2017-04-26 13:49:28

by Geoff Lansberry

Subject: [PATCH] NFC: trf7970a: Correct register settings for 27MHz clock

In prior commits the selected clock frequency does not propagate
correctly to what is written the the TRF7970A_MODULATOR_SYS_CLK_CTRL
register.
Also fixes a bug that causes the device tree property check to always
pass.

Signed-off-by: Geoff Lansberry <[email protected]>
---
drivers/nfc/trf7970a.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index 2d1c8ca..c278b0e 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -2071,7 +2071,7 @@ static int trf7970a_probe(struct spi_device *spi)
}

of_property_read_u32(np, "clock-frequency", &clk_freq);
- if ((clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) ||
+ if ((clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) &&
(clk_freq != TRF7970A_13MHZ_CLOCK_FREQUENCY)) {
dev_err(trf->dev,
"clock-frequency (%u Hz) unsupported\n",
@@ -2079,6 +2079,13 @@ static int trf7970a_probe(struct spi_device *spi)
return -EINVAL;
}

+ if (clk_freq == TRF7970A_27MHZ_CLOCK_FREQUENCY) {
+ trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_27MHZ;
+ dev_dbg(trf->dev, "trf7970a configured for 27MHz crystal\n");
+ } else {
+ trf->modulator_sys_clk_ctrl = 0;
+ }
+
if (of_property_read_bool(np, "en2-rf-quirk"))
trf->quirks |= TRF7970A_QUIRK_EN2_MUST_STAY_LOW;

--
2.7.4

2017-04-26 14:34:58

by walter harms

Subject: Re: [PATCH] NFC: trf7970a: Correct register settings for 27MHz clock

Am 26.04.2017 15:48, schrieb Geoff Lansberry:
> In prior commits the selected clock frequency does not propagate
> correctly to what is written the the TRF7970A_MODULATOR_SYS_CLK_CTRL
> register.
> Also fixes a bug that causes the device tree property check to always
> pass.
>
> Signed-off-by: Geoff Lansberry <[email protected]>
> ---
> drivers/nfc/trf7970a.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
> index 2d1c8ca..c278b0e 100644
> --- a/drivers/nfc/trf7970a.c
> +++ b/drivers/nfc/trf7970a.c
> @@ -2071,7 +2071,7 @@ static int trf7970a_probe(struct spi_device *spi)
> }
>
> of_property_read_u32(np, "clock-frequency", &clk_freq);
> - if ((clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) ||
> + if ((clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) &&
> (clk_freq != TRF7970A_13MHZ_CLOCK_FREQUENCY)) {
> dev_err(trf->dev,
> "clock-frequency (%u Hz) unsupported\n",
> @@ -2079,6 +2079,13 @@ static int trf7970a_probe(struct spi_device *spi)
> return -EINVAL;
> }
>
> + if (clk_freq == TRF7970A_27MHZ_CLOCK_FREQUENCY) {
> + trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_27MHZ;
> + dev_dbg(trf->dev, "trf7970a configured for 27MHz crystal\n");
> + } else {
> + trf->modulator_sys_clk_ctrl = 0;
> + }
> +


I am a fan of defensive programming and would move do:
trf->modulator_sys_clk_ctrl = 0;
if (clk_freq == TRF7970A_27MHZ_CLOCK_FREQUENCY) {
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_27MHZ;
dev_dbg(trf->dev, "trf7970a configured for 27MHz crystal\n");
}

perhaps using a switch/case here is appropriate IMHO a border case for 2 case
but would make the init code more clear.

just my 2 cents,

re,
wh

> if (of_property_read_bool(np, "en2-rf-quirk"))
> trf->quirks |= TRF7970A_QUIRK_EN2_MUST_STAY_LOW;
>

2017-04-26 17:04:55

by Mark Greer

Subject: Re: [PATCH] NFC: trf7970a: Correct register settings for 27MHz clock

On Wed, Apr 26, 2017 at 09:48:33AM -0400, Geoff Lansberry wrote:
> In prior commits the selected clock frequency does not propagate
> correctly to what is written the the TRF7970A_MODULATOR_SYS_CLK_CTRL
> register.
> Also fixes a bug that causes the device tree property check to always
> pass.
>
> Signed-off-by: Geoff Lansberry <[email protected]>
> ---
> drivers/nfc/trf7970a.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
> index 2d1c8ca..c278b0e 100644
> --- a/drivers/nfc/trf7970a.c
> +++ b/drivers/nfc/trf7970a.c
> @@ -2071,7 +2071,7 @@ static int trf7970a_probe(struct spi_device *spi)
> }
>
> of_property_read_u32(np, "clock-frequency", &clk_freq);
> - if ((clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) ||
> + if ((clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) &&

There is already a patch submitted to fix this issue so no need to fix
it again. For the record, it should have been in a separate patch
since it fixes a different issue than what is fixed below.

> (clk_freq != TRF7970A_13MHZ_CLOCK_FREQUENCY)) {
> dev_err(trf->dev,
> "clock-frequency (%u Hz) unsupported\n",
> @@ -2079,6 +2079,13 @@ static int trf7970a_probe(struct spi_device *spi)
> return -EINVAL;
> }
>
> + if (clk_freq == TRF7970A_27MHZ_CLOCK_FREQUENCY) {
> + trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_27MHZ;
> + dev_dbg(trf->dev, "trf7970a configured for 27MHz crystal\n");
> + } else {
> + trf->modulator_sys_clk_ctrl = 0;
> + }
> +
> if (of_property_read_bool(np, "en2-rf-quirk"))
> trf->quirks |= TRF7970A_QUIRK_EN2_MUST_STAY_LOW;

This part looks okay to me but I like Walter's suggestion too.

Mark
--