mfd: ti_tscadc: Add support for TI's TSC/ADC MFDevice

Add the mfd core driver which supports touchscreen
and ADC.
With this patch we are only adding infrastructure to
support the MFD clients.

Signed-off-by: Patil, Rachna <rachna@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 250 insertions, 0 deletions

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
new file mode 100644
index 000000000000..14df67bc390f
--- /dev/null
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -0,0 +1,250 @@
+/*
+ * TI Touch Screen / ADC MFD driver
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/regmap.h>
+#include <linux/mfd/core.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/mfd/ti_am335x_tscadc.h>
+
+static unsigned int tscadc_readl(struct ti_tscadc_dev *tsadc, unsigned int reg)
+{
+        unsigned int val;
+
+        regmap_read(tsadc->regmap_tscadc, reg, &val);
+        return val;
+}
+
+static void tscadc_writel(struct ti_tscadc_dev *tsadc, unsigned int reg,
+                                        unsigned int val)
+{
+        regmap_write(tsadc->regmap_tscadc, reg, val);
+}
+
+static const struct regmap_config tscadc_regmap_config = {
+        .name = "ti_tscadc",
+        .reg_bits = 32,
+        .reg_stride = 4,
+        .val_bits = 32,
+};
+
+static void tscadc_idle_config(struct ti_tscadc_dev *config)
+{
+        unsigned int idleconfig;
+
+        idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
+                        STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
+
+        tscadc_writel(config, REG_IDLECONFIG, idleconfig);
+}
+
+static  int __devinit ti_tscadc_probe(struct platform_device *pdev)
+{
+        struct ti_tscadc_dev    *tscadc;
+        struct resource         *res;
+        struct clk              *clk;
+        struct mfd_tscadc_board *pdata = pdev->dev.platform_data;
+        int                     irq;
+        int                     err, ctrl;
+        int                     clk_value, clock_rate;
+
+        if (!pdata) {
+                dev_err(&pdev->dev, "Could not find platform data\n");
+                return -EINVAL;
+        }
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!res) {
+                dev_err(&pdev->dev, "no memory resource defined.\n");
+                return -EINVAL;
+        }
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0) {
+                dev_err(&pdev->dev, "no irq ID is specified.\n");
+                return -EINVAL;
+        }
+
+        /* Allocate memory for device */
+        tscadc = devm_kzalloc(&pdev->dev,
+                        sizeof(struct ti_tscadc_dev), GFP_KERNEL);
+        if (!tscadc) {
+                dev_err(&pdev->dev, "failed to allocate memory.\n");
+                return -ENOMEM;
+        }
+        tscadc->dev = &pdev->dev;
+        tscadc->irq = irq;
+
+        res = devm_request_mem_region(&pdev->dev,
+                        res->start, resource_size(res), pdev->name);
+        if (!res) {
+                dev_err(&pdev->dev, "failed to reserve registers.\n");
+                err = -EBUSY;
+                goto err;
+        }
+
+        tscadc->tscadc_base = devm_ioremap(&pdev->dev,
+                        res->start, resource_size(res));
+        if (!tscadc->tscadc_base) {
+                dev_err(&pdev->dev, "failed to map registers.\n");
+                err = -ENOMEM;
+                goto err;
+        }
+
+        tscadc->regmap_tscadc = devm_regmap_init_mmio(&pdev->dev,
+                        tscadc->tscadc_base, &tscadc_regmap_config);
+        if (IS_ERR(tscadc->regmap_tscadc)) {
+                dev_err(&pdev->dev, "regmap init failed\n");
+                err = PTR_ERR(tscadc->regmap_tscadc);
+                goto err;
+        }
+
+        pm_runtime_enable(&pdev->dev);
+        pm_runtime_get_sync(&pdev->dev);
+
+        /*
+         * The TSC_ADC_Subsystem has 2 clock domains
+         * OCP_CLK and ADC_CLK.
+         * The ADC clock is expected to run at target of 3MHz,
+         * and expected to capture 12-bit data at a rate of 200 KSPS.
+         * The TSC_ADC_SS controller design assumes the OCP clock is
+         * at least 6x faster than the ADC clock.
+         */
+        clk = clk_get(&pdev->dev, "adc_tsc_fck");
+        if (IS_ERR(clk)) {
+                dev_err(&pdev->dev, "failed to get TSC fck\n");
+                err = PTR_ERR(clk);
+                goto err_disable_clk;
+        }
+        clock_rate = clk_get_rate(clk);
+        clk_put(clk);
+        clk_value = clock_rate / ADC_CLK;
+        if (clk_value < MAX_CLK_DIV) {
+                dev_err(&pdev->dev, "clock input less than min clock requirement\n");
+                err = -EINVAL;
+                goto err_disable_clk;
+        }
+        /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
+        clk_value = clk_value - 1;
+        tscadc_writel(tscadc, REG_CLKDIV, clk_value);
+
+        /* Set the control register bits */
+        ctrl = CNTRLREG_STEPCONFIGWRT |
+                        CNTRLREG_TSCENB |
+                        CNTRLREG_STEPID |
+                        CNTRLREG_4WIRE;
+        tscadc_writel(tscadc, REG_CTRL, ctrl);
+
+        /* Set register bits for Idle Config Mode */
+        tscadc_idle_config(tscadc);
+
+        /* Enable the TSC module enable bit */
+        ctrl = tscadc_readl(tscadc, REG_CTRL);
+        ctrl |= CNTRLREG_TSCSSENB;
+        tscadc_writel(tscadc, REG_CTRL, ctrl);
+
+        err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
+                        TSCADC_CELLS, NULL, 0, NULL);
+        if (err < 0)
+                goto err_disable_clk;
+
+        device_init_wakeup(&pdev->dev, true);
+        platform_set_drvdata(pdev, tscadc);
+
+        return 0;
+
+err_disable_clk:
+        pm_runtime_put_sync(&pdev->dev);
+        pm_runtime_disable(&pdev->dev);
+err:
+        return err;
+}
+
+static int __devexit ti_tscadc_remove(struct platform_device *pdev)
+{
+        struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
+
+        tscadc_writel(tscadc, REG_SE, 0x00);
+
+        pm_runtime_put_sync(&pdev->dev);
+        pm_runtime_disable(&pdev->dev);
+
+        mfd_remove_devices(tscadc->dev);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int tscadc_suspend(struct device *dev)
+{
+        struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
+
+        tscadc_writel(tscadc_dev, REG_SE, 0x00);
+        pm_runtime_put_sync(dev);
+
+        return 0;
+}
+
+static int tscadc_resume(struct device *dev)
+{
+        struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
+        unsigned int restore, ctrl;
+
+        pm_runtime_get_sync(dev);
+
+        /* context restore */
+        ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_TSCENB |
+                        CNTRLREG_STEPID | CNTRLREG_4WIRE;
+        tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
+        tscadc_idle_config(tscadc_dev);
+        tscadc_writel(tscadc_dev, REG_SE, STPENB_STEPENB);
+        restore = tscadc_readl(tscadc_dev, REG_CTRL);
+        tscadc_writel(tscadc_dev, REG_CTRL,
+                        (restore | CNTRLREG_TSCSSENB));
+
+        return 0;
+}
+
+static const struct dev_pm_ops tscadc_pm_ops = {
+        .suspend = tscadc_suspend,
+        .resume = tscadc_resume,
+};
+#define TSCADC_PM_OPS (&tscadc_pm_ops)
+#else
+#define TSCADC_PM_OPS NULL
+#endif
+
+static struct platform_driver ti_tscadc_driver = {
+        .driver = {
+                .name   = "ti_tscadc",
+                .owner  = THIS_MODULE,
+                .pm     = TSCADC_PM_OPS,
+        },
+        .probe  = ti_tscadc_probe,
+        .remove = __devexit_p(ti_tscadc_remove),
+
+};
+
+module_platform_driver(ti_tscadc_driver);
+
+MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
+MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
+MODULE_LICENSE("GPL");