Re: [PATCH 1/1] BACKLIGHT: Add Driver for ARCXCNN Chip
flat view
From: Mark Rutland <mark.rutland@arm.com>
Date: 2016-08-18 11:07:57
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On Wed, Aug 17, 2016 at 03:06:39PM -0400, Olimpiu Dejeu wrote:
This is the driver for the Arctic Sand Technologies Inc. ARCXCNN LED backlight IC family. Signed-off-by: Olimpiu Dejeu <redacted> --- drivers/video/backlight/Kconfig | 7 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/arcxcnn_bl.c | 499 +++++++++++++++++++++++++++++++++++ include/linux/i2c/arcxcnn.h | 41 +++ 4 files changed, 547 insertions(+) create mode 100644 drivers/video/backlight/arcxcnn_bl.c create mode 100644 include/linux/i2c/arcxcnn.h
This is a one-patch series with no binding, yet the code below adds a new
compatible string ("arc,arcxcnn"), and DT parsing code assuming
uncommon, non-trivial properties.
You must write a device tree binding document for this.
Please see Documentation/devicetree/bindings/submitting-patches.txt.
quoted hunk ↗ jump to hunk
+static int arcxcnn_parse_dt(struct arcxcnn *lp) +{ + struct device *dev = lp->dev; + struct device_node *node = dev->of_node; + u32 prog_length; + + if (!node) { + dev_err(dev, "no platform data\n"); + return -EINVAL; + } + + of_property_read_string(node, "bl-name", &lp->pdata->name); + of_property_read_u16(node, "init-brt", &lp->pdata->initial_brightness); + of_property_read_u32(node, "pwm-period", &lp->pdata->period_ns); + + if (lp->pdata->initial_brightness > MAX_BRIGHTNESS) + lp->pdata->initial_brightness = MAX_BRIGHTNESS; + + /* Fill program from platform data if defined + */ + lp->pdata->prog_entries = 0; + prog_length = of_get_child_count(node); + if (prog_length > 0) { + struct device_node *child; + u32 i = 0; + + for_each_child_of_node(node, child) { + if (i >= ARCXCNN_MAX_PROGENTRIES) + break; + of_property_read_u8(child, "prg-addr", &lp->pdata->prog_addr[i]); + of_property_read_u8(child, "prg-data", &lp->pdata->prog_data[i]);
Don't bother using u8. The DTB is padded to u32 boundaries anyway, so this just adds an additional burden on DT authors to use /bits/ 8 consistently, which inevitably someone will get wrong.
quoted hunk ↗ jump to hunk
+static int arcxcnn_probe(struct i2c_client *cl, const struct i2c_device_id *id) +{ + struct arcxcnn *lp; + int ret; + u32 i; + u8 regval; + u16 chipid; + + if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) + return -EIO; + + lp = devm_kzalloc(&cl->dev, sizeof(struct arcxcnn), GFP_KERNEL);
Nit: sizeof(*lp) is the preferred style.
quoted hunk ↗ jump to hunk
+static const struct of_device_id arcxcnn_dt_ids[] = { + { .compatible = "arc,arcxcnn", }, + { } +}; +MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids);
Thanks, Mark.