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SubjectRe: [PATCH v4 4/7] drm/panfrost: Add support for multiple regulators
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On 07/02/2020 05:26, Nicolas Boichat wrote:
> Some GPUs, namely, the bifrost/g72 part on MT8183, have a second
> regulator for their SRAM, let's add support for that.
>
> We extend the framework in a generic manner so that we could
> support more than 2 regulators, if required.
>
> Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>

Reviewed-by: Steven Price <steven.price@arm.com>

Thanks,

Steve

>
> ---
>
> v4:
> - nits: Run through latest version of checkpatch:
> - Use WARN instead of BUG_ON.
> - Drop braces in single expression for loop.
> - *comp not * comp
> v3:
> - Make this more generic, by allowing any number of regulators
> (in practice we fix the maximum number of regulators to 2, but
> this could be increased easily).
> - We only probe the second regulator if the device tree matching
> data asks for it.
> - I couldn't find a way to detect the number of regulators in the
> device tree, if we wanted to refuse to probe the device if there
> are too many regulators, which might be required for safety, see
> the thread on v2 [1].
> - The discussion also included the idea of a separate device tree
> entry for a "soft PDC", or at least a separate driver. I'm not
> sure to understand the full picture, and how different vendors
> implement this, so I'm still integrating everything in the main
> driver. I'd be happy to try to make mt8183 fit into such a
> framework after it's created, but I don't think I'm best placed
> to implement (and again, the main purpose of this was to test
> if the binding is correct).
>
> [1] https://patchwork.kernel.org/patch/11322839/
>
> drivers/gpu/drm/panfrost/panfrost_device.c | 26 +++++++++++++-------
> drivers/gpu/drm/panfrost/panfrost_device.h | 15 +++++++++++-
> drivers/gpu/drm/panfrost/panfrost_drv.c | 28 +++++++++++++++-------
> 3 files changed, 51 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
> index 238fb6d54df4732..3720d50f6d9f965 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.c
> @@ -87,18 +87,27 @@ static void panfrost_clk_fini(struct panfrost_device *pfdev)
>
> static int panfrost_regulator_init(struct panfrost_device *pfdev)
> {
> - int ret;
> + int ret, i;
>
> - pfdev->regulator = devm_regulator_get(pfdev->dev, "mali");
> - if (IS_ERR(pfdev->regulator)) {
> - ret = PTR_ERR(pfdev->regulator);
> - dev_err(pfdev->dev, "failed to get regulator: %d\n", ret);
> + if (WARN(pfdev->comp->num_supplies > ARRAY_SIZE(pfdev->regulators),
> + "Too many supplies in compatible structure.\n"))
> + return -EINVAL;
> +
> + for (i = 0; i < pfdev->comp->num_supplies; i++)
> + pfdev->regulators[i].supply = pfdev->comp->supply_names[i];
> +
> + ret = devm_regulator_bulk_get(pfdev->dev,
> + pfdev->comp->num_supplies,
> + pfdev->regulators);
> + if (ret < 0) {
> + dev_err(pfdev->dev, "failed to get regulators: %d\n", ret);
> return ret;
> }
>
> - ret = regulator_enable(pfdev->regulator);
> + ret = regulator_bulk_enable(pfdev->comp->num_supplies,
> + pfdev->regulators);
> if (ret < 0) {
> - dev_err(pfdev->dev, "failed to enable regulator: %d\n", ret);
> + dev_err(pfdev->dev, "failed to enable regulators: %d\n", ret);
> return ret;
> }
>
> @@ -107,7 +116,8 @@ static int panfrost_regulator_init(struct panfrost_device *pfdev)
>
> static void panfrost_regulator_fini(struct panfrost_device *pfdev)
> {
> - regulator_disable(pfdev->regulator);
> + regulator_bulk_disable(pfdev->comp->num_supplies,
> + pfdev->regulators);
> }
>
> int panfrost_device_init(struct panfrost_device *pfdev)
> diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
> index 06713811b92cdf7..c9468bc5573ac9d 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_device.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_device.h
> @@ -7,6 +7,7 @@
>
> #include <linux/atomic.h>
> #include <linux/io-pgtable.h>
> +#include <linux/regulator/consumer.h>
> #include <linux/spinlock.h>
> #include <drm/drm_device.h>
> #include <drm/drm_mm.h>
> @@ -19,6 +20,7 @@ struct panfrost_job;
> struct panfrost_perfcnt;
>
> #define NUM_JOB_SLOTS 3
> +#define MAX_REGULATORS 2
>
> struct panfrost_features {
> u16 id;
> @@ -51,6 +53,16 @@ struct panfrost_features {
> unsigned long hw_issues[64 / BITS_PER_LONG];
> };
>
> +/*
> + * Features that cannot be automatically detected and need matching using the
> + * compatible string, typically SoC-specific.
> + */
> +struct panfrost_compatible {
> + /* Supplies count and names. */
> + int num_supplies;
> + const char * const *supply_names;
> +};
> +
> struct panfrost_device {
> struct device *dev;
> struct drm_device *ddev;
> @@ -59,10 +71,11 @@ struct panfrost_device {
> void __iomem *iomem;
> struct clk *clock;
> struct clk *bus_clock;
> - struct regulator *regulator;
> + struct regulator_bulk_data regulators[MAX_REGULATORS];
> struct reset_control *rstc;
>
> struct panfrost_features features;
> + const struct panfrost_compatible *comp;
>
> spinlock_t as_lock;
> unsigned long as_in_use_mask;
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index b7a618db3ee223e..4d08507526239f2 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -584,6 +584,10 @@ static int panfrost_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, pfdev);
>
> + pfdev->comp = of_device_get_match_data(&pdev->dev);
> + if (!pfdev->comp)
> + return -ENODEV;
> +
> /* Allocate and initialze the DRM device. */
> ddev = drm_dev_alloc(&panfrost_drm_driver, &pdev->dev);
> if (IS_ERR(ddev))
> @@ -655,16 +659,22 @@ static int panfrost_remove(struct platform_device *pdev)
> return 0;
> }
>
> +const char * const default_supplies[] = { "mali" };
> +static const struct panfrost_compatible default_data = {
> + .num_supplies = ARRAY_SIZE(default_supplies),
> + .supply_names = default_supplies,
> +};
> +
> static const struct of_device_id dt_match[] = {
> - { .compatible = "arm,mali-t604" },
> - { .compatible = "arm,mali-t624" },
> - { .compatible = "arm,mali-t628" },
> - { .compatible = "arm,mali-t720" },
> - { .compatible = "arm,mali-t760" },
> - { .compatible = "arm,mali-t820" },
> - { .compatible = "arm,mali-t830" },
> - { .compatible = "arm,mali-t860" },
> - { .compatible = "arm,mali-t880" },
> + { .compatible = "arm,mali-t604", .data = &default_data, },
> + { .compatible = "arm,mali-t624", .data = &default_data, },
> + { .compatible = "arm,mali-t628", .data = &default_data, },
> + { .compatible = "arm,mali-t720", .data = &default_data, },
> + { .compatible = "arm,mali-t760", .data = &default_data, },
> + { .compatible = "arm,mali-t820", .data = &default_data, },
> + { .compatible = "arm,mali-t830", .data = &default_data, },
> + { .compatible = "arm,mali-t860", .data = &default_data, },
> + { .compatible = "arm,mali-t880", .data = &default_data, },
> {}
> };
> MODULE_DEVICE_TABLE(of, dt_match);
>

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