Input: sun4i-lradc-keys - add optional clock/reset support

Until the R329, the LRADC hardware was always active. Now it requires
enabling a clock gate and deasserting a reset line. Add support for this
variant of the hardware.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220414002349.24332-2-samuel@sholland.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
index 15aa819..e525056 100644 (file)
--- a/drivers/input/keyboard/sun4i-lradc-keys.c
+++ b/drivers/input/keyboard/sun4i-lradc-keys.c
@@ -14,6 +14,7 @@
  * there are no boards known to use channel 1.
  */
 
+#include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/input.h>
@@ -25,6 +26,7 @@
 #include <linux/pm_wakeirq.h>
 #include <linux/pm_wakeup.h>
 #include <linux/regulator/consumer.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 
 #define LRADC_CTRL             0x00
@@ -60,10 +62,12 @@
 /* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant
  * @divisor_numerator:         The numerator of lradc Vref internally divisor
  * @divisor_denominator:       The denominator of lradc Vref internally divisor
+ * @has_clock_reset:           If the binding requires a clock and reset
  */
 struct lradc_variant {
        u8 divisor_numerator;
        u8 divisor_denominator;
+       bool has_clock_reset;
 };
 
 static const struct lradc_variant lradc_variant_a10 = {
@@ -85,6 +89,8 @@ struct sun4i_lradc_data {
        struct device *dev;
        struct input_dev *input;
        void __iomem *base;
+       struct clk *clk;
+       struct reset_control *reset;
        struct regulator *vref_supply;
        struct sun4i_lradc_keymap *chan0_map;
        const struct lradc_variant *variant;
@@ -142,6 +148,14 @@ static int sun4i_lradc_open(struct input_dev *dev)
        if (error)
                return error;
 
+       error = reset_control_deassert(lradc->reset);
+       if (error)
+               goto err_disable_reg;
+
+       error = clk_prepare_enable(lradc->clk);
+       if (error)
+               goto err_assert_reset;
+
        lradc->vref = regulator_get_voltage(lradc->vref_supply) *
                      lradc->variant->divisor_numerator /
                      lradc->variant->divisor_denominator;
@@ -155,6 +169,13 @@ static int sun4i_lradc_open(struct input_dev *dev)
        writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
 
        return 0;
+
+err_assert_reset:
+       reset_control_assert(lradc->reset);
+err_disable_reg:
+       regulator_disable(lradc->vref_supply);
+
+       return error;
 }
 
 static void sun4i_lradc_close(struct input_dev *dev)
@@ -166,6 +187,8 @@ static void sun4i_lradc_close(struct input_dev *dev)
                SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
        writel(0, lradc->base + LRADC_INTC);
 
+       clk_disable_unprepare(lradc->clk);
+       reset_control_assert(lradc->reset);
        regulator_disable(lradc->vref_supply);
 }
 
@@ -244,6 +267,16 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
+       if (lradc->variant->has_clock_reset) {
+               lradc->clk = devm_clk_get(dev, NULL);
+               if (IS_ERR(lradc->clk))
+                       return PTR_ERR(lradc->clk);
+
+               lradc->reset = devm_reset_control_get_exclusive(dev, NULL);
+               if (IS_ERR(lradc->reset))
+                       return PTR_ERR(lradc->reset);
+       }
+
        lradc->vref_supply = devm_regulator_get(dev, "vref");
        if (IS_ERR(lradc->vref_supply))
                return PTR_ERR(lradc->vref_supply);