From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH] i2c: davinci: Fix bus rate calculation on Keystone SoC Date: Thu, 9 Jul 2015 21:53:09 +0200 Message-ID: <20150709195309.GI4744@katana> References: <5582870B.7030304@nokia.com> <558288B0.1020706@ti.com> <5582F049.8070407@ti.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="zqjkMoGlbUJ91oFe" Return-path: Content-Disposition: inline In-Reply-To: <5582F049.8070407-l0cyMroinI0@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Murali Karicheri Cc: Sekhar Nori , Alexander Sverdlin , Kevin Hilman , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, grygorii.strashko-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org List-Id: linux-i2c@vger.kernel.org --zqjkMoGlbUJ91oFe Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 18, 2015 at 12:22:33PM -0400, Murali Karicheri wrote: > On 06/18/2015 05:00 AM, Sekhar Nori wrote: > >On Thursday 18 June 2015 02:23 PM, Alexander Sverdlin wrote: > >>According to KeyStone Architecture I2C User Guide, > >> > >> module clock frequency > >>master clock frequency =3D ---------------------- > >> (ICCL + 6) + (ICCH + 6) > >> > >>i.e. "d" in i2c_davinci_calc_clk_dividers() should be fixed and > >>not dependent from module clock prescaler PSC on these SoCs. > >> > >>Signed-off-by: Alexander Sverdlin > >>--- > >> > >>RFC: If someone from TI has an idea how to improve the coverage of futu= re Keystone > >>revisions -- hints/patches are welcome. The current ID check is based on > >>Davinci/Keystone datasheets and is at least working on real Keystone II. > > > >+ Murali who works on Keystone devices in TI. >=20 > + Grygorii >=20 > + Grygorii has been involved in the Keystone related enhancement and > reviewing prior patches. Need to have his ack for this change Any news? >=20 > Murali > > > >> > >> drivers/i2c/busses/i2c-davinci.c | 10 ++++++++++ > >> 1 files changed, 10 insertions(+), 0 deletions(-) > >> > >>diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-= davinci.c > >>index 4a110af..3d78f6a 100644 > >>--- a/drivers/i2c/busses/i2c-davinci.c > >>+++ b/drivers/i2c/busses/i2c-davinci.c > >>@@ -60,6 +60,8 @@ > >> #define DAVINCI_I2C_IVR_REG 0x28 > >> #define DAVINCI_I2C_EMDR_REG 0x2c > >> #define DAVINCI_I2C_PSC_REG 0x30 > >>+#define DAVINCI_I2C_ICPID1_REG 0x34 > >>+#define DAVINCI_I2C_ICPID2_REG 0x38 > >> #define DAVINCI_I2C_FUNC_REG 0x48 > >> #define DAVINCI_I2C_DIR_REG 0x4c > >> #define DAVINCI_I2C_DIN_REG 0x50 > >>@@ -203,6 +205,9 @@ static void i2c_davinci_calc_clk_dividers(struct da= vinci_i2c_dev *dev) > >> * where if PSC =3D=3D 0, d =3D 7, > >> * if PSC =3D=3D 1, d =3D 6 > >> * if PSC > 1 , d =3D 5 > >>+ * > >>+ * Note: > >>+ * d is always 6 on Keystone I2C controller > >> */ > >> > >> /* get minimum of 7 MHz clock, but max of 12 MHz */ > >>@@ -211,6 +216,11 @@ static void i2c_davinci_calc_clk_dividers(struct d= avinci_i2c_dev *dev) > >> psc++; /* better to run under spec than over */ > >> d =3D (psc >=3D 2) ? 5 : 7 - psc; > >> > >>+ if (davinci_i2c_read_reg(dev, DAVINCI_I2C_ICPID2_REG) =3D=3D 0x2206) { > >>+ dev_dbg(dev->dev, "Keystone SoC detected\n"); > >>+ d =3D 6; > >>+ } > > > >I think its better to use a different compatible string for i2c on > >keystone devices rather than using a fixed hardcoded IP version. > > > >Thanks, > >Sekhar > > >=20 >=20 > --=20 > Murali Karicheri > Linux Kernel, Keystone --zqjkMoGlbUJ91oFe Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVntElAAoJEBQN5MwUoCm2Hu8P/3amCQItizJZadQsEEus5RIE UAqEnEHCmAc9XO0WXoI4c1GYSBCJ1zWvteTVnre+s9HDmNG3oozgAJ+VlieHWTpb FtNte0XieI09SympTuWVeJw+hsnFWIPiNx/5o/gEOZpgEjlR9F/8T3ktJmnN/Ghh o1vijenunlZ6qJpb0hyDIeBELppT93XeTsaKUg4RJLiNfOcyHlMAbmbNW3aARjeN l6IZoArCsF71IJOB1DT1AwGIfEVI7dq5d3p2E9MCRUyU8mUom5RF9eWo09sChDes rls8k3+GRDMaMEEHX/GHGx0ihtlXCCtGGWsf2LOy7sOQhI58hEWCX6iith0oOrwa k2Dw7n7QtNHpvLybyrfezZztzK1JGKxJfusudfZJJpWWBQ0qo7nwHJ4bRHkskHVP yx11XuSG9yQ3CXROiIFFcuNZOu9IGW2139mfawTKLEuDmDbAMELy+XpXWxYLi+3i VT1RTD0f69ojh4DwJj+ePAZ2Ek80VEPvJZzsdaJQJQ9QDutIOGCQJUKQ6XvrR6sz IqfUg+azly64JitP06GSP7eao8tmIso7MjjFbolDtoYt+9KvaPxZTLC193m557D7 jcBZpiaeauKvpAupJshYXbIguRUEuC5gptxWsuTEkYUR8916slSMqhZ4YbWt46oN 0kzyKCYk3G7izw98zrOm =vPFO -----END PGP SIGNATURE----- --zqjkMoGlbUJ91oFe--