Re: [PATCH v2 6/8] mfd: exynos-lpass: Add support for clocks

Lee Jones
2017-02-08T10:57:15Z

On Thu, 26 Jan 2017, Marek Szyprowski wrote:

> Exynos LPASS requires some clocks to be enabled to make any access to its
> registers. This patch adds code for handling such clocks. For current set
> of registers it is enough to keep sfr0_ctrl clock enabled. Till now it
> worked only because those clocks were enabled by bootloader and driver
> probe() happened before they were disabled by clock core because of lack
> of users. Handling those clocks is also needed to make it possible to
> enable support for audio power domain.
>
> This patch requires adding sfr0_ctrl clock to device tree.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
> .../devicetree/bindings/mfd/samsung,exynos5433-lpass.txt | 6 ++++++
> drivers/mfd/exynos-lpass.c | 10 ++++++++++
> 2 files changed, 16 insertions(+)

For my own reference:
Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>

> diff --git a/Documentation/devicetree/bindings/mfd/samsung,exynos5433-lpass.txt b/Documentation/devicetree/bindings/mfd/samsung,exynos5433-lpass.txt
> index a8deaee82c44..df664018c148 100644
> --- a/Documentation/devicetree/bindings/mfd/samsung,exynos5433-lpass.txt
> +++ b/Documentation/devicetree/bindings/mfd/samsung,exynos5433-lpass.txt
> @@ -5,6 +5,10 @@ Required properties:
> - compatible : "samsung,exynos5433-lpass"
> - reg : should contain the LPASS top SFR region location
> and size
> + - clock-names : should contain following required clocks: "sfr0_ctrl"
> + - clocks : should contain clock specifiers of all clocks, which
> + input names have been specified in clock-names
> + property, in same order.
> - #address-cells : should be 1
> - #size-cells : should be 1
> - ranges : must be present
> @@ -24,6 +28,8 @@ Example:
> audio-subsystem {
> compatible = "samsung,exynos5433-lpass";
> reg = <0x11400000 0x100>, <0x11500000 0x08>;
> + clocks = <&cmu_aud CLK_PCLK_SFR0_CTRL>;
> + clock-names = "sfr0_ctrl";
> #address-cells = <1>;
> #size-cells = <1>;
> ranges;
> diff --git a/drivers/mfd/exynos-lpass.c b/drivers/mfd/exynos-lpass.c
> index 17915daa2e80..be264988bdc9 100644
> --- a/drivers/mfd/exynos-lpass.c
> +++ b/drivers/mfd/exynos-lpass.c
> @@ -14,6 +14,7 @@
> * only version 2 as published by the Free Software Foundation.
> */
>
> +#include <linux/clk.h>
> #include <linux/delay.h>
> #include <linux/io.h>
> #include <linux/module.h>
> @@ -52,6 +53,7 @@
> struct exynos_lpass {
> /* pointer to the LPASS TOP regmap */
> struct regmap *top;
> + struct clk *sfr0_clk;
> };
>
> static void exynos_lpass_core_sw_reset(struct exynos_lpass *lpass, int mask)
> @@ -71,6 +73,8 @@ static void exynos_lpass_core_sw_reset(struct exynos_lpass *lpass, int mask)
>
> static void exynos_lpass_enable(struct exynos_lpass *lpass)
> {
> + clk_prepare_enable(lpass->sfr0_clk);
> +
> /* Unmask SFR, DMA and I2S interrupt */
> regmap_write(lpass->top, SFR_LPASS_INTR_CA5_MASK,
> LPASS_INTR_SFR | LPASS_INTR_DMA | LPASS_INTR_I2S);
> @@ -88,6 +92,8 @@ static void exynos_lpass_disable(struct exynos_lpass *lpass)
> /* Mask any unmasked IP interrupt sources */
> regmap_write(lpass->top, SFR_LPASS_INTR_CPU_MASK, 0);
> regmap_write(lpass->top, SFR_LPASS_INTR_CA5_MASK, 0);
> +
> + clk_disable_unprepare(lpass->sfr0_clk);
> }
>
> static const struct regmap_config exynos_lpass_reg_conf = {
> @@ -114,6 +120,10 @@ static int exynos_lpass_probe(struct platform_device *pdev)
> if (IS_ERR(base_top))
> return PTR_ERR(base_top);
>
> + lpass->sfr0_clk = devm_clk_get(dev, "sfr0_ctrl");
> + if (IS_ERR(lpass->sfr0_clk))
> + return PTR_ERR(lpass->sfr0_clk);
> +
> lpass->top = regmap_init_mmio(dev, base_top,
> &exynos_lpass_reg_conf);
> if (IS_ERR(lpass->top)) {

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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