AB8500_GPADC_STAT_REG 0x04 +#define AB8500_GPADC_MANDATAL_REG 0x05 +#define AB8500_GPADC_MANDATAH_REG 0x06 +#define AB8500_GPADC_AUTODATAL_REG 0x07 +#define AB8500_GPADC_AUTODATAH_REG 0x08 +#define AB8500_GPADC_MUX_CTRL_REG 0x09 + +/* gpadc constants */ +#define EN_VINTCORE12 0x04 +#define EN_VTVOUT 0x02 +#define EN_GPADC 0x01 +#define DIS_GPADC 0x00 +#define SW_AVG_16 0x60 +#define ADC_SW_CONV 0x04 +#define EN_BUF 0x40 +#define DIS_ZERO 0x00 +#define GPADC_BUSY 0x01 + +/** + * struct ab8500_gpadc - ab8500 GPADC device information + * @dev: pointer to the struct device + * @parent: pointer to the parent device structure ab8500 + * @ab8500_gpadc_complete: pointer to the struct completion, to indicate + * the completion of gpadc conversion + * @ab8500_gpadc_lock: structure of type mutex + * @regu: pointer to the struct regulator + * @irq: interrupt number that is used by gpadc + */ +static struct ab8500_gpadc { + struct device *dev; + struct ab8500 *parent; + struct completion ab8500_gpadc_complete; + struct mutex ab8500_gpadc_lock; + struct regulator *regu; + int irq; +} *di; + +/** + * ab8500_gpadc_convert() - gpadc conversion + * @input: analog input to be converted to digital data + * + * This function converts the selected analog i/p to digital + * data. Thereafter calibration has to be made to obtain the + * data in the required quantity measurement. + */ +int ab8500_gpadc_convert(u8 input) +{ + int ret; + u16 data = 0; + int looplimit = 0; + u8 val, low_data, high_data; + + if (!di) + return -ENODEV; + + mutex_lock(&di->ab8500_gpadc_lock); + /* Enable VTVout LDO this is required for GPADC */ + regulator_enable(di->regu); + + /* Check if ADC is not busy, lock and proceed */ + do { + ret = abx500_get_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_STAT_REG, &val); + if (ret < 0) + goto out; + if (!(val & GPADC_BUSY)) + break; + msleep(10); + } while (++looplimit < 10); + if (looplimit >= 10 && (val & GPADC_BUSY)) { + dev_err(di->dev, "gpadc_conversion: GPADC busy"); + ret = -EINVAL; + goto out; + } + + /* Enable GPADC */ + ret = abx500_mask_and_set_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_CTRL1_REG, EN_GPADC, EN_GPADC); + if (ret < 0) { + dev_err(di->dev, "gpadc_conversion: enable gpadc failed\n"); + goto out; + } + /* Select the input source and set average samples to 16 */ + ret = abx500_set_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_CTRL2_REG, (input | SW_AVG_16)); + if (ret < 0) { + dev_err(di->dev, + "gpadc_conversion: set avg samples failed\n"); + goto out; + } + /* Enable ADC, Buffering and select rising edge, start Conversion */ + ret = abx500_mask_and_set_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_CTRL1_REG, EN_BUF, EN_BUF); + if (ret < 0) { + dev_err(di->dev, + "gpadc_conversion: select falling edge failed\n"); + goto out; + } + ret = abx500_mask_and_set_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_CTRL1_REG, ADC_SW_CONV, ADC_SW_CONV); + if (ret < 0) { + dev_err(di->dev, + "gpadc_conversion: start s/w conversion failed\n"); + goto out; + } + /* wait for completion of conversion */ + if (!wait_for_completion_timeout(&di->ab8500_gpadc_complete, 2*HZ)) { + dev_err(di->dev, + "timeout: didnt recieve GPADC conversion interrupt\n"); + ret = -EINVAL; + goto out; + } + + /* Read the converted RAW data */ + ret = abx500_get_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_MANDATAL_REG, &low_data); + if (ret < 0) { + dev_err(di->dev, "gpadc_conversion: read low data failed\n"); + goto out; + } + + ret = abx500_get_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_MANDATAH_REG, &high_data); + if (ret < 0) { + dev_err(di->dev, "gpadc_conversion: read high data failed\n"); + goto out; + } + + data = (high_data << 8) | low_data; + /* Disable GPADC */ + ret = abx500_set_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_CTRL1_REG, DIS_GPADC); + if (ret < 0) { + dev_err(di->dev, "gpadc_conversion: disable gpadc failed\n"); + goto out; + } + /* Disable VTVout LDO this is required for GPADC */ + regulator_disable(di->regu); + mutex_unlock(&di->ab8500_gpadc_lock); + return data; + +out: + /* + * It has shown to be needed to turn off the GPADC if an error occurs, + * otherwise we might have problem when waiting for the busy bit in the + * GPADC status register to go low. In V1.1 there wait_for_completion + * seems to timeout when waiting for an interrupt.. Not seen in V2.0 + */ + (void) abx500_set_register_interruptible(di->dev, AB8500_GPADC, + AB8500_GPADC_CTRL1_REG, DIS_GPADC); + regulator_disable(di->regu); + mutex_unlock(&di->ab8500_gpadc_lock); + dev_err(di->dev, "gpadc_conversion: Failed to AD convert channel %d\n", + input); + return ret; +} +EXPORT_SYMBOL(ab8500_gpadc_convert); + +/** + * ab8500_bm_gpswadcconvend_handler() - isr for s/w gpadc conversion completion + * @irq: irq number + * @data: pointer to the data passed during request irq + * + * This is a interrupt service routine for s/w gpadc conversion completion. + * Notifies the gpadc completion is completed and the converted raw value + * can be read from the registers. + * Returns IRQ status(IRQ_HANDLED) + */ +static irqreturn_t ab8500_bm_gpswadcconvend_handler(int irq, void *_di) +{ + struct ab8500_gpadc *gpadc = _di; + + complete(&gpadc->ab8500_gpadc_complete); + + return IRQ_HANDLED; +} + +static int __devinit ab8500_gpadc_probe(struct platform_device *pdev) +{ + int ret = 0; + struct ab8500_gpadc *gpadc; + + gpadc = kzalloc(sizeof(struct ab8500_gpadc), GFP_KERNEL); + if (!gpadc) { + dev_err(&pdev->dev, "Error: No memory\n"); + return -ENOMEM; + } + + gpadc->parent = dev_get_drvdata(pdev->dev.parent); + gpadc->irq = platform_get_irq_byname(pdev, "SW_CONV_END"); + if (gpadc->irq < 0) { + dev_err(gpadc->dev, "failed to get platform irq-%d\n", di->irq); + ret = gpadc->irq; + goto fail; + } + + gpadc->dev = &pdev->dev; + mutex_init(&di->ab8500_gpadc_lock); + + /* Initialize completion used to notify completion of conversion */ + init_completion(&gpadc->ab8500_gpadc_complete); + + /* Register interrupt - SwAdcComplete */ + ret = request_threaded_irq(gpadc->irq, NULL, + ab8500_bm_gpswadcconvend_handler, + IRQF_NO_SUSPEND | IRQF_SHARED, "ab8500-gpadc", gpadc); + if (ret < 0) { + dev_err(gpadc->dev, "Failed to register interrupt, irq: %d\n", + gpadc->irq); + goto fail; + } + + /* VTVout LDO used to power up ab8500-GPADC */ + gpadc->regu = regulator_get(&pdev->dev, "vddadc"); + if (IS_ERR(gpadc->regu)) { + ret = PTR_ERR(gpadc->regu); + dev_err(gpadc->dev, "failed to get vtvout LDO\n"); + goto fail; + } + di = gpadc; + dev_dbg(gpadc->dev, "probe success\n"); + return 0; +fail: + kfree(gpadc); + gpadc = NULL; + return ret; +} + +static int __devexit ab8500_gpadc_remove(struct platform_device *pdev) +{ + struct ab8500_gpadc *gpadc = platform_get_drvdata(pdev); + + /* remove interrupt - completion of Sw ADC conversion */ + free_irq(gpadc->irq, di); + /* disable VTVout LDO that is being used by GPADC */ + regulator_put(gpadc->regu); + kfree(gpadc); + gpadc = NULL; + return 0; +} + +static struct platform_driver ab8500_gpadc_driver = { + .probe = ab8500_gpadc_probe, + .remove = __devexit_p(ab8500_gpadc_remove), + .driver = { + .name = "ab8500-gpadc", + .owner = THIS_MODULE, + }, +}; + +static int __init ab8500_gpadc_init(void) +{ + return platform_driver_register(&ab8500_gpadc_driver); +} + +static void __exit ab8500_gpadc_exit(void) +{ + platform_driver_unregister(&ab8500_gpadc_driver); +} + +subsys_initcall_sync(ab8500_gpadc_init); +module_exit(ab8500_gpadc_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Arun R Murthy"); +MODULE_ALIAS("platform:ab8500_gpadc"); +MODULE_DESCRIPTION("AB8500 GPADC driver"); |