Input: bcm_iproc_tsc - use syscon to access shared registers

In Cygnus SOC touch screen controller registers are shared with ADC and
flex timer. Using readl/writel could lead to race condition. So touch
screen driver is enhanced to support register access using syscon framework
API's to take care of mutually exclusive access.

Signed-off-by: Raveendra Padasalagi <raveendra.padasalagi@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt b/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt
index 34e3382a065903f546593ea1178dcba1698047d2..25541f30e38701f212c41886c23c46f4f6627cb8 100644 (file)
--- a/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt
@@ -2,11 +2,17 @@
 
 Required properties:
 - compatible: must be "brcm,iproc-touchscreen"
-- reg: physical base address of the controller and length of memory mapped
-  region.
+- ts_syscon: handler of syscon node defining physical base
+  address of the controller and length of memory mapped region.
+  If this property is selected please make sure MFD_SYSCON config
+  is enabled in the defconfig file.
 - clocks:  The clock provided by the SOC to driver the tsc
 - clock-name:  name for the clock
 - interrupts: The touchscreen controller's interrupt
+- address-cells: Specify the number of u32 entries needed in child nodes.
+  Should set to 1.
+- size-cells: Specify number of u32 entries needed to specify child nodes size
+  in reg property. Should set to 1.
 
 Optional properties:
 - scanning_period: Time between scans. Each step is 1024 us.  Valid 1-256.
@@ -53,13 +59,18 @@ Optional properties:
 - touchscreen-inverted-x: X axis is inverted (boolean)
 - touchscreen-inverted-y: Y axis is inverted (boolean)
 
-Example:
+Example: An example of touchscreen node
 
-       touchscreen: tsc@0x180A6000 {
+       ts_adc_syscon: ts_adc_syscon@180a6000 {
+               compatible = "brcm,iproc-ts-adc-syscon","syscon";
+               reg = <0x180a6000 0xc30>;
+       };
+
+       touchscreen: touchscreen@180A6000 {
                compatible = "brcm,iproc-touchscreen";
                #address-cells = <1>;
                #size-cells = <1>;
-               reg = <0x180A6000 0x40>;
+               ts_syscon = <&ts_adc_syscon>;
                clocks = <&adc_clk>;
                clock-names = "tsc_clk";
                interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;

diff --git a/arch/arm/boot/dts/bcm-cygnus.dtsi b/arch/arm/boot/dts/bcm-cygnus.dtsi
index 3878793364f0c23efe2213f3bf961fc36c06c168..b42fe5596b94a0d6c0dd5e95eb46acbf84478543 100644 (file)
--- a/arch/arm/boot/dts/bcm-cygnus.dtsi
+++ b/arch/arm/boot/dts/bcm-cygnus.dtsi
@@ -351,9 +351,16 @@
                                        <&pinctrl 142 10 1>;
                };
 
-               touchscreen: tsc@180a6000 {
+               ts_adc_syscon: ts_adc_syscon@180a6000 {
+                       compatible = "brcm,iproc-ts-adc-syscon", "syscon";
+                       reg = <0x180a6000 0xc30>;
+               };
+
+               touchscreen: touchscreen@180a6000 {
                        compatible = "brcm,iproc-touchscreen";
-                       reg = <0x180a6000 0x40>;
+                       #address-cells = <1>;
+                       #size-cells = <1>;
+                       ts_syscon = <&ts_adc_syscon>;
                        clocks = <&asiu_clks BCM_CYGNUS_ASIU_ADC_CLK>;
                        clock-names = "tsc_clk";
                        interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;

diff --git a/drivers/input/touchscreen/bcm_iproc_tsc.c b/drivers/input/touchscreen/bcm_iproc_tsc.c
index ae460a5c93d5e30974cf4510d4416318fa6e283e..4d11b27c7c434cb659bb36f59e7d0e337891047b 100644 (file)
--- a/drivers/input/touchscreen/bcm_iproc_tsc.c
+++ b/drivers/input/touchscreen/bcm_iproc_tsc.c
@@ -23,6 +23,8 @@
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/serio.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
 
 #define IPROC_TS_NAME "iproc-ts"
 
@@ -88,7 +90,11 @@
 #define TS_WIRE_MODE_BIT        BIT(1)
 
 #define dbg_reg(dev, priv, reg) \
-       dev_dbg(dev, "%20s= 0x%08x\n", #reg, readl((priv)->regs + reg))
+do { \
+       u32 val; \
+       regmap_read(priv->regmap, reg, &val); \
+       dev_dbg(dev, "%20s= 0x%08x\n", #reg, val); \
+} while (0)
 
 struct tsc_param {
        /* Each step is 1024 us.  Valid 1-256 */
@@ -141,7 +147,7 @@ struct iproc_ts_priv {
        struct platform_device *pdev;
        struct input_dev *idev;
 
-       void __iomem *regs;
+       struct regmap *regmap;
        struct clk *tsc_clk;
 
        int  pen_status;
@@ -196,22 +202,22 @@ static irqreturn_t iproc_touchscreen_interrupt(int irq, void *data)
        int i;
        bool needs_sync = false;
 
-       intr_status = readl(priv->regs + INTERRUPT_STATUS);
+       regmap_read(priv->regmap, INTERRUPT_STATUS, &intr_status);
        intr_status &= TS_PEN_INTR_MASK | TS_FIFO_INTR_MASK;
        if (intr_status == 0)
                return IRQ_NONE;
 
        /* Clear all interrupt status bits, write-1-clear */
-       writel(intr_status, priv->regs + INTERRUPT_STATUS);
-
+       regmap_write(priv->regmap, INTERRUPT_STATUS, intr_status);
        /* Pen up/down */
        if (intr_status & TS_PEN_INTR_MASK) {
-               if (readl(priv->regs + CONTROLLER_STATUS) & TS_PEN_DOWN)
+               regmap_read(priv->regmap, CONTROLLER_STATUS, &priv->pen_status);
+               if (priv->pen_status & TS_PEN_DOWN)
                        priv->pen_status = PEN_DOWN_STATUS;
                else
                        priv->pen_status = PEN_UP_STATUS;
 
-               input_report_key(priv->idev, BTN_TOUCH, priv->pen_status);
+               input_report_key(priv->idev, BTN_TOUCH, priv->pen_status);
                needs_sync = true;
 
                dev_dbg(&priv->pdev->dev,
@@ -221,7 +227,7 @@ static irqreturn_t iproc_touchscreen_interrupt(int irq, void *data)
        /* coordinates in FIFO exceed the theshold */
        if (intr_status & TS_FIFO_INTR_MASK) {
                for (i = 0; i < priv->cfg_params.fifo_threshold; i++) {
-                       raw_coordinate = readl(priv->regs + FIFO_DATA);
+                       regmap_read(priv->regmap, FIFO_DATA, &raw_coordinate);
                        if (raw_coordinate == INVALID_COORD)
                                continue;
 
@@ -239,7 +245,7 @@ static irqreturn_t iproc_touchscreen_interrupt(int irq, void *data)
                        x = (x >> 4) & 0x0FFF;
                        y = (y >> 4) & 0x0FFF;
 
-                       /* adjust x y according to lcd tsc mount angle */
+                       /* Adjust x y according to LCD tsc mount angle. */
                        if (priv->cfg_params.invert_x)
                                x = priv->cfg_params.max_x - x;
 
@@ -262,9 +268,10 @@ static irqreturn_t iproc_touchscreen_interrupt(int irq, void *data)
 
 static int iproc_ts_start(struct input_dev *idev)
 {
-       struct iproc_ts_priv *priv = input_get_drvdata(idev);
        u32 val;
+       u32 mask;
        int error;
+       struct iproc_ts_priv *priv = input_get_drvdata(idev);
 
        /* Enable clock */
        error = clk_prepare_enable(priv->tsc_clk);
@@ -279,9 +286,10 @@ static int iproc_ts_start(struct input_dev *idev)
         *  FIFO reaches the int_th value, and pen event(up/down)
         */
        val = TS_PEN_INTR_MASK | TS_FIFO_INTR_MASK;
-       writel(val, priv->regs + INTERRUPT_MASK);
+       regmap_update_bits(priv->regmap, INTERRUPT_MASK, val, val);
 
-       writel(priv->cfg_params.fifo_threshold, priv->regs + INTERRUPT_THRES);
+       val = priv->cfg_params.fifo_threshold;
+       regmap_write(priv->regmap, INTERRUPT_THRES, val);
 
        /* Initialize control reg1 */
        val = 0;
@@ -289,26 +297,23 @@ static int iproc_ts_start(struct input_dev *idev)
        val |= priv->cfg_params.debounce_timeout << DEBOUNCE_TIMEOUT_SHIFT;
        val |= priv->cfg_params.settling_timeout << SETTLING_TIMEOUT_SHIFT;
        val |= priv->cfg_params.touch_timeout << TOUCH_TIMEOUT_SHIFT;
-       writel(val, priv->regs + REGCTL1);
+       regmap_write(priv->regmap, REGCTL1, val);
 
        /* Try to clear all interrupt status */
-       val = readl(priv->regs + INTERRUPT_STATUS);
-       val |= TS_FIFO_INTR_MASK | TS_PEN_INTR_MASK;
-       writel(val, priv->regs + INTERRUPT_STATUS);
+       val = TS_FIFO_INTR_MASK | TS_PEN_INTR_MASK;
+       regmap_update_bits(priv->regmap, INTERRUPT_STATUS, val, val);
 
        /* Initialize control reg2 */
-       val = readl(priv->regs + REGCTL2);
-       val |= TS_CONTROLLER_EN_BIT | TS_WIRE_MODE_BIT;
-
-       val &= ~TS_CONTROLLER_AVGDATA_MASK;
+       val = TS_CONTROLLER_EN_BIT | TS_WIRE_MODE_BIT;
        val |= priv->cfg_params.average_data << TS_CONTROLLER_AVGDATA_SHIFT;
 
-       val &= ~(TS_CONTROLLER_PWR_LDO |        /* PWR up LDO */
+       mask = (TS_CONTROLLER_AVGDATA_MASK);
+       mask |= (TS_CONTROLLER_PWR_LDO |        /* PWR up LDO */
                   TS_CONTROLLER_PWR_ADC |      /* PWR up ADC */
                   TS_CONTROLLER_PWR_BGP |      /* PWR up BGP */
                   TS_CONTROLLER_PWR_TS);       /* PWR up TS */
-
-       writel(val, priv->regs + REGCTL2);
+       mask |= val;
+       regmap_update_bits(priv->regmap, REGCTL2, mask, val);
 
        ts_reg_dump(priv);
 
@@ -320,12 +325,17 @@ static void iproc_ts_stop(struct input_dev *dev)
        u32 val;
        struct iproc_ts_priv *priv = input_get_drvdata(dev);
 
-       writel(0, priv->regs + INTERRUPT_MASK); /* Disable all interrupts */
+       /*
+        * Disable FIFO int_th and pen event(up/down)Interrupts only
+        * as the interrupt mask register is shared between ADC, TS and
+        * flextimer.
+        */
+       val = TS_PEN_INTR_MASK | TS_FIFO_INTR_MASK;
+       regmap_update_bits(priv->regmap, INTERRUPT_MASK, val, 0);
 
        /* Only power down touch screen controller */
-       val = readl(priv->regs + REGCTL2);
-       val |= TS_CONTROLLER_PWR_TS;
-       writel(val, priv->regs + REGCTL2);
+       val = TS_CONTROLLER_PWR_TS;
+       regmap_update_bits(priv->regmap, REGCTL2, val, val);
 
        clk_disable(priv->tsc_clk);
 }
@@ -414,7 +424,6 @@ static int iproc_ts_probe(struct platform_device *pdev)
 {
        struct iproc_ts_priv *priv;
        struct input_dev *idev;
-       struct resource *res;
        int irq;
        int error;
 
@@ -422,12 +431,12 @@ static int iproc_ts_probe(struct platform_device *pdev)
        if (!priv)
                return -ENOMEM;
 
-       /* touchscreen controller memory mapped regs */
-       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       priv->regs = devm_ioremap_resource(&pdev->dev, res);
-       if (IS_ERR(priv->regs)) {
-               error = PTR_ERR(priv->regs);
-               dev_err(&pdev->dev, "unable to map I/O memory: %d\n", error);
+       /* touchscreen controller memory mapped regs via syscon*/
+       priv->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+                                                       "ts_syscon");
+       if (IS_ERR(priv->regmap)) {
+               error = PTR_ERR(priv->regmap);
+               dev_err(&pdev->dev, "unable to map I/O memory:%d\n", error);
                return error;
        }