diff mbox series

[2/3] Input: sun4i-lradc-keys: Add optional clock/reset support

Message ID 20210908034016.24119-3-samuel@sholland.org (mailing list archive)
State New
Headers show
Series Input: sun4i-lradc-keys: R329 and D1 support | expand

Commit Message

Samuel Holland Sept. 8, 2021, 3:40 a.m. UTC
Until the R329, the LRADC hardware was always active. Now it requires
enabling a clock gate and deasserting a reset line. Do this if the clock
and reset are provided in the device tree, but keep them optional to
maintain support for the existing binding.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---
 drivers/input/keyboard/sun4i-lradc-keys.c | 29 +++++++++++++++++++++++
 1 file changed, 29 insertions(+)

Comments

Philipp Zabel Sept. 8, 2021, 6:33 a.m. UTC | #1
On Tue, 2021-09-07 at 22:40 -0500, Samuel Holland wrote:
> Until the R329, the LRADC hardware was always active. Now it requires
> enabling a clock gate and deasserting a reset line. Do this if the clock
> and reset are provided in the device tree, but keep them optional to
> maintain support for the existing binding.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp
Maxime Ripard Sept. 14, 2021, 7:28 a.m. UTC | #2
Hi Samuel,

On Tue, Sep 07, 2021 at 10:40:15PM -0500, Samuel Holland wrote:
> Until the R329, the LRADC hardware was always active. Now it requires
> enabling a clock gate and deasserting a reset line. Do this if the clock
> and reset are provided in the device tree, but keep them optional to
> maintain support for the existing binding.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>
> ---
>  drivers/input/keyboard/sun4i-lradc-keys.c | 29 +++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
> index 4a796bed48ac..50fc18052829 100644
> --- 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>
> @@ -23,6 +24,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/reset.h>
>  #include <linux/slab.h>
>  
>  #define LRADC_CTRL		0x00
> @@ -83,6 +85,8 @@ 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;
> @@ -140,6 +144,14 @@ 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;
> @@ -153,6 +165,13 @@ 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)
> @@ -164,6 +183,8 @@ 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);
>  }
>  
> @@ -243,6 +264,14 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> +	lradc->clk = devm_clk_get_optional(dev, NULL);
> +	if (IS_ERR(lradc->clk))
> +		return PTR_ERR(lradc->clk);
> +
> +	lradc->reset = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(lradc->reset))
> +		return PTR_ERR(lradc->reset);
> +

This wouldn't report an error if the clocks are missing on the R329 (and
D1), even though they are required. The way we usually deal with this is
through a flag in the variant structure (at least to guard clk_get /
reset_control_get)

Maxime
diff mbox series

Patch

diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
index 4a796bed48ac..50fc18052829 100644
--- 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>
@@ -23,6 +24,7 @@ 
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 
 #define LRADC_CTRL		0x00
@@ -83,6 +85,8 @@  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;
@@ -140,6 +144,14 @@  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;
@@ -153,6 +165,13 @@  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)
@@ -164,6 +183,8 @@  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);
 }
 
@@ -243,6 +264,14 @@  static int sun4i_lradc_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	lradc->clk = devm_clk_get_optional(dev, NULL);
+	if (IS_ERR(lradc->clk))
+		return PTR_ERR(lradc->clk);
+
+	lradc->reset = devm_reset_control_get_optional_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);