From mboxrd@z Thu Jan 1 00:00:00 1970 From: walter harms Date: Wed, 26 Apr 2017 14:34:38 +0000 Subject: Re: [PATCH] NFC: trf7970a: Correct register settings for 27MHz clock Message-Id: <5900AFFE.8060702@bfs.de> List-Id: References: <1493214513-12245-1-git-send-email-geoff@kuvee.com> In-Reply-To: <1493214513-12245-1-git-send-email-geoff@kuvee.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Geoff Lansberry Cc: linux-wireless@vger.kernel.org, sameo@linux.intel.com, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfc@lists.01.org, devicetree@vger.kernel.org, mgreer@animalcreek.com, justin@kuvee.com, colin.king@canonical.com 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 > --- > 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; >