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gpu: host1x: mipi: Power down regulators when unused

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Keep track of the number of users of DSI and CSI pads and power down the
regulators that supply the bricks when all users are gone.

Signed-off-by: Thierry Reding <treding@nvidia.com>
This commit is contained in:
Thierry Reding 2015-04-10 11:29:41 +02:00
parent 5e7752436e
commit 15372d4be7
1 changed files with 98 additions and 12 deletions
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110
drivers/gpu/host1x/mipi.c
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@ -118,9 +118,12 @@ struct tegra_mipi_soc {
struct tegra_mipi {
const struct tegra_mipi_soc *soc;
struct device *dev;
void __iomem *regs;
struct mutex lock;
struct clk *clk;
unsigned long usage_count;
};
struct tegra_mipi_device {
@ -142,6 +145,67 @@ static inline void tegra_mipi_writel(struct tegra_mipi *mipi, u32 value,
writel(value, mipi->regs + (offset << 2));
}
static int tegra_mipi_power_up(struct tegra_mipi *mipi)
{
u32 value;
int err;
err = clk_enable(mipi->clk);
if (err < 0)
return err;
value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG0);
value &= ~MIPI_CAL_BIAS_PAD_PDVCLAMP;
if (mipi->soc->needs_vclamp_ref)
value |= MIPI_CAL_BIAS_PAD_E_VCLAMP_REF;
tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG0);
value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG2);
value &= ~MIPI_CAL_BIAS_PAD_PDVREG;
tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG2);
clk_disable(mipi->clk);
return 0;
}
static int tegra_mipi_power_down(struct tegra_mipi *mipi)
{
u32 value;
int err;
err = clk_enable(mipi->clk);
if (err < 0)
return err;
/*
* The MIPI_CAL_BIAS_PAD_PDVREG controls a voltage regulator that
* supplies the DSI pads. This must be kept enabled until none of the
* DSI lanes are used anymore.
*/
value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG2);
value |= MIPI_CAL_BIAS_PAD_PDVREG;
tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG2);
/*
* MIPI_CAL_BIAS_PAD_PDVCLAMP and MIPI_CAL_BIAS_PAD_E_VCLAMP_REF
* control a regulator that supplies current to the pre-driver logic.
* Powering down this regulator causes DSI to fail, so it must remain
* powered on until none of the DSI lanes are used anymore.
*/
value = tegra_mipi_readl(mipi, MIPI_CAL_BIAS_PAD_CFG0);
if (mipi->soc->needs_vclamp_ref)
value &= ~MIPI_CAL_BIAS_PAD_E_VCLAMP_REF;
value |= MIPI_CAL_BIAS_PAD_PDVCLAMP;
tegra_mipi_writel(mipi, value, MIPI_CAL_BIAS_PAD_CFG0);
return 0;
}
struct tegra_mipi_device *tegra_mipi_request(struct device *device)
{
struct device_node *np = device->of_node;
@ -178,6 +242,20 @@ struct tegra_mipi_device *tegra_mipi_request(struct device *device)
dev->pads = args.args[0];
dev->device = device;
mutex_lock(&dev->mipi->lock);
if (dev->mipi->usage_count++ == 0) {
err = tegra_mipi_power_up(dev->mipi);
if (err < 0) {
dev_err(dev->mipi->dev,
"failed to power up MIPI bricks: %d\n",
err);
return ERR_PTR(err);
}
}
mutex_unlock(&dev->mipi->lock);
return dev;
put:
@ -192,6 +270,25 @@ EXPORT_SYMBOL(tegra_mipi_request);
void tegra_mipi_free(struct tegra_mipi_device *device)
{
int err;
mutex_lock(&device->mipi->lock);
if (--device->mipi->usage_count == 0) {
err = tegra_mipi_power_down(device->mipi);
if (err < 0) {
/*
* Not much that can be done here, so an error message
* will have to do.
*/
dev_err(device->mipi->dev,
"failed to power down MIPI bricks: %d\n",
err);
}
}
mutex_unlock(&device->mipi->lock);
platform_device_put(device->pdev);
kfree(device);
}
@ -227,22 +324,10 @@ int tegra_mipi_calibrate(struct tegra_mipi_device *device)
mutex_lock(&device->mipi->lock);
value = tegra_mipi_readl(device->mipi, MIPI_CAL_BIAS_PAD_CFG0);
value &= ~MIPI_CAL_BIAS_PAD_PDVCLAMP;
if (soc->needs_vclamp_ref)
value |= MIPI_CAL_BIAS_PAD_E_VCLAMP_REF;
tegra_mipi_writel(device->mipi, value, MIPI_CAL_BIAS_PAD_CFG0);
value = MIPI_CAL_BIAS_PAD_DRV_DN_REF(soc->pad_drive_down_ref) |
MIPI_CAL_BIAS_PAD_DRV_UP_REF(soc->pad_drive_up_ref);
tegra_mipi_writel(device->mipi, value, MIPI_CAL_BIAS_PAD_CFG1);
value = tegra_mipi_readl(device->mipi, MIPI_CAL_BIAS_PAD_CFG2);
value &= ~MIPI_CAL_BIAS_PAD_PDVREG;
tegra_mipi_writel(device->mipi, value, MIPI_CAL_BIAS_PAD_CFG2);
value = tegra_mipi_readl(device->mipi, MIPI_CAL_BIAS_PAD_CFG2);
value &= ~MIPI_CAL_BIAS_PAD_VCLAMP(0x7);
value &= ~MIPI_CAL_BIAS_PAD_VAUXP(0x7);
@ -426,6 +511,7 @@ static int tegra_mipi_probe(struct platform_device *pdev)
return -ENOMEM;
mipi->soc = match->data;
mipi->dev = &pdev->dev;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mipi->regs = devm_ioremap_resource(&pdev->dev, res);