Re: [PATCH v2 2/2] clk: hi6220: initialize UART1 clock to 150MHz

[Jorge Ramirez]

On 07/07/2016 08:31 AM, Jorge Ramirez wrote:
> On 07/06/2016 11:43 PM, Michael Turquette wrote:
> > Quoting Guodong Xu (2016-06-29 01:45:55)
> > > >From: Jorge Ramirez-Ortiz<jorge.ramirez-ortiz@xxxxxxxxxx>
> > > >
> > > >Early at boot, during the sys_clk initialization, make sure UART1 uses
> > > >the higher frequency clock, 150MHz.
> > > >
> > > >This enables support for higher baud rates (up to 3Mbps) in UART1, 
> > > which
> > > >is required by faster bluetooth transfers.
> > > >
> > > >v2: use clk_set_rate() to propergate clock settings.
> > > >
> > > >Signed-off-by: Jorge Ramirez-Ortiz<jorge.ramirez-ortiz@xxxxxxxxxx>
> > > >Signed-off-by: Guodong Xu<guodong.xu@xxxxxxxxxx>
> > > >---
> > > >  drivers/clk/hisilicon/clk-hi6220.c | 4 ++++
> > > >  1 file changed, 4 insertions(+)
> > > >
> > > >diff --git a/drivers/clk/hisilicon/clk-hi6220.c 
> > > b/drivers/clk/hisilicon/clk-hi6220.c
> > > >index a36ffcb..631c56f 100644
> > > >--- a/drivers/clk/hisilicon/clk-hi6220.c
> > > >+++ b/drivers/clk/hisilicon/clk-hi6220.c
> > > >@@ -12,6 +12,7 @@
> > > >  >  #include <linux/kernel.h>
> > > >  #include <linux/clk-provider.h>
> > > >+#include <linux/clk.h>
> > > >  #include <linux/clkdev.h>
> > > >  #include <linux/io.h>
> > > >  #include <linux/of.h>
> > > >@@ -192,6 +193,9 @@ static void __init hi6220_clk_sys_init(struct 
> > > device_node *np)
> > > >  > hi6220_clk_register_divider(hi6220_div_clks_sys,
> > > >                         ARRAY_SIZE(hi6220_div_clks_sys), clk_data);
> > > >+
> > > >+       if (clk_set_rate(clk_data->clk_data.clks[HI6220_UART1_SRC], 
> > > 150000000))
> > > >+               pr_err("failed to set uart1 clock rate\n");
> > Why doesn't the UART driver call clk_get and then clk_set_rate on this
> > clock? Why do it in the clk provider driver?
>
> yes that was my initial choice as well; in the end I opted to do it in 
> the clock driver because of it being a value that will not have to 
> ever change for the SoC and - maybe more importantly- because of not 
> having a DT property available for the primecell pl011 uart where to  
> specify the value (so I thought this was a less intrusive 
> implementation).
I have v3 ready (changes done in amba-pl011.c and devicetree/bindings)
please let me know if I should send those instead.