From 28ab44c5be60a9b91021a7cc7b4e202775c04764 Mon Sep 17 00:00:00 2001
From: Ben Dooks <ben-linux@fluff.org>
Date: Thu, 18 Dec 2008 14:20:04 +0000
Subject: [ARM] S3C24XX: ADC driver core
A common core driver for the S3C24XX ADC block so that
the touchscreen, hwmon and any other drivers can share
the resource.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
---
arch/arm/plat-s3c24xx/adc.c | 372 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 372 insertions(+)
create mode 100644 arch/arm/plat-s3c24xx/adc.c
(limited to 'arch/arm/plat-s3c24xx/adc.c')
diff --git a/arch/arm/plat-s3c24xx/adc.c b/arch/arm/plat-s3c24xx/adc.c
new file mode 100644
index 0000000..9a5c767
--- /dev/null
+++ b/arch/arm/plat-s3c24xx/adc.c
@@ -0,0 +1,372 @@
+/* arch/arm/plat-s3c24xx/adc.c
+ *
+ * Copyright (c) 2008 Simtec Electronics
+ * http://armlinux.simtec.co.uk/
+ * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
+ *
+ * S3C24XX ADC device core
+ *
+ * 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.
+*/
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+
+#include <plat/regs-adc.h>
+#include <plat/adc.h>
+
+/* This driver is designed to control the usage of the ADC block between
+ * the touchscreen and any other drivers that may need to use it, such as
+ * the hwmon driver.
+ *
+ * Priority will be given to the touchscreen driver, but as this itself is
+ * rate limited it should not starve other requests which are processed in
+ * order that they are received.
+ *
+ * Each user registers to get a client block which uniquely identifies it
+ * and stores information such as the necessary functions to callback when
+ * action is required.
+ */
+
+struct s3c_adc_client {
+ struct platform_device *pdev;
+ struct list_head pend;
+
+ unsigned int nr_samples;
+ unsigned char is_ts;
+ unsigned char channel;
+
+ void (*select_cb)(unsigned selected);
+ void (*convert_cb)(unsigned val1, unsigned val2);
+};
+
+struct adc_device {
+ struct platform_device *pdev;
+ struct platform_device *owner;
+ struct clk *clk;
+ struct s3c_adc_client *cur;
+ struct s3c_adc_client *ts_pend;
+ void __iomem *regs;
+
+ unsigned int prescale;
+
+ int irq;
+};
+
+static struct adc_device *adc_dev;
+
+static LIST_HEAD(adc_pending);
+
+#define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
+
+static inline void s3c_adc_convert(struct adc_device *adc)
+{
+ unsigned con = readl(adc->regs + S3C2410_ADCCON);
+
+ con |= S3C2410_ADCCON_ENABLE_START;
+ writel(con, adc->regs + S3C2410_ADCCON);
+}
+
+static inline void s3c_adc_select(struct adc_device *adc,
+ struct s3c_adc_client *client)
+{
+ unsigned con = readl(adc->regs + S3C2410_ADCCON);
+
+ client->select_cb(1);
+
+ con &= ~S3C2410_ADCCON_MUXMASK;
+ con &= ~S3C2410_ADCCON_STDBM;
+ con &= ~S3C2410_ADCCON_STARTMASK;
+
+ if (!client->is_ts)
+ con |= S3C2410_ADCCON_SELMUX(client->channel);
+
+ writel(con, adc->regs + S3C2410_ADCCON);
+}
+
+static void s3c_adc_dbgshow(struct adc_device *adc)
+{
+ adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
+ readl(adc->regs + S3C2410_ADCCON),
+ readl(adc->regs + S3C2410_ADCTSC),
+ readl(adc->regs + S3C2410_ADCDLY));
+}
+
+void s3c_adc_try(struct adc_device *adc)
+{
+ struct s3c_adc_client *next = adc->ts_pend;
+
+ if (!next && !list_empty(&adc_pending)) {
+ next = list_first_entry(&adc_pending,
+ struct s3c_adc_client, pend);
+ list_del(&next->pend);
+ } else
+ adc->ts_pend = NULL;
+
+ if (next) {
+ adc_dbg(adc, "new client is %p\n", next);
+ adc->cur = next;
+ s3c_adc_select(adc, next);
+ s3c_adc_convert(adc);
+ s3c_adc_dbgshow(adc);
+ }
+}
+
+int s3c_adc_start(struct s3c_adc_client *client,
+ unsigned int channel, unsigned int nr_samples)
+{
+ struct adc_device *adc = adc_dev;
+ unsigned long flags;
+
+ if (!adc) {
+ printk(KERN_ERR "%s: failed to find adc\n", __func__);
+ return -EINVAL;
+ }
+
+ if (client->is_ts && adc->ts_pend)
+ return -EAGAIN;
+
+ local_irq_save(flags);
+
+ client->channel = channel;
+ client->nr_samples = nr_samples;
+
+ if (client->is_ts)
+ adc->ts_pend = client;
+ else
+ list_add_tail(&client->pend, &adc_pending);
+
+ if (!adc->cur)
+ s3c_adc_try(adc);
+ local_irq_restore(flags);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(s3c_adc_start);
+
+static void s3c_adc_default_select(unsigned select)
+{
+}
+
+struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
+ void (*select)(unsigned int selected),
+ void (*conv)(unsigned d0, unsigned d1),
+ unsigned int is_ts)
+{
+ struct s3c_adc_client *client;
+
+ WARN_ON(!pdev);
+ WARN_ON(!conv);
+
+ if (!select)
+ select = s3c_adc_default_select;
+
+ if (!conv || !pdev)
+ return ERR_PTR(-EINVAL);
+
+ client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
+ if (!client) {
+ dev_err(&pdev->dev, "no memory for adc client\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ client->pdev = pdev;
+ client->is_ts = is_ts;
+ client->select_cb = select;
+ client->convert_cb = conv;
+
+ return client;
+}
+EXPORT_SYMBOL_GPL(s3c_adc_register);
+
+void s3c_adc_release(struct s3c_adc_client *client)
+{
+ /* We should really check that nothing is in progress. */
+ kfree(client);
+}
+EXPORT_SYMBOL_GPL(s3c_adc_release);
+
+static irqreturn_t s3c_adc_irq(int irq, void *pw)
+{
+ struct adc_device *adc = pw;
+ struct s3c_adc_client *client = adc->cur;
+ unsigned long flags;
+ unsigned data0, data1;
+
+ if (!client) {
+ dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
+ return IRQ_HANDLED;
+ }
+
+ data0 = readl(adc->regs + S3C2410_ADCDAT0);
+ data1 = readl(adc->regs + S3C2410_ADCDAT1);
+ adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
+
+ (client->convert_cb)(data0 & 0x3ff, data1 & 0x3ff);
+
+ if (--client->nr_samples > 0) {
+ /* fire another conversion for this */
+
+ client->select_cb(1);
+ s3c_adc_convert(adc);
+ } else {
+ local_irq_save(flags);
+ (client->select_cb)(0);
+ adc->cur = NULL;
+
+ s3c_adc_try(adc);
+ local_irq_restore(flags);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int s3c_adc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct adc_device *adc;
+ struct resource *regs;
+ int ret;
+
+ adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
+ if (adc == NULL) {
+ dev_err(dev, "failed to allocate adc_device\n");
+ return -ENOMEM;
+ }
+
+ adc->pdev = pdev;
+ adc->prescale = S3C2410_ADCCON_PRSCVL(49);
+
+ adc->irq = platform_get_irq(pdev, 1);
+ if (adc->irq <= 0) {
+ dev_err(dev, "failed to get adc irq\n");
+ ret = -ENOENT;
+ goto err_alloc;
+ }
+
+ ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
+ if (ret < 0) {
+ dev_err(dev, "failed to attach adc irq\n");
+ goto err_alloc;
+ }
+
+ adc->clk = clk_get(dev, "adc");
+ if (IS_ERR(adc->clk)) {
+ dev_err(dev, "failed to get adc clock\n");
+ ret = PTR_ERR(adc->clk);
+ goto err_irq;
+ }
+
+ regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!regs) {
+ dev_err(dev, "failed to find registers\n");
+ ret = -ENXIO;
+ goto err_clk;
+ }
+
+ adc->regs = ioremap(regs->start, resource_size(regs));
+ if (!adc->regs) {
+ dev_err(dev, "failed to map registers\n");
+ ret = -ENXIO;
+ goto err_clk;
+ }
+
+ clk_enable(adc->clk);
+
+ writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
+ adc->regs + S3C2410_ADCCON);
+
+ dev_info(dev, "attached adc driver\n");
+
+ platform_set_drvdata(pdev, adc);
+ adc_dev = adc;
+
+ return 0;
+
+ err_clk:
+ clk_put(adc->clk);
+
+ err_irq:
+ free_irq(adc->irq, adc);
+
+ err_alloc:
+ kfree(adc);
+ return ret;
+}
+
+static int s3c_adc_remove(struct platform_device *pdev)
+{
+ struct adc_device *adc = platform_get_drvdata(pdev);
+
+ iounmap(adc->regs);
+ free_irq(adc->irq, adc);
+ clk_disable(adc->clk);
+ clk_put(adc->clk);
+ kfree(adc);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct adc_device *adc = platform_get_drvdata(pdev);
+ u32 con;
+
+ con = readl(adc->regs + S3C2410_ADCCON);
+ con |= S3C2410_ADCCON_STDBM;
+ writel(con, adc->regs + S3C2410_ADCCON);
+
+ clk_disable(adc->clk);
+
+ return 0;
+}
+
+static int s3c_adc_resume(struct platform_device *pdev)
+{
+ struct adc_device *adc = platform_get_drvdata(pdev);
+
+ clk_enable(adc->clk);
+
+ writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
+ adc->regs + S3C2410_ADCCON);
+
+ return 0;
+}
+
+#else
+#define s3c_adc_suspend NULL
+#define s3c_adc_resume NULL
+#endif
+
+static struct platform_driver s3c_adc_driver = {
+ .driver = {
+ .name = "s3c24xx-adc",
+ .owner = THIS_MODULE,
+ },
+ .probe = s3c_adc_probe,
+ .remove = __devexit_p(s3c_adc_remove),
+ .suspend = s3c_adc_suspend,
+ .resume = s3c_adc_resume,
+};
+
+static int __init adc_init(void)
+{
+ int ret;
+
+ ret = platform_driver_register(&s3c_adc_driver);
+ if (ret)
+ printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
+
+ return ret;
+}
+
+arch_initcall(adc_init);
--
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