[PATCH 04/13] media: i2c: Support 19.2MHz input clock in ov8865

Daniel Scally
2021-07-22T20:34:59Z

The ov8865 driver as written expects a 24MHz input clock, but the sensor
is sometimes found on x86 platforms with a 19.2MHz input clock supplied.
Add a set of PLL configurations to the driver to support that rate too.
As ACPI doesn't auto-configure the clock rate, check for a clock-frequency
during probe and set that rate if one is found.

Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
drivers/media/i2c/ov8865.c | 158 +++++++++++++++++++++++++++----------
1 file changed, 115 insertions(+), 43 deletions(-)

diff --git a/drivers/media/i2c/ov8865.c b/drivers/media/i2c/ov8865.c
index 66182142c28b..8739eea762c5 100644
--- a/drivers/media/i2c/ov8865.c
+++ b/drivers/media/i2c/ov8865.c
@@ -21,10 +21,6 @@
#include <media/v4l2-image-sizes.h>
#include <media/v4l2-mediabus.h>

-/* Clock rate */
-
-#define OV8865_EXTCLK_RATE 24000000
-
/* Register definitions */

/* System */
@@ -665,6 +661,9 @@ struct ov8865_sensor {
struct regulator *avdd;
struct regulator *dvdd;
struct regulator *dovdd;
+
+ unsigned long extclk_rate;
+ unsigned int extclk_rate_idx;
struct clk *extclk;

struct v4l2_fwnode_endpoint endpoint;
@@ -680,49 +679,83 @@ struct ov8865_sensor {
/* Static definitions */

/*
- * EXTCLK = 24 MHz
* PHY_SCLK = 720 MHz
* MIPI_PCLK = 90 MHz
*/
-static const struct ov8865_pll1_config ov8865_pll1_config_native = {
- .pll_pre_div_half = 1,
- .pll_pre_div = 0,
- .pll_mul = 30,
- .m_div = 1,
- .mipi_div = 3,
- .pclk_div = 1,
- .sys_pre_div = 1,
- .sys_div = 2,
+
+static const struct ov8865_pll1_config ov8865_pll1_configs_native[] = {
+ { /* 19.2 MHz input clock */
+ .pll_pre_div_half = 1,
+ .pll_pre_div = 2,
+ .pll_mul = 75,
+ .m_div = 1,
+ .mipi_div = 3,
+ .pclk_div = 1,
+ .sys_pre_div = 1,
+ .sys_div = 2,
+ },
+ { /* 24MHz input clock */
+ .pll_pre_div_half = 1,
+ .pll_pre_div = 0,
+ .pll_mul = 30,
+ .m_div = 1,
+ .mipi_div = 3,
+ .pclk_div = 1,
+ .sys_pre_div = 1,
+ .sys_div = 2,
+ },
};

/*
- * EXTCLK = 24 MHz
* DAC_CLK = 360 MHz
* SCLK = 144 MHz
*/

-static const struct ov8865_pll2_config ov8865_pll2_config_native = {
- .pll_pre_div_half = 1,
- .pll_pre_div = 0,
- .pll_mul = 30,
- .dac_div = 2,
- .sys_pre_div = 5,
- .sys_div = 0,
+static const struct ov8865_pll2_config ov8865_pll2_configs_native[] = {
+ /* 19.2MHz input clock */
+ {
+ .pll_pre_div_half = 1,
+ .pll_pre_div = 5,
+ .pll_mul = 75,
+ .dac_div = 1,
+ .sys_pre_div = 1,
+ .sys_div = 3,
+ },
+ /* 24MHz input clock */
+ {
+ .pll_pre_div_half = 1,
+ .pll_pre_div = 0,
+ .pll_mul = 30,
+ .dac_div = 2,
+ .sys_pre_div = 5,
+ .sys_div = 0,
+ }
};

/*
- * EXTCLK = 24 MHz
* DAC_CLK = 360 MHz
* SCLK = 72 MHz
*/

-static const struct ov8865_pll2_config ov8865_pll2_config_binning = {
+static const struct ov8865_pll2_config ov8865_pll2_configs_binning[] = {
+ /* 19.2MHz input clock */
+ {
+ .pll_pre_div_half = 1,
+ .pll_pre_div = 2,
+ .pll_mul = 75,
+ .dac_div = 2,
+ .sys_pre_div = 10,
+ .sys_div = 0,
+ },
+ /* 24MHz input clock */
+ {
.pll_pre_div_half = 1,
.pll_pre_div = 0,
.pll_mul = 30,
.dac_div = 2,
.sys_pre_div = 10,
.sys_div = 0,
+ }
};

static const struct ov8865_sclk_config ov8865_sclk_config_native = {
@@ -934,8 +967,8 @@ static const struct ov8865_mode ov8865_modes[] = {
.frame_interval = { 1, 30 },

/* PLL */
- .pll1_config = &ov8865_pll1_config_native,
- .pll2_config = &ov8865_pll2_config_native,
+ .pll1_config = ov8865_pll1_configs_native,
+ .pll2_config = ov8865_pll2_configs_native,
.sclk_config = &ov8865_sclk_config_native,

/* Registers */
@@ -990,8 +1023,8 @@ static const struct ov8865_mode ov8865_modes[] = {
.frame_interval = { 1, 30 },

/* PLL */
- .pll1_config = &ov8865_pll1_config_native,
- .pll2_config = &ov8865_pll2_config_native,
+ .pll1_config = ov8865_pll1_configs_native,
+ .pll2_config = ov8865_pll2_configs_native,
.sclk_config = &ov8865_sclk_config_native,

/* Registers */
@@ -1050,8 +1083,8 @@ static const struct ov8865_mode ov8865_modes[] = {
.frame_interval = { 1, 30 },

/* PLL */
- .pll1_config = &ov8865_pll1_config_native,
- .pll2_config = &ov8865_pll2_config_binning,
+ .pll1_config = ov8865_pll1_configs_native,
+ .pll2_config = ov8865_pll2_configs_binning,
.sclk_config = &ov8865_sclk_config_native,

/* Registers */
@@ -1116,8 +1149,8 @@ static const struct ov8865_mode ov8865_modes[] = {
.frame_interval = { 1, 90 },

/* PLL */
- .pll1_config = &ov8865_pll1_config_native,
- .pll2_config = &ov8865_pll2_config_binning,
+ .pll1_config = ov8865_pll1_configs_native,
+ .pll2_config = ov8865_pll2_configs_binning,
.sclk_config = &ov8865_sclk_config_native,

/* Registers */
@@ -1266,6 +1299,13 @@ static const struct ov8865_register_value ov8865_init_sequence[] = {
{ 0x4503, 0x10 },
};

+/* Clock rate */
+
+static const unsigned long supported_extclk_rates[] = {
+ 19200000,
+ 24000000,
+};
+
static const s64 ov8865_link_freq_menu[] = {
360000000,
};
@@ -1513,12 +1553,11 @@ static int ov8865_isp_configure(struct ov8865_sensor *sensor)
static unsigned long ov8865_mode_pll1_rate(struct ov8865_sensor *sensor,
const struct ov8865_mode *mode)
{
- const struct ov8865_pll1_config *config = mode->pll1_config;
- unsigned long extclk_rate;
+ const struct ov8865_pll1_config *config;
unsigned long pll1_rate;

- extclk_rate = clk_get_rate(sensor->extclk);
- pll1_rate = extclk_rate * config->pll_mul / config->pll_pre_div_half;
+ config = &mode->pll1_config[sensor->extclk_rate_idx];
+ pll1_rate = sensor->extclk_rate * config->pll_mul / config->pll_pre_div_half;

switch (config->pll_pre_div) {
case 0:
@@ -1552,10 +1591,12 @@ static int ov8865_mode_pll1_configure(struct ov8865_sensor *sensor,
const struct ov8865_mode *mode,
u32 mbus_code)
{
- const struct ov8865_pll1_config *config = mode->pll1_config;
+ const struct ov8865_pll1_config *config;
u8 value;
int ret;

+ config = &mode->pll1_config[sensor->extclk_rate_idx];
+
switch (mbus_code) {
case MEDIA_BUS_FMT_SBGGR10_1X10:
value = OV8865_MIPI_BIT_SEL(10);
@@ -1622,9 +1663,11 @@ static int ov8865_mode_pll1_configure(struct ov8865_sensor *sensor,
static int ov8865_mode_pll2_configure(struct ov8865_sensor *sensor,
const struct ov8865_mode *mode)
{
- const struct ov8865_pll2_config *config = mode->pll2_config;
+ const struct ov8865_pll2_config *config;
int ret;

+ config = &mode->pll2_config[sensor->extclk_rate_idx];
+
ret = ov8865_write(sensor, OV8865_PLL_CTRL12_REG,
OV8865_PLL_CTRL12_PRE_DIV_HALF(config->pll_pre_div_half) |
OV8865_PLL_CTRL12_DAC_DIV(config->dac_div));
@@ -2053,9 +2096,11 @@ static int ov8865_mode_configure(struct ov8865_sensor *sensor,
static unsigned long ov8865_mode_mipi_clk_rate(struct ov8865_sensor *sensor,
const struct ov8865_mode *mode)
{
- const struct ov8865_pll1_config *config = mode->pll1_config;
+ const struct ov8865_pll1_config *config;
unsigned long pll1_rate;

+ config = &mode->pll1_config[sensor->extclk_rate_idx];
+
pll1_rate = ov8865_mode_pll1_rate(sensor, mode);

return pll1_rate / config->m_div / 2;
@@ -2783,7 +2828,8 @@ static int ov8865_probe(struct i2c_client *client)
struct ov8865_sensor *sensor;
struct v4l2_subdev *subdev;
struct media_pad *pad;
- unsigned long rate;
+ unsigned int rate;
+ unsigned int i;
int ret;

sensor = devm_kzalloc(dev, sizeof(*sensor), GFP_KERNEL);
@@ -2858,13 +2904,39 @@ static int ov8865_probe(struct i2c_client *client)
goto error_endpoint;
}

- rate = clk_get_rate(sensor->extclk);
- if (rate != OV8865_EXTCLK_RATE) {
- dev_err(dev, "clock rate %lu Hz is unsupported\n", rate);
+ /*
+ * We could have either a 24MHz or 19.2MHz clock rate. Check for a
+ * clock-frequency property and if found, set that rate. This should
+ * cover ACPI case. If the system uses devicetree then the configured
+ * rate should already be set, so we'll have to check it.
+ */
+
+ ret = fwnode_property_read_u32(dev_fwnode(dev), "clock-frequency",
+ &rate);
+ if (!ret) {
+ ret = clk_set_rate(sensor->extclk, rate);
+ if (ret) {
+ dev_err(dev, "failed to set clock rate\n");
+ return ret;
+ }
+ }
+
+ sensor->extclk_rate = clk_get_rate(sensor->extclk);
+
+ for (i = 0; i < ARRAY_SIZE(supported_extclk_rates); i++) {
+ if (sensor->extclk_rate == supported_extclk_rates[i])
+ break;
+ }
+
+ if (i == ARRAY_SIZE(supported_extclk_rates)) {
+ dev_err(dev, "clock rate %lu Hz is unsupported\n",
+ sensor->extclk_rate);
ret = -EINVAL;
goto error_endpoint;
}

+ sensor->extclk_rate_idx = i;
+
/* Subdev, entity and pad */

subdev = &sensor->subdev;
--
2.25.1