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Subject[PATCH v7 2/4] media: ov5675: add device-tree support and support runtime PM
Date
From: Quentin Schulz <quentin.schulz@theobroma-systems.com>

Until now, this driver only supported ACPI. This adds support for
Device Tree too while enabling clock and regulators in runtime PM.

Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
---

v6:
- inverted-xmas-tree ordering,
- space alignment instead of tab after data type for clk and
reset_gpio,
- added pm_runtime_set_suspended to remove callback as suggested by
Tommaso (please cc the mailing list next time too so everyone can
benefit from your reviews :) ),
c.f. https://lists.linuxfoundation.org/pipermail/linux-pm/2012-July/034705.html
- added Reviewed-by,

v5:
- fixed -Wdeclaration-after-statement for delay_us,

v4:
- added delays based on clock cycles as specified in datasheet for
pre-power-off and post-power-on,
- re-arranged clk handling, shutdown toggling and regulator handling to
better match power up/down sequence defined in datasheet,
- added comment on need for regulator being stable before releasing
shutdown pin,

v3:
- added linux/mod_devicetable.h include,
- moved delay for reset pulse right after the regulators are enabled,
- removed check on is_acpi_node in favor of checks on presence of OF
properties (e.g. devm_clk_get_optional returns NULL),
- moved power management out of system suspend/resume into runtime PM
callbacks,
- removed ACPI specific comment since it's not specific to this driver,
- changed devm_clk_get to devm_clk_get_optional,
- remove OF use of clock-frequency (handled by devm_clk_get_optional
directly),
- removed name of clock (only one, so no need for anything explicit)
when requesting a clock from OF,
- wrapped lines to 80 chars,

v2:
- fixed unused-const-variable warning by removing of_match_ptr in
of_match_table, reported by kernel test robot,
drivers/media/i2c/ov5675.c | 150 +++++++++++++++++++++++++++++++------
1 file changed, 129 insertions(+), 21 deletions(-)

diff --git a/drivers/media/i2c/ov5675.c b/drivers/media/i2c/ov5675.c
index 82ba9f56baec..e671fb24ebb4 100644
--- a/drivers/media/i2c/ov5675.c
+++ b/drivers/media/i2c/ov5675.c
@@ -3,10 +3,14 @@

#include <asm/unaligned.h>
#include <linux/acpi.h>
+#include <linux/clk.h>
#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fwnode.h>
@@ -17,7 +21,7 @@

#define OV5675_LINK_FREQ_450MHZ 450000000ULL
#define OV5675_SCLK 90000000LL
-#define OV5675_MCLK 19200000
+#define OV5675_XVCLK_19_2 19200000
#define OV5675_DATA_LANES 2
#define OV5675_RGB_DEPTH 10

@@ -76,6 +80,14 @@

#define to_ov5675(_sd) container_of(_sd, struct ov5675, sd)

+static const char * const ov5675_supply_names[] = {
+ "avdd", /* Analog power */
+ "dovdd", /* Digital I/O power */
+ "dvdd", /* Digital core power */
+};
+
+#define OV5675_NUM_SUPPLIES ARRAY_SIZE(ov5675_supply_names)
+
enum {
OV5675_LINK_FREQ_900MBPS,
};
@@ -484,6 +496,9 @@ struct ov5675 {
struct v4l2_subdev sd;
struct media_pad pad;
struct v4l2_ctrl_handler ctrl_handler;
+ struct clk *xvclk;
+ struct gpio_desc *reset_gpio;
+ struct regulator_bulk_data supplies[OV5675_NUM_SUPPLIES];

/* V4L2 Controls */
struct v4l2_ctrl *link_freq;
@@ -944,6 +959,56 @@ static int ov5675_set_stream(struct v4l2_subdev *sd, int enable)
return ret;
}

+static int ov5675_power_off(struct device *dev)
+{
+ /* 512 xvclk cycles after the last SCCB transation or MIPI frame end */
+ u32 delay_us = DIV_ROUND_UP(512, OV5675_XVCLK_19_2 / 1000 / 1000);
+ struct v4l2_subdev *sd = dev_get_drvdata(dev);
+ struct ov5675 *ov5675 = to_ov5675(sd);
+
+ usleep_range(delay_us, delay_us * 2);
+
+ clk_disable_unprepare(ov5675->xvclk);
+ gpiod_set_value_cansleep(ov5675->reset_gpio, 1);
+ regulator_bulk_disable(OV5675_NUM_SUPPLIES, ov5675->supplies);
+
+ return 0;
+}
+
+static int ov5675_power_on(struct device *dev)
+{
+ u32 delay_us = DIV_ROUND_UP(8192, OV5675_XVCLK_19_2 / 1000 / 1000);
+ struct v4l2_subdev *sd = dev_get_drvdata(dev);
+ struct ov5675 *ov5675 = to_ov5675(sd);
+ int ret;
+
+ ret = clk_prepare_enable(ov5675->xvclk);
+ if (ret < 0) {
+ dev_err(dev, "failed to enable xvclk: %d\n", ret);
+ return ret;
+ }
+
+ gpiod_set_value_cansleep(ov5675->reset_gpio, 1);
+
+ ret = regulator_bulk_enable(OV5675_NUM_SUPPLIES, ov5675->supplies);
+ if (ret) {
+ clk_disable_unprepare(ov5675->xvclk);
+ return ret;
+ }
+
+ /* Reset pulse should be at least 2ms and reset gpio released only once
+ * regulators are stable.
+ */
+ usleep_range(2000, 2200);
+
+ gpiod_set_value_cansleep(ov5675->reset_gpio, 0);
+
+ /* 8192 xvclk cycles prior to the first SCCB transation */
+ usleep_range(delay_us, delay_us * 2);
+
+ return 0;
+}
+
static int __maybe_unused ov5675_suspend(struct device *dev)
{
struct v4l2_subdev *sd = dev_get_drvdata(dev);
@@ -1106,32 +1171,60 @@ static const struct v4l2_subdev_internal_ops ov5675_internal_ops = {
.open = ov5675_open,
};

-static int ov5675_check_hwcfg(struct device *dev)
+static int ov5675_get_hwcfg(struct ov5675 *ov5675, struct device *dev)
{
struct fwnode_handle *ep;
struct fwnode_handle *fwnode = dev_fwnode(dev);
struct v4l2_fwnode_endpoint bus_cfg = {
.bus_type = V4L2_MBUS_CSI2_DPHY
};
- u32 mclk;
+ u32 xvclk_rate;
int ret;
unsigned int i, j;

if (!fwnode)
return -ENXIO;

- ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
+ ov5675->xvclk = devm_clk_get_optional(dev, NULL);
+ if (IS_ERR(ov5675->xvclk))
+ return dev_err_probe(dev, PTR_ERR(ov5675->xvclk),
+ "failed to get xvclk: %ld\n",
+ PTR_ERR(ov5675->xvclk));

- if (ret) {
- dev_err(dev, "can't get clock frequency");
- return ret;
+ if (ov5675->xvclk) {
+ xvclk_rate = clk_get_rate(ov5675->xvclk);
+ } else {
+ ret = fwnode_property_read_u32(fwnode, "clock-frequency",
+ &xvclk_rate);
+
+ if (ret) {
+ dev_err(dev, "can't get clock frequency");
+ return ret;
+ }
}

- if (mclk != OV5675_MCLK) {
- dev_err(dev, "external clock %d is not supported", mclk);
+ if (xvclk_rate != OV5675_XVCLK_19_2) {
+ dev_err(dev, "external clock rate %u is unsupported",
+ xvclk_rate);
return -EINVAL;
}

+ ov5675->reset_gpio = devm_gpiod_get_optional(dev, "reset",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(ov5675->reset_gpio)) {
+ ret = PTR_ERR(ov5675->reset_gpio);
+ dev_err(dev, "failed to get reset-gpios: %d\n", ret);
+ return ret;
+ }
+
+ for (i = 0; i < OV5675_NUM_SUPPLIES; i++)
+ ov5675->supplies[i].supply = ov5675_supply_names[i];
+
+ ret = devm_regulator_bulk_get(dev, OV5675_NUM_SUPPLIES,
+ ov5675->supplies);
+ if (ret)
+ return ret;
+
ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
if (!ep)
return -ENXIO;
@@ -1186,6 +1279,10 @@ static int ov5675_remove(struct i2c_client *client)
pm_runtime_disable(&client->dev);
mutex_destroy(&ov5675->mutex);

+ if (!pm_runtime_status_suspended(&client->dev))
+ ov5675_power_off(&client->dev);
+ pm_runtime_set_suspended(&client->dev);
+
return 0;
}

@@ -1195,25 +1292,31 @@ static int ov5675_probe(struct i2c_client *client)
bool full_power;
int ret;

- ret = ov5675_check_hwcfg(&client->dev);
+ ov5675 = devm_kzalloc(&client->dev, sizeof(*ov5675), GFP_KERNEL);
+ if (!ov5675)
+ return -ENOMEM;
+
+ ret = ov5675_get_hwcfg(ov5675, &client->dev);
if (ret) {
- dev_err(&client->dev, "failed to check HW configuration: %d",
+ dev_err(&client->dev, "failed to get HW configuration: %d",
ret);
return ret;
}

- ov5675 = devm_kzalloc(&client->dev, sizeof(*ov5675), GFP_KERNEL);
- if (!ov5675)
- return -ENOMEM;
-
v4l2_i2c_subdev_init(&ov5675->sd, client, &ov5675_subdev_ops);

+ ret = ov5675_power_on(&client->dev);
+ if (ret) {
+ dev_err(&client->dev, "failed to power on: %d\n", ret);
+ return ret;
+ }
+
full_power = acpi_dev_state_d0(&client->dev);
if (full_power) {
ret = ov5675_identify_module(ov5675);
if (ret) {
dev_err(&client->dev, "failed to find sensor: %d", ret);
- return ret;
+ goto probe_power_off;
}
}

@@ -1243,11 +1346,6 @@ static int ov5675_probe(struct i2c_client *client)
goto probe_error_media_entity_cleanup;
}

- /*
- * Device is already turned on by i2c-core with ACPI domain PM.
- * Enable runtime PM and turn off the device.
- */
-
/* Set the device's state to active if it's in D0 state. */
if (full_power)
pm_runtime_set_active(&client->dev);
@@ -1262,12 +1360,15 @@ static int ov5675_probe(struct i2c_client *client)
probe_error_v4l2_ctrl_handler_free:
v4l2_ctrl_handler_free(ov5675->sd.ctrl_handler);
mutex_destroy(&ov5675->mutex);
+probe_power_off:
+ ov5675_power_off(&client->dev);

return ret;
}

static const struct dev_pm_ops ov5675_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(ov5675_suspend, ov5675_resume)
+ SET_RUNTIME_PM_OPS(ov5675_power_off, ov5675_power_on, NULL)
};

#ifdef CONFIG_ACPI
@@ -1279,11 +1380,18 @@ static const struct acpi_device_id ov5675_acpi_ids[] = {
MODULE_DEVICE_TABLE(acpi, ov5675_acpi_ids);
#endif

+static const struct of_device_id ov5675_of_match[] = {
+ { .compatible = "ovti,ov5675", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ov5675_of_match);
+
static struct i2c_driver ov5675_i2c_driver = {
.driver = {
.name = "ov5675",
.pm = &ov5675_pm_ops,
.acpi_match_table = ACPI_PTR(ov5675_acpi_ids),
+ .of_match_table = ov5675_of_match,
},
.probe_new = ov5675_probe,
.remove = ov5675_remove,
--
2.36.1
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