Messages in this thread | | | Date | Mon, 17 Oct 2022 10:08:10 +0300 | Subject | Re: [PATCH v9 2/2] iio: adc: ad4130: add AD4130 driver | From | Cosmin Tanislav <> |
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On 10/9/22 20:31, Jonathan Cameron wrote: > On Thu, 6 Oct 2022 17:07:37 +0300 > Cosmin Tanislav <demonsingur@gmail.com> wrote: > >> AD4130-8 is an ultra-low power, high precision, measurement solution for >> low bandwidth battery operated applications. >> >> The fully integrated AFE (Analog Front-End) includes a multiplexer for up >> to 16 single-ended or 8 differential inputs, PGA (Programmable Gain >> Amplifier), 24-bit Sigma-Delta ADC, on-chip reference and oscillator, >> selectable filter options, smart sequencer, sensor biasing and excitation >> options, diagnostics, and a FIFO buffer. >> >> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com> >> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> > Hi Cosmin, > > I've cropped down (mostly) to the clock changes. > A few minor things in there + this looks like it would suffer from the issue > with IIO_CONST_ATTR() not being handled correctly for buffer attributes. > > Jonathan > > > >> +static IIO_CONST_ATTR(hwfifo_watermark_min, "1"); >> +static IIO_CONST_ATTR(hwfifo_watermark_max, __stringify(AD4130_FIFO_SIZE)); > > These look like they'd suffer from same problem > https://lore.kernel.org/all/cover.1664782676.git.mazziesaccount@gmail.com/ > tackles. Short term fix is don't use IIO_CONST_ATTR for buffer attributes. >
Right, this only works downstream.
Should I switch to IIO_STATIC_CONST_DEVICE_ATTR?
> >> +static IIO_DEVICE_ATTR_RO(hwfifo_watermark, 0); >> +static IIO_DEVICE_ATTR_RO(hwfifo_enabled, 0); >> + >> +static const struct attribute *ad4130_fifo_attributes[] = { >> + &iio_const_attr_hwfifo_watermark_min.dev_attr.attr, >> + &iio_const_attr_hwfifo_watermark_max.dev_attr.attr, >> + &iio_dev_attr_hwfifo_watermark.dev_attr.attr, >> + &iio_dev_attr_hwfifo_enabled.dev_attr.attr, >> + NULL >> +}; > > >> +static void ad4130_clk_disable_unprepare(void *clk) >> +{ >> + clk_disable_unprepare(clk); >> +} >> + >> +static int ad4130_set_mclk_sel(struct ad4130_state *st, >> + enum ad4130_mclk_sel mclk_sel) >> +{ >> + return regmap_update_bits(st->regmap, AD4130_ADC_CONTROL_REG, >> + AD4130_ADC_CONTROL_MCLK_SEL_MASK, >> + FIELD_PREP(AD4130_ADC_CONTROL_MCLK_SEL_MASK, >> + mclk_sel)); >> +} >> + >> +static unsigned long ad4130_int_clk_recalc_rate(struct clk_hw *hw, >> + unsigned long parent_rate) >> +{ >> + return AD4130_MCLK_FREQ_76_8KHZ; >> +} >> + >> +static int ad4130_int_clk_is_enabled(struct clk_hw *hw) >> +{ >> + struct ad4130_state *st = container_of(hw, struct ad4130_state, int_clk_hw); >> + >> + return st->mclk_sel == AD4130_MCLK_76_8KHZ_OUT; >> +} >> + >> +static int ad4130_int_clk_prepare(struct clk_hw *hw) >> +{ >> + struct ad4130_state *st = container_of(hw, struct ad4130_state, int_clk_hw); >> + int ret; >> + >> + ret = ad4130_set_mclk_sel(st, AD4130_MCLK_76_8KHZ_OUT); >> + if (ret) >> + return ret; >> + >> + st->mclk_sel = AD4130_MCLK_76_8KHZ_OUT; >> + >> + return 0; >> +} >> + >> +static void ad4130_int_clk_unprepare(struct clk_hw *hw) >> +{ >> + struct ad4130_state *st = container_of(hw, struct ad4130_state, int_clk_hw); >> + int ret; >> + >> + ret = ad4130_set_mclk_sel(st, AD4130_MCLK_76_8KHZ); >> + if (ret) >> + return; >> + >> + st->mclk_sel = AD4130_MCLK_76_8KHZ; >> +} >> + >> +static const struct clk_ops ad4130_int_clk_ops = { >> + .recalc_rate = ad4130_int_clk_recalc_rate, >> + .is_enabled = ad4130_int_clk_is_enabled, >> + .prepare = ad4130_int_clk_prepare, >> + .unprepare = ad4130_int_clk_unprepare, >> +}; >> + >> +static int ad4130_setup_int_clk(struct ad4130_state *st) >> +{ >> + struct device *dev = &st->spi->dev; >> + struct device_node *of_node = dev->of_node; > > Hmm. There goes our careful use of generic firmware properties. > I guess there still isn't much we can do about that for clks > so at least it's contained to this one function. > > Also is this code safe to of_node == NULL? >
No, I guess it is not. I'll fix it. Should I just if (!of_node) return 0; ?
>> + struct clk_init_data init; >> + const char *clk_name; >> + struct clk *clk; >> + >> + if (st->int_pin_sel == AD4130_INT_PIN_CLK || >> + st->mclk_sel != AD4130_MCLK_76_8KHZ) >> + return 0; >> + >> + clk_name = of_node->name; >> + of_property_read_string(of_node, "clock-output-names", &clk_name); > > Probably want to check success of that read before using it. > I'd also expect that these to be optional + doesn't he dt binding need > updating to add this stuff? >
It does need updating, sorry. of_node->name is the default clk_name, if clock-output-names is present then the of_property_read_string() result will be used instead. If not, there's no trouble, and we don't care about the return value since we have the default clk_name assigned just above. I can also switch to device_property_read_string() here to minimize the damage from using OF.
> >> + >> + init.name = clk_name; >> + init.ops = &ad4130_int_clk_ops; >> + >> + st->int_clk_hw.init = &init; >> + clk = devm_clk_register(dev, &st->int_clk_hw); >> + if (IS_ERR(clk)) >> + return PTR_ERR(clk); >> + >> + return of_clk_add_provider(of_node, of_clk_src_simple_get, clk); >> +} >> +
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