Hi Wolfgang, Thanks for reviewing the patch On Tue, Apr 03, 2012 at 18:14:55, Wolfgang Grandegger wrote: > On 04/03/2012 02:32 PM, AnilKumar Ch wrote: > > This patch adds the support for Bosch D_CAN controller. > > > > Bosch D_CAN controller is a full-CAN implementation compliant to > > CAN protocol version 2.0 part A and B. Bosch D_CAN user manual > > can be obtained from: http://www.semiconductors.bosch.de/media/ > > en/pdf/ipmodules_1/can/d_can_users_manual_111.pdf > > > > D_CAN device is used on many SoCs like AM335x, DM8148 and DM813x > > EVMs from TI, D_CAN details on AM335x can be accessed from: > > http://www.ti.com/lit/ug/spruh73c/spruh73c.pdf > > > > D_CAN can be configurable for 16, 32, 64 and 128 message objects. > > The driver implementation is based on 64 message objects. > > > > Following are the design choices made while writing the controller > > driver: > > 1. Interface Register set IF0 has be used for receive and IF1 is > > used for transmit message objects. > > 2. Out of the total Message objects available, half of it are kept > > aside for RX purposes and the rest for TX purposes. > > 3. NAPI implementation is such that both the TX and RX paths > > functions in polling mode. > > > > Signed-off-by: AnilKumar Ch <anilkumar@xxxxxx> > > Please explain why this CAN controller cannot be handled by the existing > C_CAN driver, eventually with some extensions. The register layout seems > almost identical, at least. > > Wolfgang. > These are the some of the pointers I can say, why I had gone for separate file instead of existing driver: * In case of D_CAN driver we can see all the registers are 32bit length but in case of C_CAN registers are in 16bit length. * Some of the registers, bit masks are different, so we have to add checks on every API for differentiating the kind of device * In case of D_CAN we have some extra features like direct message RAM access, DMA support, TX/RX pins can be used as GPIO lines (if applicable), more interrupt lines and three sets of interface registers. * Wait timings while init bit set/reset during bit-timing initialization are different in both the cases * bittiming configurations are different. Thanks AnilKumar -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
