[PATCH v6 2/3] media: ov8856: Add devicetree support

From: Robert Foss
Date: Wed Apr 29 2020 - 12:24:53 EST

Add match table, enable ov8856_probe() to support
both ACPI and DT modes.

ACPI and DT modes are primarily distinguished from
each other by relying on devm_XXX_get_optional()
will return NULL instead of a reference for the
desired managed resource.

Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxx>
---

- Changes since v5:
* Maxime & Sakari: Replaced clock tolerance check with warning

- Changes since v4:
* Maxime & Sakari: Switch to clock-frequency

- Changes since v3:
* Remove redundant {}-brackets
* Compare xvclk_rate to 5% tolerance
* Andy: Use dev_fwnode()
* Andy: Use %pe instead of %ld + PTR_ERR()
* Andy: Invert reset_gpio logic
* Andy: Remove dev_dbg() from failing reset_gpio setup
* Andy: Use dev_err for logging for failures
* Andy: Remove dev_warn from EDEFER/regulator error path
* Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
* Maxime & Sakari: Verify clock frequency from DT
* Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
* Sakari: Remove duplicate ov8856->dev assignment

- Changes since v2:
* Added "struct device *dev" member to struct ov8856
* Andy: Switch to optional version of devm_gpiod_get
* Andy: Switch to optional version of devm_clk_get
* Fabio: Add reset sleep period
* Sakari: Unify defines for 19.2Mhz
* Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
* Sakari: Replace dev_info() with dev_dbg()
* Sakari: Switch induction variable type to unsigned
* Sakari: Don't wait for reset_gpio when in ACPI mode
* Sakari: Pull reset GPIO high on power on failure
* Sakari: Add power on/off to resume/suspend
* Sakari: Fix indentation
* Sakari: Power off during ov8856_remove()
* Sakari: Don't sleep during power-on in ACPI mode
* Sakari: Switch to getting xvclk from clk_get_rate

- Changes since v1:
* Andy & Sakari: Make XVCLK optional since to not break ACPI
* Fabio: Change n_shutdown_gpio name to reset_gpio
* Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW change
* Fabio: Remove empty line
* Fabio: Remove real error from devm_gpiod_get() failures
* Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
* Sakari: Use XVCLK rate as provided by DT

drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
1 file changed, 123 insertions(+), 14 deletions(-)

diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
index 8655842af275..4749dc74d5ad 100644
--- a/drivers/media/i2c/ov8856.c
+++ b/drivers/media/i2c/ov8856.c
@@ -3,10 +3,13 @@

#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/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>
@@ -18,7 +21,7 @@
#define OV8856_LINK_FREQ_360MHZ 360000000ULL
#define OV8856_LINK_FREQ_180MHZ 180000000ULL
#define OV8856_SCLK 144000000ULL
-#define OV8856_MCLK 19200000
+#define OV8856_XVCLK_19_2 19200000
#define OV8856_DATA_LANES 4
#define OV8856_RGB_DEPTH 10

@@ -64,6 +67,12 @@

#define to_ov8856(_sd) container_of(_sd, struct ov8856, sd)

+static const char * const ov8856_supply_names[] = {
+ "dovdd", /* Digital I/O power */
+ "avdd", /* Analog power */
+ "dvdd", /* Digital core power */
+};
+
enum {
OV8856_LINK_FREQ_720MBPS,
OV8856_LINK_FREQ_360MBPS,
@@ -566,6 +575,11 @@ struct ov8856 {
struct media_pad pad;
struct v4l2_ctrl_handler ctrl_handler;

+ struct device *dev;
+ struct clk *xvclk;
+ struct gpio_desc *reset_gpio;
+ struct regulator_bulk_data supplies[ARRAY_SIZE(ov8856_supply_names)];
+
/* V4L2 Controls */
struct v4l2_ctrl *link_freq;
struct v4l2_ctrl *pixel_rate;
@@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd, int enable)
return ret;
}

+static int __ov8856_power_on(struct ov8856 *ov8856)
+{
+ struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
+ int ret;
+
+ ret = clk_prepare_enable(ov8856->xvclk);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to enable xvclk\n");
+ return ret;
+ }
+
+ if (is_acpi_node(dev_fwnode(ov8856->dev)))
+ return 0;
+
+ if (ov8856->reset_gpio) {
+ gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
+ usleep_range(1000, 2000);
+ }
+
+ ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
+ ov8856->supplies);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to enable regulators\n");
+ goto disable_clk;
+ }
+
+ gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
+ usleep_range(1500, 1800);
+
+ return 0;
+
+disable_clk:
+ gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
+ clk_disable_unprepare(ov8856->xvclk);
+
+ return ret;
+}
+
+static void __ov8856_power_off(struct ov8856 *ov8856)
+{
+ gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
+ regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
+ ov8856->supplies);
+ clk_disable_unprepare(ov8856->xvclk);
+}
+
static int __maybe_unused ov8856_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
@@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
if (ov8856->streaming)
ov8856_stop_streaming(ov8856);

+ __ov8856_power_off(ov8856);
mutex_unlock(&ov8856->mutex);

return 0;
@@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev)
int ret;

mutex_lock(&ov8856->mutex);
+
+ __ov8856_power_on(ov8856);
if (ov8856->streaming) {
ret = ov8856_start_streaming(ov8856);
if (ret) {
@@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
return 0;
}

-static int ov8856_check_hwcfg(struct device *dev)
+static int ov8856_get_hwcfg(struct ov8856 *ov8856)
{
+ struct device *dev = ov8856->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);
+ ret = fwnode_property_read_u32(fwnode, "clock-frequency",
+ &xvclk_rate);
if (ret)
return ret;

- if (mclk != OV8856_MCLK) {
- dev_err(dev, "external clock %d is not supported", mclk);
- return -EINVAL;
+ if (!is_acpi_node(fwnode)) {
+ ov8856->xvclk = devm_clk_get(dev, "xvclk");
+ if (IS_ERR(ov8856->xvclk)) {
+ dev_err(dev, "could not get xvclk clock (%pe)\n",
+ ov8856->xvclk);
+ return PTR_ERR(ov8856->xvclk);
+ }
+
+ clk_set_rate(ov8856->xvclk, xvclk_rate);
+ xvclk_rate = clk_get_rate(ov8856->xvclk);
}

+ if (xvclk_rate != OV8856_XVCLK_19_2)
+ dev_warn(dev, "external clock rate %d is unsupported", xvclk_rate);
+
+ ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(ov8856->reset_gpio))
+ return PTR_ERR(ov8856->reset_gpio);
+
+ for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
+ ov8856->supplies[i].supply = ov8856_supply_names[i];
+
+ ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ov8856_supply_names),
+ ov8856->supplies);
+ if (ret)
+ return ret;
+
ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
if (!ep)
return -ENXIO;
@@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
pm_runtime_disable(&client->dev);
mutex_destroy(&ov8856->mutex);

+ __ov8856_power_off(ov8856);
+
return 0;
}

@@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
struct ov8856 *ov8856;
int ret;

- ret = ov8856_check_hwcfg(&client->dev);
+ ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
+ if (!ov8856)
+ return -ENOMEM;
+
+ ov8856->dev = &client->dev;
+
+ ret = ov8856_get_hwcfg(ov8856);
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;
}

- ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
- if (!ov8856)
- return -ENOMEM;
-
v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
+
+ ret = __ov8856_power_on(ov8856);
+ if (ret) {
+ dev_err(&client->dev, "failed to power on\n");
+ return ret;
+ }
+
ret = ov8856_identify_module(ov8856);
if (ret) {
dev_err(&client->dev, "failed to find sensor: %d", ret);
- return ret;
+ goto probe_power_off;
}

mutex_init(&ov8856->mutex);
@@ -1238,6 +1337,9 @@ static int ov8856_probe(struct i2c_client *client)
v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
mutex_destroy(&ov8856->mutex);

+probe_power_off:
+ __ov8856_power_off(ov8856);
+
return ret;
}

@@ -1254,11 +1356,18 @@ static const struct acpi_device_id ov8856_acpi_ids[] = {
MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);
#endif

+static const struct of_device_id ov8856_of_match[] = {
+ { .compatible = "ovti,ov8856" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ov8856_of_match);
+
static struct i2c_driver ov8856_i2c_driver = {
.driver = {
.name = "ov8856",
.pm = &ov8856_pm_ops,
.acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
+ .of_match_table = ov8856_of_match,
},
.probe_new = ov8856_probe,
.remove = ov8856_remove,
--
2.25.1