From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srinivas Kandagatla Subject: Re: [alsa-devel] [RESEND PATCH v4 2/4] soundwire: core: add device tree support for slave devices Date: Fri, 23 Aug 2019 16:47:05 +0100 Message-ID: <06fb60b4-72e1-5898-8eb9-d9a46efd3b3a@linaro.org> References: <20190822233759.12663-1-srinivas.kandagatla@linaro.org> <20190822233759.12663-3-srinivas.kandagatla@linaro.org> <2f1b5e2e-4699-1d06-e28e-708d5ed99b6a@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <2f1b5e2e-4699-1d06-e28e-708d5ed99b6a@linux.intel.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Pierre-Louis Bossart , broonie@kernel.org, robh+dt@kernel.org, vkoul@kernel.org Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org, bgoswami@codeaurora.org, spapothi@codeaurora.org, lgirdwood@gmail.com, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org On 23/08/2019 16:44, Pierre-Louis Bossart wrote: > > > On 8/22/19 6:37 PM, Srinivas Kandagatla wrote: >> This patch adds support to parsing device tree based >> SoundWire slave devices. >> >> Signed-off-by: Srinivas Kandagatla >> --- >>   drivers/soundwire/bus.c   |  2 ++ >>   drivers/soundwire/bus.h   |  1 + >>   drivers/soundwire/slave.c | 52 +++++++++++++++++++++++++++++++++++++++ >>   3 files changed, 55 insertions(+) >> >> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c >> index 49f64b2115b9..c2eaeb5c38ed 100644 >> --- a/drivers/soundwire/bus.c >> +++ b/drivers/soundwire/bus.c >> @@ -77,6 +77,8 @@ int sdw_add_bus_master(struct sdw_bus *bus) >>        */ >>       if (IS_ENABLED(CONFIG_ACPI) && ACPI_HANDLE(bus->dev)) >>           ret = sdw_acpi_find_slaves(bus); >> +    else if (IS_ENABLED(CONFIG_OF) && bus->dev->of_node) >> +        ret = sdw_of_find_slaves(bus); >>       else >>           ret = -ENOTSUPP; /* No ACPI/DT so error out */ >> diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h >> index 3048ca153f22..ee46befedbd1 100644 >> --- a/drivers/soundwire/bus.h >> +++ b/drivers/soundwire/bus.h >> @@ -15,6 +15,7 @@ static inline int sdw_acpi_find_slaves(struct >> sdw_bus *bus) >>   } >>   #endif >> +int sdw_of_find_slaves(struct sdw_bus *bus); >>   void sdw_extract_slave_id(struct sdw_bus *bus, >>                 u64 addr, struct sdw_slave_id *id); >> diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c >> index f39a5815e25d..3ef265d2ee89 100644 >> --- a/drivers/soundwire/slave.c >> +++ b/drivers/soundwire/slave.c >> @@ -2,6 +2,7 @@ >>   // Copyright(c) 2015-17 Intel Corporation. >>   #include >> +#include >>   #include >>   #include >>   #include "bus.h" >> @@ -35,6 +36,7 @@ static int sdw_slave_add(struct sdw_bus *bus, >>       slave->dev.release = sdw_slave_release; >>       slave->dev.bus = &sdw_bus_type; >> +    slave->dev.of_node = of_node_get(to_of_node(fwnode)); >>       slave->bus = bus; >>       slave->status = SDW_SLAVE_UNATTACHED; >>       slave->dev_num = 0; >> @@ -112,3 +114,53 @@ int sdw_acpi_find_slaves(struct sdw_bus *bus) >>   } >>   #endif >> + >> +/* >> + * sdw_of_find_slaves() - Find Slave devices in master device tree node >> + * @bus: SDW bus instance >> + * >> + * Scans Master DT node for SDW child Slave devices and registers it. >> + */ >> +int sdw_of_find_slaves(struct sdw_bus *bus) >> +{ >> +    struct device *dev = bus->dev; >> +    struct device_node *node; >> + >> +    for_each_child_of_node(bus->dev->of_node, node) { >> +        int link_id, sdw_version, ret, len; >> +        const char *compat = NULL; >> +        struct sdw_slave_id id; >> +        const __be32 *addr; >> + >> +        compat = of_get_property(node, "compatible", NULL); >> +        if (!compat) >> +            continue; >> + >> +        ret = sscanf(compat, "sdw%01x%04hx%04hx%02hhx", &sdw_version, >> +                 &id.mfg_id, &id.part_id, &id.class_id); >> + >> +        if (ret != 4) { >> +            dev_err(dev, "Invalid compatible string found %s\n", >> +                compat); >> +            continue; >> +        } >> + >> +        addr = of_get_property(node, "reg", &len); >> +        if (!addr || (len < 2 * sizeof(u32))) { >> +            dev_err(dev, "Invalid Instance and Link ID\n"); >> +            continue; >> +        } >> + >> +        id.unique_id = be32_to_cpup(addr++); >> +        link_id = be32_to_cpup(addr); > > So here the link ID is obviously not in the address, so you are not > using the MIPI spec as we discussed initially? No, Rob rejected that approach (https://lkml.org/lkml/2019/8/22/490) with the fact that compatible string should be constant for each instance. --srini > >> +        id.sdw_version = sdw_version; >> + >> +        /* Check for link_id match */ >> +        if (link_id != bus->link_id) >> +            continue; >> + >> +        sdw_slave_add(bus, &id, of_fwnode_handle(node)); >> +    } >> + >> +    return 0; >> +} >>