On Fri, May 11, 2018 at 5:22 PM, Mark Jonas [off-list ref] wrote:

Add Rohm BU21029 resistive touch panel controller support with I2C
interface.

+#include <linux/of.h>

This becomes redundant (see below).

+#define STOP_DELAY_US  50L
+#define START_DELAY_MS 2L
+#define BUF_LEN        8L

No need to use L for such small numbers. Integer promotion is a part
of C standard.

+#define SCALE_12BIT    (1 << 12)
+#define MAX_12BIT      ((1 << 12) - 1)

BIT(12)
GENMASK(11, 0)

+static int bu21029_touch_report(struct bu21029_ts_data *bu21029)
+{
+       struct i2c_client *i2c = bu21029->client;
+       u8 buf[BUF_LEN];
+       int error = bu21029_touch_report(bu21029);

+

Redundant empty line.

+       if (error) {

+               dev_err(&i2c->dev, "failed to report (error: %d)\n", error);

Potential spamming case.

+               return IRQ_NONE;
+       }

+static void bu21029_stop_chip(struct input_dev *dev)
+{
+       struct bu21029_ts_data *bu21029 = input_get_drvdata(dev);
+
+       disable_irq(bu21029->client->irq);
+       del_timer_sync(&bu21029->timer);
+
+       /* put chip into reset */
+       gpiod_set_value_cansleep(bu21029->reset_gpios, 1);

+       udelay(STOP_DELAY_US);

udelay() ?!

+}
+

+static int bu21029_start_chip(struct input_dev *dev)
+{

+       u16 hwid;
+
+       /* take chip out of reset */
+       gpiod_set_value_cansleep(bu21029->reset_gpios, 0);

+       mdelay(START_DELAY_MS);

mdelay()?!

+
+       error = i2c_smbus_read_i2c_block_data(i2c,
+                                             BU21029_HWID_REG,
+                                             2,
+                                             (u8 *)&hwid);
+       if (error < 0) {
+               dev_err(&i2c->dev, "failed to read HW ID\n");
+               goto out;
+       }
+

+       if (cpu_to_be16(hwid) != SUPPORTED_HWID) {

Hmm... Why cpu_to_be16() is required?

+               dev_err(&i2c->dev, "unsupported HW ID 0x%x\n", hwid);
+               error = -ENODEV;
+               goto out;
+       }
+}

+static int bu21029_parse_dt(struct bu21029_ts_data *bu21029)

You can get rid of DT requirement by...

+{
+       struct device *dev = &bu21029->client->dev;
+       struct device_node *np = dev->of_node;
+       u32 val32;
+       int error;

+       if (!np) {
+               dev_err(dev, "no device tree data\n");
+               return -EINVAL;
+       }

(this becomes redundant)

+
+       bu21029->reset_gpios = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+       if (IS_ERR(bu21029->reset_gpios)) {
+               error = PTR_ERR(bu21029->reset_gpios);
+               if (error != -EPROBE_DEFER)
+                       dev_err(dev, "invalid 'reset-gpios':%d\n", error);
+               return error;
+       }
+

+       if (of_property_read_u32(np, "rohm,x-plate-ohms", &val32)) {

...simple calling device_property_read_u32() instead.

+               dev_err(dev, "invalid 'x-plate-ohms' supplied\n");
+               return -EINVAL;
+       }
+       bu21029->x_plate_ohms = val32;
+
+       touchscreen_parse_properties(bu21029->in_dev, false, &bu21029->prop);
+
+       return 0;
+}

+#ifdef CONFIG_PM_SLEEP

Instead...

+static int bu21029_suspend(struct device *dev)

...use __maby_unused annotation.

+static int bu21029_resume(struct device *dev)

Ditto.

-- 
With Best Regards,
Andy Shevchenko