From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TgbWS-0007ID-Pa for barebox@lists.infradead.org; Thu, 06 Dec 2012 13:29:55 +0000 From: Sascha Hauer Date: Thu, 6 Dec 2012 14:29:45 +0100 Message-Id: <1354800588-23053-4-git-send-email-s.hauer@pengutronix.de> In-Reply-To: <1354800588-23053-1-git-send-email-s.hauer@pengutronix.de> References: <1354800588-23053-1-git-send-email-s.hauer@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 3/6] clk: Add clk table based divider support To: barebox@lists.infradead.org For easy support of table based dividers. Signed-off-by: Sascha Hauer --- drivers/clk/Makefile | 2 +- drivers/clk/clk-divider-table.c | 119 +++++++++++++++++++++++++++++++++++++++ include/linux/clk.h | 10 ++++ 3 files changed, 130 insertions(+), 1 deletion(-) create mode 100644 drivers/clk/clk-divider-table.c diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 3cc7163..656b859 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -1,3 +1,3 @@ obj-$(CONFIG_COMMON_CLK) += clk.o clk-fixed.o clk-divider.o clk-fixed-factor.o \ - clk-mux.o clk-gate.o + clk-mux.o clk-gate.o clk-divider-table.o obj-$(CONFIG_CLKDEV_LOOKUP) += clkdev.o diff --git a/drivers/clk/clk-divider-table.c b/drivers/clk/clk-divider-table.c new file mode 100644 index 0000000..204e24d --- /dev/null +++ b/drivers/clk/clk-divider-table.c @@ -0,0 +1,119 @@ +/* + * clk-divider-table.c - generic barebox clock support. Based on Linux clk support + * + * Copyright (c) 2012 Sascha Hauer , Pengutronix + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ +#include +#include +#include +#include +#include + +struct clk_divider_table { + struct clk clk; + u8 shift; + u8 width; + void __iomem *reg; + const char *parent; + const struct clk_div_table *table; + int table_size; + int max_div_index; +}; + +static int clk_divider_set_rate(struct clk *clk, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_divider_table *div = + container_of(clk, struct clk_divider_table, clk); + unsigned int val; + int i, div_index = -1; + unsigned long best = 0; + + if (rate > parent_rate) + rate = parent_rate; + if (rate < parent_rate / div->table[div->max_div_index].div) + rate = parent_rate / div->table[div->max_div_index].div; + + for (i = 0; i < div->table_size; i++) { + unsigned long now = parent_rate / div->table[i].div; + + if (now <= rate && now >= best) { + best = now; + div_index = i; + } + } + + val = readl(div->reg); + val &= ~(((1 << div->width) - 1) << div->shift); + val |= div_index << div->shift; + writel(val, div->reg); + + return 0; +} + +static unsigned long clk_divider_recalc_rate(struct clk *clk, + unsigned long parent_rate) +{ + struct clk_divider_table *div = + container_of(clk, struct clk_divider_table, clk); + unsigned int val; + + val = readl(div->reg) >> div->shift; + val &= (1 << div->width) - 1; + + if (val >= div->table_size) + return 0; + + return parent_rate / div->table[val].div; +} + +struct clk_ops clk_divider_table_ops = { + .set_rate = clk_divider_set_rate, + .recalc_rate = clk_divider_recalc_rate, +}; + +struct clk *clk_divider_table(const char *name, + const char *parent, void __iomem *reg, u8 shift, u8 width, + const struct clk_div_table *table) +{ + struct clk_divider_table *div = xzalloc(sizeof(*div)); + const struct clk_div_table *clkt; + int ret, max_div = 0; + + div->shift = shift; + div->reg = reg; + div->width = width; + div->parent = parent; + div->clk.ops = &clk_divider_table_ops; + div->clk.name = name; + div->clk.parent_names = &div->parent; + div->clk.num_parents = 1; + div->table = table; + + for (clkt = div->table; clkt->div; clkt++) { + if (clkt->div > max_div) { + max_div = clkt->div; + div->max_div_index = div->table_size; + } + div->table_size++; + } + + ret = clk_register(&div->clk); + if (ret) { + free(div); + return ERR_PTR(ret); + } + + return &div->clk; +} diff --git a/include/linux/clk.h b/include/linux/clk.h index 00588bf..91574f2 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -181,9 +181,19 @@ struct clk { struct clk **parents; }; +#define CLK_ALWAYS_ENABLED (1 << 0) + +struct clk_div_table { + unsigned int val; + unsigned int div; +}; + struct clk *clk_fixed(const char *name, int rate); struct clk *clk_divider(const char *name, const char *parent, void __iomem *reg, u8 shift, u8 width); +struct clk *clk_divider_table(const char *name, + const char *parent, void __iomem *reg, u8 shift, u8 width, + const struct clk_div_table *table); struct clk *clk_fixed_factor(const char *name, const char *parent, unsigned int mult, unsigned int div); struct clk *clk_mux(const char *name, void __iomem *reg, -- 1.7.10.4 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox