Hi Alexandru
On Thu, Sep 24, 2020 at 03:05:05PM -0500, Alexandru Gagniuc wrote:
> On the SII9022, the IOVCC and CVCC12 supplies must reach the correct
> voltage before the reset sequence is initiated. On most boards, this
> assumption is true at boot-up, so initialization succeeds.
>
> However, when we try to initialize the chip with incorrect supply
> voltages, it will not respond to I2C requests. sii902x_probe() fails
> with -ENXIO.
>
> To resolve this, look for the "iovcc" and "cvcc12" regulators, and
> make sure they are enabled before starting the reset sequence. If
> these supplies are not available in devicetree, then they will default
> to dummy-regulator. In that case everything will work like before.
>
> This was observed on a STM32MP157C-DK2 booting in u-boot falcon mode.
> On this board, the supplies would be set by the second stage
> bootloader, which does not run in falcon mode.
>
> Signed-off-by: Alexandru Gagniuc <mr.nuke.me@xxxxxxxxx>
One nitpick here. The binding should be present in the tree before
you start using it. So this patch should be applied after the binding.
One detail below - I think others have already commented on the rest.
Sam
> ---
> drivers/gpu/drm/bridge/sii902x.c | 54 ++++++++++++++++++++++++++++----
> 1 file changed, 48 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
> index 33fd33f953ec..a5558d83e4c5 100644
> --- a/drivers/gpu/drm/bridge/sii902x.c
> +++ b/drivers/gpu/drm/bridge/sii902x.c
> @@ -17,6 +17,7 @@
> #include <linux/i2c.h>
> #include <linux/module.h>
> #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> #include <linux/clk.h>
>
> #include <drm/drm_atomic_helper.h>
> @@ -168,6 +169,8 @@ struct sii902x {
> struct drm_connector connector;
> struct gpio_desc *reset_gpio;
> struct i2c_mux_core *i2cmux;
> + struct regulator *iovcc;
> + struct regulator *cvcc12;
> /*
> * Mutex protects audio and video functions from interfering
> * each other, by keeping their i2c command sequences atomic.
> @@ -954,13 +957,13 @@ static const struct drm_bridge_timings default_sii902x_timings = {
> | DRM_BUS_FLAG_DE_HIGH,
> };
>
> +static int sii902x_init(struct sii902x *sii902x);
> +
> static int sii902x_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> struct device *dev = &client->dev;
> - unsigned int status = 0;
> struct sii902x *sii902x;
> - u8 chipid[4];
> int ret;
>
> ret = i2c_check_functionality(client->adapter,
> @@ -989,6 +992,43 @@ static int sii902x_probe(struct i2c_client *client,
>
> mutex_init(&sii902x->mutex);
>
> + sii902x->iovcc = devm_regulator_get(dev, "iovcc");
> + if (IS_ERR(sii902x->iovcc))
> + return PTR_ERR(sii902x->iovcc);
Consider using dev_err_probe() here.
> +
> + sii902x->cvcc12 = devm_regulator_get(dev, "cvcc12");
> + if (IS_ERR(sii902x->cvcc12))
> + return PTR_ERR(sii902x->cvcc12);
Consider using dev_err_probe() here.
> +
> + ret = regulator_enable(sii902x->iovcc);
> + if (ret < 0) {
> + dev_err(dev, "Failed to enable iovcc supply: %d\n", ret);
> + return ret;
> + }
> +
> + ret = regulator_enable(sii902x->cvcc12);
> + if (ret < 0) {
> + dev_err(dev, "Failed to enable cvcc12 supply: %d\n", ret);
> + regulator_disable(sii902x->iovcc);
> + return PTR_ERR(sii902x->cvcc12);
> + }
> +
> + ret = sii902x_init(sii902x);
> + if (ret < 0) {
> + regulator_disable(sii902x->cvcc12);
> + regulator_disable(sii902x->iovcc);
> + }
> +
> + return ret;
> +}
> +
> +static int sii902x_init(struct sii902x *sii902x)
> +{
> + struct device *dev = &sii902x->i2c->dev;
> + unsigned int status = 0;
> + u8 chipid[4];
> + int ret;
> +
> sii902x_reset(sii902x);
>
> ret = regmap_write(sii902x->regmap, SII902X_REG_TPI_RQB, 0x0);
> @@ -1012,11 +1052,11 @@ static int sii902x_probe(struct i2c_client *client,
> regmap_read(sii902x->regmap, SII902X_INT_STATUS, &status);
> regmap_write(sii902x->regmap, SII902X_INT_STATUS, status);
>
> - if (client->irq > 0) {
> + if (sii902x->i2c->irq > 0) {
> regmap_write(sii902x->regmap, SII902X_INT_ENABLE,
> SII902X_HOTPLUG_EVENT);
>
> - ret = devm_request_threaded_irq(dev, client->irq, NULL,
> + ret = devm_request_threaded_irq(dev, sii902x->i2c->irq, NULL,
> sii902x_interrupt,
> IRQF_ONESHOT, dev_name(dev),
> sii902x);
> @@ -1031,9 +1071,9 @@ static int sii902x_probe(struct i2c_client *client,
>
> sii902x_audio_codec_init(sii902x, dev);
>
> - i2c_set_clientdata(client, sii902x);
> + i2c_set_clientdata(sii902x->i2c, sii902x);
>
> - sii902x->i2cmux = i2c_mux_alloc(client->adapter, dev,
> + sii902x->i2cmux = i2c_mux_alloc(sii902x->i2c->adapter, dev,
> 1, 0, I2C_MUX_GATE,
> sii902x_i2c_bypass_select,
> sii902x_i2c_bypass_deselect);
> @@ -1051,6 +1091,8 @@ static int sii902x_remove(struct i2c_client *client)
>
> i2c_mux_del_adapters(sii902x->i2cmux);
> drm_bridge_remove(&sii902x->bridge);
> + regulator_disable(sii902x->cvcc12);
> + regulator_disable(sii902x->iovcc);
>
> return 0;
> }
> --
> 2.25.4
>
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