This patch adds a 3-channel ADC driver for the LPC32xx ARM SoC
Signed-off-by: Roland Stigge <[email protected]>
diff --git a/arch/arm/mach-lpc32xx/clock.c b/arch/arm/mach-lpc32xx/clock.c
index c269ef5..9cda6fa 100644
--- a/arch/arm/mach-lpc32xx/clock.c
+++ b/arch/arm/mach-lpc32xx/clock.c
@@ -760,6 +760,36 @@ static struct clk clk_tsc = {
.get_rate = local_return_parent_rate,
};
+static int adc_onoff_enable(struct clk *clk, int enable)
+{
+ u32 tmp;
+
+ /* Use PERIPH_CLOCK */
+ tmp = __raw_readl(LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
+ tmp |= LPC32XX_CLKPWR_ADCCTRL1_PCLK_SEL;
+ /*
+ * Set clock divider so that we have equal to or less than
+ * 4.5MHz clock at ADC
+ */
+ tmp |= clk->get_rate(clk) / 4500000 + 1;
+ __raw_writel(tmp, LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
+
+ if (enable == 0)
+ __raw_writel(0, clk->enable_reg);
+ else
+ __raw_writel(clk->enable_mask, clk->enable_reg);
+
+ return 0;
+}
+
+static struct clk clk_adc = {
+ .parent = &clk_pclk,
+ .enable = adc_onoff_enable,
+ .enable_reg = LPC32XX_CLKPWR_ADC_CLK_CTRL,
+ .enable_mask = LPC32XX_CLKPWR_ADC32CLKCTRL_CLK_EN,
+ .get_rate = local_return_parent_rate,
+};
+
static int mmc_onoff_enable(struct clk *clk, int enable)
{
u32 tmp;
@@ -1097,6 +1127,7 @@ static struct clk_lookup lookups[] = {
_REGISTER_CLOCK("dev:ssp1", NULL, clk_ssp1)
_REGISTER_CLOCK("lpc32xx_keys.0", NULL, clk_kscan)
_REGISTER_CLOCK("lpc32xx-nand.0", "nand_ck", clk_nand)
+ _REGISTER_CLOCK("lpc32xx-adc", NULL, clk_adc)
_REGISTER_CLOCK(NULL, "i2s0_ck", clk_i2s0)
_REGISTER_CLOCK(NULL, "i2s1_ck", clk_i2s1)
_REGISTER_CLOCK("ts-lpc32xx", NULL, clk_tsc)
diff --git a/arch/arm/mach-lpc32xx/common.c b/arch/arm/mach-lpc32xx/common.c
index f220eb0..2f869c0 100644
--- a/arch/arm/mach-lpc32xx/common.c
+++ b/arch/arm/mach-lpc32xx/common.c
@@ -137,6 +137,27 @@ struct platform_device lpc32xx_rtc_device = {
.resource = lpc32xx_rtc_resources,
};
+/*
+ * ADC support
+ */
+static struct resource adc_resources[] = {
+ {
+ .start = LPC32XX_ADC_BASE,
+ .end = LPC32XX_ADC_BASE + SZ_4K - 1,
+ .flags = IORESOURCE_MEM,
+ }, {
+ .start = IRQ_LPC32XX_TS_IRQ,
+ .end = IRQ_LPC32XX_TS_IRQ,
+ .flags = IORESOURCE_IRQ,
+ },
+};
+struct platform_device lpc32xx_adc_device = {
+ .name = "lpc32xx-adc",
+ .id = -1,
+ .num_resources = ARRAY_SIZE(adc_resources),
+ .resource = adc_resources,
+};
+
#if defined(CONFIG_USB_OHCI_HCD)
/* The dmamask must be set for OHCI to work */
static u64 ohci_dmamask = ~(u32) 0;
diff --git a/arch/arm/mach-lpc32xx/common.h b/arch/arm/mach-lpc32xx/common.h
index e42d702..5bf0050 100644
--- a/arch/arm/mach-lpc32xx/common.h
+++ b/arch/arm/mach-lpc32xx/common.h
@@ -30,6 +30,7 @@ extern struct platform_device lpc32xx_i2c0_device;
extern struct platform_device lpc32xx_i2c1_device;
extern struct platform_device lpc32xx_i2c2_device;
extern struct platform_device lpc32xx_tsc_device;
+extern struct platform_device lpc32xx_adc_device;
extern struct platform_device lpc32xx_rtc_device;
extern struct platform_device lpc32xx_ohci_device;
diff --git a/arch/arm/mach-lpc32xx/phy3250.c b/arch/arm/mach-lpc32xx/phy3250.c
index 69a5ceb..23b484c 100644
--- a/arch/arm/mach-lpc32xx/phy3250.c
+++ b/arch/arm/mach-lpc32xx/phy3250.c
@@ -317,6 +317,9 @@ static struct platform_device *phy3250_devs[] __initdata = {
#if defined(CONFIG_LPC_ENET)
&lpc32xx_net_device,
#endif
+#if defined(CONFIG_LPC32XX_ADC)
+ &lpc32xx_adc_device,
+#endif
};
static struct amba_device *amba_devs[] __initdata = {
diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
index d9decea..592eabd 100644
--- a/drivers/staging/iio/adc/Kconfig
+++ b/drivers/staging/iio/adc/Kconfig
@@ -193,4 +193,13 @@ config MAX1363_RING_BUFFER
Say yes here to include ring buffer support in the MAX1363
ADC driver.
+config LPC32XX_ADC
+ tristate "NXP LPC32XX ADC"
+ depends on ARCH_LPC32XX && !TOUCHSCREEN_LPC32XX
+ help
+ Say yes here to build support for the integrated ADC inside the
+ LPC32XX SoC. Note that this feature uses the same hardware as the
+ touchscreen driver, so you can only select one of the two drivers
+ (lpc32xx_adc or lpc32xx_ts). Provides direct access via sysfs.
+
endmenu
diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
index ceee7f3..f83ab95 100644
--- a/drivers/staging/iio/adc/Makefile
+++ b/drivers/staging/iio/adc/Makefile
@@ -37,3 +37,4 @@ obj-$(CONFIG_AD7192) += ad7192.o
obj-$(CONFIG_ADT7310) += adt7310.o
obj-$(CONFIG_ADT7410) += adt7410.o
obj-$(CONFIG_AD7280) += ad7280a.o
+obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
diff --git a/drivers/staging/iio/adc/lpc32xx_adc.c b/drivers/staging/iio/adc/lpc32xx_adc.c
new file mode 100644
index 0000000..6b27446
--- /dev/null
+++ b/drivers/staging/iio/adc/lpc32xx_adc.c
@@ -0,0 +1,286 @@
+/*
+ * lpc32xx_adc.c - Support for ADC in LPC32XX
+ *
+ * Copyright (C) 2011 Roland Stigge <[email protected]>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/completion.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+
+/*
+ * LPC32XX registers definitions
+ */
+
+#define LPC32XX_ADC_SELECT(x) ((x) + 0x04)
+#define LPC32XX_ADC_CTRL(x) ((x) + 0x08)
+#define LPC32XX_ADC_VALUE(x) ((x) + 0x48)
+
+/* Bit definitions for LPC32XX_ADC_SELECT: */
+#define AD_REFm 0x00000200 /* constant, always write this value! */
+#define AD_REFp 0x00000080 /* constant, always write this value! */
+#define AD_IN 0x00000010 /* multiple of this is the */
+ /* channel number: 0, 1, 2 */
+#define AD_INTERNAL 0x00000004 /* constant, always write this value! */
+
+/* Bit definitions for LPC32XX_ADC_CTRL: */
+#define AD_STROBE 0x00000002
+#define AD_PDN_CTRL 0x00000004
+
+/* Bit definitions for LPC32XX_ADC_VALUE: */
+#define ADC_VALUE_MASK 0x000003FF
+
+#define MOD_NAME "lpc32xx-adc"
+
+/*
+ * chip specifc information
+ */
+
+struct lpc32xx_adc_info {
+ struct iio_dev *dev;
+ void __iomem *adc_base;
+ int irq;
+ struct clk *clk;
+ struct completion completion;
+
+ u32 value;
+};
+
+/*
+ * sysfs nodes
+ */
+static ssize_t lpc32xx_adin_value(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *dev_info = dev_get_drvdata(dev);
+ struct lpc32xx_adc_info *info = iio_priv(dev_info);
+ struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+ int result;
+
+ mutex_lock(&dev_info->mlock);
+ /* Measurement setup */
+ __raw_writel(AD_INTERNAL | (AD_IN * this_attr->address) |
+ AD_REFp | AD_REFm,
+ LPC32XX_ADC_SELECT(info->adc_base));
+ /* Trigger conversion */
+ __raw_writel(AD_PDN_CTRL | AD_STROBE,
+ LPC32XX_ADC_CTRL(info->adc_base));
+
+ wait_for_completion(&info->completion); /* set by ISR */
+
+ result = sprintf(buf, "%d\n", info->value);
+
+ mutex_unlock(&dev_info->mlock);
+
+ return result;
+}
+
+static IIO_DEVICE_ATTR(in0_raw, S_IRUGO, lpc32xx_adin_value, NULL, 0);
+static IIO_DEVICE_ATTR(in1_raw, S_IRUGO, lpc32xx_adin_value, NULL, 1);
+static IIO_DEVICE_ATTR(in2_raw, S_IRUGO, lpc32xx_adin_value, NULL, 2);
+
+static struct attribute *lpc32xx_adin_attributes[] = {
+ &iio_dev_attr_in0_raw.dev_attr.attr,
+ &iio_dev_attr_in1_raw.dev_attr.attr,
+ &iio_dev_attr_in2_raw.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group lpc32xx_adin_attribute_group = {
+ .attrs = lpc32xx_adin_attributes,
+};
+
+static const struct iio_info lpc32xx_adc_iio_info = {
+ .attrs = &lpc32xx_adin_attribute_group,
+ .driver_module = THIS_MODULE,
+};
+
+static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
+{
+ struct lpc32xx_adc_info *info = (struct lpc32xx_adc_info *) dev_id;
+
+ /* Read value and clear irq */
+ info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base)) &
+ ADC_VALUE_MASK;
+ complete(&info->completion);
+
+ return IRQ_HANDLED;
+}
+
+static int __devinit lpc32xx_adc_probe(struct platform_device *pdev)
+{
+ struct lpc32xx_adc_info *info = NULL;
+ struct resource *res;
+ int retval = -ENODEV;
+ struct iio_dev *iodev = NULL;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get platform I/O memory\n");
+ retval = -EBUSY;
+ goto errout1;
+ }
+
+ iodev = iio_allocate_device(sizeof(struct lpc32xx_adc_info));
+ if (!iodev) {
+ dev_err(&pdev->dev, "failed allocating iio device\n");
+ retval = -ENOMEM;
+ goto errout1;
+ }
+
+ info = iio_priv(iodev);
+ info->dev = iodev;
+
+ info->adc_base = ioremap(res->start, res->end - res->start + 1);
+ if (!info->adc_base) {
+ dev_err(&pdev->dev, "failed mapping memory\n");
+ retval = -EBUSY;
+ goto errout3;
+ }
+
+ iodev->name = MOD_NAME;
+ iodev->dev.parent = &pdev->dev;
+ iodev->info = &lpc32xx_adc_iio_info;
+ iodev->modes = INDIO_DIRECT_MODE;
+
+ retval = iio_device_register(iodev);
+ if (retval)
+ goto errout4;
+
+ info->clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(info->clk)) {
+ dev_err(&pdev->dev, "failed getting clock\n");
+ goto errout5;
+ }
+ clk_enable(info->clk);
+
+ info->irq = platform_get_irq(pdev, 0);
+ if ((info->irq < 0) || (info->irq >= NR_IRQS)) {
+ dev_err(&pdev->dev, "failed getting interrupt resource\n");
+ retval = -EINVAL;
+ goto errout6;
+ }
+
+ retval = request_irq(info->irq, lpc32xx_adc_isr, 0, MOD_NAME, info);
+ if (retval < 0) {
+ dev_err(&pdev->dev, "failed requesting interrupt\n");
+ goto errout6;
+ }
+
+ platform_set_drvdata(pdev, info);
+
+ device_init_wakeup(&pdev->dev, 1);
+ init_completion(&info->completion);
+
+ printk(KERN_INFO "LPC32XX ADC driver loaded, IRQ %d\n", info->irq);
+
+ return 0;
+
+errout6:
+ clk_disable(info->clk);
+ clk_put(info->clk);
+errout5:
+ iio_device_unregister(info->dev);
+errout4:
+ iounmap(info->adc_base);
+errout3:
+ iio_free_device(info->dev);
+errout1:
+ return retval;
+}
+
+static int __devexit lpc32xx_adc_remove(struct platform_device *pdev)
+{
+ struct lpc32xx_adc_info *info = platform_get_drvdata(pdev);
+
+ free_irq(info->irq, info->dev);
+ platform_set_drvdata(pdev, NULL);
+ clk_disable(info->clk);
+ clk_put(info->clk);
+ iio_device_unregister(info->dev);
+ iio_free_device(info->dev);
+ iounmap(info->adc_base);
+ kfree(info);
+
+ printk(KERN_INFO "LPC32XX ADC driver unloaded\n");
+
+ return 0;
+}
+
+#if defined(CONFIG_SUSPEND)
+static int lpc32xx_adc_suspend(struct device *dev)
+{
+ struct lpc32xx_adc_info *info = dev_get_drvdata(dev);
+
+ clk_disable(info->clk);
+ return 0;
+}
+
+static int lpc32xx_adc_resume(struct device *dev)
+{
+ struct lpc32xx_adc_info *info = dev_get_drvdata(dev);
+
+ clk_enable(info->clk);
+ return 0;
+}
+
+static const struct dev_pm_ops lpc32xx_adc_pm_ops = {
+ .suspend = lpc32xx_adc_suspend,
+ .resume = lpc32xx_adc_resume,
+};
+#define LPC32XX_ADC_PM_OPS (&lpc32xx_adc_pm_ops)
+#else
+#define LPC32XX_ADC_PM_OPS NULL
+#endif
+
+static struct platform_driver lpc32xx_adc_driver = {
+ .probe = lpc32xx_adc_probe,
+ .remove = __devexit_p(lpc32xx_adc_remove),
+ .driver = {
+ .name = MOD_NAME,
+ .owner = THIS_MODULE,
+ .pm = LPC32XX_ADC_PM_OPS,
+ },
+};
+
+static int __init lpc32xx_adc_init(void)
+{
+ return platform_driver_register(&lpc32xx_adc_driver);
+}
+
+static void __exit lpc32xx_adc_exit(void)
+{
+ platform_driver_unregister(&lpc32xx_adc_driver);
+}
+
+module_init(lpc32xx_adc_init);
+module_exit(lpc32xx_adc_exit);
+
+MODULE_AUTHOR("Roland Stigge <[email protected]>");
+MODULE_DESCRIPTION("LPC32XX ADC driver");
+MODULE_LICENSE("GPL");
My comments are down near the iio bits.
> This patch adds a 3-channel ADC driver for the LPC32xx ARM SoC
>
> Signed-off-by: Roland Stigge<[email protected]>
>
> diff --git a/arch/arm/mach-lpc32xx/clock.c b/arch/arm/mach-lpc32xx/clock.c
> index c269ef5..9cda6fa 100644
> --- a/arch/arm/mach-lpc32xx/clock.c
> +++ b/arch/arm/mach-lpc32xx/clock.c
> @@ -760,6 +760,36 @@ static struct clk clk_tsc = {
> .get_rate = local_return_parent_rate,
> };
>
> +static int adc_onoff_enable(struct clk *clk, int enable)
> +{
> + u32 tmp;
> +
> + /* Use PERIPH_CLOCK */
> + tmp = __raw_readl(LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
> + tmp |= LPC32XX_CLKPWR_ADCCTRL1_PCLK_SEL;
> + /*
> + * Set clock divider so that we have equal to or less than
> + * 4.5MHz clock at ADC
> + */
> + tmp |= clk->get_rate(clk) / 4500000 + 1;
> + __raw_writel(tmp, LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
> +
> + if (enable == 0)
> + __raw_writel(0, clk->enable_reg);
> + else
> + __raw_writel(clk->enable_mask, clk->enable_reg);
> +
> + return 0;
> +}
> +
> +static struct clk clk_adc = {
> + .parent =&clk_pclk,
> + .enable = adc_onoff_enable,
> + .enable_reg = LPC32XX_CLKPWR_ADC_CLK_CTRL,
> + .enable_mask = LPC32XX_CLKPWR_ADC32CLKCTRL_CLK_EN,
> + .get_rate = local_return_parent_rate,
> +};
> +
> static int mmc_onoff_enable(struct clk *clk, int enable)
> {
> u32 tmp;
> @@ -1097,6 +1127,7 @@ static struct clk_lookup lookups[] = {
> _REGISTER_CLOCK("dev:ssp1", NULL, clk_ssp1)
> _REGISTER_CLOCK("lpc32xx_keys.0", NULL, clk_kscan)
> _REGISTER_CLOCK("lpc32xx-nand.0", "nand_ck", clk_nand)
> + _REGISTER_CLOCK("lpc32xx-adc", NULL, clk_adc)
> _REGISTER_CLOCK(NULL, "i2s0_ck", clk_i2s0)
> _REGISTER_CLOCK(NULL, "i2s1_ck", clk_i2s1)
> _REGISTER_CLOCK("ts-lpc32xx", NULL, clk_tsc)
> diff --git a/arch/arm/mach-lpc32xx/common.c b/arch/arm/mach-lpc32xx/common.c
> index f220eb0..2f869c0 100644
> --- a/arch/arm/mach-lpc32xx/common.c
> +++ b/arch/arm/mach-lpc32xx/common.c
> @@ -137,6 +137,27 @@ struct platform_device lpc32xx_rtc_device = {
> .resource = lpc32xx_rtc_resources,
> };
>
> +/*
> + * ADC support
> + */
> +static struct resource adc_resources[] = {
> + {
> + .start = LPC32XX_ADC_BASE,
> + .end = LPC32XX_ADC_BASE + SZ_4K - 1,
> + .flags = IORESOURCE_MEM,
> + }, {
> + .start = IRQ_LPC32XX_TS_IRQ,
> + .end = IRQ_LPC32XX_TS_IRQ,
> + .flags = IORESOURCE_IRQ,
> + },
> +};
> +struct platform_device lpc32xx_adc_device = {
> + .name = "lpc32xx-adc",
> + .id = -1,
> + .num_resources = ARRAY_SIZE(adc_resources),
> + .resource = adc_resources,
> +};
> +
> #if defined(CONFIG_USB_OHCI_HCD)
> /* The dmamask must be set for OHCI to work */
> static u64 ohci_dmamask = ~(u32) 0;
> diff --git a/arch/arm/mach-lpc32xx/common.h b/arch/arm/mach-lpc32xx/common.h
> index e42d702..5bf0050 100644
> --- a/arch/arm/mach-lpc32xx/common.h
> +++ b/arch/arm/mach-lpc32xx/common.h
> @@ -30,6 +30,7 @@ extern struct platform_device lpc32xx_i2c0_device;
> extern struct platform_device lpc32xx_i2c1_device;
> extern struct platform_device lpc32xx_i2c2_device;
> extern struct platform_device lpc32xx_tsc_device;
> +extern struct platform_device lpc32xx_adc_device;
> extern struct platform_device lpc32xx_rtc_device;
> extern struct platform_device lpc32xx_ohci_device;
>
> diff --git a/arch/arm/mach-lpc32xx/phy3250.c b/arch/arm/mach-lpc32xx/phy3250.c
> index 69a5ceb..23b484c 100644
> --- a/arch/arm/mach-lpc32xx/phy3250.c
> +++ b/arch/arm/mach-lpc32xx/phy3250.c
> @@ -317,6 +317,9 @@ static struct platform_device *phy3250_devs[] __initdata = {
> #if defined(CONFIG_LPC_ENET)
> &lpc32xx_net_device,
> #endif
> +#if defined(CONFIG_LPC32XX_ADC)
> + &lpc32xx_adc_device,
> +#endif
> };
>
> static struct amba_device *amba_devs[] __initdata = {
> diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
> index d9decea..592eabd 100644
> --- a/drivers/staging/iio/adc/Kconfig
> +++ b/drivers/staging/iio/adc/Kconfig
> @@ -193,4 +193,13 @@ config MAX1363_RING_BUFFER
> Say yes here to include ring buffer support in the MAX1363
> ADC driver.
>
> +config LPC32XX_ADC
> + tristate "NXP LPC32XX ADC"
> + depends on ARCH_LPC32XX&& !TOUCHSCREEN_LPC32XX
> + help
> + Say yes here to build support for the integrated ADC inside the
> + LPC32XX SoC. Note that this feature uses the same hardware as the
> + touchscreen driver, so you can only select one of the two drivers
> + (lpc32xx_adc or lpc32xx_ts). Provides direct access via sysfs.
This should be a good base for messing around with the in kernel
interfaces then ;)
> +
> endmenu
A few structural changes needed, mainly to catch up with newer
interfaces than used here, but
fundamentally sound.
> diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
> index ceee7f3..f83ab95 100644
> --- a/drivers/staging/iio/adc/Makefile
> +++ b/drivers/staging/iio/adc/Makefile
> @@ -37,3 +37,4 @@ obj-$(CONFIG_AD7192) += ad7192.o
> obj-$(CONFIG_ADT7310) += adt7310.o
> obj-$(CONFIG_ADT7410) += adt7410.o
> obj-$(CONFIG_AD7280) += ad7280a.o
> +obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
> diff --git a/drivers/staging/iio/adc/lpc32xx_adc.c b/drivers/staging/iio/adc/lpc32xx_adc.c
> new file mode 100644
> index 0000000..6b27446
> --- /dev/null
> +++ b/drivers/staging/iio/adc/lpc32xx_adc.c
> @@ -0,0 +1,286 @@
> +/*
> + * lpc32xx_adc.c - Support for ADC in LPC32XX
> + *
> + * Copyright (C) 2011 Roland Stigge<[email protected]>
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> + */
> +
> +#include<linux/module.h>
> +#include<linux/platform_device.h>
> +#include<linux/interrupt.h>
> +#include<linux/device.h>
> +#include<linux/kernel.h>
> +#include<linux/slab.h>
> +#include<linux/io.h>
> +#include<linux/clk.h>
> +#include<linux/err.h>
> +#include<linux/completion.h>
> +
> +#include "../iio.h"
> +#include "../sysfs.h"
> +
> +/*
> + * LPC32XX registers definitions
> + */
> +
> +#define LPC32XX_ADC_SELECT(x) ((x) + 0x04)
> +#define LPC32XX_ADC_CTRL(x) ((x) + 0x08)
> +#define LPC32XX_ADC_VALUE(x) ((x) + 0x48)
> +
> +/* Bit definitions for LPC32XX_ADC_SELECT: */
> +#define AD_REFm 0x00000200 /* constant, always write this value! */
> +#define AD_REFp 0x00000080 /* constant, always write this value! */
> +#define AD_IN 0x00000010 /* multiple of this is the */
> + /* channel number: 0, 1, 2 */
> +#define AD_INTERNAL 0x00000004 /* constant, always write this value! */
> +
> +/* Bit definitions for LPC32XX_ADC_CTRL: */
> +#define AD_STROBE 0x00000002
> +#define AD_PDN_CTRL 0x00000004
> +
> +/* Bit definitions for LPC32XX_ADC_VALUE: */
> +#define ADC_VALUE_MASK 0x000003FF
> +
> +#define MOD_NAME "lpc32xx-adc"
> +
> +/*
> + * chip specifc information
> + */
> +
> +struct lpc32xx_adc_info {
> + struct iio_dev *dev;
> + void __iomem *adc_base;
irq is only used where the platform device is readily available so you could
drop it from this structure.
There is provision in iio via the iio_device_allocate parameter and iio_priv
to embed this structure within an iio_dev structure. It makes for a
cleaner code
but will require a trivial bit of reorganizing in your probe and remove
> + int irq;
> + struct clk *clk;
> + struct completion completion;
> +
> + u32 value;
> +};
> +
> +/*
> + * sysfs nodes
> + */
> +static ssize_t lpc32xx_adin_value(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct iio_dev *dev_info = dev_get_drvdata(dev);
> + struct lpc32xx_adc_info *info = iio_priv(dev_info);
> + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> + int result;
> +
> + mutex_lock(&dev_info->mlock);
> + /* Measurement setup */
> + __raw_writel(AD_INTERNAL | (AD_IN * this_attr->address) |
> + AD_REFp | AD_REFm,
> + LPC32XX_ADC_SELECT(info->adc_base));
> + /* Trigger conversion */
> + __raw_writel(AD_PDN_CTRL | AD_STROBE,
> + LPC32XX_ADC_CTRL(info->adc_base));
> +
> + wait_for_completion(&info->completion); /* set by ISR */
> +
> + result = sprintf(buf, "%d\n", info->value);
> +
> + mutex_unlock(&dev_info->mlock);
> +
> + return result;
> +}
> +
> +static IIO_DEVICE_ATTR(in0_raw, S_IRUGO, lpc32xx_adin_value, NULL, 0);
> +static IIO_DEVICE_ATTR(in1_raw, S_IRUGO, lpc32xx_adin_value, NULL, 1);
> +static IIO_DEVICE_ATTR(in2_raw, S_IRUGO, lpc32xx_adin_value, NULL, 2);
> +
> +static struct attribute *lpc32xx_adin_attributes[] = {
> + &iio_dev_attr_in0_raw.dev_attr.attr,
> + &iio_dev_attr_in1_raw.dev_attr.attr,
> + &iio_dev_attr_in2_raw.dev_attr.attr,
> + NULL,
Please use iio_chan_info structures and the read_raw callback
rather than doing these attributes like this. That will make for a much
easier
job if anyone ever wants to use the inkernel interfaces (highly likely
with a soc adc).
> +};
> +
> +static const struct attribute_group lpc32xx_adin_attribute_group = {
> + .attrs = lpc32xx_adin_attributes,
> +};
> +
> +static const struct iio_info lpc32xx_adc_iio_info = {
> + .attrs =&lpc32xx_adin_attribute_group,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
> +{
> + struct lpc32xx_adc_info *info = (struct lpc32xx_adc_info *) dev_id;
> +
> + /* Read value and clear irq */
> + info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base))&
> + ADC_VALUE_MASK;
> + complete(&info->completion);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int __devinit lpc32xx_adc_probe(struct platform_device *pdev)
> +{
> + struct lpc32xx_adc_info *info = NULL;
> + struct resource *res;
> + int retval = -ENODEV;
> + struct iio_dev *iodev = NULL;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(&pdev->dev, "failed to get platform I/O memory\n");
> + retval = -EBUSY;
> + goto errout1;
> + }
> +
> + iodev = iio_allocate_device(sizeof(struct lpc32xx_adc_info));
> + if (!iodev) {
> + dev_err(&pdev->dev, "failed allocating iio device\n");
> + retval = -ENOMEM;
> + goto errout1;
> + }
> +
> + info = iio_priv(iodev);
> + info->dev = iodev;
> +
> + info->adc_base = ioremap(res->start, res->end - res->start + 1);
> + if (!info->adc_base) {
> + dev_err(&pdev->dev, "failed mapping memory\n");
> + retval = -EBUSY;
> + goto errout3;
> + }
> +
> + iodev->name = MOD_NAME;
> + iodev->dev.parent =&pdev->dev;
> + iodev->info =&lpc32xx_adc_iio_info;
> + iodev->modes = INDIO_DIRECT_MODE;
> +
> + retval = iio_device_register(iodev);
> + if (retval)
> + goto errout4;
Generally we'd make the iio_device_register call only after everything
else is set up as it is
at this point that the userspace interface becomes active. Hence there
might be a racecondition
if someone reads just after here. I haven't checked thoroughly, but as
a general rule, keeping
any interfaces from becoming available until everything else is done
makes for easier to review
code if nothing else!
> +
> + info->clk = clk_get(&pdev->dev, NULL);
> + if (IS_ERR(info->clk)) {
> + dev_err(&pdev->dev, "failed getting clock\n");
> + goto errout5;
> + }
> + clk_enable(info->clk);
> +
> + info->irq = platform_get_irq(pdev, 0);
> + if ((info->irq< 0) || (info->irq>= NR_IRQS)) {
> + dev_err(&pdev->dev, "failed getting interrupt resource\n");
> + retval = -EINVAL;
> + goto errout6;
> + }
> +
> + retval = request_irq(info->irq, lpc32xx_adc_isr, 0, MOD_NAME, info);
> + if (retval< 0) {
> + dev_err(&pdev->dev, "failed requesting interrupt\n");
> + goto errout6;
> + }
> +
> + platform_set_drvdata(pdev, info);
> +
> + device_init_wakeup(&pdev->dev, 1);
> + init_completion(&info->completion);
> +
> + printk(KERN_INFO "LPC32XX ADC driver loaded, IRQ %d\n", info->irq);
> +
> + return 0;
> +
> +errout6:
> + clk_disable(info->clk);
> + clk_put(info->clk);
> +errout5:
> + iio_device_unregister(info->dev);
> +errout4:
> + iounmap(info->adc_base);
> +errout3:
> + iio_free_device(info->dev);
> +errout1:
> + return retval;
> +}
> +
> +static int __devexit lpc32xx_adc_remove(struct platform_device *pdev)
> +{
> + struct lpc32xx_adc_info *info = platform_get_drvdata(pdev);
> +
> + free_irq(info->irq, info->dev);
> + platform_set_drvdata(pdev, NULL);
> + clk_disable(info->clk);
> + clk_put(info->clk);
> + iio_device_unregister(info->dev);
> + iio_free_device(info->dev);
> + iounmap(info->adc_base);
> + kfree(info);
> +
> + printk(KERN_INFO "LPC32XX ADC driver unloaded\n");
> +
> + return 0;
> +}
> +
> +#if defined(CONFIG_SUSPEND)
> +static int lpc32xx_adc_suspend(struct device *dev)
> +{
> + struct lpc32xx_adc_info *info = dev_get_drvdata(dev);
> +
> + clk_disable(info->clk);
> + return 0;
> +}
> +
> +static int lpc32xx_adc_resume(struct device *dev)
> +{
> + struct lpc32xx_adc_info *info = dev_get_drvdata(dev);
> +
> + clk_enable(info->clk);
> + return 0;
> +}
> +
> +static const struct dev_pm_ops lpc32xx_adc_pm_ops = {
> + .suspend = lpc32xx_adc_suspend,
> + .resume = lpc32xx_adc_resume,
> +};
> +#define LPC32XX_ADC_PM_OPS (&lpc32xx_adc_pm_ops)
> +#else
> +#define LPC32XX_ADC_PM_OPS NULL
> +#endif
> +
> +static struct platform_driver lpc32xx_adc_driver = {
> + .probe = lpc32xx_adc_probe,
> + .remove = __devexit_p(lpc32xx_adc_remove),
> + .driver = {
> + .name = MOD_NAME,
> + .owner = THIS_MODULE,
> + .pm = LPC32XX_ADC_PM_OPS,
> + },
> +};
> +
> +static int __init lpc32xx_adc_init(void)
> +{
> + return platform_driver_register(&lpc32xx_adc_driver);
> +}
> +
> +static void __exit lpc32xx_adc_exit(void)
> +{
> + platform_driver_unregister(&lpc32xx_adc_driver);
> +}
> +
> +module_init(lpc32xx_adc_init);
> +module_exit(lpc32xx_adc_exit);
> +
> +MODULE_AUTHOR("Roland Stigge<[email protected]>");
> +MODULE_DESCRIPTION("LPC32XX ADC driver");
> +MODULE_LICENSE("GPL");
On Thu, Feb 2, 2012 at 7:02 AM, <[email protected]> wrote:
> This patch adds a 3-channel ADC driver for the LPC32xx ARM SoC
>
> Signed-off-by: Roland Stigge <[email protected]>
>
> diff --git a/arch/arm/mach-lpc32xx/clock.c b/arch/arm/mach-lpc32xx/clock.c
> index c269ef5..9cda6fa 100644
> --- a/arch/arm/mach-lpc32xx/clock.c
> +++ b/arch/arm/mach-lpc32xx/clock.c
> @@ -760,6 +760,36 @@ static struct clk clk_tsc = {
> ? ? ? ?.get_rate ? ? ? = local_return_parent_rate,
> ?};
>
> +static int adc_onoff_enable(struct clk *clk, int enable)
> +{
> + ? ? ? u32 tmp;
> +
> + ? ? ? /* Use PERIPH_CLOCK */
> + ? ? ? tmp = __raw_readl(LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
> + ? ? ? tmp |= LPC32XX_CLKPWR_ADCCTRL1_PCLK_SEL;
> + ? ? ? /*
> + ? ? ? ?* Set clock divider so that we have equal to or less than
> + ? ? ? ?* 4.5MHz clock at ADC
> + ? ? ? ?*/
> + ? ? ? tmp |= clk->get_rate(clk) / 4500000 + 1;
> + ? ? ? __raw_writel(tmp, LPC32XX_CLKPWR_ADC_CLK_CTRL_1);
For this clock, also set clk->rate = (actual rate of the ADC input clock).
Something like clk->rate = clk->get_rate(clk->parent) / (computed divider)
If the clk->rate stays at 0, the clk_get_rate() function for the ADC will
return 13Mhz instead of around 4.5MHz.
(I know the driver doesn't use clk_get_rate(), but this might save some
debugging later if it ever does).
> +
> + ? ? ? if (enable == 0)
> + ? ? ? ? ? ? ? __raw_writel(0, clk->enable_reg);
> + ? ? ? else
> + ? ? ? ? ? ? ? __raw_writel(clk->enable_mask, clk->enable_reg);
> +
> + ? ? ? return 0;
> +}
> +
...
...
> +config LPC32XX_ADC
> + ? ? ? tristate "NXP LPC32XX ADC"
> + ? ? ? depends on ARCH_LPC32XX && !TOUCHSCREEN_LPC32XX
> + ? ? ? help
> + ? ? ? ? Say yes here to build support for the integrated ADC inside the
> + ? ? ? ? LPC32XX SoC. Note that this feature uses the same hardware as the
> + ? ? ? ? touchscreen driver, so you can only select one of the two drivers
> + ? ? ? ? (lpc32xx_adc or lpc32xx_ts). Provides direct access via sysfs.
I like how clean this driver is. Thanks for taking the time to write and submit
this.
> +
> ?endmenu
> diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
> index ceee7f3..f83ab95 100644
> --- a/drivers/staging/iio/adc/Makefile
> +++ b/drivers/staging/iio/adc/Makefile
> @@ -37,3 +37,4 @@ obj-$(CONFIG_AD7192) += ad7192.o
...
...
> + ? ? ? platform_set_drvdata(pdev, info);
> +
> + ? ? ? device_init_wakeup(&pdev->dev, 1);
I don't think you need this for this driver.
> + ? ? ? init_completion(&info->completion);
> +
> + ? ? ? printk(KERN_INFO "LPC32XX ADC driver loaded, IRQ %d\n", info->irq);
dev_info instead of printk
> +
> + ? ? ? return 0;
> +
> +errout6:
> + ? ? ? clk_disable(info->clk);
> + ? ? ? clk_put(info->clk);
> +errout5:
> + ? ? ? iio_device_unregister(info->dev);
> +errout4:
> + ? ? ? iounmap(info->adc_base);
> +errout3:
> + ? ? ? iio_free_device(info->dev);
> +errout1:
> + ? ? ? return retval;
> +}
> +
> +static int __devexit lpc32xx_adc_remove(struct platform_device *pdev)
> +{
> + ? ? ? struct lpc32xx_adc_info *info = platform_get_drvdata(pdev);
> +
> + ? ? ? free_irq(info->irq, info->dev);
> + ? ? ? platform_set_drvdata(pdev, NULL);
> + ? ? ? clk_disable(info->clk);
> + ? ? ? clk_put(info->clk);
> + ? ? ? iio_device_unregister(info->dev);
> + ? ? ? iio_free_device(info->dev);
> + ? ? ? iounmap(info->adc_base);
> + ? ? ? kfree(info);
This may be ok. Needs a sanity check only.
kfree() is used in remove() but not used in probe() failure path. Might be
missing in probe() or not needed here.
> +
> + ? ? ? printk(KERN_INFO "LPC32XX ADC driver unloaded\n");
dev_info()
> +
> + ? ? ? return 0;
> +}
> +
> +#if defined(CONFIG_SUSPEND)
> +static int lpc32xx_adc_suspend(struct device *dev)
> +{
> + ? ? ? struct lpc32xx_adc_info *info = dev_get_drvdata(dev);
> +
> + ? ? ? clk_disable(info->clk);
The ADC block doesn't have to remain clocked when it's not being used.
You might just encapsulate the main ADC read code with clock enable/disable
and remove the suspend code and enable/disable code in probe/remove.
This should save a little power when the ADC is idle.
> + ? ? ? return 0;
> +}
> +
> +static int lpc32xx_adc_resume(struct device *dev)
> +{
> + ? ? ? struct lpc32xx_adc_info *info = dev_get_drvdata(dev);
> +
> + ? ? ? clk_enable(info->clk);
> + ? ? ? return 0;
> +}
> +
> +static const struct dev_pm_ops lpc32xx_adc_pm_ops = {
> + ? ? ? .suspend ? ? ? ?= lpc32xx_adc_suspend,
> + ? ? ? .resume ? ? ? ? = lpc32xx_adc_resume,
> +};
> +#define LPC32XX_ADC_PM_OPS (&lpc32xx_adc_pm_ops)
> +#else
> +#define LPC32XX_ADC_PM_OPS NULL
> +#endif
> +
> +static struct platform_driver lpc32xx_adc_driver = {
> + ? ? ? .probe ? ? ? ? ?= lpc32xx_adc_probe,
> + ? ? ? .remove ? ? ? ? = __devexit_p(lpc32xx_adc_remove),
> + ? ? ? .driver ? ? ? ? = {
> + ? ? ? ? ? ? ? .name ? = MOD_NAME,
> + ? ? ? ? ? ? ? .owner ?= THIS_MODULE,
> + ? ? ? ? ? ? ? .pm ? ? = LPC32XX_ADC_PM_OPS,
> + ? ? ? },
> +};
> +
> +static int __init lpc32xx_adc_init(void)
> +{
> + ? ? ? return platform_driver_register(&lpc32xx_adc_driver);
> +}
> +
> +static void __exit lpc32xx_adc_exit(void)
> +{
> + ? ? ? platform_driver_unregister(&lpc32xx_adc_driver);
> +}
> +
> +module_init(lpc32xx_adc_init);
> +module_exit(lpc32xx_adc_exit);
> +
> +MODULE_AUTHOR("Roland Stigge <[email protected]>");
> +MODULE_DESCRIPTION("LPC32XX ADC driver");
> +MODULE_LICENSE("GPL");
>
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