Re: [PATCH 6/6 V4] input: STMPE touch controller support

[Rabin VINCENT]

On Thu, Jun 24, 2010 at 13:13:41 +0200, Luotao Fu wrote:
> +       adc_ctrl1 = SAMPLE_TIME(ts->sample_time) | MOD_12B(ts->mod_12b) |
> +               REF_SEL(ts->ref_sel);
> +       ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL1,
> +                       adc_ctrl1, adc_ctrl1);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Could not setup ADC\n");
> +               goto err_free_irq;
> +       }
> +
> +       ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL2,
> +                       ADC_FREQ(ts->adc_freq), ADC_FREQ(ts->adc_freq));
> +       if (ret) {
> +               dev_err(&pdev->dev, "Could not setup ADC\n");
> +               goto err_free_irq;
> +       }
> +
> +       tsc_cfg = AVE_CTRL(ts->ave_ctrl) | DET_DELAY(ts->touch_det_delay) |
> +                       SETTLING(ts->settling);
> +       ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg, tsc_cfg);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Could not config touch\n");
> +               goto err_free_irq;
> +       }
> +
> +       ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
> +                       FRACTION_Z(ts->fraction_z),
> +                       FRACTION_Z(ts->fraction_z));

I think your earlier revisions had this same behaviour, but this only
writes the bits you are trying to set, and it may be a problem if there
are other bits already set in this field.  I don't know if this is a
concern with this block, but if it is, you can do something like the
following to clear out the field before writing:

stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL2,
	       ADC_FREQ(0xff), ADC_FREQ(ts->adc_freq));

or perhaps:

stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL2,
	       0xff, ADC_FREQ(ts->adc_freq));

Rabin
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