From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Bostic Subject: [PATCH v4 23/23] drivers/fsi: Use asynchronous slave mode Date: Wed, 29 Mar 2017 12:43:40 -0500 Message-ID: <20170329174340.89109-24-cbostic@linux.vnet.ibm.com> References: <20170329174340.89109-1-cbostic@linux.vnet.ibm.com> Return-path: In-Reply-To: <20170329174340.89109-1-cbostic-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org, mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Cc: Jeremy Kerr , joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, andrew-zrmu5oMJ5Fs@public.gmane.org, alistair-Y4h6yKqj69EXC2x5gXVKYQ@public.gmane.org, benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org, Chris Bostic List-Id: devicetree@vger.kernel.org From: Jeremy Kerr For slaves that are behind a software-clocked master, we want FSI CFAMs to run asynchronously to the FSI clock, so set up our slaves to be in async mode. Signed-off-by: Jeremy Kerr Signed-off-by: Chris Bostic --- drivers/fsi/fsi-core.c | 22 +++++++++++++++++++++- drivers/fsi/fsi-master-gpio.c | 1 + drivers/fsi/fsi-master.h | 2 ++ 3 files changed, 24 insertions(+), 1 deletion(-) diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c index 747d0e3..a6ed34f 100644 --- a/drivers/fsi/fsi-core.c +++ b/drivers/fsi/fsi-core.c @@ -47,6 +47,7 @@ #define FSI_SMODE 0x0 /* R/W: Mode register */ #define FSI_SISC 0x8 /* R/W: Interrupt condition */ #define FSI_SSTAT 0x14 /* R : Slave status */ +#define FSI_LLMODE 0x100 /* R/W: Link layer mode register */ /* * SMODE fields @@ -62,6 +63,11 @@ #define FSI_SMODE_LBCRR_SHIFT 8 /* Clk ratio shift */ #define FSI_SMODE_LBCRR_MASK 0xf /* Clk ratio mask */ +/* + * LLMODE fields + */ +#define FSI_LLMODE_ASYNC 0x1 + #define FSI_SLAVE_SIZE_23b 0x800000 static DEFINE_IDA(master_ida); @@ -560,8 +566,8 @@ static void fsi_slave_release(struct device *dev) static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id) { + uint32_t chip_id, llmode; struct fsi_slave *slave; - uint32_t chip_id; uint8_t crc; int rc; @@ -597,6 +603,20 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id) return -ENODEV; } + /* If we're behind a master that doesn't provide a self-running bus + * clock, put the slave into async mode + */ + if (master->flags & FSI_MASTER_FLAG_SWCLOCK) { + llmode = cpu_to_be32(FSI_LLMODE_ASYNC); + rc = fsi_master_write(master, link, id, + FSI_SLAVE_BASE + FSI_LLMODE, + &llmode, sizeof(llmode)); + if (rc) + dev_warn(&master->dev, + "can't set llmode on slave:%02x:%02x %d\n", + link, id, rc); + } + /* We can communicate with a slave; create the slave device and * register. */ diff --git a/drivers/fsi/fsi-master-gpio.c b/drivers/fsi/fsi-master-gpio.c index 84d5595..f3fcede 100644 --- a/drivers/fsi/fsi-master-gpio.c +++ b/drivers/fsi/fsi-master-gpio.c @@ -573,6 +573,7 @@ static int fsi_master_gpio_probe(struct platform_device *pdev) master->gpio_mux = gpio; master->master.n_links = 1; + master->master.flags = FSI_MASTER_FLAG_SWCLOCK; master->master.read = fsi_master_gpio_read; master->master.write = fsi_master_gpio_write; master->master.term = fsi_master_gpio_term; diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h index d6a4885..fd39924 100644 --- a/drivers/fsi/fsi-master.h +++ b/drivers/fsi/fsi-master.h @@ -19,6 +19,8 @@ #include +#define FSI_MASTER_FLAG_SWCLOCK 0x1 + struct fsi_master { struct device dev; int idx; -- 1.8.2.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html